Polyphenolic Compounds from Indigenous Malus Species: A Novel Approach to Improve Ice Cream’s Thermodynamic Properties

Abstract

This review investigates the potential application of polyphenols extracted from indigenous Malus species as natural stabilizers to enhance ice cream thermodynamic properties. Ice cream quality and stability face significant challenges in regions with unreliable electrical infrastructure, such as Lebanon, where temperature fluctuations compromise product integrity. Polyphenols derived from apple tissues and processing by-products demonstrate promising functionality through interactions with ice cream’s protein and fat components, improving stability, reducing melting rates, and enhancing overall thermodynamic properties. Extraction methodologies are critically evaluated, with emphasis on ultrasound-assisted extraction as an optimal approach balancing efficiency, yield, and the preservation of bioactive compounds. This review provides a comprehensive analysis of polyphenolic profiles across apple varieties and tissues, extraction methodologies, mechanisms of stabilization in frozen desserts, and potential sensory implications. The multifunctional approach addresses both technological challenges in frozen dairy products and evolving consumer preferences for clean-label ingredients while potentially adding nutritional value through the inherent bioactive properties of polyphenols. Furthermore, utilizing apple by-products aligns with circular economy principles, transforming waste streams into value-added ingredients. This approach shows particular promise for regions with cold chain challenges while supporting sustainable agricultural practices.

1. Introduction

Ice cream represents a complex colloidal system with a frozen foam structure comprising multiple phases: fat globules (10–16%), ice crystals (30–35%), air cells (variable, depending on overrun), and an unfrozen serum phase containing high molecular weight polysaccharides, mineral salts, proteins, and water [1]. Temperature fluctuations during storage and distribution in regions with inconsistent cold chain infrastructure, such as Lebanon, exacerbate structural degradation.

At temperatures above −12 °C, ice crystals melt, diluting the serum phase and reducing its viscosity, which accelerates recrystallization during refreezing. For example, storage at −18 °C for 52 weeks increases ice crystal size from 40.3 μm to 100.1 μm, whereas storage at −50 °C limits growth to 57–58 μm [2]. These fluctuations also destabilize fat networks, as shown in ice creams with T80 emulsifiers, where fat coalescence dominates the microstructure, creating a network that initially resists meltdown but collapses with repeated thermal cycling [3]. The serum phase’s viscosity plays a critical role in stabilizing the matrix during partial melting. For instance, a 10% increase in serum viscosity reduces ice crystal coarsening rates by 23% at −15 °C [4]. However, in melted ice cream (0 °C), fat destabilization becomes the primary factor influencing rheological behavior, contributing to 68% of the variance in yield stress (σY) [5]. Overrun further modulates these effects: high overrun (>80%) amplifies melt sensitivity in ice crystal-dominated structures, whereas fat network-dominated systems retain shape better but exhibit higher hysteresis losses during thermal stress [6].

In Lebanon, where power outages cause storage temperatures to oscillate between −8 °C and −2 °C, ice cream experiences irreversible phase separation within 12–18 h as serum phase sugars crystallize and air cells coalesce [7]. These dynamics are compounded by lipid oxidation, which increases by 42% for every 5 °C rise above −20 °C, degrading flavor compounds like diacetyl and introducing rancid off-notes [2]. Sensitivities vary by formulation: gelato (lower fat) requires tighter temperature control (−12 °C to −14 °C) to prevent structural collapse compared to high-fat ice creams (−18 °C to −20 °C) [4]. Mitigation strategies proposed for Lebanon include integrating polyphenol-rich apple pomace extracts, which reduce ice crystal growth rates by 31% through hydrogen bonding with serum proteins while simultaneously enhancing melt resistance via fat network reinforcement [1,3].

Lebanon faces significant challenges in both its electrical and agricultural sectors. With the country’s severe electricity crisis leaving many areas with less than 8 h of power daily [7], maintaining proper cold chain conditions becomes extremely difficult. Simultaneously, Lebanon’s apple industry, which represents 23% of total fruit output and 20% of agricultural exports [8,9], experiences substantial losses across the supply chain. Harvest losses can reach up to 8%, while postharvest losses range from 25% to 28%, primarily due to inadequate handling practices and storage facilities [8,9].

The growing consumer preference for natural ingredients has stimulated research into plant-derived alternatives to synthetic stabilizers [10]. Apple polyphenols have emerged as promising candidates due to their functional properties, potential health benefits, and natural origin. These bioactive compounds—representing a diverse group of secondary metabolites including flavanols, hydroxycinnamic acids, flavonols, and dihydrochalcones—demonstrate remarkable variability across apple varieties and tissues, with indigenous varieties often containing elevated concentrations compared to commercial cultivars [11].

Recent research has revealed that apple polyphenols can interact with ice cream components, particularly proteins and fats, to create structures that enhance stability and modify melting behavior [10]. These natural compounds appear to function through mechanisms including protein-mediated fat clumping, increased viscosity, and enhanced water binding, potentially offering dual functionality as both stabilizers and bioactive ingredients. Studies with similar plant-derived polyphenols have demonstrated significant improvements in ice cream melting resistance, shape retention, and textural properties [12,13].

However, a comprehensive polyphenolic characterization of indigenous and heritage apple varieties remains severely limited in the literature. Most studies focus on commercial cultivars, creating a significant knowledge gap regarding the functional potential of traditional varieties like Lebanese Malus trilobata.

Recent breakthrough research at University of Wisconsin-Madison [14] confirmed that adding polyphenols to ice cream dramatically slows melting, with treated samples maintaining structural integrity for over four hours at room temperature compared to conventional ice cream that becomes liquid ‘in no time’.

This review aims to provide a comprehensive analysis of the potential application of polyphenols from indigenous Malus species in improving ice cream thermodynamic properties. Specifically, we examine the following:

• The polyphenolic profile of apples, with emphasis on indigenous varieties;
• Extraction methodologies for apple polyphenols, evaluating efficiency, yield, and compound preservation;
• Mechanisms by which polyphenols interact with ice cream components to enhance stability;
• Sensory implications and consumer acceptance considerations;
• Potential health benefits of apple polyphenols as a value-added aspect;
• Technical challenges and future research directions.

The development of ice cream formulations stabilized with indigenous apple polyphenols represents a promising approach to address both technical challenges in frozen dairy products and evolving consumer preferences for natural ingredients, while potentially creating added value from agricultural by-products.

2. Polyphenolic Profile of Apples

2.1. Classification and Distribution of Apple Polyphenols

Apples (Malus domestica) contain a diverse array of polyphenolic compounds that vary significantly in concentration and distribution across different apple tissues and varieties. These compounds can be classified into several major groups:

• Flavanols (Flavan-3-ols): Constituting 60–65% of total phenolic content, this group includes catechins, epicatechins, and procyanidins (oligomeric forms). Flavanols represent the predominant class of polyphenols in most apple varieties [15].
• Phenolic Acids: Accounting for 30–35% of total phenolics, this group is primarily represented by hydroxycinnamic acids, with chlorogenic acid being the most abundant. Other phenolic acids include caffeic acid, p-coumaric acid, ferulic acid, and neochlorogenic acid [15].
• Dihydrochalcones: Contributing 5–10% of total phenolic content, this group includes phloridzin and its derivatives, which are relatively unique to apples and closely related species [15].
• Flavonols: These compounds, particularly quercetin glycosides, are present primarily in apple peel tissues and contribute to the antioxidant capacity of apples.
• Anthocyanins: Found exclusively in red-skinned varieties, anthocyanins contribute to the red coloration and represent approximately 1% of total polyphenols in colored varieties.

The thermodynamic properties of polyphenolic compounds significantly influence their distribution across different apple tissues during storage and processing. These compounds vary markedly across different apple tissues, with comprehensive studies showing that apple peels consistently contain substantially higher polyphenol concentrations (401.6–952.9 μg/g fresh weight) compared to flesh (202.5–423.5 μg/g fresh weight) and the core (368.6–684.0 μg/g fresh weight) [16]. This tissue-specific distribution has important implications for extraction strategies, particularly when utilizing apple processing by-products like pomace, which typically contains significant amounts of peel material.

Specific polyphenolic compounds also demonstrate distinctive tissue distribution patterns. Chlorogenic acid dominates in the core section of many apple varieties, representing between 3.08% and 45.46% of total phenolic content, with concentrations ranging from 21.49 to 389.68 μg/g fresh weight. In apple pulp, chlorogenic acid concentrations range from 25.37 to 215.06 μg/g fresh weight, comprising 14.86–75.47% of total polyphenols. Peel tissue contains chlorogenic acid in concentrations of 16.80–234.57 μg/g fresh weight, accounting for 4.51–50.08% of total phenolics [16].

Flavonols, particularly quercetin derivatives, show another distinctive tissue distribution pattern. Quercetin-3-O-galactoside is especially abundant in apple cores (71.48–202.44 μg/g fresh weight; 9.90–22.19% of total polyphenols) while occurring at lower concentrations in pulp (12.24–30.20 μg/g fresh weight; 6.15–13.58% of total) and peels (37.16–114.04 μg/g fresh weight; 7.56–18.25% of total) [16].

Characterizing exact polyphenol profiles enables the prediction of functional performance in ice cream applications. Specific compounds like chlorogenic acid demonstrate different stabilization mechanisms than procyanidins, requiring targeted extraction strategies for optimal ice cream matrix interactions [17].

2.2. Varietal Differences in Polyphenolic Composition

The polyphenolic composition and concentration in apples exhibit remarkable variability across different cultivars, representing a critical factor in their potential applications and bioactive properties. These variations result from the genetic regulation of phenylpropanoid pathway enzymes, environmental adaptation responses, and historical breeding selections that emphasized different agronomic traits over polyphenol content. Comprehensive evaluations of European apple cultivars have revealed that the total polyphenol content can range dramatically from 49 mg to 377 mg catechin equivalents per 100 g fresh weight, demonstrating the profound impact of genetic factors on polyphenol accumulation [11].

Research examining 67 apple varieties found total polyphenol levels ranging from 523.02 to 2723.96 mg/100 g dry weight, further highlighting the extensive range of polyphenol concentrations across different varieties. Beyond quantitative differences, qualitative variations in polyphenolic profiles enable the classification of apple cultivars into distinct categories based on their predominant compounds—specifically, whether they are flavan-3-ol predominant or phenolic acid predominant [11].

Interestingly, comparative studies between old and new varieties have revealed that newer cultivars like Ozark Gold, Julyred, and Jester may contain equivalent or even higher levels of bioactive compounds compared to traditional varieties such as Golden Delicious, Idared, and Jonagold. These findings challenge the assumption that modern breeding programs, which often prioritize traits like yield and appearance, necessarily result in reduced phytochemical content [11].

Indigenous varieties like Malus trilobata potentially contain elevated polyphenol concentrations compared to commercial cultivars, as shown in

Table 1. Phenolic content of the Malus trilobata variety [18].

Phenolic Compound	Quantity (μg/g)
Chlorogenic acid	2388
Epicatechin	2036
Rutin	980
Protocatechuic acid	89.9

, though rigorous comparative data remains scarce. This data scarcity represents a significant limitation for evaluating their functional food potential. This varietal diversity represents an opportunity for selecting optimal sources for polyphenol extraction in functional food applications. The Lebanese agricultural sector, with its diverse apple cultivation, offers potential for utilizing indigenous Malus species for this purpose [14].

Significant variation exists between apple genotypes, with studies documenting more than ten-fold differences in compound abundances between apples with the highest and lowest phenolic contents. This remarkable range underscores the potential for breeding programs targeting enhanced polyphenol profiles. Research has established strong correlations between total phenolic content and antioxidant capacity, with the ABTS method showing the strongest correlation (r = 0.871), followed by the FRAP (r = 0.839) and DPPH methods (r = 0.804).

Understanding these varietal differences is crucial for selecting appropriate apple cultivars for specific extraction purposes and targeted applications, particularly when considering their potential use in functional food systems like ice cream.

Despite this extensive varietal screening, systematic polyphenolic profiling of indigenous Middle Eastern varieties remains notably absent from the literature. Specifically, Lebanese Malus trilobata and other regional heritage cultivars lack comprehensive phytochemical characterization, representing a critical research gap.

2.3. Environmental and Postharvest Factors Affecting Polyphenolic Content

Environmental optimization is crucial for maximizing polyphenol extraction yields from indigenous varieties. Understanding these factors enables the selection of optimal harvest timing and processing conditions for ice cream stabilization applications. While genetic factors largely determine the baseline polyphenolic profile of apple varieties, environmental conditions and postharvest handling significantly influence the final concentration and composition of these compounds. Several key factors have been identified:

• Light exposure: Light intensity and quality affect the synthesis of certain phenolic compounds, particularly anthocyanins and flavonols, in apple peels. Higher sun exposure typically results in increased phenolic content, especially in the peel tissue [15].
• Temperature stress: Both cold and heat stress can trigger increased polyphenol production as part of the plant’s adaptive response to environmental challenges. Apples grown in regions with greater temperature fluctuations may develop higher polyphenol concentrations.
• Soil composition: Mineral availability in the soil impacts enzyme activity involved in the phenylpropanoid pathway, which is responsible for polyphenol synthesis. Soil composition therefore affects both the quantity and profile of polyphenols [15].
• Water availability: Water stress typically increases polyphenol production in apples, though extreme drought conditions may ultimately reduce overall biosynthetic capacity.
• Maturity at harvest: Polyphenol content generally decreases during apple ripening, though the changes are compound-specific. Procyanidins and flavanols tend to decrease more substantially than phenolic acids during maturation.
• Storage conditions: Postharvest storage affects polyphenol stability, with different classes showing varied degradation rates. Low-temperature storage generally preserves polyphenols better, though some compounds, particularly flavanols, still show significant decreases during long-term storage [19].
• Processing methods: Common processing techniques can significantly impact polyphenol content. Pressing for juice extraction removes a substantial portion of polyphenols with the pomace, while thermal processing can lead to the degradation of heat-sensitive compounds.

These factors have important implications for maximizing polyphenol content in extraction processes. For applications in ice cream stabilization, identifying optimal harvest timing, selecting appropriate storage conditions, and utilizing processing methods that preserve key polyphenols would be crucial for ensuring maximal functional benefits.

3. Extraction Methods for Apple Polyphenols

The extraction of polyphenols from apple tissues requires careful consideration of numerous factors including solvent selection, processing conditions, and the specific apple matrix being utilized. Various extraction methods have been developed, each with distinct advantages and limitations for recovering these valuable compounds.

3.1. Conventional Extraction Techniques

3.1.1. Maceration

Maceration represents one of the oldest and simplest extraction methods for recovering polyphenols from plant materials. The process involves soaking ground apple material in a selected solvent under controlled conditions, allowing diffusion-based mass transfer to extract the target compounds [20].

The typical maceration procedure involves preliminary processing through drying at 30–40 °C and grinding to 0.5–2 mm particle sizes, followed by mixing with extraction solvent at solid-to-liquid ratios from 1:10 to 1:20. The process continues with agitation in water baths at controlled temperatures for 24–72 h, then filtration, concentration via rotary evaporation, and refrigerated storage in amber glass containers.

While maceration offers the advantages of simplicity and minimal equipment requirements, it suffers from several drawbacks, including extended processing times, high solvent consumption, batch-to-batch variations, and the potential oxidative degradation of sensitive phenolic compounds during the lengthy extraction period [20,21].

3.1.2. Percolation

Percolation employs a continuous flow approach where solvent passes through a stationary bed of plant material. For apple polyphenol extraction, a cone-shaped percolator is filled with ground apple tissue, and solvent (water or ethanol–water mixtures) is allowed to flow through the material under gravity, typically at rates of 1–3 mL/min [22].

Key parameters affecting percolation efficiency include:

• Particle size distribution and uniformity;
• Bed height-to-diameter ratio (typically from 3:1 to 5:1);
• Flow rate control;
• Solvent selection and concentration.

Percolation offers improved solvent economy compared to maceration but generally yields lower polyphenol recovery. The technique is also time-consuming, typically requiring 24–48 h for complete extraction, and presents challenges for industrial scaling due to flow channeling issues and packing requirements [22].

3.2. Non-Conventional Extraction Techniques

3.2.1. Ultrasound-Assisted Extraction (UAE)

Ultrasound-assisted extraction has emerged as one of the most promising techniques for improving efficiency in polyphenol recovery from apple tissues. The method employs high-intensity ultrasonic waves (20–100 kHz) to enhance mass transfer through a phenomenon called cavitation: the formation, growth, and collapse of microbubbles in the extraction medium [22].

The cavitation process generates several effects that enhance extraction:

• The physical disruption of cell walls through microjet formation;
• Improved solvent penetration into the plant matrix;
• Enhanced mass transfer rates due to turbulent mixing;
• Localized heating that increases the solubility of target compounds.

The optimization of UAE for apple polyphenols typically focuses on several key parameters [23]:

• Frequency (typically 20–40 kHz for optimal cavitation effects);
• Power density (10–100 W/cm², with higher values increasing extraction efficiency but potentially causing degradation);
• Temperature (30–60 °C, as higher temperatures reduce cavitation intensity);
• Processing time (10–60 min, with diminishing returns beyond this range);
• Solvent composition (ethanol–water mixtures of 50–80% typically yield best results).

Comparative studies have demonstrated that UAE can increase polyphenol yields by 20–35% while reducing extraction time by 70–90% compared to conventional methods. The technique is particularly effective for recovering compounds from apple peel tissues, where the ultrasonic waves help disrupt the waxy cuticle that can impede solvent penetration [22,24].

3.2.2. Microwave-Assisted Extraction (MAE)

Microwave-assisted extraction utilizes electromagnetic energy (300 MHz to 300 GHz) to generate rapid and volumetric heating of the extraction mixture. Unlike conventional heating methods that rely on conductive heat transfer, microwaves penetrate the sample and directly interact with polar molecules, particularly water, within plant cells [24].

For apple polyphenol extraction, MAE offers several advantages:

• Significantly reduced extraction times (1–30 min versus hours for conventional methods);
• Lower solvent consumption;
• Higher extraction yields for certain compound classes;
• Rapid heating that disrupts cell structures through internal pressure generation.

Critical parameters for MAE optimization include the following:

• Power level (typically 400–800 W, with higher power accelerating extraction but potentially causing degradation);
• Temperature (50–150 °C, with optimal conditions depending on target compounds);
• Solvent selection (water–ethanol mixtures are particularly effective due to their high dielectric constants);
• Solid-to-liquid ratio (typically 1:10 to 1:20).

Research demonstrates that MAE can reduce extraction time by 90–95% compared to conventional techniques while achieving similar or higher yields. However, concerns regarding the thermal degradation of sensitive phenolic compounds, particularly at high power levels or extended durations, must be carefully managed [24].

3.2.3. Enzyme-Assisted Extraction (EAE)

Enzyme-assisted extraction employs specific enzymes to degrade plant cell wall components, facilitating the release of polyphenols trapped within cellular structures. For apple tissues, enzymes such as cellulases, pectinases, and hemicellulases are commonly used to target different structural components [25].

The EAE process typically involves the following:

• Sample preparation (often without drying to preserve enzyme activity);
• pH adjustment for optimal enzymatic activity (usually 4.0–6.0);
• The addition of enzymes (0.5–5% w/w);
• Incubation at the optimal temperature (30–50 °C for 1–24 h);
• Enzyme inactivation (by heating or pH adjustment);
• Extraction with the appropriate solvent.

Studies have shown that pectinase treatment can increase polyphenol yields from apple pomace by 24–32% compared to conventional extraction. Additionally, enzyme pre-treatment alters the polyphenolic profile, enhancing the extraction of compounds typically bound to cell wall materials, such as procyanidins [25].

While EAE offers advantages such as mild processing conditions, reduced solvent consumption, and potentially altered compound profiles, challenges with this method include higher costs, longer processing times compared to UAE or MAE, and the need for precise pH and temperature control.

3.3. Comparison of Extraction Methods

Based on an analysis of the literature and evaluation using key criteria including environmental impact, cost, safety, reproducibility, and feasibility, the extraction methods for apple polyphenols can be compared, as shown in

Table 2. Comparative evaluation of extraction methods for apple polyphenols using a 5-point scoring system (1 = poor, 5 = excellent).

Criteria	Ultrasound-Assisted Extraction (UAE)	Microwave-Assisted Extraction (MAE)	Enzyme-Assisted Extraction (EAE)	Maceration	Percolation
Cost	3	3	2	5	4
Environmental impact	4	4	5	2	2
Safety	4	3	5	4	4
Reproducibility	5	5	3	2	2
Feasibility	4	3	3	4	3
Total score	20	18	18	17	15

.

As evident from the comparison, UAE emerges as the optimal extraction method for apple polyphenols, particularly when considering both laboratory-scale research and potential commercial applications. UAE offers an excellent balance between efficiency, yield, compound preservation, and practical feasibility. The high reproducibility of UAE is particularly valuable for ensuring consistent quality in food applications like ice cream stabilization.

3.4. Extraction from Apple Processing By-Products

The recovery of polyphenols from apple processing by-products, particularly apple pomace, represents a sustainable approach to valorizing what would otherwise be considered waste material. Apple pomace—the solid residue remaining after juice extraction—constitutes approximately 25–30% of the original fruit mass and contains significant quantities of valuable polyphenolic compounds, especially from the peel component [16].

Research shows that commercial apple pomace extracted with 80–20% ethanol–water plus 5% acetic acid yields 0.5615 ± 0.007 g total polyphenols per 100 g fresh weight, transforming waste into valuable bioactive compounds [16]. The pomace extract contains chlorogenic acid, phloridzin, quercetin glycosides, epicatechin, caffeic acid, catechin, and rutin, reflecting the original fruit’s polyphenol distribution.

For Lebanese apple production, where postharvest losses can range from 25% to 28% [26], the extraction of polyphenols from processing by-products could transform a waste management challenge into a value-added opportunity while potentially addressing stability issues in locally produced ice cream caused by electricity shortages.

4. Mechanisms of Ice Cream Stabilization by Polyphenols

4.1. Thermodynamic Properties of Ice Cream

The quality and stability of ice cream are fundamentally linked to its thermodynamic properties, which govern how the product responds to temperature changes during storage, distribution, and consumption. Understanding these properties is essential for elucidating how polyphenols might enhance stability [17].

Ice cream represents a complex frozen food matrix consisting of several structural components: fat globules (10–16%), ice crystals (30–35%), air cells (variable, depending on overrun), and an unfrozen serum phase containing high molecular weight polysaccharides, mineral salts, proteins, and water [1,27]. The interactions between these components determine the product’s response to temperature fluctuations.

Key thermodynamic aspects of ice cream include [17]:

• Freezing point depression: The freezing point of an ice cream mix varies with its composition; it is primarily influenced by sugars, while milk solids and whey solids play a minor role. Typically, the initial freezing point ranges from −2.2 °C to −2.8 °C, with freezing occurring progressively as temperature decreases [28].
• Ice crystal formation: During freezing, ice crystals form when the temperature drops below the freezing point of the mix. The initial nucleation temperature typically ranges from −5 °C to −8 °C, with optimal crystal sizes ranging from 20–50 μm for a smooth texture [28]. Temperature fluctuations during storage cause recrystallization, with smaller crystals melting and water refreezing onto larger crystals, leading to perceived textural deterioration.
• Melting behavior: Melting starts on the outside and progresses inward as heat penetrates. The melting rate is influenced by several factors, with fat destabilization having the greatest impact because it forms clumps and chains that support air cells, resulting in a fat network that increases resistance to serum phase flow when ice melts [29].
• Viscosity of unfrozen phase: The consistency coefficient of the unfrozen serum phase significantly affects melting behavior. Higher viscosity indicates greater resistance to flow, resulting in slower melting rates and improved shape retention [29].
• Air cell structure and stability: Overrun, or incorporated air, affects ice cream’s texture and melting behavior. Products with larger overruns typically melt more slowly due to reduced heat transfer efficiency [30].

Understanding these thermodynamic properties provides the foundation for exploring how polyphenols might enhance ice cream stability through modifications to structural elements and phase behavior.

4.2. Polyphenol Interactions with Ice Cream Components

4.2.1. Protein Interactions

Polyphenols don’t prevent ice melting but rather create protein–fat networks that resist the flow of melted ice. As polyphenol concentration increases, viscosity increases through the formation of large protein-polyphenol complexes that cause fat clustering. Figure 1 shows the interaction between proteins and polyphenols.

Polyphenols, particularly higher molecular weight compounds like procyanidins, interact with milk proteins through multiple binding mechanisms:

• Hydrogen bonding: The numerous hydroxyl groups in polyphenols form hydrogen bonds with protein amino acid residues, creating protein–polyphenol complexes.
• Hydrophobic associations: Aromatic rings in polyphenols interact with hydrophobic protein regions, further stabilizing the complexes.
• Covalent binding: Under certain conditions, polyphenols can form covalent bonds with protein nucleophilic sites, particularly those containing thiol or amino groups.

Wicks et al. [31] demonstrated that adding tannic acid (a model polyphenol) to cream increases viscosity and induces gelation at higher concentrations (1.5% and 3%), even when the pH is above the isoelectric point of dairy proteins. This gelation results from tannic acid’s interactions with proteins, leading to aggregation and structural reorganization.

4.2.2. Fat Structuring

Polyphenols appear to promote protein-mediated fat clumping, creating structures that limit serum flow during melting. This mechanism was demonstrated by Wicks [10], who found that tannic acid created protein-fat complexes that enhanced ice cream shape retention during melting.

The polyphenol-induced fat structuring occurs through a complex mechanism involving adsorption of protein-polyphenol complexes at the fat globule interface, which subsequently displaces or modifies existing emulsifiers at the interface. This interfacial modification enables cross-linking between partially coalesced fat globules, creating a strengthened network structure that enhances the ice cream’s resistance to melting and maintains textural integrity under temperature stress.

These effects collectively enhance the structural integrity of the fat network, which plays a crucial role in stabilizing air cells and resisting phase separation during melting.

4.2.3. Viscosity Modification

Polyphenols can significantly increase the viscosity of the unfrozen serum phase in ice cream through the formation of protein–polyphenol complexes that occupy greater hydrodynamic volume than individual components. These complexes create weak gel networks through cross-linking effects while simultaneously enhancing water binding capacity, resulting in increased resistance to flow and improved structural stability of the ice cream matrix.

Bilbao-Sainz et al. [13] reported that viscosity, measured by the consistency index (K), was twice as high in strawberry polyphenol-containing ice cream samples compared to controls. This increased viscosity contributes to slower melting rates and improved shape retention at ambient temperatures.

4.2.4. Water Binding Effects

Polyphenols contain numerous hydroxyl groups capable of hydrogen bonding with water molecules. This interaction may reduce water mobility in the unfrozen phase, decrease the rate of water migration during temperature fluctuations, and potentially inhibit ice crystal growth during storage, thereby enhancing the overall stability and quality retention of the ice cream product [32,33].

These water binding effects could be particularly valuable for maintaining product quality during storage, especially under conditions of temperature abuse that commonly occur in regions with unreliable refrigeration infrastructure.

In fact, polyphenols extracted from indigenous Malus species will demonstrate superior stabilization performance compared to conventional synthetic stabilizers in ice cream formulations, particularly under temperature-stressed conditions typical of regions with unreliable cold chain infrastructure. Specifically, apple polyphenols will be able to achieve the following:

• Reduce ice crystal growth rates by ≥25% compared to untreated controls;
• Enhance melting resistance equivalent to or exceeding commercial stabilizers (carrageenan, guar gum);
• Provide dual functionality as both stabilizers and bioactive compounds;
• Offer sustainable alternatives derived from agricultural waste streams.

Table 3. Comparative synthesis table between conventional vs. polyphenol stabilizers.

Parameter	Synthetic Stabilizers	Apple Polyphenols	Technological Gap Addressed	References
Mechanism	Physical thickening, water binding	Protein–fat network formation, hydrogen bonding	Multifunctional approach vs. single-mode action	[1,3,10,30]
Stability range	−18 °C to −12 °C optimal	Potentially effective −8 °C to −2 °C	Enhanced temperature abuse tolerance	[2,5,8]
Melting resistance	Moderate (varies by type)	Up to 31% improvement demonstrated	Superior performance under stress conditions	[1,3,12,13]
Health benefits	None/minimal	Antioxidant, cardiovascular protection	Added nutritional value	[11,34,35]
Clean label appeal	Low (E-numbers)	High (natural origin)	Consumer preference alignment	[10,26,36]
Cost	$2–5/kg	Estimated $8–15/kg *	Value justified by multifunctionality	[16,25]
Sustainability	Petroleum/synthetic origin	Agricultural waste valorization	Circular economy integration	[16,26,37]
Regulatory status	Established (E407, E412)	GRAS potential **	Natural ingredient advantage	[10,38]

*: estimated according to current prices. **: Apple polyphenols are Generally Recognized as Safe.

represents a comparative synthesis table between conventional vs. polyphenol stabilizers to show the added value of the use of polyphenols in ice cream across eight key parameters.

Table 4. Quantitative dose–response relationships for polyphenols in ice cream systems.

Polyphenol Source	Concentration	Quantitative Effect	Measurement Condition	References
Temperature Effects
General ice cream	Storage at −18 °C	Ice crystal size: 40.3 μm → 100.1 μm (52 weeks)	Commercial storage conditions	[2]
General ice cream	Storage at −50 °C	Ice crystal size: limited to 57–58 μm (52 weeks)	Controlled storage conditions	[2]
Viscosity and Stabilization
General serum phase	10% viscosity increase	23% reduction in ice crystal coarsening rates	At −15 °C	[4]
Apple pomace extract	0.5615 ± 0.007 g/100 g FW	Total polyphenol content in commercial pomace	80–20% ethanol–water extraction	[16]
Apple pomace extract	Not specified	31% reduction in ice crystal growth rates	Through hydrogen bonding mechanism	[1,3]
Fat destabilization	N/A	Contributes 68% of variance in yield stress (σY)	In melted ice cream at 0 °C	[5]
Specific Polyphenol Concentrations
Tannic acid	0.75% (w/w)	Progressive increase in complex viscosity	In cream system	[10,30]
Tannic acid	1.5% (w/w)	Gelation effects observed	Above protein isoelectric point	[10,30]
Tannic acid	3.0% (w/w)	Maximum gelation and viscosity	Concentrated system	[10,30]
Melting Resistance
Barberry anthocyanins (copigmented)	5.0%	Melting start time: 18.30 → 30.52 min	Room temperature conditions	[12]
Strawberry polyphenols	Not specified	Two-fold increase in consistency index (K)	Compared to control samples	[13]
Apple peel polyphenol extract	Variable	Enhanced hardness and reduced melting rate	In yogurt ice cream	[39]
Tissue-Specific Polyphenol Content
Apple peel	N/A	401.6–952.9 μg/g fresh weight	Various apple varieties	[16]
Apple flesh	N/A	202.5–423.5 μg/g fresh weight	Various apple varieties	[16]
Apple core	N/A	368.6–684.0 μg/g fresh weight	Various apple varieties	[16]
Individual Compound Concentrations
Chlorogenic acid (core)	Variable	21.49–389.68 μg/g FW (3.08–45.46% total phenolics)	Different apple varieties	[16]
Chlorogenic acid (pulp)	Variable	25.37–215.06 μg/g FW (14.86–75.47% total phenolics)	Different apple varieties	[16]
Quercetin-3-O-galactoside (core)	Variable	71.48–202.44 μg/g FW (9.90–22.19% total phenolics)	Different apple varieties	[16]
Extraction Optimization
UAE vs. conventional	N/A	20–35% increase in polyphenol yields	70–90% reduction in extraction time	[22,24]
MAE vs. conventional	N/A	Similar or higher yields	90–95% reduction in extraction time	[24]
Enzyme-assisted (pectinase)	0.5–5% w/w	24–32% increase in polyphenol yields	From apple pomace	[25]

FW = Fresh Weight. UAE = Ultrasound-Assisted Extraction. MAE = Microwave-Assisted Extraction. N/A = Not applicable or concentration not specified in original study.

represents the quantitative dose–response relationships for polyphenols in ice cream systems.

4.2.5. Quantitative Performance Metrics

Recent studies provide specific concentration–effect relationships. Polyphenol concentrations of 0.5% provide minimal improvements (10–15% melting resistance), while 1.0–2.5% concentrations achieve significant stabilization (25–40% improvement) with acceptable sensory properties. Concentrations exceeding 3.0% maximize functional effects but risk sensory acceptance issues.

• Concentration–Effect Relationships:
  • 0.5% polyphenols: Minimal melting resistance improvement (~10–15%);
  • 1.0–2.5% polyphenols: Significant melting resistance (25–40% improvement);
  • >3.0% polyphenols: Maximum effect but potential sensory issues.

4.3. Evidence of Stabilization in Frozen Desserts

Several studies provide evidence supporting the stabilizing effects of plant-derived polyphenols in frozen dessert systems:

• Apple peel polyphenol extract (APPE): Ahmad et al. [30] reported that APPE in yogurt ice cream increased acidity, lowered melting rate, and improved overrun. The fortified samples exhibited greater hardness compared to controls and demonstrated enhanced sensory properties.
• Strawberry polyphenols: Researchers at Japan’s Biotherapy Development Research Center developed melt-resistant ice cream using strawberry polyphenol extract. This ice cream could maintain its shape and remain stable at room temperature, likely due to interactions between phenolic compounds and milk proteins [12].
• Barberry anthocyanins: Dara et al. [11] studied the impact of copigmented and unpigmented barberry anthocyanins on ice cream properties. Higher anthocyanin levels improved firmness, consistency, and melting resistance by stabilizing milk protein networks. Ice cream with 5% copigmented anthocyanins exhibited better melting stability, with melting start times increasing from 18.30 min in the control to 30.52 min.

These findings collectively demonstrate that various plant-derived polyphenols can significantly improve ice cream stability through multiple mechanisms. The effects appear consistent across different polyphenol sources, suggesting that indigenous apple varieties rich in these compounds could provide similar benefits for ice cream stabilization.

Table 5. Comprehensive study comparison matrix.

Study	Polyphenol Source	Concentration	Key Findings	Melting Improvement	Limitations
[31]	Apple peel extract	0.5–2%	↓ melting rate, ↑ overrun	15–25%	Limited temperature range
[11]	Barberry anthocyanins	1–5%	↑ firmness, ↑ melting resistance	67% (at 5%)	High astringency
[12]	Strawberry polyphenols	1–3%	2× viscosity ↑	30–40%	Color interference
[26]	Tannic acid (model)	0.5–3%	Protein–fat netweork formation	20–35%	Model compound study
[40]	Persimmom puree	5–15%	Natural stabilization	25%	High sugar content

↓ = Decrease. ↑ = Increase.

uses PRISMA-style literature inclusion criteria to show the systematic comparison matrix between the studies that used polyphenols in their dessert systems. The inclusion criteria were based on:

• Peer-reviewed articles (2015–2025);
• Studies on polyphenol–ice cream interactions;
• Quantitative melting/stability data;
• Temperature range: −20 °C to +25 °C;
• English-language publications.

The exclusion criteria were as follows:

• Conference abstracts only;
• Studies without quantitative data;
• Non-dairy frozen desserts only;
• Studies focusing solely on color/flavor.

5. Potential Health Benefits of Apple Polyphenols

While the primary focus of this review is on the functional properties of apple polyphenols for ice cream stabilization, these compounds also offer potential health benefits that could provide added value to fortified products.

5.1. Antioxidant Activity

Apple polyphenols are renowned for their potent antioxidant activities, which form the basis for many of their potential health benefits. These compounds can neutralize reactive oxygen species through several mechanisms [41]:

• Free radical scavenging: Apple polyphenols readily donate hydrogen atoms to neutralize free radicals, with the resulting polyphenol radicals stabilized through resonance delocalization.
• Metal chelation: Compounds like quercetin glycosides and chlorogenic acid can chelate transition metals such as iron and copper, preventing their participation in Fenton reactions that generate hydroxyl radicals.
• Enzyme modulation: Apple polyphenols can inhibit enzymes involved in ROS generation, including xanthine oxidase and NADPH oxidase.

The antioxidant capacity of apple extracts correlates strongly with their total polyphenol content, with various assays including ABTS, FRAP, and DPPH demonstrating correlation coefficients of r = 0.871, 0.839, and 0.804, respectively [10].

5.2. Cardiovascular Protection

Epidemiological studies consistently associate apple consumption with reduced cardiovascular disease risk [42]. Several mechanisms have been proposed:

• Cholesterol modulation: Apple polyphenols, particularly procyanidins and phloridzin, may reduce total and LDL cholesterol while increasing HDL cholesterol through the inhibition of HMG-CoA reductase and the modulation of reverse cholesterol transport.
• Anti-inflammatory effects: Apple polyphenols demonstrate anti-inflammatory activity through the inhibition of NF-κB signaling and the reduced expression of inflammatory cytokines including TNF-α, IL−6, and IL-1β.
• Endothelial function improvement: Clinical studies have demonstrated improved flow-mediated dilation following apple polyphenol consumption, suggesting enhanced nitric oxide bioavailability and vascular function.
• Platelet aggregation inhibition: Certain apple polyphenols, particularly flavanols, inhibit platelet activation and aggregation, potentially reducing thrombosis risk.

A meta-analysis of prospective cohort studies found that individuals consuming apples regularly had a 22% lower risk of cardiovascular disease compared to those with the lowest consumption levels [39].

5.3. Glycemic Control and Metabolic Effects

Apple polyphenols may beneficially impact glucose metabolism through several mechanisms:

• Carbohydrate digestion modulation: Polyphenols, particularly procyanidins, can inhibit digestive enzymes, including α-amylase and α-glucosidase, slowing carbohydrate digestion and reducing postprandial glucose spikes.
• Glucose transport inhibition: Phloridzin and its derivatives competitively inhibit sodium-glucose transport proteins (SGLTs), reducing intestinal glucose absorption and potentially decreasing postprandial glycemia.
• Insulin signaling enhancement: Certain apple polyphenols may improve insulin sensitivity by activating insulin receptor substrates and downstream signaling pathways, particularly in skeletal muscle and adipose tissue.

Clinical studies have shown modest but significant reductions in postprandial glucose and insulin levels following apple polyphenol supplementation [34]. While these effects are not as pronounced as those of pharmacological interventions, they suggest potential benefits for glycemic control when consumed as part of a balanced diet.

5.4. Gastrointestinal Effects

The interaction between apple polyphenols and gut microbiota has attracted increasing research attention. These compounds influence gastrointestinal health through multiple pathways:

• Prebiotic effects: Unabsorbed apple polyphenols, particularly high molecular weight procyanidins, reach the colon, where they can selectively stimulate beneficial bacteria, including the Bifidobacterium and Lactobacillus species.
• Microbial metabolism: Gut microbes transform apple polyphenols into metabolites with distinct biological activities. For example, chlorogenic acid is converted to caffeic acid and quinic acid, while flavanols undergo C-ring cleavage to produce phenylvaleric acids.
• Anti-pathogenic activity: Several apple polyphenols demonstrate direct antimicrobial effects against gastrointestinal pathogens, including Helicobacter pylori and Escherichia coli O157:H7.

Research indicates that a regular consumption of apple polyphenols may reduce the risk of colorectal cancer, potentially through mechanisms including antioxidant protection, anti-inflammatory effects, and the modulation of cell signaling pathways involved in cancer progression [35].

5.5. Implications for Functional Ice Cream

While ice cream remains an occasional component of balanced diets, the incorporation of apple polyphenols may provide added value beyond stabilization effects. Several considerations are relevant:

• Bioactive concentration: The concentration of polyphenols required for stabilization effects (typically 0.5–3%) likely exceeds levels needed for potential health benefits, potentially enabling dual functionality.
• Matrix effects: The dairy matrix of ice cream may influence polyphenol bioavailability. Milk proteins can bind polyphenols, potentially reducing immediate absorption but providing a controlled release mechanism in the digestive tract.
• Thermal stability: Many apple polyphenols maintain bioactivity following the pasteurization and freezing processes used in ice cream production. Procyanidins and chlorogenic acid derivatives demonstrate good stability under these conditions.
• Target consumer segments: Functional ice cream containing apple polyphenols could appeal to health-conscious consumers seeking indulgent treats with added benefits.

It’s important to emphasize that these potential health benefits represent a complementary aspect to the primary technological function of improving ice cream stability, particularly in challenging cold chain environments.

6. Sensory Considerations and Consumer Acceptance

6.1. Impact of Polyphenols on Sensory Properties

The incorporation of polyphenols into ice cream formulations introduces complex sensory considerations that must be carefully managed to ensure consumer acceptance. Polyphenolic compounds—particularly those with higher molecular weights, such as procyanidins—impart several sensory attributes that can influence the overall perception of the product. These include:

Astringency: Polyphenols often create a tactile sensation of dryness or puckering, which intensifies with increasing molecular weight. This is particularly evident in tannins and procyanidins, which interact with salivary proteins and influence mouthfeel [26,35].

Bitterness: Flavanols and certain flavonols contribute to bitterness, which may clash with the sweet profile of ice cream unless carefully balanced [26,35].

Color Modifications: Polyphenols can alter the color of ice cream, introducing hues that may either complement or detract from the intended flavor profile. For example, anthocyanins impart vibrant colors while enhancing antioxidant activity [26,35].

Flavor Notes: Polyphenols can add unique aromatic profiles that may enhance or conflict with base flavors depending on their concentration and source [26,35].

Research by Wicks [14,29] demonstrated that polyphenols form protein–polyphenol complexes in ice cream, enhancing viscosity and slowing melting rates but also introducing sensory challenges like astringency and bitterness. Bolling & Hartel [35] observed similar effects in experiments with tannic acid-enriched ice cream samples, where the fat–protein–polyphenol network significantly improved viscosity and structural integrity while altering flavor profiles. Additionally, studies on strawberry popsicles fortified with polyphenols revealed enhanced melting resistance due to stabilizing effects on fat–water networks [35]. Finding the right compromise between the functional benefits of different concentrations with sensory acceptance remains critical.

6.2. Strategies for Sensory Optimization

• Variety Selection

Choosing apple varieties with polyphenolic profiles optimized for minimal sensory interference is critical. For instance, Bolling & Hartel [35] demonstrated that low-tannin apple cultivars (e.g., Fuji or Gala) exhibit reduced astringency while retaining functional benefits. Their study found that procyanidin B2-rich extracts from specific cultivars improved melt resistance without exceeding bitterness thresholds. Wicks [26] further validated this by showing that polyphenol-rich Granny Smith extracts require < 3% concentration to avoid sensory overload, whereas sweeter varieties tolerate higher doses.

2.

Extraction Optimization

Adjusting extraction parameters can selectively recover compounds with minimal sensory impact. Ahmad et al. [31] used ethanol–water (70:30) extraction at 50 °C to isolate apple peel polyphenols with balanced bioactivity and reduced bitterness. Rathnakumar et al. [3] emphasized ultrasound-assisted extraction, which increases yields of low-molecular-weight polyphenols (e.g., phloridzin) that impart less astringency compared to polymeric tannins. Microencapsulation (as reviewed in Sharma et al. [40]) further masks bitterness by embedding polyphenols in maltodextrin or gum arabic matrices, delaying their release in the oral cavity.

3.

Complementary Flavoring

Stronger flavors like chocolate or caramel can mask polyphenol-derived notes. Dara et al. [11] demonstrated that barberry anthocyanins paired with chocolate base flavors reduced perceived bitterness by 40% in sensory panels. Similarly, persimmon-enriched ice cream [36] showed improved acceptance when combined with cinnamon or vanilla, leveraging flavor synergy to counteract astringency. Wicks [26] noted that caramelized sugar interacts with polyphenols to create Maillard reaction products that neutralize metallic off-notes.

4.

Sweetness Modulation

Increasing sweetness can mask bitterness but requires nutritional balance. Bolling & Hartel [35] achieved a 15% sweetness increase using stevia–maltitol blends, which offset bitterness without adding calories. Ahmad et al. [31] found that honey-based formulations enhanced flavor complexity while providing natural sweetness to mask apple polyphenol astringency. However, excessive sweetness risks overpowering delicate fruit notes, necessitating precise titration.

5.

pH Adjustment

Slight pH modifications alter polyphenol interactions and sensory perception. Rathnakumar et al. [3] showed that raising pH from 6.2 to 6.8 reduced astringency by weakening polyphenol–protein binding. Conversely, acidic conditions (pH 5.5) in lemon-flavored ice cream enhanced the bright, fruity notes of apple polyphenols while minimizing bitterness [40].

6.3. Consumer Acceptance Considerations

The consumer acceptance of novel food ingredients, such as apple polyphenols in ice cream formulations, is influenced by multiple factors beyond direct sensory perception. Clean-label perceptions are critical, as consumers often associate natural, plant-derived ingredients with healthiness and environmental sustainability. For instance, Karaman et al. [40] demonstrated that using fruit-based additives like persimmon puree in ice cream formulations aligns with consumer preferences for ecological and nutrient-rich products. Similarly, Scheibenzuber et al. [38] emphasized that consumers value products derived from food industry by-products due to their contribution to reducing food waste and promoting sustainability. The health halo effect also plays a significant role in driving consumer acceptance. Polyphenols are widely recognized for their antioxidant and anti-inflammatory properties, which can positively influence consumer attitudes even in indulgent categories like ice cream. According to Laureati et al. [36], emphasizing health benefits increases consumer willingness to adopt novel food products, particularly those enriched with bioactive compounds.

Sustainability messaging further enhances consumer acceptance by appealing to environmentally conscious individuals. Highlighting the use of agricultural by-products to extract polyphenols supports circular economy practices and resonates with consumers who prioritize sustainable food systems [38]. Cultural factors are particularly relevant in regions like Lebanon, where apple production is deeply ingrained in agricultural heritage. Utilizing indigenous apple varieties for polyphenol extraction can strengthen local pride and cultural connections while increasing familiarity with the product. Familiarity is a crucial driver of acceptance, as studies have shown that incorporating novel ingredients into familiar foods significantly reduces neophobia and encourages adoption [36]. Transparent communication about ingredient sourcing and benefits further builds trust among consumers, facilitating gradual exposure to novel ingredients while emphasizing their functional advantages [36,38].

In the following,

Table 6. Standardized quantitative metrics framework for apple polyphenol ice cream evaluation.

Metric Category	Parameter	Measurement Method	Target Range	Reference Standard	Validation Studies
Melting Resistance
Melting rate coefficient	g/min at 22 °C, 50% RH	Weight loss measurement every 5 min for 60 min	0.10–0.25 g/min (control: 0.30–0.45 g/min)	ASTM D3418 modified	[11,12,31,43]
Melting start time	Minutes to first drip	Visual observation at standardized conditions	15–35 min (control: 8–15 min)	Based on [11] methodology	[11]
Shape Retention
Shape retention index	% original shape after 30 min	Digital image analysis	60–85% (control: 30–45%)	Comparative visual scoring	[12,31]
Structural integrity	Time to 50% collapse	Video analysis	25–45 min (control: 10–20 min)	Modified from [35]	[35]
Rheological Properties
Viscosity enhancement ratio	Fold increase vs. control	Rheometer at 4 °C	1.5–3.0× (control: 1.0×)	Consistency index (K) measurement	[12,30]
Yield stress	Pa at 4 °C	Controlled stress rheometry	25–50 Pa (control: 15–25 Pa)	Based on [4] methodology	[4]
Microstructural Analysis
Ice crystal size	μm average diameter	Polarized light microscopy	25–45 μm (control: 35–55 μm)	Image Tool 3.0; UTHSCSA, San Antonio, TX, USA Avizo 2019.4	[2,3]
Fat globule size	μm average diameter	Confocal microscopy	3–8 μm (control: 2–5 μm)	Particle size analyzer	[2,26]
Sensory Thresholds
Astringency detection	Intensity scale 1–9	Trained sensory panel	<3 for acceptability	Triangle test methodology	[26,35]
Bitterness threshold	mg/L equivalent	Chemical analysis + sensory	<150 mg/L tannic acid equiv.	Based on [26] data	[26]
Chemical Composition
Total polyphenol content	mg GAE/100 g product	Folin–Ciocalteu method	50–300 mg GAE/100 g	Standard GAE curve	[10,15]
Individual compounds	μg/g product	HPLC–DAD analysis	Variable by compound	Authentic standards	[15]

will summarize the standardized quantitative metrics framework for apple polyphenol ice cream evaluation.

7. Conclusions

This comprehensive review has examined the potential application of polyphenols derived from indigenous Malus species for improving ice cream thermodynamic properties, with particular relevance to regions facing cold chain challenges such as Lebanon. The evidence presented supports several key conclusions:

• Apple polyphenols represent a complex and diverse group of compounds whose composition and concentration vary significantly across different varieties and tissues. Indigenous varieties often contain elevated polyphenol concentrations compared to commercial cultivars, offering promising sources for extraction.
• Advanced extraction methodologies, particularly ultrasound-assisted extraction (UAE), demonstrate superior efficiency and yield compared to conventional methods while maintaining compound integrity. These techniques can be systematically optimized through the design of experimental approaches to maximize extraction efficiency.
• Polyphenols interact with ice cream components, particularly proteins and fats, through multiple mechanisms, including hydrogen bonding, hydrophobic associations, and potential covalent interactions. These interactions modify the structure and behavior of the frozen dessert matrix, enhancing stability and resistance to melting.
• Studies with various plant polyphenols have demonstrated significant improvements in ice cream stability, including reduced melting rates, enhanced shape retention, and improved textural properties. These findings suggest that indigenous apple polyphenols could provide similar benefits.
• Beyond their functional properties, apple polyphenols offer potential health benefits including antioxidant activity, cardiovascular protection, and glycemic control, potentially adding value to fortified ice cream products.
• Sensory considerations require careful management to balance functional benefits against potential impacts on flavor, astringency, and color. Several strategies including variety selection, flavor complementation, and formulation optimization can address these challenges.
• Significant knowledge gaps remain, particularly regarding compound-specific effects, structure–function relationships, and the specific properties of indigenous Lebanese apple varieties. These gaps present opportunities for future research.
• Current industry context includes these factors:
  • Guar gum and locust bean gum prices increased 7–8x in recent years (2024).
  • Consumer demand for “clean label” alternatives drive polyphenol research.
  • Strawberry polyphenol-based ice cream is already commercialized in Japan (Kanazawa Ice) [44,45,46,47].

The systematic application of indigenous Lebanese apple polyphenols addresses critical unexplored gaps: characterization of Malus trilobata varieties, optimization for temperature-stressed conditions (−8 °C to −2 °C), and integration with agricultural waste valorization.

• Cold chain resilience: Enhanced stability could reduce product losses due to temperature fluctuations, particularly relevant in regions with inconsistent electrical supply.
• Clean label formulation: Natural stabilizers align with consumer preferences for recognizable, plant-derived ingredients.
• Agricultural waste valorization: Utilizing apple processing by-products transforms an environmental challenge into a value-added opportunity, supporting circular economy principles.
• Health benefits: The inherent bioactive properties of polyphenols may provide complementary nutritional advantages beyond technological functionality.
• Local resource utilization: For countries with significant apple production like Lebanon, developing value-added applications for indigenous varieties could support local agricultural practices and reduce dependence on imported stabilizers.

This approach demonstrates how traditional knowledge about indigenous food plants can be combined with modern scientific understanding to develop innovative solutions that are technologically effective, environmentally sustainable, and potentially health-promoting.

A critical limitation identified in this review is the scarcity of comprehensive polyphenolic data for indigenous apple varieties, particularly Middle Eastern species like Lebanese Malus trilobata. This literature gap severely limits our understanding of their potential for functional applications and necessitates urgent systematic characterization studies.

Future research should focus on the systematic characterization of indigenous varieties, optimization of extraction methods, detailed investigation of structure-function relationships, and comprehensive evaluation of product performance under realistic usage conditions. With appropriate development, apple polyphenol-stabilized ice cream holds particular promise for regions facing infrastructure challenges while supporting sustainable agricultural practices.