Search Results (473)

This study evaluated the effects of dietary olive leaf extract (OLE) on Nile tilapia (Oreochromis niloticus) juveniles, focusing on growth parameters, centesimal composition, biochemical responses, and lipid peroxidation. OLE was extracted with 60% ethanol (1:20 w/v). Five diets, containing 34% crude protein and 8% lipids, were tested: a control (0 g/kg) and four with increasing OLE levels (0.25, 0.5, 1, and 2 g/kg). The 46-day trial included 225 fish (0.56 ± 0.11 g) distributed in 15 tanks. Growth performance was not affected, except for a higher condition factor in OLE0.25. This dose also resulted in lower moisture and higher lipid content, while all OLE treatments increased crude protein in fish. Muscle glycogen decreased in all OLE-fed groups, and liver glycogen was reduced in OLE0.25. Plasma triglycerides decreased in OLE0.5 and OLE0.25, while total plasma protein was lower in OLE2.0. Liver triglycerides were lower in OLE0.25 and higher in OLE0.5, whereas glucose showed a glycemic peak in OLE2.0. Hepatic lipid peroxidation was reduced in OLE2.0. Overall, dietary OLE did not compromise the growth performance of Nile tilapia, and 0.25 g/kg promoted beneficial effects on centesimal composition, biochemical parameters, and lipid peroxidation, highlighting its potential as a functional ingredient in aquafeeds. Full article

This study evaluated the effect of dietary supplementation with different levels of spray-dried phenolic compounds, extracted from olive mill wastewater, on the volatile compound profile of Caciotta cheese produced from cow’s milk. Thirty dairy cows were divided into three groups and fed diets containing 0% (C), 0.1% (T0.1), and 0.2% (T0.2) polyphenols on a dry matter basis. Milk from each group was used in three cheesemaking sessions, and 27 cheese samples ripened for 21 days were analyzed. Volatile compounds were extracted using solid phase microextraction (SPME) coupled with mass spectrometry, while the odour fingerprint was assessed using an electronic nose (PEN3). Principal Component Analysis (PCA) revealed a clear separation among groups, indicating distinct aromatic profiles associated with dietary polyphenol levels. In summary, incorporating by-products from olive mill wastewater into the diets of dairy cows can significantly affect the aroma of cheese. This approach represents a sustainable and innovative strategy that promotes waste valorization, reduces environmental impact, and supports circular economy principles by transforming a pollutant into a valuable additive. Full article

The olive tree (Olea europaea L.) has been cultivated for millennia, with olive oil representing both a cornerstone of the Mediterranean diet and a major agricultural commodity. Its composition, rich in monounsaturated fatty acids, polyphenols, tocopherols and squalene, supports well-documented cardioprotective, antioxidant and anti-inflammatory benefits. Olive oil production generates substantial secondary streams, including pomace, leaves, pits and mill wastewater, which are rich in phenols, triterpenes and fibers. This review consolidates recent advances in their phytochemical characterization, innovative extraction technologies and health-promoting effects, while highlighting the economic and regulatory prospects for industrial adoption. Comparative analysis shows that olive leaves can produce up to 16,674.0–50,594.3 mg/kg total phenolics; oleuropein 4570.0–27,547.7 mg/kg, pomace retains 2.24 g GAE/100 g dried matrix (DM)total phenolics; oil 13.66% DM; protein 6.64% DM, and wastewater contains high concentration of phenolics content of olives. Innovative extraction techniques, such as ultrasound and microwave-assisted methods, allow for a recovery, while reducing solvent use and energy input. The analysis highlights opportunities for integrating these by-products into circular bioeconomy models, supporting the development of functional foods, nutraceutical applications and sustainable waste management. Future research should address techno-economic feasibility, regulatory harmonization and large-scale clinical validation to accelerate market translation. Full article

This study investigated the effects of ultrasonic treatment of olive paste prior to malaxation on oil yield (Y), enzyme activity and virgin olive oil (VOO) quality in four Croatian olive varieties: Istarska Bjelica, Rosulja, Oblica and Levantinka. The oils were extracted using the Abencor system according to a central composite experiment design, with treatment durations of 3–17 min and power levels of 256–640 W. The parameters analyzed included Y, oxidative stability index (OSI), antioxidant capacity (AC), phenolic and α-tocopherol content, volatile compounds, fatty acid profile, and the activity of lipoxygenase, β-glucosidase, polyphenol oxidase, and peroxidase. Olive variety was the most influential factor in all variables. The response surface methodology showed that ultrasonic treatment at low-to-medium intensity improved several quality attributes. For example, Y increased by 4% in Oblica, phenolic content increased by up to 17% in Istarska Bjelica, and OSI and AC increased by 13–15% in Istarska Bjelica and Levantinka. In contrast, longer treatment and higher ultrasound power had a negative effect. No significant differences were found in other parameters examined. Overall, the application of ultrasound led to measurable, though moderate, improvements in Y and VOO quality, with results strongly dependent on olive variety and treatment conditions. These results underline the need for further optimization tailored to each variety. Full article

The bioactive properties of a phenolic extract (PE) obtained from olive mill vegetation water (OVW) in powder formulation were utilized to enrich a meat analog composed of lentils and champignon mushrooms. The primary phenolic compounds in this extract were oleacein, verbascoside, and hydroxytyrosol. The effects on the final product were assessed over eight days of storage at 4 °C ± 2 under 12 h of light. The control samples were compared with two meat analogs enriched with ascorbic acid (AA) at 5 g kg⁻¹ and one enriched with PE at 30 g kg⁻¹. The physicochemical parameters (pH, aw, color, texture, and total phenol content), antioxidant activity, microbial assessment, and sensory evaluations of meat analog samples were evaluated at three different time points (T0, T4, T8) during shelf life. The PE-enriched meat analogs maintained a relatively high and stable phenolic concentration throughout their shelf life, significantly enhancing the antioxidant activities of the final product. The addition of PE also influenced the growth of Enterococcus spp., Lactococcus spp., and Lactobacillus spp. during storage. The results of the triangular test indicated perceptible differences between AA and PE meat analogs. Meanwhile, the quantitative descriptive analysis (QDA) emphasized notable enhancements in odor and texture characteristics for PE-enriched samples. Plant-based meat analogs can benefit from the effective use of PE (antioxidant and sensory properties), supporting the sustainable reuse of olive oil by-products. Full article

This study aimed to evaluate the effects of brine enriched with an olive vegetation water (OVW) extract on the physico-chemical, oxidative, and sensory characteristics of cooked ham during storage, as a strategy to partially or totally replace nitrites. Four brines formulated with different concentrations of nitrites in combination with 200 mg of OVW extract/kg product were tested; the cooked ham samples were sliced, placed in trays, packed in a protective atmosphere, and monitored for 30 days at 4 °C. The results showed that phenolic compounds derived from OVW effectively reduced lipid and protein oxidation, limiting the formation of secondary oxidation products such as thiobarbituric acid reactive substances, volatile aldehydes, and cholesterol oxides. Sensory analysis confirmed that the extract did not negatively affect the organoleptic properties of the ham, while also helping to preserve color stability. These findings suggest that brine enriched with OVW phenols can be a promising green strategy to reduce nitrites in cooked ham, which also promotes the sustainable valorization of olive oil by-products. Full article

Exhausted olive oil pomace (EOP), Fucus spiralis, and Limnospira sp. extracts—rich in bioactives, polysaccharides, or proteins—were incorporated into alginate-based edible coatings and applied to strawberries to evaluate their effects on postharvest quality parameters, including decay, weight loss, color, antioxidant activity, and microbial growth. Among the tested formulations, the EOP-based coating (0.25% bioactive rich-extract) was the most effective, reducing weight loss to approximately 18% after 10 days at 10 °C, compared with higher losses in the control and other coatings, while also better preserving color through higher hue and chroma retention. Antioxidant activity, measured by ABTS and DPPH assays, was consistently higher in EOP-coated strawberries, despite a general decline in total phenolic content across treatments. Specifically, ABTS values decreased from 21.43 ± 0.90 (day 0) to 12.88 ± 0.39 (day 10) mmol TE/100 mg DW, while DPPH values declined from 10.23 ± 1.39 (day 0) to 5.96 ± 1.03 (day 10) mmol TE/100 mg DW. Microbial analyses further showed that the EOP coating strongly inhibited spoilage fungi, yeasts, and bacteria, whereas coatings containing Fucus spiralis or Limnospira sp. extracts (0.25% bioactive rich-extract plus 0.5% polysaccharide- or protein-rich extract) offered only moderate protection and, in some cases, promoted microbial growth. Overall, the EOP coating demonstrated superior performance in maintaining freshness, delaying microbial spoilage, and extending the shelf life of strawberries, highlighting its potential as a sustainable and functional strategy for fruit preservation. Full article

The valorization of agro-industrial by-products is a key component of sustainability goals in food production. Olive pomace (OP), a major by-product of olive oil extraction, is characterized by a high content of dietary fiber and bioactive phenolic compounds with antioxidant activity, which contribute to its nutritional and functional potential. The present study investigated the effect of the fortification of sheep milk yogurt with freeze-dried OP (1% w/w), added either before pasteurization (YOPB) or after overnight refrigeration (YOPA). The OP showed considerable antioxidant capacity and was microbiologically safe. Its addition significantly increased the yogurt’s total phenolic content, with YOPB displaying the lowest syneresis and the highest water-holding capacity and apparent viscosity. Textural and scanning electron microscopy analyses revealed that the timing of OP addition affected the gel structure, with pre-pasteurization incorporation facilitating a superior integration into the protein network. The microbial viability was preserved, and the sensory evaluation showed no significant differences in consumer acceptance between the control and YOPB. These findings highlight OP’s potential as a functional ingredient for dairy fortification, contributing to waste reduction and improving gel structure. The findings obtained provide support for the development of sustainable and functional dairy products enriched with by-products derived from the olive oil industry. Full article

Pistacia terebinthus L. which has been traditionally used in diet and medicine, remains underexplored in Greece, particularly regarding its chemical composition and antioxidant activity. The current study aims to comparatively evaluate the chemical profile of cold-pressed terebinth fruit oils, obtained from wild trees growing in the Greek Island of Chios (North East Aegean Sea), harvested during three years (2019, 2020 and 2021). The oils’ lipid profile was dominated by oleic acid (C18:1 cis-9) (42–45%) followed by palmitic acid (C16:0) (24–30%) and linoleic acid (C18:2 cis-9,12) (19–22%). Their phenolic acid content, expressed as anacardic acids—known for their bioactive properties—was quantified via q-¹H-NMR and found to be markedly high (1.91–2.98 mmol/kg oil). Total phenolic content (TPC) of the fruit extract showed interesting high value (185.92 ± 2.61 mg GAE/g) accompanied by strong antioxidant activity (DPPH, exhibiting > 80% inhibition at a concentration of 100 µg/mL) which was positively correlated with TPC. Additionally, the fruits demonstrated a rich nutritional profile, particularly in crude fibers (38.9%) and essential minerals (K, Mg, and Zn), along with low sodium content, suggesting notable dietary benefits. The cold-pressed oil exhibited high lipid content and low specific extinction coefficients (K₂₃₂, K₂₇₀), indicating minimal oxidation and confirming the oil’s freshness. These findings highlight the potential of P. terebinthus fruit oil as a high-value functional raw material with nutritional and antioxidant properties. Comparable to olive oil in lipid quality, Greek turpentine fruit and oil could play a promising role towards further applications in the food, cosmetic and pharmaceutical sectors. Full article

Background: Olive leaves are a rich source of bioactive phenolic compounds, but extraction yields vary depending on methodological choices. The aim was to identify optimal parameters for maximizing recovery and preserving antioxidant activity. Methods: Fourteen studies (149 samples) were included, following predefined eligibility criteria and PRISMA guidelines for systematic review. Data on TPC, TFC, and antioxidant assays (DPPH, FRAP, ABTS) were extracted and analyzed according to extraction method, solvent type, and processing conditions. Results: Soxhlet extraction and shaking achieved the highest TPC and antioxidant capacity, whereas ultrasound-assisted and high-voltage electrical discharge extractions showed lower averages unless intensity or duration was increased. Solvent polarity was critical: ≥75% aqueous methanol provided the highest TPC and FRAP, while ≥75% ethanol yielded the greatest TFC and ABTS activity. Pure water consistently gave the lowest yields. Extractions at >50 °C increased TPC up to fivefold compared to room temperature but did not proportionally improve radical-scavenging capacity. Most phenolic compounds were recovered within ≤1 h under optimized, heated, or assisted conditions, with longer times offering no significant advantage. Conclusions: Optimizing solvent composition, temperature, and extraction time is essential for maximizing yield and maintaining antioxidant quality in olive leaf extracts, and standardized protocols are needed to enable direct comparisons across studies. Full article

Olive mill wastewaters (OMWW) generated during olive oil extraction represent a significant environmental challenge due to their high organic matter content, acidic pH, phenolic content, and toxicity. Their composition varies widely depending on the extraction method and remains difficult to treat, particularly for small-scale producers lacking access to complex infrastructure. This study evaluates the combined effect of the extraction system (traditional vs. three-phase continuous) and filtration level (single vs. double) on the physicochemical and biological properties of OMWW. The methodologies employed included the analysis of water content, density, fatty acid composition, acidity, pH, total solids, chemical and biochemical oxygen demand, and biodegradability. The results indicate that traditional systems consistently produced OMWW with higher organic matter and phenolic loads, while filtration moderately reduced antioxidant potential and acidity, especially in traditional systems. The use of simple, low-cost filtration materials proved effective in improving effluent clarity and could serve as a practical pre-treatment option. This approach offers an accessible strategy for small producers aiming to valorise OMWW or reduce environmental impact. However, the study was conducted at the laboratory scale, and the long-term behaviour of filtered OMWW under real operating conditions remains to be evaluated. Full article

New types of fortified breads have been developed from a new ingredient obtained by a two-step process for olive oil extraction, without external water addition, called high-quality dried olive (HQDO). HQDO is a minimally processed ingredient rich in phenolic compounds with beneficial health properties. HQDO has been incorporated in different percentages (1% HDQO1, 5% HDQO5, 10% HDQO10, and control CON) to study how it affects the properties of bread. The effects on the texture and shelf-life extension of the breads have also been studied. The bread samples were evaluated by a trained panel in descriptive sensorial analysis (1–10 scale). Fortified breads improve their nutraceutical quality by increasing their phenolic content from 0.19 mg GAE g⁻¹ CON to 0.73 mg GAE g⁻¹ at HDQO10 (using the Folin–Ciocalteu method). Antioxidant activity was increased from 1.24 mg AAE g⁻¹ CON to 1.49 mg AAE g⁻¹ HDQO10 (using the DPPH method). In sensory properties, all fortified breads obtained a high punctuation with a rating near to seven or superior. In “Aroma” and “Aftertaste”, the fortified breads obtained superior ratings. Finally, in “Flavour”, except for HQDO10, all of them had values close to eight. HDQO1 and HDQO5 were selected for their equilibrium between nutritional qualities and sensorial evaluation. Full article

In this study, changes in total phenolic content, total flavonoids, tannin content and phenolic constituents, and mineral content of the leaves of five olive varieties (Ayvalık, Gemlik, Sarıulak, Çöpaşı and Delice) collected in Mersin province in Turkey were investigated. Tannin contents of olive leaves extracts were determined to be between 1.73 (Sarıulak) and 5.33% (Çöpaşı). Total phenolic and flavonoid amounts in olive leaves were assayed to be between 2122.02 (Sarıulak) and 2338.69 mgGAE/100 g (Çöpaşı), and between 9010.71 (Sarıulak) and 18,910.71 mg quercetin equivalent/100 g (Çöpaşı), respectively. Also, the antioxidant activities of methanol extracts of the olive leaves were discovered to be between 0.85 mmolTE/kg (Gemlik) and 21.04 mmolTE/kg (Sarıulak). The phenolic components of the olive leaves studied showed differences depending on the variety of olive. Catechin, rutin, and 3,4-dihydroxybenzoic acid were the most abundant phenolics in leaf extracts. Also, “Delice” olive leaves in the wild form generally had more caffeic acid, syringic acid and rutin, compared to the other olive varieties studied. While the olive leaves were determined to be high in macroelements, the microelement contents detected in olive leaves were low. In general, there was a linear connection between the total phenols and antioxidant activities of leaf samples. This connection was also exhibited between the total flavonoid content and antioxidant activities of olive leaves (except for Sarıulak). Full article

The present study focuses on recovering phenolic compounds and terpenes from olive leaves, which are generated as by-products during olive oil processing. To this end, conventional extraction/maceration (CE) and advanced extraction techniques such as subcritical water extraction (SWE), pressurized fluid extraction (PLE) and ultrasound-assisted extraction (UAE) were employed to compare and determine the most effective procedure. The phenolic and terpenoid composition of the extracts revealed a total of 33 compounds in HPLC-QTOF-MS analysis. According to these findings, the optimal extraction techniques for the maximum recovery of secoiridoids from olive leaves were PLE and UAE, with no significant difference between them (21.9891 ± 2.5521 mg/g DW and 21.0888 ± 1.3494 mg/g DW, respectively). Regarding to flavonoids, UAE was the most effective extraction technique, yielding 4.9837 ± 0.6739 mg/g DW. However, SWE recovered the highest amount of phenolic alcohols (7.4201 ± 0.9848 mg/g DW), which could be due to degradation of the secoiridoids during extraction. Conversely, UAE was more successful than the other techniques for the extraction of the terpene family (0.7373 ± 0.0601 mg/g DW). The present study therefore focuses on comparing different extraction techniques for revalorizing olive leaves as a source of bioactive compounds, specifically polyphenols and terpenes, due to their beneficial health properties. Full article

Olive leaves (Olea europaea) are the most abundant agricultural by-product of olive tree cultivation, generating substantial waste each year. Their disposal is deemed an environmental challenge, particularly in Mediterranean countries that dominate the olive oil sector, yet their rich bioactive profile makes them promising candidates for functional food development. This study aimed to determine the total antioxidant capacity (TAC) and total phenolic content (TPC) of olive leaf powder extracts using different extraction solvents and methods to identify the most efficient strategy for possible incorporation into functional food systems. Extractions were performed with distilled water, 70% ethanol, 80% methanol, and 50% acetone using three methods: stirring, soaking, and ultrasound-assisted extraction (UAE). TAC and TPC were quantified using the FRAP and Folin–Ciocalteu assays, respectively. Among solvents, acetone consistently yielded the highest values across most methods (TAC: 19.02 mmol Fe²⁺/L, TPC: 1289.95 mg GA/L), while ethanol also showed strong extraction performance (TAC: 15.35 mmol Fe²⁺/L; TPC: 1214.76 mg GA/L), offering a safer and more scalable option for food applications. Method-wise, UAE achieved the greatest phenolic recovery, while both UAE and stirring proved effective for antioxidant extraction. Overall, these findings provide quantitative evidence supporting possible incorporation of olive leaf powder as a valuable ingredient in functional foods and other sustainable applications, while also contributing to the circular economy through the sustainable valorization of agricultural waste. Full article