Search Results (19)

Knowledge about the composition (volatile and non-volatile) and functionality of natural extracts from Mediterranean plants serves as a basis for their further application. In this study, five selected plants were used for the extraction of plant metabolites. Leaves and flowers of Critmum maritimum, Rosmarinus officinalis, Olea europea, Phylliera latifolia and Mellisa officinalis were collected, and a total of 12 extracts were prepared. Extractions were performed under microwave-assisted conditions, with two solvent types: water (W) and a hydroalcoholic (ethanolic) solution (HA). Detailed extract analysis was conducted. Phenolics were analyzed by detecting individual bioactive compounds using high-performance liquid chromatography and by calculating total phenolic and total flavonoid content through spectrophotometric analysis. Higher concentrations of total phenolics and total flavonoids were obtained in the hydroalcoholic extracts, with the significantly highest total phenolic and flavonoid values in the rosemary hydroalcoholic extract (3321.21 mg_GAE/L) and sea fennel flower extract (1794.63 mg_QE/L), respectively; and the lowest phenolics in the water extract of olive leaves (204.55 mg_GAE/L) and flavonoids in the water extracts of sea fennel leaves, rosemary, olive and mock privet (around 100 mg_QE/L). Volatile organic compounds (VOC) were detected using HS-SPME/GC–MS (Headspace Solid-Phase Microextraction coupled with Gas Chromatography-Mass Spectrometry), and antioxidant capacity was estimated using DPPH (2,2-diphenyl-1-picrylhydrazyl assay) and FRAP (Ferric Reducing Antioxidant Power) methods. HS-SPME/GC–MS analysis of samples revealed that sea fennel had more versatile profile, with the presence of 66 and 36 VOCs in W and HA sea fennel leaf extracts, 52 and 25 in W and HA sea fennel flower extracts, 57 in rosemary W and 40 in HA, 20 in olive leaf W and 9 in HA, 27 in W mock privet and 11 in HA, and 35 in lemon balm W and 10 in HA extract. The lowest values of chlorophyll a were observed in sea fennel leaves (2.52 mg/L) and rosemary (2.21 mg/L), and chlorophyll b was lowest in sea fennel leaf and flower (2.47 and 2.25 mg/L, respectively), while the highest was determined in olive (6.62 mg/L). Highest values for antioxidant activity, determined via the FRAP method, were obtained in the HA plant extracts (up to 11,216 mg_AAE/L for lemon balm), excluding the sea fennel leaf (2758 mg_AAE/L) and rosemary (2616 mg_AAE/L). Considering the application of these plants for fresh fish preservation, antimicrobial activity of water extracts was assessed against Vibrio fischeri JCM 18803, Vibrio alginolyticus 3050, Aeromonas hydrophila JCM 1027, Moraxella lacunata JCM 20914 and Yersinia ruckeri JCM 15110. No activity was observed against Y. ruckeri and P. aeruginosa, while the sea fennel leaf showed inhibition against V. fisheri (inhibition zone of 24 mm); sea fennel flower was active against M. lacunata (inhibition zone of 14.5 mm) and A. hydrophila (inhibition zone of 20 mm); and rosemary and lemon balm showed inhibition only against V. fisheri (inhibition zone from 18 to 30 mm). This study supports the preparation of natural extracts from Mediterranean plants using green technology, resulting in extracts rich in polyphenolics with strong antioxidant potential, but with no clear significant antimicrobial efficiency at the tested concentrations. Full article

This study explores the potential of olive leaves, long integral to Mediterranean traditional medicine, as a rich source of valuable compounds. The challenge lies in their considerable water content, hindering these compounds’ full valorization. Four drying methods (air-drying, oven-drying, freeze-drying and solar-drying) were investigated for their impact on nutrient and bioactive compound content in the leaves of four olive varieties (“Arbequina”, “Koroneiki”, “Menara” and “Picholine Marocaine”) cultivated in Morocco. In their fresh state, “Picholine Marocaine” exhibited the highest protein levels (6.11%), “Arbequina” had the highest phenolic content (20.18 mg gallic acid equivalents/g fresh weight (FW)), and “Koroneiki” and “Menara” were highest in flavonoids (3.28 mg quercetin equivalents/g FW). Specific drying methods proved optimal for different varieties. Oven-drying at 60 °C and 70 °C effectively preserved protein, while phenolic content varied with drying conditions. Air-drying and freeze-drying demonstrated effectiveness for flavonoids. In addition, an analytical approach using high-performance liquid chromatography and diode array detection (HPLC-DAD) was applied to investigate the effects of the different drying methods on the bioactive fraction of the analyzed samples. The results showed qualitative and quantitative differences depending on both the variety and the drying method used. A total of 11 phenolic compounds were tentatively identified, with oleuropein being the most abundant in all the samples analyzed. The freeze-dried samples showed the highest content of oleuropein in the varieties “Arbequina” and “Picholine Marocaine” compared to the other methods analyzed. In contrast, “Koroneiki” and “Menara” had higher oleuropein content when air dried. Overall, the obtained results highlight the importance of tailored drying techniques for the preservation of nutrients and bioactive compounds in olive leaves. Full article

Osmotically dehydrated cherry tomatoes and spinach leaves were incorporated into Greek salad-type (including OD-treated and air-dried feta cheese trimmings and air-dried olive rings) and green salad-type (including OD-treated and air-dried feta cheese trimmings and roasted ground peanuts) ready-to-eat (RTE) product prototypes, respectively. The osmotic dehydration of cherry tomatoes and spinach leaves was conducted in a pilot scale setting (100 L) in a 60% glycerol-based solution at 35 °C and 25 °C for 180 min and 60 min, respectively. To quantify the moisture transfer between the three ingredients of different moisture content (and water activity), the moisture equilibrium curves for each ingredient of the RTE product were determined. The equilibrium water activity of RTE products was 0.86 and 0.76, respectively. The quality of the RTE products (more specifically, tomato and spinach color and texture, instrumentally measured and sensorially perceived, sensory characteristics) was evaluated. The shelf life of the prototypes (from 4 °C to 20 °C) was kinetically modeled based on sensory deterioration and microbial growth, using the zero-order kinetic model and the Gompertz model, respectively. In the case of the tomato-based product, a shelf life of 54 days (based on sensory deterioration) was achieved at 4 °C, a shelf-life extension of 40 days compared to untreated, fresh-cut tomato. The shelf life of the spinach-based product (based on sensory deterioration) was 36 days at 4 °C, 30 days longer when compared to untreated spinach. Our results indicate that osmotic dehydration was successful in significantly extending the shelf life of such products, contributing to the increased temperature resilience of their keeping quality and allowing for their distribution and storage in a variable cold chain. Full article

Fresh-cut leafy vegetables are produced in Southern Italy in very intensive crop systems under tunnel greenhouses in which continuous cropping has triggered soil organic carbon (SOC) depletion and the risk of degradation of soil fertility. A two-year trial of soil organic amendment was carried out on a private farm producing baby-leaf crops on a very poor OC soil (<1%). Biowaste compost, two types of olive pomace composts and buffalo manure were compared to evaluate their ability to recover a positive SOC balance and sustain crop growth and yield. The effects on soil health and crop system were studied by measuring different aspects such as SOC stock change and SOC sequestration rate, soil microbial biomass and nine enzyme activities, yields of rocket and concentration of nitrates in leaves. Soil amendments were distributed once a year at doses of 15 and 30 Mg ha⁻¹ as fresh matter without integration of mineral fertilizers. In our study, the SOC stock improved in the amended soils in a range of 4–6 Mg ha⁻¹, except for dose 30 of buffalo manure, with the highest values where biowaste compost was applied. Our data showed an increase in biological parameters in all the amended soils with respect to Control. In soil amended with olive pomace, however, compost mineralization rates likely did not match crops’ nutrient needs so the yields of rocket were lower than with the biowaste compost and buffalo manure. Biowaste compost showed the best results as it balanced the best C conversion efficiency, the higher increment of SOC and yields of rocket. Full article

Coriander is a medicinal and aromatic plant (MAP) traditionally cultivated and used in Alentejo, Portugal. However, few publications are available about its ethnobotanical applications. Four independent ethnobotanical surveys were carried out: throughout the region (2002–2003), in three villages (2013), and in city markets (2007 and 2022). Coriander was the most common fresh cultivated MAP (75% of the total area) and also the most representative MAP fresh herb in city markets. The leaves, mostly, were used fresh or frozen or transformed in piso. Some of the recipes have agro-industrial potential, such as piso and aromatized olive oil. Coriander essential oils (EOs) were isolated by hydrodistillation from aerial parts with inflorescence emergence (APIs) and from fruits, and fatty acids (FA) by solvent extraction from the fruits. Gas chromatography and gas chromatography-mass spectrometry analysis showed EOs dominated by n-decanal (21–24%), 2-trans-decenal (12–18%) and n-nonane (10–17%) in APIs, and linalool dominance (73–78%) in the fruits. Petroselinic acid (32–55%) was the dominant fatty acid. A literature survey on conventional and nonconventional extraction techniques showed a constancy in the dominant compounds isolated, highlighted piso as a home-made green-extraction procedure, but also reflected the relevance of coriander as a MAP with diverse industrial potential uses. Full article

The possibility of enriching the oil produced from Leccino cultivar olive fruits with phenolic and volatile compounds by adding olive leaves (2.5%) during industrial-scale production were investigated. Furthermore, the influence of the addition of leaves on the oil quality, composition, and oxidative stability during storage for 6 and 12 months was studied. A slight negative impact on the oil quality after processing with leaves was determined. The addition of leaves had no influence on the total saturated, monounsaturated, and polyunsaturated fatty acids in oils, while it influenced increases in total phenolic compounds (+29.55%), total secoiridoids (+29.43%), chlorophylls (+47.59%), and the oil stability index (+18.70%), and their higher values were also determined in the stored oils. The addition of leaves increased C5 volatiles (+10.50%) but decreased C6 volatiles (−10.48%). The intensity of most of the positive sensory characteristics increased in fresh oils obtained with leaves, and the established improvements were also maintained in the stored oils. The extractability of olive paste was positively affected by the addition of olive leaves, which increased the oil yield (+27.17%). The obtained results significantly contribute to the knowledge about the possibilities of enriching olive oils with bioactive compounds. Full article

(1) Background: Since 2013, the pathogenic bacterium Xylella fastidiosa has been severely affecting olive production in Apulia, Italy, with consequences for the economy, local culture, landscape and biodiversity. The production of a phenolic extract from fresh olive leaves was employed for endotherapeutic injection into naturally infected olive trees by Xylella fastidiosa in Apulia region, Italy. (2) Methods: The effectiveness of the extract was tested in vitro and in planta in comparison with analogous treatments based on garlic powder and potassium phosphite. (3) Results: The uptake of phenolic compounds from olive leaves through a trunk injection system device resulted in a statistically significant increase in leaf area index and leaf area density, as well as in the growth of newly formed healthy shoots. Plant growth-promoting effects were also observed for potassium phosphite. Moreover, the bacteriostatic activities of the phenolic extract and of the garlic-powder-based solution have been demonstrated in in vitro tests. (4) Conclusions: The results obtained and the contained costs of extraction make the endotherapeutic treatment with phenolic compounds a promising strategy for controlling X fastidiosa to be tested on a larger scale, although the experiments conducted in this study proved not to be suitable for centenary trees. Full article

The proper management of treated agricultural wastes (e.g., composts) contributes to the protection of water and soil quality by reducing the use of chemical fertilizers, lowering leachate, and protecting renewable and nonrenewable resources. Natural zeolites, particularly clinoptilolite, can be used in agriculture to improve soil quality and increase yields due to their unique properties. The objective of the study was to test the effects of the co-addition of compost, zeolite and ammonium-based fertilizer on the Above-ground Fresh Weight (AFW) of lettuce (Lactuca sativa L.), leaf nutrients and soil fertility. To this aim, a soil pot experiment was carried out at the Department of Soil Science of Athens, which is located in the region of Attica, in the area of central Greece. Two levels of olive compost originated from olive leaves (0% and 10% v/v), three levels of zeolite (0%, 2%, and 5% w/w) and two levels of chemical fertilization (no fertilization and NPK fertilization) were combined. Furthermore, two different soils were introduced, one moderately acidic (pH = 5.6) and sandy loam in texture (Ac-LT), and the other slightly alkaline (pH = 7.7) and sandy clay in texture (Al-HT). Results showed that the response of lettuce yield to chemical fertilization and zeolite application is soil type-dependent, whereas compost application significantly improved AFW in both soil types. The availability of macronutrients (P, K, and Na) in the soil, as well as their concentration in leaves, were significantly increased by NPK fertilization in most cases. Conversely, the impact of inorganic fertilization on DTPA extractable micronutrients and leaf micronutrient contents was found to be associated with the type of soil. The study recorded a significant reduction in available Fe, Cu, and Mn in AL-HT soil, whereas DTPA-Mn and -Zn were significantly enhanced in Ac-LT soil. Comparable patterns were also documented for the micronutrient concentration in leaves. In most cases, compost application had significant and beneficial effects on plant nutrients. On the contrary, different responses of soil properties to compost addition were registered. The main effect of compost treatment on soil pH, EC, SOM, total N, and available P was significant and positive in both soil types, except for pH and EC in Al-HT soil. On the other hand, exchangeable K and Na were significantly reduced by compost. Zeolite substantially increased the availability of P, K, and Na in soil and plants, whereas the concentrations of DTPA-extractable micronutrients and leaf macronutrients were largely unaffected. In addition, the results of our study indicated that co-additions of organic and inorganic amendments did not yield any significant impact on the lettuce yield, leaf nutrient content and soil fertility. It is suggested that the degree of changes in main soil properties (e.g., pH, EC, SOM) as a result of amendment application as well as the interaction of the amendments with nutrient availability are strongly related to soil type. Full article

Agri-food industries generate a large amount of waste that offers great revalorization opportunities within the circular economy framework. In recent years, new methodologies for the extraction of compounds with more eco-friendly solvents have been developed, such as the case of natural deep eutectic solvents (NADES). In this study, a methodology for extracting phenolic compounds from olive tree leaves using NADES has been optimized. The conditions established as the optimal rely on a solvent composed of choline chloride and glycerol at a molar ratio of 1:5 with 30% water. The extraction was carried out at 80 °C for 2 h with constant agitation. The extracts obtained have been analyzed by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) in MRM mode. The comparison with conventional ethanol/water extraction has shown that NADES, a more environmentally friendly alternative, has improved extraction efficiency. The main polyphenols identified in the NADES extract were Luteolin-7-O-glucoside, Oleuropein, 3-Hydroxytyrosol, Rutin, and Luteolin at the concentrations of 262, 173, 129, 34, and 29 mg kg⁻¹ fresh weight, respectively. Full article

Olive leaves are generated as by-products in the olive industry and contain substances with biological properties that provide health benefits. Although these compounds have been characterized in many leaves from olive cultivars devoted to olive oil extraction, few data are available on leaves from the processing of table olives. In this study, the concentration of polyphenols, triterpenic acids, sugars and enzymatic activities (polyphenol oxidase, peroxidase, β-glucosidase and esterase) were determined in the leaves of the olive tree (Olea europaea L.) of cvs. Aloreña, Cacereña, Empeltre, Hojiblanca, Manzanilla, Verdial, Gordal and Morona. The mean total phenolic content in olive leaves reached 75.58 g/kg fresh weight, and oleuropein was the main polyphenol identified (89.7–96.5%). The main triterpenic acid identified was oleanolic acid, and the main sugar was mannitol, with mean values of 15.83 and 22.31 g/kg, respectively. However, the content of these biocompounds was influenced by the type of cultivar and the orchards of origin. The highest oleuropein content was found in the Manzanilla variety, while the Gordal had the highest triterpene and mannitol content. In particular, the phenolic content could also be affected by endogenous enzymatic activities. High polyphenol oxidase, peroxidase and β-glucosidase activity and low esterase activity were detected, compared to the fruit. Similar to the phenolic compounds, enzymatic activities varied with the harvesting season. The lowest phenolic content corresponded to the highest polyphenol oxidase activity detected during spring. The rest of the enzymatic activities also varied throughout the year, but no common trend was observed. Full article

Pestalotiod fungi are associated with a wide variety of plants worldwide and occur as endophytes, pathogens, and saprobes. The present study provides an updated phylogeny for genera Neopestalotiopsis, Pestalotiopsis, and Seiridium using fresh collections from woody oil plants (Camellia oleifera, Olea europaea, Paeonia suffruticosa, Sapium sebiferum, and Vernicia fordii) in Sichuan Province, China. We coupled morphology and combined sequence data analyses of ITS, tub2, and tef1-α for Neopestalotiopsis and Pestalotiopsis, with ITS, LSU, tub2, tef1-α, and rpb2 for Seiridium. Three novel species of Neopestalotiopsis (N. mianyangensis, N. paeonia-suffruticosa, N. terricola) and three of Seiridium (S. guangyuanum, S. vernicola, S. oleae), were found. Three other species, Pestalotiopsis kenyana, Seiridium ceratosporum, and S. rosarum were identified and reported as new records. All isolated species are fully described and illustrated. Additionally, the sexual morph of Pestalotiopsis kenyana is described for the first time. Pathogenicity tests revealed that Neopestalotiopsis mianyangensis, N. paeonia-suffruticosa, N. terricola, Pestalotiopsis kenyana, Seiridium guangyuanum, S. vernicola, and S. oleae are pathogenic on detached olive leaves. Full article

Olive leaves (OLL) are reported as a source of valuable antioxidants and as an agricultural by-product/waste. Thus, a twofold objective with multi-level cost and environmental benefits arises for a “green” standalone extraction technology. This study evaluates the OLL waste valorization through maximizing OLL extracts polyphenol concentration utilizing an emerging “green” non-thermal technology, Pulsed Electric Field (PEF). It also provides further insight into the PEF assistance span for static solid-liquid extraction of OLL by choosing and fine-tuning important PEF parameters such as the extraction chamber geometry, electric field strength, pulse duration, pulse period (and frequency), and extraction duration. The produced extracts were evaluated via comparison amongst them and against extracts obtained without the application of PEF. The Folin-Ciocalteu method, high-performance liquid chromatography, and differential scanning calorimetry were used to determine the extraction efficiency. The optimal PEF contribution on the total polyphenols extractability (38% increase with a 117% increase for specific metabolites) was presented for rectangular extraction chamber, 25% v/v ethanol:water solvent, pulse duration (t_pulse) 2 μs, electric field strength (E) 0.85 kV cm⁻¹, 100 μs period (Τ), and 15 min extraction duration (t_extraction), ascertaining a significant dependence of PEF assisting extraction performance to the parameters chosen. Full article

A new Galeommatid bivalve is described for the Mediterranean Sea, tentatively assigned to the elusive genus Draculamya Oliver and Lützen, 2011. “Draculamya” uraniae n. sp is described upon a number of dead but fresh and articulated specimens, plus many loose valves. Its distribution is almost basin-wide in the Mediterranean, and it possibly occurs in the adjacent Gulf of Cadiz. As for many members in Galeommatida, we hypothesize that “Draculamya” uraniae lives as commensal upon a still-unknown host. The possible co-identity of the extant genus Draculamya with the morphologically similar Pliocene Glibertia Van der Meulen, 1951, is discussed, although the lack of anatomical and genetic support leaves the problem open. Full article

In recent years, soil addition with organic amendments, such as biochar and compost, has gained attention as an effective agronomic practice to sustain soil fertility, enhance plant growth and crop yield. Well known are the positive effects of compost on yield of a wide crop varieties, while both positive and negative responses are reported for biochar Therefore, the aim of the study was to verify the effect of biochar mixed with three types of compost on quanti-qualitative response of Swiss chard (Beta vulgaris L. cycla), a leafy green vegetable rich in dietary antioxidants, largely consumed worldwide. A factorial experiment in pots with two factors, including biochar (without biochar and with biochar from vine pruning residues) and compost (without compost, with compost from olive pomace, with vermicompost from cattle manure, and with compost from cattle anaerobic digestate), was setup. Two growth cycles were considered, and a set of quantitative (height of plants, number, area and fresh weight of leaves) and qualitative parameters (carotenoids, chlorophyll, total N, and NO₃⁻content of leaves) were analyzed. Biochar decreased plant growth and NO₃⁻ leaf content; on the contrary, it increased total N leaf content, while compost improved all the considered parameters. The interactive effect of biochar and compost was evident only on total N and NO₃⁻ leaf content. In our experimental conditions, the compost showed to be the best option to improve Swiss chard growth and increase the content of phytopigments, while the biochar-compost mixtures did not produce the expected effect. Full article

Consumers are interested in consuming clean label foods. Replacing synthetic additives with natural alternatives (especially sources rich in polyphenols) is a valid solution to produce and also preserve foods, especially meat and meat products. Olea europaea leaves and olive pomace and wastewater contain polyphenols that can be explored in this context. In this review, we summarize the main aspects related to the phenolic composition, extraction conditions, antimicrobial potential, and antioxidant activity (in vitro and in vivo) of Olea europaea leaves, olive pomace and wastewater as well as their applications in the production of meat and meat products. This review found evidence that extracts and isolated polyphenols from the Olea europaea tree and olive processing by-products can be explored as natural antioxidant and antimicrobial additives to improve the preservation of meat and meat products. The polyphenols found in these residues (especially oleuropein, hydroxytyrosol and tyrosol) increased the redox state in the main meat-producing animals and, consequently, the oxidative stability of fresh meat obtained from these animals. Moreover, the extracts and isolated polyphenols also improved the shelf life of fresh meat and meat products (as additive and as active component in film) by delaying the growth of microorganisms and the progression of oxidative reactions during storage. The accumulated evidence supports further investigation as a natural additive to improve the preservation of reformulated muscle products and in the production of edible and sustainable films and coatings for fresh meat and meat products. Full article