Preservation of Fruit Quality at Postharvest Through Plant-Based Extracts and Elicitors

Abstract

Plant-based extracts and elicitors (signaling molecules that activate the fruit’s innate defense responses) have emerged as promising and sustainable alternatives to synthetic chemicals for preserving postharvest fruit quality and extending shelf life. This review provides a comprehensive analysis, uniquely complemented by a bibliometric assessment of the research landscape from 2005 to 2025, to identify key trends and effective solutions. This review systematically examined the efficacy of various natural compounds including essential oils (complex volatile compounds with potent antimicrobial activity such as lemongrass and thyme), phenolic-rich botanical extracts like neem and aloe vera, and plant-derived elicitors such as methyl jasmonate and salicylic acid. Their preservative mechanisms are multifaceted, involving direct antimicrobial activity by disrupting microbial membranes, potent antioxidant effects that scavenge free radicals, and the induction of a fruit’s innate defense systems, enhancing the activity of enzymes like superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Applications of edible coatings of chitosan or aloe vera gel, nano-emulsions, and pre- or postharvest treatments effectively reduce decay by Botrytis cinerea and Penicillium spp.), delay ripening by suppressing ethylene production, minimize water loss, and alleviate chilling injury. Despite their potential, challenges such as sensory changes, batch-to-batch variability, regulatory hurdles, and scaling production costs limit widespread commercialization. Future prospects hinge on innovative technologies like nano-encapsulation to improve stability and mask flavors, hurdle technology combining treatments synergistically, and optimizing elicitor application protocols. This review demonstrates the potential of continued research and advanced formulation to create plant-based preservatives, that can become integral components of an eco-friendly postharvest management strategy, effectively reducing losses and meeting consumer demands for safe, high-quality fruit.

1. Introduction

Plants have been a long-standing, renewable source of basic human needs for food, shelter, and clothing, and medicinal plants have been extensively used as traditional medicines to treat various diseases for millennia. Bioactive ingredients derived from plant-based drugs have also served as the initial compounds for modern formulations. Humans have used plant extracts for a variety of purposes since prehistoric times, and the cumulative knowledge about these extracts shows that they can also be useful in the preservation of foods and especially fruits for human consumption [1,2]. Plant metabolites such as alkaloids, tannins, terpenoids, and phenolics originate from lipids, amino acids, and polysaccharides, which can act as natural preservatives for fresh fruits [3,4]. Following harvest, biological processes in fruits frequently cause negative quality shifts, including diminished flavor and compromised appearance. During long-distance fruit transport, these alterations often result in measurable weight depletion, shriveling, shortened shelf life, and compromised sensory attributes [5,6]. Ripening constitutes a precisely coordinated biochemical transition marked by color fading, astringency loss, seed maturation, tissue softening, and browning [7].

As prospective sources of natural biochemical preservatives, plant materials can be processed using multiple extraction methods [8]. Recently, the food packaging industry has been exploring natural plant materials to satisfy consumers’ desire for more healthful organic food that can be packaged in an eco-friendly manner [9,10,11]. A number of different packaging techniques have been explored utilizing plant substances with potential to maintain fresh fruit quality and desirable sensory characteristics, and to inhibit microbial growth [10,12].

While there have been reviews that explored the general application of plant extracts in food preservation, this review makes a novel contribution by employing a systematic bibliometric analysis supported by quantitative publication data to map the global research landscape, highlight emerging trends, and identify the most effective plant-derived compounds to extend the shelf-life of freshly harvested fruit [13]. Unlike previous summaries, our analysis not only proposed potential mechanisms (Figure 1) and applications, but also critically evaluated the real-world efficacy and commercial potential of these treatments. This is a new perspective that bridges traditional medical knowledge with modern scientific validation.

Plant-derived extracts or hormonal elicitors may be used individually or within formulations to prevent spoilage by inhibiting the growth of bacteria and fungi and to prolong shelf life by inhibiting oxidation and respiration (Figure 2). Fresh-cut harvested fruit is vulnerable to pests, microbial attack, physical changes, and biochemical degradation [14]. Plant-based preservatives, primarily those containing high concentrations of polyphenols and carotenoids, are now widely adopted across food sectors. These substances possess antimicrobial properties and antioxidants that efficiently lower free radical activity after harvest, preventing the development of off-flavors, enhancing color stability, and prolonging shelf life [4,15]. These natural compounds may be able to replace synthetic counterparts, for example, in edible antioxidant/antimicrobial coatings on fresh fruit (grapes (V. vinifera L. cv. ‘Sultani Çekirdeksiz’) [16], nectarines (Prunus persica) [17], strawberries (Fragaria x ananassa Duch.) [18], guavas (Psidium guajava L.) [19], apricots (Prunus armeniaca L.) [20] and sweet cherries (Prunus avium L.) [21]. In the following section, detailed information regarding these plant-derived extracts and their applications is presented [22].

2. Main Sources of Literature and Bibliometric Analysis

To provide an evidence-based overview of the research landscape, a bibliometric analysis was conducted using literature retrieved from the Web of Science Core Collection. Most of the references cited in this review fall within the scope of this quantitative analysis, with a limited number of older foundational publications also included to ensure comprehensive contextual coverage. The search strategy incorporated key terms such as “postharvest treatment”, “fruit”, “plant extracts”, or “plant elicitors”, with inclusion criteria restricted to experimental articles published between 2005 and 2025. Following initial retrieval, papers were screened for relevance based on title, keywords, and abstracts, resulting in 1160 articles eligible for analysis. Bibliometric evaluation was performed using R (v4.4.1) and the wordcloud R package [23], examining metadata related to countries/territories, keywords, and publication years to visualize research trends and intellectual structure in this field.

2.1. Publication Trends

All of the publications on fruit preservation with plant extracts or elicitors used in this bibliometric analysis were research articles in English from 2005 to 2025. The data was screened according to countries/territories to identify the key contributors in this field. Changes in the number of yearly publications in specific areas, to some extent, can indicate shifts in focus. Figure 3 shows that the numbers of research publications per year on fruit preservation by treatment with plant extracts or elicitors, has steadily increased from 2005 to 2025.

2.2. Most Popular Keywords

Authors employ keywords to provide a brief, clear, representative, description of the study content; therefore keyword analysis may be used to identify popular topics and themes in a research area [24]. To efficiently identify the most common study subjects and active research hotspots in scientific disciplines and sectors [25], the word cloud of author keywords is displayed (Figure 4) [26]. The greater the keyword collection, the more frequently it appeared in a dataset [27]. The keyword “antioxidant” (total frequency of 97) was the most frequent, indicating that antioxidant is one of the most attention-attracting topics for studies on fruit preservation with plant extracts or elicitors. The terms “postharvest” (95), “antifungal” (67), “quality” (65), “essential oil” (40), “edible coating” (39), “shelf life” (33), “botrytis cinerea” (47), “elicitor” (27), “phenolic” (25), “anthracnose” (21), “plant extracts” (18), “penicillium digitatum” (17), “colletotrichum gloeosporioides” (17), “alternaria alternata” (16), “ethylene” (14), “induced resistance” (14), “salicylic acid” (14), and “methyl jasmonate” (12) have all contributed significantly to the literature on plant-based preservatives.

2.3. Publications by Country/Territory

The analysis of English language publications by categorizing statistical data on fruit preservation with plant extracts or elicitors published on Web of Science revealed a diverse landscape of research contributions from the top ten countries/territories with a total number of 997 publications representing 85.95% of the total (Figure 5). China ranks first among these nations with 363 publications. Italy is ranked the second with 100 publications. USA, Spain, India and Brazil are placed the third, fourth, fifth and sixth, respectively, with 87, 83, 74 and 72 research publications. The concentration of research in these top countries highlights their significant roles in both global fruit production and scientific innovation, while also suggesting a potential disparity in research focus and resource allocation across different regions. This trend may reflect these nations’ urgent need to reduce postharvest losses and aligns with their strategic agricultural economic interests.

The significant research output from these leading countries underscores the global importance of developing natural preservation methods, primarily driven by nations with substantial fruit production and postharvest challenges. The subsequent sections will review the major types of plant extracts and elicitors investigated in these studies, their mechanisms of action, and their practical applications in maintaining fruit quality after harvest.

3. Essential Oils (EOs), Botanical Extracts, and Volatile Constituents

Botanical extracts, such as those from neem [28], thyme [29], eucalyptus [30], lemongrass [31], rue [32], and tea tree [33], contain EOs that can inhibit the postharvest growth of pathogens [34]. Formulations of these extracted EOs for application also usually include aromatic terpenoids with fungistatic properties. In addition to EOs, plants are rich reservoirs of volatile compounds—organic molecules characterized by low molecular weight and significant volatility at ambient temperatures [35]. These volatile substances play a vital role in natural defenses against microorganisms and can impede the growth of pathogens [36]. Techniques such as steam distillation or hydrodistillation are commonly employed to isolate these compounds [37]. Notable plant sources yielding valuable volatiles include black pepper, nutmeg, clove, thyme, and oregano. Importantly, numerous volatile compounds derived from such sources have been designated as GRAS (generally recognized as safe), affirming their safety for food applications [30]. A selection of plant-derived preservatives and their biological activities are shown in

Table 1. Examples of plant-derived preservatives and their biological activities.

Plant Species	Extracts/Key Compounds	Biological Activities	References
Oregano and thyme	Proanthocyanidins and carvacrol EOs	Proanthocyanidins possess extensive bioactive profiles, primarily scavenging free radicals in the human body, and reducing inflammation. Carvacrol EOs inhibit a wide range of microorganisms.	[38]
Turmeric	Curcumin and turmerone	Turmeric roots have remarkable antimicrobial, antioxidant, antiviral, anti-inflammatory, and anticancer activities, and its antioxidant activity prevents enzymatic browning of fruits and prolongs shelf life.	[39]
Cloves	β-caryophyllene, eugenol, and other phenolic compounds	Antioxidant, anti-inflammatory, antibacterial, and anticancer properties.	[40]
Orange	Limonene and β-myrcene	Remarkable antimicrobial and antioxidant properties.	[41]
Angelica sinensis	δ-3-carene and limonene	δ-3-carene and limonene were predominantly effective against migraine, anorexia, bronchitis, menstrual complaints, and gastrointestinal disorders. As a chitosan nanoemulsion, its EO inhibited the biosynthesis of ergosterol and enhanced the release of Ca2+, Mg2+, and K+ ions, suggesting the plasma membrane as possible antifungal site of action, against the growth and development of Botrytis cinerea mycelia.	[42]
Curcumin and orange	Oxygenated turmerone and limonene	Excellent bacteriostatic properties against Escherichia coli and Staphylococcus aureus. Weight loss and deterioration of strawberries were effectively reduced, and shelf life was prolonged.	[43]
Lavender	Linalool, 1,8-cineole, camphor, and borneol	L. spica EO showed antimicrobial activity against Gram-positive bacteria.	[44]
Pomegranate	Polyphenols	Exhibited antioxidant, antidiabetic, anticancer, antiviral, anti-inflammatory, and antimicrobial properties.	[45]
Prickly pear	Methyl jasmonate	MeJA treatment effectively reduced decay, maintained fruit firmness and brightness, suppressed respiration, and decreased malondialdehyde concentration.	[46]
Crystal grapes	Methyl jasmonate	MeJA treatment inhibited accumulation of soluble solids, reduced decay, weight loss, and browning, and improved fruit appearance.	[47]

.

Spices and plant-derived condiments have a long history of use in food preparation and also for supposed health benefits, for example, as antioxidants [30]. Essential oils are complex mixtures of volatile compounds that can be used as natural preservatives to control microbial growth and prolong the shelf life of fruit products [48]. Plant-based aromatics are extracted from herbs, spices, and certain flowers and may be used as additives in packaging materials or as coatings to extend the shelf life of fresh fruits; but they can also enhance the desirable qualities of products such as firmness, color, weight, and aroma [49,50]. The US Food and Drug Administration (FDA) has designated these substances as GRAS [51]. The extracted aromatic oils from Origanum vulgare and Verbena officinalis were shown to prevent Phytophthora citrophthora infections [52] and another study concluded that Lavandula spica EO showed promising antimicrobial activity, particularly against Gram-positive bacteria, suggesting its potential use in formulations to preserve fruits [44]. The antimicrobial properties of certain substances are attributed to their unique chemical architectures, specifically the presence of hydrophilic moieties such as phenolic hydroxyl groups along with lipophilic EOs [53].

Fresh-cut melons were treated with malic acid plus cinnamon, lemongrass, and palmarosa EOs to evaluate the impact of natural antibacterial compounds. Coating minimally processed fruit slices with malic acid prolonged their shelf life compared with untreated controls by maintaining physical parameters and hindering microbial growth. Coatings containing malic acid and EOs demonstrated >21-day antimicrobial stability, because of their potent antibacterial qualities [54,55]. Coating fresh-cut peaches with pectin and cinnamon leaf extract prolonged their shelf life as the increased antioxidant content resulted in less microbial growth [56,57]. Menthol isolated from Mentha piperita was effective in preventing fruit diseases during storage. The volatiles extracted from Zingiber officinale, Ocimum canum, and Mentha arvensis were successful in controlling blue mold on oranges, indicating a synergistic interaction among these compounds [39,58]. Acorus calamus is a medicinal plant known for its multifaceted health benefits, especially against inflammation and infections. Time-kill kinetics revealed high lethality of A. calamus essential oil (ACEO) at minimum inhibitory concentrations against Staphylococcus aureus and Pseudomonas aeruginosa, resulting in a significant reduction in colony-forming units within 12–24 h. Studies of the antibacterial mechanisms of ACEO demonstrated that it disrupted the integrity of the bacterial cell membrane and enhanced membrane permeability [59].

Harvested fruit crops encounter diverse microorganisms capable of colonizing tissue and accelerating spoilage. Various plant extracts and formulations exhibit broad-spectrum antimicrobial capabilities [60], and may serve as nontoxic biopreservatives with no negative effects on human health [61]. Their application is straightforward and efficacy persists under ambient storage conditions. Laboratory testing demonstrated that 10% ginger and garlic extracts effectively inhibit most microbial isolates [62]. Ocimum sanctum (Tulsi) leaf extracts contain polyamine biosynthesis inhibitors that block the Zn-dependent ornithine decarboxylase pathway, suppressing fungal rot development and enhancing postharvest storage [63]. Research on preservation of Crystal grapes showed that treatment with 50 µM methyl jasmonic acid (MeJA) reduced decay, weight loss, and browning, inhibited the accumulation of soluble solids, and improved fruit appearance and marketability for a period of 32 days [47]. Experiments on the postharvest immersion of papayas in 1 mM MeJA revealed that this treatment significantly decreased weight loss, disease incidence and chilling injury (CI) during low-temperature storage (10 °C) for 28 days; the accumulation of malondialdehyde (MDA) and hydrogen peroxide was also markedly lower after treatment with MeJA [64].

Azadirachtin, neem oil’s bioactive constituent, reinforces pectin networks by altering galacturonan residues and preventing de-esterification. This approach effectively inhibits pectin degradation during storage, thereby reducing fruit softening and decay [65]. Treatment with 20% neem leaf extract (NLE) followed by cold storage completely suppressed pathogen growth throughout the experimental period, with no observable spoilage [66]. Pre-storage application of 30% NLE to Shamber grapefruits maintained optimal physicochemical attributes including weight, ascorbic acid content, total sugars (TSs), reducing sugars (RS), non-reducing sugars, soluble solid content (SSC), total acidity (TA), and SSC:TA ratio, while enhancing activities of antioxidant enzymes (SOD, POD, CAT) and extending the shelf life to 43 days [67].

Preharvest or postharvest MeJA application effectively boosted antioxidant capacity and phenolic content in fresh fruit. These enhancements prolonged shelf life, improved fruit quality, and mitigated CI [68,69].

Other plant-derived formulations offer solutions to specific postharvest challenges. For instance, an apple preservation study investigated rice bran extract (RE) blended with vitamin C (VC). Fresh-cut apples immersed in 3% VC + 1% RE exhibited comparable L* and browning index (BI) measurements to those treated with 4% rice bran extract (RE) blended with vitamin C. This demonstrates that RE can synergize with VC to provide greater anti-browning efficacy and elevated polyphenol retention in fresh-cut apples [70].

Across multiple industrial sectors, plant-derived extracts serve as versatile functional agents, demonstrating efficacy as natural antimicrobials and antioxidants, flavor enhancers, enzyme stimulants, nutrient fortifiers, and sustainable packaging additives [4,13]. Based on which plant parts contain the desired active components, the extracts are derived from roots, leaves, stems, flowers and seeds [71].

3.1. Leaves Compared with Other Parts as Sources of Bioactive Compounds

Foliar structures perform the essential metabolic functions of synthesizing carbohydrates, generating atmospheric oxygen, and serving as repositories of nutraceutical phytochemicals. Leaves contain anthocyanins (red to purple) and carotenoids (orange to yellow), in addition to green chlorophyll. These colored compounds are responsible for the high antioxidant activity of leaves [72]. Additionally, some leaf extracts possess antimicrobial activity owing to the presence of flavonoids. Foliar extracts demonstrate significantly higher free radical quenching capacity compared with polyphenolic compounds from seeds, stems, or bark (

Table 2. Plant species, relevant parts, applications and function.

Plant Species	Source	Industrial Applications	Functions	Reference
Tea	Leaves	Packaging films	Provide mechanical strength, act as a water barrier, inhibit spoilage by microbes and prevent rancidity.	[73]
Olive	Leaves	Natural preservative	Reduce microbial growth and maintain the quality and sensory attributes of poultry.	[74]
Fig	Leaves	Natural preservative	Prolong shelf life of pasteurized buffalo milk, without altering its properties.	[75]
Mentha arvensis	Leaves	Prolong shelf life	Increase the shelf life of squid mantle cuts during refrigerated storage.	[76]
Ginkgo	Leaves	Bioactive composite films	Inhibit microbial growth and loss of color and delay fat and protein oxidation in chilled beef during storage.	[77]
Peperomia pellucida	Leaves	Edible coatings	Preserve the quality and prolong the shelf life of apples by combating oxidation and inhibiting microbes.	[78]
Aloe	Leaves	Edible coatings	Inhibit the growth of microorganisms in blueberries, reduce water loss, and extend shelf life.	[79]
Aloe	Leaves	Edible coatings	Increase phenolic compounds and total antioxidant capacity of fresh grapes during storage.	[80]
Neem	Leaves	Preservatives impact	Extend the shelf life of bananas and reduce the incidence of spoilage.	[81]
Neem	Leaves	Preservative impact	Inhibit fungi, maintain firmness and delay fruit ripening.	[82]
Black mulberry	Fruit	Preservative impact	Reduce lipid oxidation and microbial invasion during storage.	[83]
Jaboticaba	Peel	Cosmeceutical	Counteract the toxic effects of peroxide, accelerate wound healing, and treat skin diseases and wounds related to oxidative stress.	[84]
Baobab tree	Seeds	Preservative impact	Improve storage stability, antioxidant content and cooking properties of beef patties.	[85]
Black cumin	Seeds	Edible coatings	Retard oxidative rancidity.	[86]
Quercus suber	Bark	Packaging films	Enhance film pliability and photostability while strengthening antimicrobial efficacy and antioxidant performance.	[87]
Cinnamon	Bark	Edible coatings	Inhibit invasion by pathogenic microbes in minced beef.	[88]
Osmanthus	Flower	Preservatives impact	Prevents pear tissue oxidation, effectively reduces microbial growth, and extends shelf life.	[89]
Beet	Root peel	Packaging films	Delay protein and lipid oxidation, stabilize meat color, inhibit microbial growth, and prolong shelf life.	[90]

). They are widely used as natural preservatives in many different kinds of food including meat and milk as well as fresh-cut fruit.

3.2. Fruits, Vegetables and Flowers as Sources of Natural Preservatives

Fruits and vegetables contain numerous functional ingredients, including phenolics, lignans, stilbenes, proanthocyanidins, and tannins [71]. The most common phenolic substances in addition to flavonoids are cinnamic acid and benzoic acid, which have many applications in the food industry [91]. The extracts that are produced from Arbutus unedo [92], mango [93], blueberries [94], grapes [95], pomegranates [96,97], berries [98], chestnuts [99], and murta plants [100] are prepared by using different extraction technologies and are used in products such as cheese [101], meat [98], and poultry [102,103]. Fruit and vegetable peels constitute a significant category of agro-industrial processing residues with great potential as a source of phytonutrients to add to feed, superior to pulp as a source of natural antioxidants [104]. Rich in phenolic constituents, particularly catechin, epicatechin, proanthocyanidins, flavanols, and gallate, seed products such as grape-seed extract demonstrate broad food industry applicability [105]. Flower extracts also have potent antioxidant and antimicrobial activity, as well as being useful as coloring agents and flavorings [106]. These bioactive extracts are integrated into diverse applications as fruit preservatives including functional beverages, food-grade packaging films, and edible coating matrices [107,108]. The bark of some trees such as cinnamon has a high phenolic content, which contributes to the body’s defense mechanisms [109]. Chinese chive (Allium tuberosum) roots are rich in polyphenols and antimicrobial constituents [110].

4. Isolation Methods for Plant Extracts

The isolation of bioactive compounds from botanical matrices can employ both traditional and modern methods but necessitates the use of inert reagents and non-toxic solvents [111,112,113]. Extraction of bioactive compounds from plant materials involves basic techniques like maceration and Soxhlet extraction but also utilizes ultrasound- or microwave-assisted release, pressurized extractants, supercritical fluids, and pulsed electric fields. The efficacy of the extraction method depends on the nature of the plant matrix, the chemical types being separated, the type of solvent used, and the methodology used for extraction [114]. One major study compared the effect of various different extraction methods on the pharmaceutical and cosmetic properties of medicinal and aromatic plants (MAPs) [115]. For this purpose, the dried plant materials were extracted using modern advanced microwave- (MAEs), ultrasonic- (UAE), and homogenizer-assisted extractions (HAEs) compared with traditional techniques like maceration, percolation, decoction, infusion, and Soxhlet extraction. The new approaches included solid-phase microextraction, supercritical fluid extraction, pressurized liquid extraction, microwave-assisted extraction, solid-phase extraction, and surfactant-mediated extraction [116]. Customized plant material extractions for maximum yield and efficiency is the current goal, and tests of advanced techniques such as accelerated solvent extraction, supercritical fluid extraction, and negative pressure cavitation extraction in combination with ultrasound- and microwave-assisted release have shown great promise in overcoming problems in industrial scale-up [117].

Variability in extract yield and quality with different methods may stem from multiple parameters: processing duration, botanical material particle size, solvent pH, temperature, and sample/solvent ratio [118]. The basic protocol involves pulverizing fresh or dried plant material into a powder to maximize surface exposure. Studies demonstrate substantially higher extraction efficiency when processing finely ground particles (10 µm) for 5 min compared to coarsely fragmented material subjected to 24-h extraction. Optimal solvent: sample ratios established in prior research approach 10:1 (v/dry weight) [118]. For efficient extraction, fresh or dried botanical samples should be homogenized using a blender, followed by either vigorous agitation for 5–10 min, or gentle shaking for 24 h, followed by filtration.

5. The Efficacy of Extracts from Medicinal Plants

5.1. Aloe Vera (AV)

Banana fruit metabolism and anthracnose susceptibility can be reduced using AV gel sprays, preserving postharvest quality [119]. Blueberry shelf life increased by five days with AV spray versus chitosan, suggesting synergistic potential for extending shelf life [79]. AV gel maintained grape quality and prolonged storage [80]. AV extracts effectively prevent litchi surface browning, extending storage and preserving quality as a non-toxic alternative to synthetics [120,121]. Papaya quality was maintained for 15 days with AV coatings [120,122]. The antifungal properties of AV in coatings effectively extended blueberry shelf life without synthetic fungicides [123,124].

5.2. Lemongrass

Mycelial growth and sporulation of pathogenic fungi were inhibited by lemongrass extract in a concentration-dependent manner; notably reducing Colletotrichum gloeosporioides in guava [125,126]. Vaporized lemongrass EO efficiently controlled Penicillium on oranges and also proved effective against Aspergillus niger and C. musae [127,128].

5.3. Neem

Neem leaf extract (40%) preserved banana freshness over extended storage times [81]. NLE also reduced postharvest fungal losses in other tropical/subtropical fruits [129]. It inhibited the growth of Neofusicoccum parvum, Lasiodiplodia theobromae, Aspergillus flavus, B. cinerea, and A. niger. Postharvest neem spraying significantly extended mango storage life and maintained quality versus controls [82].

5.4. Other Extracts

Specific plant protein sprays effectively conserved strawberry quality and shelf life, maintaining ascorbic acid levels crucial for antioxidant activity [130]. For Hass and Gem avocados, moringa seed/leaf extracts with 1% carboxymethyl cellulose significantly preserved quality and extended shelf life. This treatment reduced ethylene production and respiration while enhancing firmness compared to uncoated fruit. Moringa ethanol extracts also showed strong antibacterial activity against foodborne pathogens, indicating utility as an organic postharvest spray [131]. Crude extracts of dukung anak or turmeric powder (10 g/L) functioned as fungicides against dragon fruit anthracnose. Ginger and turmeric extracts also conserved natural color and flavor [132]. A blend of 10% gum arabic and garlic extract minimized guava weight loss, skin browning, and disease incidence while extending shelf life, and preserving optimal physiological, biochemical, and sensory qualities [133]. Separate treatments with ginger, garlic extract, aloe vera gel, or gum arabic also effectively maintained Surahi guava quality during ambient storage [134].

6. Plant-Derived Elicitors for Enhancing Fruits Quality

As autotrophic organisms, plants utilize photosynthesis to transform light energy into biochemical energy, primarily for glucose production. This energy, coupled with essential nutrients, positions plants at the producer level of the global food chain. In response to their ever-changing environment, plants have developed key adaptations, including the synthesis of signaling molecules called elicitors. The critical role elicitors play in plant defense mechanisms is the focus of the following discussion.

6.1. Methyl Jasmonic Acid (MeJA)

Jasmonic acid (JA) acts as a negative growth regulator in plants as it suppresses organ growth and accelerates flowering and fruit ripening as well as senescence and abscission. JA and its derivative, MeJA, regulate plant defense mechanisms as well as root growth, the maturation of fruit and senescence. The JA family comprises compounds of lipid origin with a molecular structure like that of prostaglandins in animals. Synthesized across the entire plant, the signaling molecules known as JAs reach their highest concentrations in growing tissues like stem and root tips, young foliage, and unripe fruits. These compounds function in both defense and development [135], enabling plants to respond to environmental challenges such as wounding, drought, and pathogen/pest invasion.

The concentration of MeJA required to effectively induce systemic acquired resistance (SAR) differs among fruit types. Notably, studies on tomatoes demonstrate this variation: a minimum effective dose of 0.045 mM suppresses anthracnose diseases [136], whereas controlling Botrytis cinerea necessitates a significantly higher application of 10 mM. In order to determine if MeJA reduced B. cinerea infection of grapes, it was treated in vitro with MeJA and the results showed that the growth was markedly inhibited. The inhibitory rate of 100 μM MeJA on mycelial growth of B. cinerea was 83.7% after 3-day treatment at 25 °C or 87.2% after 20-day treatment at 0 °C [137]. Exposure to MeJA and methyl salicylate (MeSa) vapors at 10 and 100 µM was investigated as an alternative to the commercial fungicide, Prochloraz^® used by fruit and vegetable growers [138].

The application of preharvest MeJA significantly influenced fruit ripening in both climacteric and non-climacteric types. For example, in plums, 0.5 mM MeJA delayed postharvest maturation through reductions in respiration rate and ethylene production, which postponed softening [139]. Preharvest foliar applications of 0.5 mM MeJA were applied to various sweet cherry cultivars, including ‘Prime Giant’, ‘Early Lory’, ‘Sweetheart’, and ‘Staccato’, and its effect on the cracking tolerance of these cultivars was evaluated. The results demonstrated that preharvest treatment with MeJA effectively reduced fruit cracking and enhanced abiotic stress tolerance. Additionally, these treatments induced a general delay in fruit ripening of the examined cultivars [140]. Notably, MeJA application boosted table grape and pomegranate yields (Table 3) while promoting larger fruit [97,141]. Plum studies further revealed that 0.5–2.0 mM treatments significantly improved the key quality parameters of firmness, coloration, and total acidity (TA). Concurrently, MeJA elevated total phenolic content and amplified antioxidant activity in a dose-dependent manner [142]. Crucially, this compound activated antioxidant defense pathways, stimulating expression of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and superoxide dismutase (SOD) enzymes in pomegranates [97,143], table grapes [141], blood oranges [144], and plums [139].

CI constitutes a primary constraint for refrigerated storage of postharvest fruits, triggering compromised quality attributes and significant economic losses [145]. Recent studies revealed that MeJA was pivotal for the regulation of resistance to CI in harvested fruit. Min et al. [146] noted that MeJA application substantially suppressed CI in postharvest fresh produce, and proposed that the mechanism of MeJA action on fruit CI tolerance could involve: (1) reinforcing membrane stability and maintaining energy flux; (2) elevating free radical scavenging potential; (3) upregulating the arginine pathway; (4) improving sugar metabolism; (5) regulating metabolism of phenolics; (6) activating the C-repeat/dehydration response element binding factor (CBF) pathway, crucial for plant low-temperature stress adaptation; (7) modulating heat shock protein expression and accumulation; or (8) engaging in phytohormone signaling crosstalk. MeJA treatments preserve membrane integrity in postharvest crops by mitigating CI, effectively suppressing electrolyte leakage and malondialdehyde (MDA) accumulation across fruit commodities (Table 3). Supporting this, Bagheri and Esna-Ashari [147] documented reduced electrolyte leakage and MDA content in persimmons treated with 8–24 µmol/L MeJA. Mechanistically, MeJA enhanced antioxidant defense through dual mechanisms: enzymatic activation and phenolic/anthocyanin upregulation via phenylalanine ammonia-lyase (PAL) induction [141]. Preharvest application further demonstrated multifunctional benefits, boosting yields, improving quality, and elevating bioactive compounds, as evidenced in lemons [148,149], table grapes [141] and pomegranates [143] (Table 3).

Table 3. Effects of preharvest treatments of different plant elicitors on postharvest quality of fruits.

Treatment	Fruit	Effect	Reference
MeJA	Table grapes	Accelerated fruit ripening. Application of 0.1 mM and 0.01 mM MeJA significantly increased total yield while enhancing berry quality attributes and bioactive compound levels.	[141]
	Lemons	Increased content of antioxidants such as phenolics at 0.1 mM MeJA. Antioxidant enzyme activities were significantly elevated, with no adverse effects on yield or fruit quality.	[148]
	Blood oranges	Decreased electrolyte leakage and MDA content and enhanced SOD, APX and CAT activities. Suppressed electrolyte leakage and MDA levels, concomitant with elevated activities of SOD, APX, and CAT.	[144]
	Pomegranates	Treatments with 1 mM and 5 mM MeJA accelerated on-tree fruit maturation while suppressing storage losses of firmness, weight, and organic acid content at 10 °C. And aril coloration was significantly enhanced.	[97]
	Pomegranates	Reduced internal/external CI symptoms and ion leakage, attributed to preserved harvest-stage unsaturated fatty acids, enhanced membrane stability, and maintained antioxidant levels during storage.	[143]
	Lemons	Elevated antioxidant parameters including total antioxidant activity, phenolic content, key phenolics (eriocitrin, hesperidin), and enzymatic activity.	[149]
	Pomegranates	Alleviated CI and maintained intact pericarp structure.	[150]
	Persimmons	Preserved fruit quality, content of phenolic compounds and antioxidant properties, reduced CI and membrane peroxidation, and enhanced membrane integrity during cold storage.	[147]
	Sweet cherries	Improvement in abiotic stress tolerance and reduction in fruit cracking and ripening delay.	[140]
	Plums	Elevated carotenoid and phenolic levels at harvest and antioxidant activity, with no effect on ripening of fruits on the tree.	[151]
SA	Plums	Elevated bioactive and antioxidant levels upon harvesting.	[151]
	Sweet cherries	Improved physicochemical properties (color, SSC, firmness), bioactive constituents (phenolics, anthocyanins), and antioxidant metrics (hydrophilic capacity, enzyme activities).	[152]
	Plums	Enhanced postharvest quality evidenced by increased weight, firmness, TA; elevated phenolics (anthocyanins), carotenoids; sustained antioxidant enzyme activity; delayed ripening/senescence; and extended shelf-life.	[153]
	Plums	Elevated harvest-stage phenolics and carotenoids with enhanced antioxidant capacity, without altering on-tree fruit ripening.	[151]
	Plums	At harvest, higher levels of firmness, weight, sugars, acids, phenolics, carotenoids, and anthocyanins were observed. SA treatment delayed softening, color shifts, and acidity loss upon storage.	[154]
	Pomegranates	The best improvement in quality was attained with 10 mM SA, mainly in terms of color and maintaining concentrations of anthocyanins, phenolics, and ascorbic acid during prolonged storage at 10 °C.	[96]
	Table grapes	0.1 mM SA treatment elevated antioxidants and yield, promoted faster on-vine ripening, and maintained storage stability.	[155]
	Table grapes	Notable increases occurred in TA levels, bioactive compound concentrations, antioxidant enzyme functionality, and resistance to B. cinerea infection.	[156]
	Jujubes	Increased antioxidant capacity and total phenolics.	[157]
	Table grapes	Elevated antioxidant activity, total phenolic content, and bioactive constituent levels were observed.	[158]
ASA	Sweet cherries	Enhanced firmness, color, total phenolics, SSC, total anthocyanin content, hydrophilic total antioxidant activity and antioxidant enzyme activity.	[152]
	Plums	Enhanced weight, firmness, acid/sugar profiles, phenolic content, anthocyanins, and total carotenoids at harvest, with postponed softening, discoloration, and acidity loss during storage.	[154]
	Table grapes	0.1 mM MeSA maximally promoted ripening, yield, and anthocyanin-mediated color enhancement in berries.	[155]
	Table grapes	Increased TA, content of bioactive compounds, activity of antioxidant enzymes, and resistance to Botrytis cinerea spoilage.	[156]
	Loquats	ASA was proven to be the most effective compound for both maintaining postharvest appearance and enhancing fruit quality attributes.	[159]
MeSa	Plums	Harvested fruit exhibited heightened firmness, mass, organic acid diversity, phenolic compounds, soluble sugars, carotenoid content, and anthocyanin levels. Postharvest storage manifested suppressed softening, chromatic alterations, and acid depletion.	[154]
	Pomegranates	Treatment with 10 mM SA was most effective, with improvement in red color and maintenance of anthocyanin/phenolic/ascorbic acid levels under prolonged 10 °C storage.	[96]
	Table grapes	Accelerated ripening, enhanced yield and berry color via elevated anthocyanin accumulation.	[156]
	Table grapes	Increased TA, bioactive compounds, antioxidant enzyme efficacy, and B. cinerea resistance.	[156]
	Apricots	Enhanced antioxidant capacity, reduced CI, maintenance of soluble solid and organic acids, and reduced decay.	[160]
Oxalic Acid (OA)	Sweet cherries	Elevated fresh mass, textural rigidity, and SSC.	[152]
	Pineapples	Diminished internal browning and increased ascorbic acid accumulation.	[161]
	Strawberries	Higher fruit yield and ascorbic acid levels and improved sensory attributes.	[162]
	Plums	Enhanced crop yield, fruit weight, and antioxidant level. Delayed maturation on-tree and during cold storage.	[163]
	Kiwifruit	Lower off-flavor intensity, reduced acetaldehyde/ethanol levels, and higher ascorbate content.	[120]
	Pomegranates	Yield enhancement and preharvest ripening acceleration exhibited dose dependency. Optimal firmness, peel chromaticity, respiratory activity, and organoleptic properties occurred with application of 10 mM OA.	[164]
	Apricots	Diminished moisture loss, ethylene emission, and respiration intensity.	[165]
	Apricots	Augmented firmness, ascorbic acid, mass and juice yield. Diminished moisture loss and antioxidative efficacy.	[166]
	Lemons	Reduced losses in weight and firmness, SSC and TA. Antioxidant enzymatic activity and total phenolic levels showed significant augmentation.	[167]
	Table grapes	Delayed senescence with stimulation of antioxidant enzyme activity.	[168]
	Blueberries	Elevated textural integrity, anthocyanin accumulation, and free radical scavenging capacity.	[169]
Polyamines (PAs)	Apricots	Increased shelf-life up to 30 d with good quality under MAP conditions.	[170]
	Jujubes	Improved antioxidant capacity and total phenolics.	[157]
	Pistachios	Increased fresh pistachio storability, delayed softening and weight loss, and inhibition of fungal infection.	[171]
	Table grapes	Greater firmness, lower susceptibility to microbial infection, elevated phenolic/anthocyanin accumulation with enhanced antioxidant capacity.	[172]
	Pears	Spermidine (Spd) (0.05 mM) and putrescine (Put) (0.25 mM) elicited significantly higher June fruit set. Maturity index peaked at 0.25 mM Put, with 0.05 mM Spd ranking second. Spd (0.25 mM) markedly elevated total sugars, antioxidants (anthocyanins and phenolics), and phytochemical accumulation.	[173]

Table 3. Effects of preharvest treatments of different plant elicitors on postharvest quality of fruits.

Treatment	Fruit	Effect	Reference
MeJA	Table grapes	Accelerated fruit ripening. Application of 0.1 mM and 0.01 mM MeJA significantly increased total yield while enhancing berry quality attributes and bioactive compound levels.	[141]
	Lemons	Increased content of antioxidants such as phenolics at 0.1 mM MeJA. Antioxidant enzyme activities were significantly elevated, with no adverse effects on yield or fruit quality.	[148]
	Blood oranges	Decreased electrolyte leakage and MDA content and enhanced SOD, APX and CAT activities. Suppressed electrolyte leakage and MDA levels, concomitant with elevated activities of SOD, APX, and CAT.	[144]
	Pomegranates	Treatments with 1 mM and 5 mM MeJA accelerated on-tree fruit maturation while suppressing storage losses of firmness, weight, and organic acid content at 10 °C. And aril coloration was significantly enhanced.	[97]
	Pomegranates	Reduced internal/external CI symptoms and ion leakage, attributed to preserved harvest-stage unsaturated fatty acids, enhanced membrane stability, and maintained antioxidant levels during storage.	[143]
	Lemons	Elevated antioxidant parameters including total antioxidant activity, phenolic content, key phenolics (eriocitrin, hesperidin), and enzymatic activity.	[149]
	Pomegranates	Alleviated CI and maintained intact pericarp structure.	[150]
	Persimmons	Preserved fruit quality, content of phenolic compounds and antioxidant properties, reduced CI and membrane peroxidation, and enhanced membrane integrity during cold storage.	[147]
	Sweet cherries	Improvement in abiotic stress tolerance and reduction in fruit cracking and ripening delay.	[140]
	Plums	Elevated carotenoid and phenolic levels at harvest and antioxidant activity, with no effect on ripening of fruits on the tree.	[151]
SA	Plums	Elevated bioactive and antioxidant levels upon harvesting.	[151]
	Sweet cherries	Improved physicochemical properties (color, SSC, firmness), bioactive constituents (phenolics, anthocyanins), and antioxidant metrics (hydrophilic capacity, enzyme activities).	[152]
	Plums	Enhanced postharvest quality evidenced by increased weight, firmness, TA; elevated phenolics (anthocyanins), carotenoids; sustained antioxidant enzyme activity; delayed ripening/senescence; and extended shelf-life.	[153]
	Plums	Elevated harvest-stage phenolics and carotenoids with enhanced antioxidant capacity, without altering on-tree fruit ripening.	[151]
	Plums	At harvest, higher levels of firmness, weight, sugars, acids, phenolics, carotenoids, and anthocyanins were observed. SA treatment delayed softening, color shifts, and acidity loss upon storage.	[154]
	Pomegranates	The best improvement in quality was attained with 10 mM SA, mainly in terms of color and maintaining concentrations of anthocyanins, phenolics, and ascorbic acid during prolonged storage at 10 °C.	[96]
	Table grapes	0.1 mM SA treatment elevated antioxidants and yield, promoted faster on-vine ripening, and maintained storage stability.	[155]
	Table grapes	Notable increases occurred in TA levels, bioactive compound concentrations, antioxidant enzyme functionality, and resistance to B. cinerea infection.	[156]
	Jujubes	Increased antioxidant capacity and total phenolics.	[157]
	Table grapes	Elevated antioxidant activity, total phenolic content, and bioactive constituent levels were observed.	[158]
ASA	Sweet cherries	Enhanced firmness, color, total phenolics, SSC, total anthocyanin content, hydrophilic total antioxidant activity and antioxidant enzyme activity.	[152]
	Plums	Enhanced weight, firmness, acid/sugar profiles, phenolic content, anthocyanins, and total carotenoids at harvest, with postponed softening, discoloration, and acidity loss during storage.	[154]
	Table grapes	0.1 mM MeSA maximally promoted ripening, yield, and anthocyanin-mediated color enhancement in berries.	[155]
	Table grapes	Increased TA, content of bioactive compounds, activity of antioxidant enzymes, and resistance to Botrytis cinerea spoilage.	[156]
	Loquats	ASA was proven to be the most effective compound for both maintaining postharvest appearance and enhancing fruit quality attributes.	[159]
MeSa	Plums	Harvested fruit exhibited heightened firmness, mass, organic acid diversity, phenolic compounds, soluble sugars, carotenoid content, and anthocyanin levels. Postharvest storage manifested suppressed softening, chromatic alterations, and acid depletion.	[154]
	Pomegranates	Treatment with 10 mM SA was most effective, with improvement in red color and maintenance of anthocyanin/phenolic/ascorbic acid levels under prolonged 10 °C storage.	[96]
	Table grapes	Accelerated ripening, enhanced yield and berry color via elevated anthocyanin accumulation.	[156]
	Table grapes	Increased TA, bioactive compounds, antioxidant enzyme efficacy, and B. cinerea resistance.	[156]
	Apricots	Enhanced antioxidant capacity, reduced CI, maintenance of soluble solid and organic acids, and reduced decay.	[160]
Oxalic Acid (OA)	Sweet cherries	Elevated fresh mass, textural rigidity, and SSC.	[152]
	Pineapples	Diminished internal browning and increased ascorbic acid accumulation.	[161]
	Strawberries	Higher fruit yield and ascorbic acid levels and improved sensory attributes.	[162]
	Plums	Enhanced crop yield, fruit weight, and antioxidant level. Delayed maturation on-tree and during cold storage.	[163]
	Kiwifruit	Lower off-flavor intensity, reduced acetaldehyde/ethanol levels, and higher ascorbate content.	[120]
	Pomegranates	Yield enhancement and preharvest ripening acceleration exhibited dose dependency. Optimal firmness, peel chromaticity, respiratory activity, and organoleptic properties occurred with application of 10 mM OA.	[164]
	Apricots	Diminished moisture loss, ethylene emission, and respiration intensity.	[165]
	Apricots	Augmented firmness, ascorbic acid, mass and juice yield. Diminished moisture loss and antioxidative efficacy.	[166]
	Lemons	Reduced losses in weight and firmness, SSC and TA. Antioxidant enzymatic activity and total phenolic levels showed significant augmentation.	[167]
	Table grapes	Delayed senescence with stimulation of antioxidant enzyme activity.	[168]
	Blueberries	Elevated textural integrity, anthocyanin accumulation, and free radical scavenging capacity.	[169]
Polyamines (PAs)	Apricots	Increased shelf-life up to 30 d with good quality under MAP conditions.	[170]
	Jujubes	Improved antioxidant capacity and total phenolics.	[157]
	Pistachios	Increased fresh pistachio storability, delayed softening and weight loss, and inhibition of fungal infection.	[171]
	Table grapes	Greater firmness, lower susceptibility to microbial infection, elevated phenolic/anthocyanin accumulation with enhanced antioxidant capacity.	[172]
	Pears	Spermidine (Spd) (0.05 mM) and putrescine (Put) (0.25 mM) elicited significantly higher June fruit set. Maturity index peaked at 0.25 mM Put, with 0.05 mM Spd ranking second. Spd (0.25 mM) markedly elevated total sugars, antioxidants (anthocyanins and phenolics), and phytochemical accumulation.	[173]

6.2. Salicylates

Salicylic acid (SA), a phenolic phytohormone, features a benzene ring with hydroxyl and carboxyl functional groups synthesized endogenously in plants. Acetyl salicylic acid (ASA) is a hydrolytic derivative of SA. A second derivative, MeSa, functions as a volatile membrane-permeable signaling compound. SA’s principal physiological role involves induction of systemic acquired resistance (SAR), a pathogen-responsive immune mechanism mediating plant responses to both biotic and abiotic stressors [174,175]. Following its biosynthesis, SA undergoes phloematic translocation throughout the plant, protecting it from future infections. These chemically very different products are now recognized as acting as plant hormones; despite structural dissimilarities, complex molecular cross-talk may drive defined biological responses [176].

These SA derivatives regulate critical physiological processes including seed germination, developmental progression, floral induction, and fruit maturation. Preharvest applications of ASA, SA, and MeSa demonstrate broad horticultural utility across diverse fruit crops, such as sweet cherries [152,177,178,179], pomegranates [96,143,150], plums [153] and table grapes [155,156]. These treatments improved fruit quality at harvest, with greater firmness, SSC, TA, and color. Furthermore, SA and its derivatives attenuate respiratory rates by suppressing ethylene biosynthesis and modulating stomatal conductance [180]. These treatments concomitantly enhance cellular biosynthesis of bioactive constituents, notably anthocyanins, phenolic compounds, and antioxidant capacity. Postharvest analyses further confirm superior retention of quality parameters and phytochemical concentrations in salicylate-treated horticultural commodities. Notably, exogenous SA or MeSa application elevates antioxidative potential in apricots [181], grapes [158], and strawberries [182] under storage.

In fruits sensitive to chilling, preharvest treatment with SA reduced the negative effects of CI, which was attributed to elevated activity of CAT, POD, SOD and APX. These enzymes and phenolics jointly combat CI stress via ROS scavenging and membrane protection [143,154,183]. Treatment with 1 μM SA for 15 min prior to storage at 4 °C delayed and reduced internal fruit browning, a symptom of CI. Studies show that SA alleviates CI in peaches by multiple mechanisms, including increasing sucrose content and activating cold response genes [184].

6.3. Oxalic Acid (OA)

The biosynthesis of OA in plants can occur through multiple metabolic pathways, depending on the type of cell or tissue. Li et al. [185] have recently identified three main pathways for the biosynthesis of oxalates in plants: the glycolic or glyoxalic acid pathway, the oxaloacetic acid pathway, and the ascorbic acid pathway [186,187]. Glycolate oxidase converts photorespiratory glycolate/glyoxylate to oxalate [188]. A parallel pathway involving oxaloacetate acetylhydrolase-catalyzed oxaloacetate breakdown may also contribute oxalate.

Preharvest treatment with OA delays senescence and preserves fruit quality, as in the case of cherries [189], peaches [190], lemons [167] apricots [181], plums [165], and nectarines [191]. OA exerts its effects by scavenging ROS, inhibiting ADH, accumulating proline, and conserving ATP [192], controlling the balance between unsaturated and saturated fatty acids [193], and regulating sugar metabolism [194]. OA treatments enhance POD, APX, SOD, and CAT activities, key enzymes conferring biotic (e.g., pathogen defense) and abiotic stress tolerance. This response may be mediated by the accumulation of phenolic compounds [195]. OA treatment reduced browning in fresh-cut apples by suppressing oxidative stress, regulating phenol metabolism, and stimulating energy metabolism [196]; OA also enhanced ascorbic acid levels in strawberries [162]. OA treatment stabilized cellular equilibrium through oxidative burden mitigation in harvested fruit. Studies on Arabidopsis thaliana demonstrated that OA treatments < 5 mM effectively induced gene expression related to defense from infection but did not affect plant development. Similarly, 5 mM OA applied to kiwifruit reduced the incidence of decay from blue mold, by upregulation of defense-related enzymes [197]. However, concentrations exceeding 6 mM induced apoptosis and enhanced pathogen colonization by pathogenic fungi [198].

Elevated OA concentration may impair postharvest fruit quality. Table 3 demonstrates the superior efficacy of preharvest OA sprays (1–10 mM) across diverse cultivars and application frequencies relative to other concentrations. Notably, preharvest application of 2 mM OA substantially enhanced fruit size [166], antioxidant potential [167], ripening delay [199], and quality retention [169] during storage. Concentration-dependent responses vary unpredictably among crops, consistent with Garcia-Pastor et al. [168] who identified 5 mM OA as optimal for table grape yield, maturation, and bioactive accumulation when comparing 1, 5, and 10 mM treatments across two growing seasons.

6.4. Effects of Polyamines (PAs) on Fruit Preservation

PAs are cationic aliphatic metabolites with multiple amino groups. Unlike classical phytohormones, PA concentrations typically exceed micromolar thresholds in plant systems. These low-molecular-weight nitrogenous compounds modulate fundamental processes including mitotic regulation, fruit ontogeny, and senescence suppression [200]. Ubiquitous across biological kingdoms (bacteria, animals, plants), PAs exert pleiotropic effects on cellular proliferation, differentiation, and development. Among plant species, the predominant PAs, Put, Spd, and Spm demonstrate species-dependent accumulation patterns with characteristically elevated tissue concentrations [201]. These PAs are metabolically produced from arginine through dedicated biochemical routes involving arginine decarboxylase (ADC) and ornithine decarboxylase (ODC) (Figure 6) [202] from three basic amino acids. The carbon skeletons for polyamine biosynthesis derive primarily from arginine, lysine, and ornithine precursors, whereas methionine furnishes essential aminopropyl moieties. Put, the minimal PA containing two amino groups, is biosynthesized via two enzymatic pathways: arginine → agmatine → Put catalyzed by ADC, or ornithine → Put mediated ODC. Spd containing three amino groups and Spm containing four amino groups are formed through sequential aminopropyl transfer from decarboxylated S-adenosylmethionine to Put, with spermidine synthase and spermine synthase catalyzing these reactions, respectively [203].

Previous research indicated that declining PA levels in fruits correlate with senescence, whereas the accumulation of free PAs like Spd and Spm may be linked to tissue growth and organogenesis [204]. As summarized in Table 3, several studies have investigated preharvest PA application effects on fruit quality. Applying 1–2 mM Put or Spd preharvest notably prolonged the shelf life of fresh pistachios and apricots’ by slowing quality deterioration [170,171,205]. Similarly, preharvest treatments with Put and Spd enhanced the antioxidant system in grape and jujube fruit [157,172]. Sayyad-Amin et al. [173] also examined the impact of PAs applied preharvest on pears, and found that 0.25 mM Spd specifically increased total sugar content and antioxidant levels relative to controls.

6.5. Effectiveness of Plant Essential Oils, Extracts, and Elicitors in Fruit Preservation

Postharvest losses due to spoilage remain a significant challenge, driving research into natural preservation methods. Essential oils (EOs), plant extracts (PEs), and elicitors represent distinct approaches with different mechanisms and varying effectiveness (Figure 1). EOs are volatile compounds extracted from plant material via distillation, and are highly effective broad-spectrum antimicrobials. Their lipophilic nature disrupts microbial cell membranes, inhibiting growth on fruit surfaces. Recent studies showed that chitosan-based coatings incorporating thyme or citral EOs significantly reduced decay in citrus and mangoes [206,207]. However, their major drawback is their strong odor and potential phytotoxicity at higher doses, which can compromise fruit aroma, taste, and even cause surface scalding, limiting practical application.

Other types of plant extracts have broader bioactivity but may present problems in standardizing formulations, ensuring stability, and eliminating undesirable residues on fruit. For example, extracts from pomegranate peel or rosemary leaves [27] require specific solvents to obtain the wider range of nonvolatile compounds like polyphenols and flavonoids. These offer the dual benefits of antimicrobial and antioxidant activity, which slows enzymatic browning and oxidative spoilage. Another example is coatings of aloe vera-ginger extract that increase the shelf life of strawberries by reducing microbial load and lipid oxidation [208]. The primary challenge is the active compound concentration and developing stable formulations that do not leave.

Elicitors like jasmonic acid and salicylic acid are indirect defense activators for systemic resistance. They are applied to stimulate a fruit’s innate defense responses, triggering the production of natural antimicrobial compounds such as phytoalexins or strengthening cell walls. This approach is sustainable and can create a systemic resistance against pathogens. A 2022 study demonstrated that melatonin pretreatment effectively elicited defense enzymes in peaches, enhancing resistance against Monilinia fructicola [209]. The limitation is that effectiveness depends on the fruit’s physiological response, which can vary by species and maturity, and it typically works best as a pre-or post-harvest dip rather than an immediate curative treatment. For fruit preservation, EOs produce a rapid, powerful antimicrobial action but risk altering sensory qualities. Plant extracts provide a more balanced antioxidant and antimicrobial benefit but may require more involved formulation. Elicitors are a proactive, sustainable strategy that boosts the fruit’s own defenses, but they lack immediate potency and the effects are less predictable. The most effective future applications may lie in synergistic combinations, such as using a jasmonic acid elicitor coating embedded with low doses of thyme EO to simultaneously provide immediate protection while inducing long-term resistance.

7. Efficacy, Mechanisms, and Commercial Challenges

7.1. Controlling Postharvest Fruit Decay with Plant Extracts

Following harvest, fruits experience complex physiological shifts that heighten susceptibility to specific diseases, accelerate quality decline, and ultimately lead to increased wastage [5]. Postharvest deterioration is predominantly caused by fungal pathogens such as Penicillium spp. and Botrytis cinerea [210,211]. While the application of synthetic fungicides remains the most efficacious strategy for controlling postharvest fungal infections due to their rapid action [212], concerns regarding their potential adverse impacts on human health have spurred interest in green alternatives for fruit protection and preservation [213]. Numerous phytochemicals and antioxidants have demonstrated efficacy in maintaining quality and suppressing diseases during storage [214]. Notably, extracts derived from Ruta chalepensis and Eucalyptus globulus, along with NLE, exhibit potent efficacy in managing postharvest fruit diseases and prolonging shelf life, positioning them as safer alternatives to synthetic chemicals [32,213].

Despite substantial ethnobotanical documentation, scientific evidence regarding the preparation, phytochemistry, efficacy, and practical application of extracts of indigenous medicinal plants for safeguarding and preserving fruit commodities after harvesting are limited. Fungi constitute the predominant cause of postharvest spoilage in fresh fruits during transit and storage, rendering produce inedible and potentially harmful from mycotoxins, and causing significant economic losses [210].

Although global food security and sustainability fundamentally depend on crop protection and conservation, approximately one-third of annual human food production is still lost [215]. To minimize these losses, capital-intensive machinery and synthetic fungicides are commonly deployed on harvested fruit to control disease [216,217]. While advancements in food preservation technologies have mitigated disease-related deterioration [218,219,220], research continues into commercially viable, consumer-safe, and environmentally benign plant-based alternatives [221]. Concurrently, significant progress has been made by the food, pharmaceutical, and agrochemical industries in developing and utilizing natural preservatives and pesticides [222].

While conventional fruit preservation for commerce heavily relies on synthetic pesticides and fungicides [223], this underscores the necessity of evaluating plant extracts as potential replacements. The antifungal and antioxidant capacities of these extracts are associated with diverse phytochemical classes, such as cyanogenic glycosides, alkaloids, phenylpropanoids, polyketides, carbohydrates, lipids, nucleic acids, anthocyanins, and amino acids [224]. Specific examples include: fukugetin in Garcinia brasiliensis; carnosic acid, rosmanol, and carnosol in Lepidium meyenii; and citral, aspilactonol B, and 8-methyl-6-prenylquercetin in Cymbopogon citratus [213]. A critical step involves comprehensively investigating the active constituents, nutritional elements, and mineral profiles of medicinal plants to assess their biological activities, especially antimicrobial and antioxidant properties, and potential human cytotoxic and genotoxic effects. This evaluation is vital for determining the feasibility of plant-derived treatments to replace synthetic agents in postharvest fruit preservation [225].

Estimates indicate over 400,000 known plant species existed by 2015, including more than 360,000 flowering plants, with approximately 2000 new species reportedly identified each year [226]. The effectiveness of neem (Azadirachta indica) leaf extract, for instance, is attributed to a complex mixture of compounds [227,228], such as phytol, nonanoic acid, dibutyl phthalate, tritriacontane, and 1,2-benzenedicarboxylic acid. Many plants synthesize bioactive secondary compounds, including EOs and biocidal substances. Commercially available botanical fungicides like tea tree oil, jojoba oil, neem oil, and AV gel [229] are increasingly proposed as viable substitutes for synthetic fungicides in controlling postharvest fungal decay on fruit [230].

Table 4. Antimicrobial and antioxidant plant extracts and their application in post-harvest fruit preservation.

Plant Name	Part Used	Research Focus	Treatment	Reference
Azadirachta indica	NLE	Effects of NLE application on the antioxidant activity and physicochemical characteristics of peaches.	Peaches treated with different NLE concentrations were stored at room temperature for 9 days, then tested for antioxidant activity and physicochemical properties. The 30% NLE treatment reduced weight loss and SSC, maintained higher acidity, and extended shelf life.	[231]
Thyme	EO	Preservation ability of different plant EOs on post-harvest quality and shelf life of mangoes.	Mangoes were treated with thyme oil and postharvest properties were recorded every 3 d. Thyme oil was most effective at preservation of mangoes compared with other EOs.	[232]
Astragalus	Astragalus polysaccharides (APS)	The effect of APS on peel browning and CI of banana fruit.	Bananas were immersed in a solution of 0.1 g/L APS, 0.5 g/L APS, or sterile water at 25 °C for 5 min. The treated fruit were placed into perforated plastic boxes and stored at 7 ± 1 °C.	[233]
Aloe	Leaf extract	Effects of AV coating on grapes, before and after harvest, and the combined application before and after harvest, on storage characteristics and grape quality.	For both preharvest and postharvest periods, AV coatings were applied at a concentration of 33%. For the preharvest treatment, the entire foliage was sprayed with the solution 10 d before harvesting. On the day of harvest, clusters were picked, immersed in 33% AV solution for 5 min and stored. The control group was treated with distilled water (DW).	[80]
Aloe	Leaf extract	Aloe-based edible coating to maintain quality of fresh-cut Italian pears (Pyrus communis L.) during cold storage.	Two edible coatings were tested: (1) 120 mL AV gel + 6 g hydroxypropyl-methylcellulose (HPMC) + 3 g pomegranate seeds oil (PSO) dissolved in 300 mL of DW (2) 120 mL AV gel + 3 g HPMC dissolved in 300 mL DW.	[234]
Moringa	Leaf extract	Preservative effect of coatings made of gum arabic (GA) and carboxymethyl cellulose (CMC), containing moringa (M) leaf extract effective against Colletotrichum gloeosporioides on Maluma avocados.	Avocados were coated with 10% and 15% GA, 10% and 15% GA + M, or 1% CMC + M. Uncoated fruit served as control. The fruits were kept at 5.5 °C and 95% relative humidity for 21 days before being transferred to 21.1 °C and 60% RH for 7 days to imitate the natural environment.	[235]
Lippia javanica	EO from leaves	The minimum inhibitory concentration of EO for visible growth of Fusarium graminearum.	Experimental concentrations of 0.87, 0.65, 0.43, 0.22, 0.11, 0.054 and 0.027 mg/mL of EO were tested in bioassays.	[236]
Aloe, Indian fagonbush	Plant powder	Effect of AV gel alone or enriched with Fagonia indica (FI) extract on storage of sapodilla fruit.	Treatments: DW control, 50% AV, 100% AV, 50% AV + 1% FI, and 100% AV + 1% FI. Fruit were dipped in the corresponding solutions for 5 min and then air dried at ambient temperature and stored.	[119]
Thyme, aloe	Thyme oil + extract	Effect of thyme oil and edible coatings on the growth of anthracnose on artificially infected avocados.	The ‘poisoned food technique’ was used to compare the effect of various plant extract treatments. Infected avocados were coated with chitosan, aloe, thyme oil, chitosan + thyme oil (3:1), or aloe + thyme oil (3:1) before storage at room temperature for 5 d.	[237]
Aloe, ginger, garlic	AV gel	Effect of GA, AV gel, ginger and garlic extracts on preservation of guava.	Treatments: DW control, 20% ginger extract + 10% GA, 20% garlic extract + 10% GA, 100% AV gel + 10% GA.	[133]
Moringa	Moringa leaf extract (MLE)	Effect of preharvest foliar applications of MLE on morphological and physiological attributes and yield of freesia corms, Freesia hybrida L.	Experiment I: corms were soaked in 1%, 2%, 5% or 10% MLE for 24 h and air dried before planting. Experiment II: untreated corms were planted and 1%, 2%, 3% or 5% MLE was applied to the planted area until runoff at 30 and 60 d after planting.	[238]
Aloe	Leaf extract	Effect of edible coating of salicylic acid (SA) and AV on microbial load and CI of oranges.	Thomson navel oranges (Citrus sinensis L. Osbeck) were coated with SA and AV, stored at 4  ±  1 °C and 80  ±  5% RH, and microbial load, CI and quality were evaluated.	[239]

reviews studies on postharvest fruit preservation using medicinal plant extracts.

7.2. Preventive Functions of Plant Extracts

The infrequent occurrence of phytopathogenic infections in medicinal plants indicates highly effective innate resistance mechanisms [240]. Research characterizing microbial dynamics on fruit surfaces and wound sites remains limited, primarily due to methodological challenges in analyzing complex interactions among pathogens, antagonists, host tissues, and co-occurring microorganisms. Understanding the fundamental mechanisms governing fruit disease biocontrol is essential for enhancing and expanding practical applications of plant-derived antimicrobials [241]. On fruit surfaces, bioactive phytocompounds can operate either independently or synergistically. Their antagonistic effects involve multifaceted mechanisms including nutritional competition, induced resistance, spatial dominance, antimicrobial activity, and parasitic action. Implementing effective postharvest control via plant extracts necessitates a better understanding of pathogens, antagonistic bacteria, the produce, and the environment [242].

Grigore-Gurgu et al. [243] delineated diverse pathways through which plant-derived phytochemicals exerted antimicrobial actions, including enzyme suppression, bacterial membrane destabilization, virulence factor downregulation, biofilm interference, protein synthesis inhibition and quorum sensing disruption. Tannins likely function through binding to microbial targets and inhibiting protein biosynthesis [244]. In contrast, most phenolic compounds compromise pathogen membrane integrity. Nevertheless, comprehensive understanding of these botanical agents’ mechanisms remains essential before deploying them against postharvest fruit diseases [245].

The chemical diversity in plant extracts suggests complex antimicrobial interactions rather than single-mode actions [246]. EOs function as direct antimicrobial agents against phytopathogens within plant defense systems [247]. Their synergy with other constituents further impedes resistant fungal strain development. Notably, orange [248] and shittah tree [213] extracts enhance host immunity to suppress green mold, demonstrating significant efficacy [249].

According to Zhang et al. [250], pathogen activation of the defense response brought about the toughening of cell walls, which function as a protective physical barrier, to block pathogen entry. Furthermore, this process may increase soluble phenolic concentrations in citrus peel tissues [251]. Plant-derived phytochemicals contribute to fruit defense through multiple mechanisms: microbial membrane disruption, suppression of critical metabolic pathways, and induction of pH stress via intracellular anion accumulation [251]. In vitro studies confirm these compounds significantly inhibit growth of phytopathogenic fungi [252]. Pathogenic fungi of citrus preferentially thrive in acidic-to-neutral environments rather than alkaline conditions. Acidophilic species such as P. digitatum consequently divert metabolic energy toward organic acid production rather than hyphal development, inhibiting proliferation [253]. Medicinal plant extracts effectively combat P. italicum, P. digitatum, and G. citri-aurantii by disrupting mitochondrial oxidative phosphorylation, inhibiting enzymatic activity and protein biosynthesis, and altering membrane transport dynamics [254].

The pH of plant extracts is critical for managing postharvest citrus diseases, directly influencing conidial germination [251], and it reduces the aggressiveness of pathogens in colonizing host tissues. Yusoff et al. [255] investigated the mode of action of antifungal compounds derived from bitter leaf extract (Vernonia amygdalina), and showed that the hyphal structure of B. cinerea was modified after exposure to bitter leaf phytochemicals. Fungal mycelia displayed morphological alterations including contorted structures with serrated margins and agglutinated forms featuring desiccated hyphal tips and collapsed conidia, effectively suppressing fungal development [256]. B. cinerea’s prolific asexual spores, while readily dispersed, may paradoxically limit gray mold transmission between proximate fruits by saturating infection sites. Synergistic combinations of antifungal agents demonstrate enhanced efficacy against B. cinerea growth and proliferation. Regarding oxidative mechanisms, Yang et al. (2015) [257] delineated multiple antioxidant pathways: (i) localized oxygen depletion, (ii) radical scavenging to inhibit chain initiation, (iii) metal ion chelation preventing peroxide decomposition, and (iv) peroxide conversion to non-radical species. Phenolic compounds and aromatic amines function as chain-terminating antioxidants. Within postharvest horticulture and food industries, antioxidants are defined as compounds that inhibit oxidation of susceptible substrates, such as lipids, at low concentrations [213]. Medicinal plant alkaloids exhibit dual functionality. Their hydroxyl groups neutralize reactive species while tertiary nitrogen enables ferrous ion chelation [258,259]. Similarly, terpenoids and saponins mitigate reactive oxygen species (ROS) generation, inhibiting lipid peroxidation and reducing oxidative stress [260,261].

7.3. Limits and Practical Challenges to Commercialization

The shift from synthetic fungicides to natural alternatives like plant extracts and elicitors is a promising field driven by consumer demand for safer food and sustainable agricultural practices. However, their path to widespread commercial adoption is fraught with significant technical and practical hurdles that must be critically addressed.

7.3.1. Limits of Plant Extracts and Elicitors

Firstly, there are toxicity and safety concerns. While many source plants are deemed “Generally Recognized As Safe” (GRAS), the safety profile of a concentrated extract can differ vastly from that of the whole plant. The extraction process can concentrate not only beneficial compounds but also potential toxins, allergens, or compounds that may cause off-target effects in humans. For instance, some herbal extracts rich in alkaloids or specific polyphenols may require extensive toxicological evaluation. Furthermore, in many jurisdictions (e.g., EU, USA, UK), a new plant extract used as a preservative may be classified as a “Novel Food,” requiring extensive and expensive toxicological studies (acute, sub-chronic toxicity, genotoxicity) to prove its safety for human consumption, a major regulatory and financial barrier [262]. While generally considered safe, the long-term health impacts of routinely consuming fruits treated with elicitors like methyl jasmonate at commercial doses are not fully understood and require rigorous assessment. Secondly, there are concerns about sensory acceptance, a critical consumer-facing challenge. This is perhaps the most immediate barrier to consumer adoption. Many plant extracts at effective antimicrobial concentrations, impart strong, bitter, pungent, or herbal notes (e.g., from thyme, oregano, or neem) that are undesirable in most fruits, which have a distinctive aroma and are expected to be sweet [263,264]. Some extracts, particularly those rich in polyphenols, can have intense colors (deep yellow, brown, green) that can stain the fruit’s surface an unnatural and unappealing color. As noted by Sivakumar & Bautista-Baños (2014), oil-based extracts or crude formulations can also leave a greasy or sticky residue on the fruit surface, adversely affecting the tactile experience and overall consumer acceptability [265]. Thirdly, stability and efficacy of the extracts need to be considered. Bioactive compounds like phenolics, flavonoids, and terpenes are often sensitive to light, heat, and oxygen, and their potency can degrade rapidly during storage, which is unacceptable for industrial supply chains [266]. The compounds can bind to fruit tissues or other components in a coating formulation, reducing their bioavailability to act against pathogens, and the pH of the fruit surface and its native microbiota can also deactivate certain compounds. Another significant challenge is the limited spectrum of activity of some extracts, which may be effective against one common mold (e.g., Botrytis cinerea) but completely ineffective against another (e.g., Penicillium expansum), necessitating complex mixtures that further complicate formulation, safety, and regulation.

7.3.2. Industrial Feasibility and Practical Challenges for Commercialization

First, standardization and quality control need to be considered. Reproducing an extract with identical efficacy across thousands of batches is extremely difficult and costly. The chemical profile of a plant extract is highly dependent on the plant’s genotype, the climate and soil, the harvest time, and postharvest processing. This leads to significant batch-to-batch variability [267]. For many botanicals, the specific compound(s) responsible for the antimicrobial effect, the active principles, are unknown. Without this knowledge, standardizing the product based on a consistent marker compound is impossible, which may lead to unpredictable results and problems gaining regulatory approval. Second, regulatory hurdles need to be confronted and overcome. Navigating the complex regulatory landscape is a time-consuming task. Obtaining approval from agencies like the FDA (USA), EFSA (EU), or Codex (FAO/WHO) for a new natural antimicrobial requires a substantial investment of time (often several years) and capital (millions of dollars), which is often prohibitive for small and medium-sized enterprises. The requirement for extensive toxicological data for novel food applications, as mentioned earlier, is the single biggest regulatory hurdle [268]. Third, cost-effectiveness and scalability must be considered. Sourcing sufficient high-quality, consistent plant material without competing with the food, feed, and pharmaceutical industries is a major challenge. Sophisticated extraction techniques like supercritical CO₂ extraction are efficient but have high initial capital and operational costs compared to the application of approved synthetic fungicides. Solvent extraction requires additional steps for solvent removal and purification, adding to the cost [269]. Furthermore, developing efficient, large-scale application methods (e.g., spraying, dipping, fumigation) that ensure uniform coverage without damaging delicate fruits adds another layer of engineering complexity and cost.

The preservative formulation itself must have a long shelf life to fit into existing logistics, which can be difficult for unstable extracts. While “natural” is a selling point, labels stating “treated with rosemary extract” might confuse some consumers, requiring clear, positive messaging. Ultimately, the performance must be comparable to conventional methods. A shorter extension of shelf-life or a slightly higher failure rate can be unacceptable to retailers and distributors who rely on the predictable and long-lasting efficacy of synthetic fungicides. To sum up, while plant extracts and elicitors offer a compelling, sustainable alternative to synthetic postharvest fungicides, their journey “from lab to supermarket” is complex. The primary limitations are not just scientific (efficacy) but deeply practical: ensuring sensory acceptance, guaranteeing consistent quality, navigating regulatory pathways, and achieving cost-effectiveness at an industrial scale. Overcoming these challenges will require interdisciplinary efforts involving food chemists, engineers, toxicologists, and marketers. Future success likely lies in optimizing delivery systems (e.g., nanoencapsulation for stability and to mask unacceptable odors and flavors) and using these natural treatments as part of a hurdle technology approach within an integrated management strategy.

8. Current Status, Limits, and Future Prospects

8.1. Current Status

Research on plant extracts and elicitors for fruit preservation has moved from laboratory proof-of-concept to applied and commercial exploration. The field is driven by consumer demand for reduced synthetic pesticide residues and sustainable “green” technologies. Numerous studies confirm the efficacy of various extracts (e.g., from pomegranate peel [143], citrus [104], neem [81], and many spices) against key postharvest pathogens in vitro and on fruit. Application methods have advanced from simple dipping to incorporation into edible coatings (e.g., chitosan, alginate) which improve adhesion and provide for controlled-release [265]. The elicitor approach focuses on enhancing the fruit’s own defense mechanisms. Compounds like jasmonic acid, salicylic acid, chitosan, and yeast extracts are widely shown to induce systemic resistance, delay ripening, and reduce chilling injury in various fruits [270]. Commercial products exist, but some effects are significant, while others are not [271]. Many patents have been filed for specific formulations [272]. which indicates strong commercial interest and a move towards protecting innovative formulations for market advantage.

8.2. Limitations

First, the strong odor, flavor, and sometimes color of many plant extracts can alter the sensory properties of the fruit, making consumer acceptance a major hurdle [273]. Second, the chemical composition of plant extracts varies with genetic, environmental, and processing factors, leading to batch-to-batch inconsistency. Many bioactive compounds are also unstable and degrade under light, heat, or oxygen, compromising efficacy during storage. The third limitation is regulatory hurdles. In most regions, new plant-based preservatives require extensive safety toxicology data and approval as a “Novel Food” additive, which is a costly and time-consuming process [274]. In addition, sourcing raw materials, extraction, and stabilization processes are often more expensive than producing synthetic fungicides, making cost-competitiveness a significant challenge for large-scale adoption.

8.3. Future Prospects

The future lies in innovative technologies that overcome current limitations. First, nano-encapsulation, which involves encapsulating extracts in nanocarriers such as liposomes and cyclodextrins, is a promising strategy to mask flavors, protect bioactive compounds from degradation, and enable their controlled release, thereby enhancing efficacy and sensory properties. Second, ‘hurdle technology’ creates synergistic effects by combining low doses of plant extracts with other non-thermal methods like UV-C, biocontrol agents, and hot water treatment. This approach allows for the use of lower, sensorially acceptable doses of extracts while improving overall efficacy. Third, using elicitors to stimulate the fruit’s innate immunity is a highly sustainable approach with strong potential, especially for organic production systems. Research will focus on optimizing application protocols for different fruit types. In conclusion, while already a commercial reality for specific applications (notably chitosan-based products), the broader use of plant extracts and elicitors depends on advancing formulation science to ensure consistency, stability, and no compromise on the sensory quality of the fresh fruit.

9. Conclusions

Plant-based extracts and elicitors represent a promising and sustainable strategy for mitigating postharvest losses and preserving fruit quality. As evidenced by extensive research and bibliometric analysis, these natural alternatives, ranging from essential oils and botanical extracts to signaling molecules like methyl jasmonate and salicylic acid, exert their effects through multifaceted mechanisms. These include direct antimicrobial and antioxidant activities, as well as the induction of the fruit’s own defense systems, thereby delaying ripening, reducing decay, and alleviating chilling injury.

However, the transition from laboratory research to widespread commercial application faces significant challenges. Key limitations include the potential impact of strong odors and flavors on sensory acceptability, batch-to-batch variability in extract composition, regulatory hurdles for novel food applications, and cost-effectiveness compared to synthetic fungicides. Future prospects necessitate overcoming these barriers through technological innovations. The development of nano-encapsulation techniques to improve stability and mask flavors, the strategic integration of these natural compounds within hurdle technologies, and the optimization of elicitor application protocols are critical directions. By addressing these challenges, plant-based preservatives can move beyond niche applications to become reliable, eco-friendly components of integrated postharvest management, effectively meeting consumer demand for safe, high-quality fruit with minimal synthetic chemical residues.