Olive pomace as a valuable source of bioactive compounds: A study regarding its lipid- and water-soluble components

Do Lignin Nanoparticles Pave the Way for a Sustainable Nanocircular Economy? Biostimulant Effect of Nanoscaled Lignin in Tomato Plants

Agriculture has a significant environmental impact and is simultaneously called to major challenges, such as responding to the need to develop more sustainable cropping systems with higher productivity. In this context, the present study aimed to obtain lignin nanoparticles (LNs) from pomace, a waste product of the olive oil chain, to be used as a nanobiostimulant in tomato plants. The biostimulant effect of this biopolymer is known, but its reduction to nanometer size can emphasize this property. Tomato plants were subjected to different LN dosages (25, 50, and 100 mg L-1) by foliar application, and inductive effects on photosynthetic machinery, aerial and root biomass production, and root morphology were observed. The treated plants showed increased efficiency in catching and using light, while they reduced the fraction dissipated as heat or potentially toxic to cells for the possibility of creating reactive oxygen species (ROS). Finally, this benefit was matched by increased pigment content and a stimulatory action on the content of nitrogen (NBI) and antioxidant substances such as flavonoids. In conclusion, the present study broadens the horizon of substances with biostimulant action by demonstrating the validity and efficacy of nanobiostimulants obtained from biological residues from the olive oil production chain.

Metabolome classification of olive by-products from different oil presses providing insights into its potential health benefits and valorization as analyzed via multiplex MS-based techniques coupled to chemometrics

INTRODUCTION

The Olive (Olea europaea L.) is one of the most popular edible oil-producing fruits, consumed worldwide for its myriad nutritional and health benefits. Olive oil production generates huge quantities of by-products from the fruit, which are considered environmental hazards. Recently, more and more efforts have been made to valorize olive by-products as a source of low-cost, value-added food applications.

OBJECTIVE

The main objective of this study was to globally assess the metabolome of olive fruit by-products, including olive mill wastewater, olive pomace, and olive seeds from fruits from two areas, Siwa and Anshas, Egypt.

METHODS

Gas chromatography-mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography with mass spectrometry (UPLC-MS) were used for profiling primary and secondary metabolites in olive by-products. Also, multivariate data analyses were used to assess variations between olive by-product samples.

RESULTS

A total of 103 primary metabolites and 105 secondary metabolites were identified by GC-MS and UPLC-MS, respectively. Fatty acids amounted to a major class in the olive by-products at 53-91%, with oleic acid dominating, especially in the pomace of Siwa. Mill wastewater was discriminated from other by-products by the presence of phenolics mainly tyrosol, hydroxyl tyrosol, and α-tocopherol as analyzed by UPLC-MS indicating their potential antioxidant activity. Pomace and seeds were rich in fatty acids/esters and hydroxy fatty acids and not readily distinguishable from each other.

CONCLUSION

The current work discusses the metabolome profile of olive waste products for valorization purposes. Pomace and seeds were enriched in fatty acids/esters, though not readily distinguishable from each other.

Unraveling the effect of phenolic extract derived from olive mill solid wastes on agro-physiological and biochemical traits of pomegranate and its associated rhizospheric soil properties

Agricultural waste management poses a significant challenge in circular economy strategies. Olive mill wastes (OMW) contain valuable biomolecules, especially phenolic compounds, with significant agricultural potential. Our study evaluate the effects of phenolic extract (PE) derived from olive mill solid wastes (OMSW) on pomegranate agro-physiological and biochemical responses, as well as soil-related attributes. Pomegranate plants were treated with PE at doses of 100 ppm and 200 ppm via foliar spray (L100 and L200) and soil application (S100 and S200). Results showed increased biomass with PE treatments, especially with soil application (S100 and S200). Proline and soluble sugar accumulation in leaves suggested plant adaptation to PE with low-level stress. Additionally, PE application reduced malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents. Higher doses of PE (S200) significantly improved net photosynthesis (Pn), transpiration rate (E), water use efficiency (WUEi), and photosynthetic efficiency (fv/fm and PIabs). Furthermore, PE treatments enhanced levels of chlorophylls, carotenoids, polyphenols, flavonoids, and antioxidant activity. Soil application of PE also increased soil enzyme activities and microbial population. Our findings suggest the beneficial impact of PE application on pomegranate agro-physiological responses, laying the groundwork for further research across various plant species and soil types to introduce nutrient-enriched PE as an eco-friendly biostimulant.

A New Culture Medium Rich in Phenols Used for Screening Bitter Degrading Strains of Lactic Acid Bacteria to Employ in Table Olive Production

The olive oil industry recently introduced a novel multi-phase decanter with the "Leopard DMF" series, which gives a by-product called pâté, made up of pulp and olive wastewater with a high content of phenolic substances and without pits. This study aims to create a new culture medium, the Olive Juice Broth (OJB), from DMF pâté, and apply it to select bacteria strains able to survive and degrade the bitter substances normally present in the olive fruit. Thirty-five different bacterial strains of Lactiplantibacillus plantarum from the CREA-IT.PE Collection of Microorganisms were tested. Seven strains characterized by ≥50% growth in OJB (B31, B137, B28, B39, B124, B130, and B51) showed a degradation of the total phenolic content of OJB ≥ 30%. From this set, L. plantarum B51 strain was selected as a starter for table olive production vs. spontaneous fermentation. The selected inoculant effectively reduced the debittering time compared to spontaneous fermentation. Hydroxytyrosol, derived from oleuropein and verbascoside degradation, and tyrosol, derived from ligstroside degradation, were produced faster than during spontaneous fermentation. The OJB medium is confirmed to be useful in selecting bacterial strains resistant to the complex phenolic environment of the olive fruit.

Effects of Electron Beam Radiation on the Phenolic Composition and Bioactive Properties of Olive Pomace Extracts

Olive pomace is an agro-industrial waste product generated from the olive oil industry and constituted by bioactive compounds with potential applications in several industrial sectors. The purpose of this work was to evaluate the effects of electron beam (e-beam) radiation on olive pomace, specifically on phenolic compounds (by HPLC-DAD-ESI/MS) and the bioactive properties (antioxidant, antiproliferative, and antimicrobial activities) of crude olive pomace (COP) and extracted olive pomace (EOP) extracts. The amount of total flavonoid content and the reducing power of COP extracts were higher than those obtained for EOP extracts. The results suggested that e-beam radiation at 6 kGy increased both total phenolic and total flavonoid contents as well as the reducing power of COP extracts, due to the higher extractability (>2.5-fold) of phenolic compounds from these samples, while decreasing the scavenging activity of extracts. The extracts of both olive pomaces showed antibacterial potential, and COP extracts at 400 µg/mL also presented antiproliferative activity against A549, Caco-2, 293T, and RAW264.7 cell lines, with both properties preserved with the e-beam treatment. All in all, e-beam radiation at 6 kGy appears to be a promising technology to valorize the pollutant wastes of the olive oil industry through enhancing phenolic extractability and bioactive properties, and, furthermore, to contribute to the environmental and economical sustainability of the olive oil industry.

High-Value Compounds in Papaya By-Products (Carica papaya L. var. Formosa and Aliança): Potential Sustainable Use and Exploitation

BACKGROUND

Food waste is a global and growing problem that is gaining traction due to its environmental, ethical, social, and economic repercussions. Between 2022 and 2027, the worldwide papaya market is expected to have a huge increase, meaning a growth in organic waste, including peels and seeds. Thus, this study evaluated the potential use of peels and seeds of two mature papaya fruits as a source of bioactive compounds, converting these by-products into value-added products. Proximate analysis (AOAC methods), mineral content (ICP-MS), free sugars (HPLC-ELSD), fatty acid composition (GC-FID), vitamin E profile (HPLC-DAD-FLD), and antioxidant activity (DPPH and FRAP assays) were evaluated.

RESULTS

Both by-products showed high total protein (20-27%), and dietary fiber (32-38%) contents. Papaya peels presented a high ash content (14-16%), indicating a potential application as a mineral source. 14 fatty acids were detected, with α-linolenic acid (30%) as the most abundant in the peels and oleic acid (74%) in the seeds. Both by-products showed high antioxidant activity.

CONCLUSION

Papaya by-products display great potential for industrial recovery and application, such as formulation of new functional food ingredients.

Improving the Rheological Properties of Dough Obtained by Partial Substitution of Wheat Flour with Freeze-Dried Olive Pomace

Mediterranean countries are known for their high-quality olives and the production and consumption of olive oil. Olive pomace (OP), the major by-product of olive oil extraction, is receiving attention for its potential as a functional compound in food products, reflecting its physiology- and health-promoting attributes. This study assessed the physico-chemical characteristics of OP obtained from two Sardinian olive cultivars, Bosana and Semidana, and the effect of OP incorporation on the baking performance of wheat dough. We assessed the rheological parameters, pasting profile, and fermentation of doughs obtained through the partial substitution of wheat flour with OP at 0 (control), 1, 2, 3, and 5%. OP inclusion resulted in significant differences in the studied parameters compared with control samples. Positive effects included a decrease in development time, improved dough stability and storage, and superior loss modulus and gas retention capacity. Negative effects comprised an increase in dough resistance and a decrease in dough development height, gas production, gas retention, pasting profile, stickiness, and elasticity. These differences in the OP dough were due to the interactions between polyphenols and fibre with water and the starch-gluten matrix. This study found improvements in dough characteristics following the substitution of wheat flour with low percentages of OP, especially Semidana at 1%. Although higher percentages of OP would be associated with greater nutritional and health benefits, they resulted in a degradation of the dough's attributes, producing a gluten-free-like matrix in the final product.

Olive oil and its derivatives for promoting performance, health, and struggling thermal stress effects on broilers

Olive oil (OL) production is the most significant agro-industrial business and has a high impact on the economy of numerous Mediterranean countries. However, OL extraction results in massive amounts of byproducts, including a solid residue (olive cake or olive pomace) and an aqueous stage (olive mill wastewater), which have serious environmental effects due to their hazardous nature and excessive organic content. Despite these byproducts causing environmental pollution, they can be applied for animal feeding. According to the literature, OL or its derivatives have been used to promote broiler performance, feed utilization, and health status in broilers as growth promoters or protein sources. Furthermore, using OL and its derivatives could improve heat resistance in stressed broilers via struggling thermal stress effects. In this framework, we highlighted the use of OL and its byproducts in broiler feeding to promote performance and health status. Additionally, the role of these byproducts and OL in combating thermal stress is investigated for sustainable strategy and promoting circular economy in broiler industry.

Isolation and structural determination of cis- and trans-p-coumaroyl-secologanoside (comselogoside) from olive oil waste (alperujo). Photoisomerization with ultraviolet irradiation and antioxidant activities

p-Coumaroyl-6́-secologanoside (comselogoside) is a secoiridoid identified in large amounts in olive fruits, although no studies in vitro or in vivo of comselogoside have been reported. This work focuses on the recovery and purification of this compound from olive mill waste (alperujo). The successive isolation on Amberlite XAD-16 and Sephadex LH-20 resins, allowed a comselogoside extract with 80-85% of purity. A photoisomerization of the vinyl-double bond in the p-coumaroyl moiety occurred when the extract was exposed to ultraviolet radiation and a mixture of the trans and cis-isomers was obtained. Both isomers were characterized using NMR, mass spectroscopy, and UV spectrometry. The J (coupling constant) of the protons on the C7 and C8 on the unsaturated chain were found to be the difference between cis (12.8 Hz) and trans- (15.9 Hz) comselogoside. Cis-isomer exhibited lower radical-scavenging activity than trans, although a synergistic effect occurred when the cis-isomer was supplement by the trans-isomer.

Olive mill wastewater and hydroxytyrosol inhibits atherogenesis in apolipoprotein E-deficient mice

The Mediterranean diet, which is characterized by high consumption of olive oil, prevents cardiovascular disease. Meanwhile, olive mill wastewater (OMWW), which is obtained as a byproduct during olive oil production, contains various promising bioactive components such as water-soluble polyphenols. Hydroxytyrosol (HT), the major polyphenol in OMWW, has anti-oxidative and anti-inflammatory properties; however, the atheroprotective effects of OMWW and HT remain to be fully understood. Here, we investigated the effect of OMWW and HT on atherogenesis. Male 8-week-old apolipoprotein E-deficient mice were fed a western-type diet supplemented with OMWW (0.30%w/w) or HT (0.02%w/w) for 20 weeks. The control group was fed a non-supplemented diet. OMWW and HT attenuated the development of atherosclerosis in the aortic arch as determined by Sudan IV staining (P < 0.01, respectively) without alteration of body weight, plasma lipid levels, and blood pressure. OMWW and HT also decreased the production of oxidative stress (P < 0.01, respectively) and the expression of NADPH oxidase subunits (e.g., NOX2 and p22phox) and inflammatory molecules (e.g. IL-1β and MCP-1) in the aorta. The results of in vitro experiments demonstrated that HT inhibited the expression of these molecules that were stimulated with LPS in RAW264.7 cells, murine macrophage-like cells. OMWW and HT similarly attenuated atherogenesis. HT is a major component of water-soluble polyphenols in OMWW, and it inhibited inflammatory activation of macrophages. Therefore, our results suggest that the atheroprotective effects of OMWW are at least partially attributable to the anti-inflammatory effects of HT.

Characterization of the antioxidant activity, carotenoid profile by HPLC-MS of exotic colombian fruits (goldenberry and purple passion fruit) and optimization of antioxidant activity of this fruit blend

The consumption of antioxidants can prevent chronic non-communicable diseases and the exotic Colombian fruits, goldenberry (Physalis peruviana L.) and purple passion fruit (Passiflora edulis f. Edulis Sims), are rich in bioactive compounds. The aim of this work was to characterize and optimize the antioxidant activity of these fruits blend. The fruits were classified according to their maturity stages, the freeze-dried extracts were physiochemically characterized, and polyphenols, carotenoids and antioxidant activity were quantified, and an experimental mixture design was applied to optimize the antioxidant activity of the bend. For the goldenberry the maturity stage 3 had higher iron-reducing capacity and higher content of polyphenols. Meanwhile, for the purple passion fruit, this maturity stage had higher antioxidant activity by all methodologies and a higher concentration of polyphenols; the ultrasound-assisted extraction showed statistical differences for polyphenols, ABTS and FRAP. Antioxidant activity showed significant differences (p < 0.05) between samples (TBARS (3.98 ± 0.14 and 7.03 ± 0.85 μM-MDA/g), ABTS (36.53 ± 2.66 and 29.4 ± 4.88 μMTrolox/g), DPPH (36.53 ± 2.66 and 23.90 ± 0.96μMTrolox/g), ORAC (23.02 ± 0.36 and 32.44 ± 0.94 μM Trolox/g) and total polyphenols (5, 29 ± 0.34 and 9.12 ± 0.37mgGA/g). Some of the carotenoids identified by HPLC-MS in both fruits were lutein, α and β-carotene, phytoene and lycopene. The optimum bend was goldenberry 0.83 and purple passion fruit 0.17.

Towards a circular economy in virgin olive oil production: Valorization of the olive mill waste (OMW) "alpeorujo" through polyphenol recovery with natural deep eutectic solvents (NADESs) and vermicomposting

Virgin olive oil (VOO) production generates large amounts of a harmful by-product, olive mill waste (OMW) or alpeorujo, which has a strong environmental impact and that must be recycled to adapt VOO production to a circular economy model. Here, the valorization of OMW was studied by considering three consecutive stages: Stage 1 involves the generation of OMW; Stage 2 the recovery of bioactive phenolic compounds from the fresh OMW using natural deep eutectic solvents (NADESs), generating a valuable phenolic extract and a new by-product, a dephenolized OMW named "alpeoNADES"; and Stage 3 involves vermicomposting alpeoNADES with Eisenia fetida earthworms. Six NADES were formulated and tested, selecting a NADES composed of citric acid and fructose (CF) derived from food grade and biodegradable substances. CF was the most effective solvent to obtain phenolic extracts for nutraceutical and agronomical purposes, extracting 3988.74 mg/kg of polyphenols from fresh OMW. This alpeoNADES is a non-palatable substrate for E. fetida earthworms, as the residual CF gives it an acidic pH (pH 2). Its palatability was improved by mixing it with horse manure and straw for vermicomposting, in a 1:1 and 3:1 dry weight ratio. When these substrates were precomposted for 3 weeks they reached pH 5.5-6 and they could then be vermicomposted for 23 weeks (using OMW as a control). The best substrate for vermicomposting was determined by the worm biomass, growth rate, carbon to nitrogen (C:N) ratio, and N and P content. AlpeoNADES and manure 3:1 produced the highest quality vermicompost in the shortest time, generating a product that complied with European standards for organic fertilizers. Hence, alpeoNADES was recycled to a low-cost, organic balanced fertilizer in Stage 3, enabling the olive oil industry to transition to sustainable production through this integrated circular economy design.

Effect of Different Time/Temperature Binomials on the Chemical Features, Antioxidant Activity, and Natural Microbial Load of Olive Pomace Paste

Olive pomace is a by-product from olive oil production that can be further processed to obtain olive pomace paste. In this work, the influence of different time/temperature binomials (65 °C/30 min; 77 °C/1 min; 88 °C/15 s; and 120 °C/20 min) on the nutritional quality, chemical composition, and efficiency on control/elimination of natural microbial load of olive pomace paste was ascertained. The treatments significantly impacted the contents of ash, fat, vitamin E, phenolics (including hydroxytyrosol), flavonoids, and antioxidant activity, but not the fatty acids profile. The binomial 88 °C/15 s showed the greatest potential since it better preserved the phytochemical and antioxidant properties as well as the protein and fiber contents. This binomial is also faster and easy to be implemented at an industrial level, allowing the obtention of a safe functional ingredient to satisfy consumers' demands for novel sustainable products, simultaneously, responding to food safety and food security concerns.

Characterization and Biological Activities of In Vitro Digested Olive Pomace Polyphenols Evaluated on Ex Vivo Human Immune Blood Cells

Olive pomace (OP) represents one of the main by-products of olive oil production, which still contains high quantities of health-promoting bioactive compounds. In the present study, three batches of sun-dried OP were characterized for their profile in phenolic compounds (by HPLC-DAD) and in vitro antioxidant properties (ABTS, FRAP and DPPH assays) before (methanolic extracts) and after (aqueous extracts) their simulated in vitro digestion and dialysis. Phenolic profiles, and, accordingly, the antioxidant activities, showed significant differences among the three OP batches, and most compounds showed good bioaccessibility after simulated digestion. Based on these preliminary screenings, the best OP aqueous extract (OP-W) was further characterized for its peptide composition and subdivided into seven fractions (OP-F). The most promising OP-F (characterized for its metabolome) and OP-W samples were then assessed for their potential anti-inflammatory properties in ex vivo human peripheral mononuclear cells (PBMCs) triggered or not with lipopolysaccharide (LPS). The levels of 16 pro-and anti-inflammatory cytokines were measured in PBMC culture media by multiplex ELISA assay, whereas the gene expressions of interleukin-6 (IL-6), IL-10 and TNF-α were measured by real time RT-qPCR. Interestingly, OP-W and PO-F samples had a similar effect in reducing the expressions of IL-6 and TNF-α, but only OP-W was able to reduce the release of these inflammatory mediators, suggesting that the anti-inflammatory activity of OP-W is different from that of OP-F.

Exploring Olive Pomace for Skincare Applications: A Review

The cosmetic industry is continuously searching for new active ingredients in an effort to attend to consumer demands which, in recent years, are focused on more natural and environmentally friendly products, obtained from sustainable resources. Nevertheless, they are required to provide cosmetologically appealing skincare products, ultimately with the purpose of improving skin appearance. The olive oil industry generates a large amount of liquid and semi-solid by-products such as olive pomace. Their phytotoxicity impairs safe disposal, so valorization strategies that promote by-product reuse are needed, which may include skincare products. Hydroxytyrosol is the main phenolic compound present in olive pomace and possesses biological effects that make it a desirable active compound for cosmetic formulations such as antioxidant and anti-aging activities as well as photoprotector, depigmenting, antimicrobial and anti-inflammatory actions. Other compounds present in olive pomace can also have functional properties and skin-related benefits. However, the application of this by-product can be a challenge in terms of formulation’s design, stability, and proven efficacy, so appropriate methodologies should be used to validate its incorporation and may include extraction and further encapsulation of bioactive compounds in order to achieve effective and aesthetic appealing skincare products.

Treatment technologies for olive mill wastewater with impacts on plants

Olive mill wastewater (OMW), produced during olive oil production, contains high levels of salt contents, organic matter, suspended particles, and toxic chemicals (particularly phenols), which all result in increased biological and chemical oxygen demand. Olive Oil Mills' Wastes (OMW), which have dark brown color with unpleasant smell, consist mainly of water, high organic (mainly phenols and polyphenols) and low inorganic compounds (e.g. potassium and phosphorus), as well as grease. OMW components can negatively affect soil's physical, chemical, and biological properties, rendering it phytotoxic. However, OMW can positively affect plants' development when it's applied to the soil after pretreatment and treatment processes due to its high mineral contents and organic matter. There are various approaches for removing impurities and the treatment of OMW including chemical, biological, thermal, physiochemical, and biophysical processes. Physical techniques involve filtration, dilution, and centrifugation. Thermal methods include combustion and pyrolysis; biological techniques use anaerobic and aerobic techniques, whereas adsorption and electrocoagulation act as physiochemical methods, and coagulation and flocculation as biophysical methods. In contrast, combined biological treatment methods use co-digestion and composting. A comparison of the effects of both treated and untreated OMW samples on plant development and soil parameters can help us to understand the potential role of OMW in increasing soil fertility. This review discusses the impacts of untreated OMW and treated OMW in terms of soil characteristics, seed germination, and plant growth. This review summarizes all alternative approaches and technologies for pretreatment, treatment, and recovery of valuable byproducts and reuse of OMW across the world.

Mediterranean Food Industry By-Products as a Novel Source of Phytochemicals with a Promising Role in Cancer Prevention

The Mediterranean diet is recognized as a sustainable dietary approach with beneficial health effects. This is highly relevant, although the production of typical Mediterranean food, i.e., olive oil or wine, processed tomatoes and pomegranate products, generates significant amounts of waste. Ideally, this waste should be disposed in an appropriate, eco-friendly way. A number of scientific papers were published recently showing that these by-products can be exploited as a valuable source of biologically active components with health benefits, including anticancer effects. In this review, accordingly, we elaborate on such phytochemicals recovered from the food waste generated during the processing of vegetables and fruits, typical of the Mediterranean diet, with a focus on substances with anticancer activity. The molecular mechanisms of these phytochemicals, which might be included in supporting treatment and prevention of various types of cancer, are presented. The use of bioactive components from food waste may improve the economic feasibility and sustainability of the food processing industry in the Mediterranean region and can provide a new strategy to approach prevention of cancer.

Anaerobic Digestion of the Residue (Combination of Wastewater and Solid Waste) from a New Olive-Oil Manufacturing Process Based on an Olive Cold-Pressing System: Kinetic Approach and Process Performance

This research evaluates the anaerobic digestion (AD) process of the residue generated in a new olive-oil manufacturing process for cold-pressed olive, a residue consisting of a mixture of the wastewater and solid waste obtained from this process. Additionally, in order to assess the possible influence of the level of ripening of the olives on the performance of anaerobic processing, olives of the Picual variety were collected at two stages, i.e., green olives and olives in veraison. The AD processes of the residues obtained from the cold-pressing process and the process without pressure (control) were comparatively assessed by means of biochemical methane potential (BMP) assays conducted at mesophilic temperature (35 ± 1 °C). Maximum values for methane yield (390 ± 1 NL CH4/kg VSadded) and biodegradability (84.5%) were obtained from the cold-pressed green olive residues. For the rest of the wastes studied, biodegradability also reached high values, ranging from 79.1 to 79.6%. The logistic model adequately fit the experimental data and allowed for the assessment of the anaerobic biodegradation of these wastes and for obtaining the kinetic parameters for each case studied. The theoretical values for ultimate methane production predicted from this model showed less than a 1% deviation from the experimental values. A decrease was detected for both types of olives tested in the rate of maximum methane production, Rm, during the cold-pressing process, from 44.3 ± 0.1 to 30.1 ± 1.3 L CH4/(kg VS·d) (green olives) and from 43.9 ± 1.5 to 38.7 ± 1.6 L CH4/(kg VS·d) (olives in veraison). Finally, the highest energy output result was detected in the waste from cold-pressed green olives (15.7 kJ/g VSremoved), which coincided with its high methane yield.

Optimization of Autohydrolysis of Olive Pomaces to Obtain Bioactive Oligosaccharides: The Effect of Cultivar and Fruit Ripening

The valorisation of agro-industrial residues presents a challenge in obtaining economically sustainable and environmentally friendly industrial processes. Olive pomace is a by-product generated in large quantities, from olive oil extraction. This residue mostly consists of lignocellulosic materials. The aim of this study was to evaluate the potential use of extracted olive pomaces (EOP) obtained from olives with different ripening indexes (RI) and from different cultivars (Cobrançosa; RI = 2.5; 3.3 and 4.7; and Galega Vulgar; RI = 1.8; 2.9 and 4.8), to produce bioactive oligosaccharides from hemicelluloses by autohydrolysis. The hydrothermal treatment conditions were optimized by Response Surface Methodology, following a central composite rotatable design (CCRD), as a function of temperature (T: 142–198 °C) and time (t: 48–132 min), corresponding to severity factor (SF) values from 3.2 to 4.9. For all pomace samples, soluble sugar production was described by concave surfaces as a function of temperature and time. Autohydrolysis with SF equal or higher than 4.0 produced higher sugar yields, with maximum values around 180 g glucose equivalent/kg EOP for SF of 4.7 (190 °C/120 min) or 4.9 (198 °C/90 min). These values were similar for both cultivars and were not dependent on the ripening stage of the olives. Maximum oligosaccharide (OS) yields of 98% were obtained by autohydrolysis with SF of 4.0. The increase in SF to 4.9 resulted in a decrease in OS yield to 86–92%, due to the release of monomeric sugars. The monosaccharides were mostly xylose (55.8–67.7% in Galega; 50.4–69.0% in Cobrançosa liquid phases), and glucose, galactose, arabinose and rhamnose, in smaller quantities. Therefore, the production of bioactive xylo-oligosaccharides (XOS) from olive pomaces mainly depends on the hydrothermal conditions used.

Sustainable vs. Conventional Approach for Olive Oil Wastewater Management: A Review of the State of the Art

The main goal of this review is to collect and analyze the recently published research concerning the conventional and sustainable treatment processes for olive mill wastewater (OMW). In the conventional treatment processes, it is noticed that the main objective is to meet the environmental regulations for remediated wastewater without considering the economical values of its valuable constituents such as polyphenols. These substances have many important environmental values and could be used in many vital applications. Conversely, sustainable treatment processes aim to recover the valuable constituents through different processes and then treat the residual wastewater. Both approaches’ operational and design parameters were analyzed to generalize their advantages and possible applications. A valorization-treatment approach for OMW is expected to make it a sustainable resource for ingredients of high economical value that could lead to a profitable business. In addition, inclusion of a recovery process will detoxify the residual OMW, simplify its management treatment, and allow the possible reuse of the vast amounts of processed water. In a nutshell, the proposed approach led to zero waste with a closed water cycle development.

Higher Yield and Polyphenol Content in Olive Pomace Extracts Using 2-Methyloxolane as Bio-Based Solvent

Despite its severe toxicity and negative environmental impact, hexane remain the solvent of choice for the extraction of vegetable oils. This is in contrast with the constantly growing demand for sustainable and green extraction processes. In recent years a variety of alternatives to hexane have been reported, among them 2-methyloxolane (2-MeOx), which has emerged as a promising bio-based alternative. This study evaluates the possibility of replacing hexane, in the extraction of olive pomace (OP), with 2-MeOx, both dry and saturated with water (4.5%), the latter of which is called 2-MeOx 95.5%. The three solvents have been compared in terms of extraction yield and quality, as well as the lipid and polyphenol profiles of the extracts. The work concluded that both dry 2-MeOx and 2-MeOx 95.5% can replace hexane in OP extraction, resulting in higher yields and extracts richer in phenolic compounds. This study should open the road to further semi-industrial scale investigations toward more sustainable production processes.

Olive Cake Powder as Functional Ingredient to Improve the Quality of Gluten-Free Breadsticks

The growing demand for high-quality gluten-free baked snacks has led researchers to test innovative ingredients. The aim of this work was to assess the feasibility of olive cake powder (OCP) to be used as a functional ingredient in gluten-free (GF) breadsticks. OCP was used by replacing 1, 2, and 3% of maize flour into GF breadstick production (BS1, BS2, BS3, respectively), and their influence on nutritional, bioactive, textural, and sensorial properties was assessed and compared with a control sample (BSC). BS1, BS2, and BS3 showed a higher lipid, moisture, and ash content. BS2 and BS3 had a total dietary fibre higher than 3 g 100 g⁻¹, achieving the nutritional requirement for it to be labelled as a “source of fibre”. The increasing replacement of olive cake in the formulation resulted in progressively higher total phenol content and antioxidant activity for fortified GF breadsticks. The L* and b* values decreased in all enriched GF breadsticks when compared with the control, while hardness was the lowest in BS3. The volatile profile highlighted a significant reduction in aldehydes, markers of lipid oxidation, and Maillard products (Strecker aldehydes, pyrazines, furans, ketones) in BS1, BS2, and BS3 when compared with BSC. The sensory profile showed a strong influence of OCP addition on GF breadsticks for almost all the parameters considered, with a higher overall pleasantness score for BS2 and BS3.

Nutritional Improvement of Gluten-Free Breadsticks by Olive Cake Addition and Sourdough Fermentation: How Texture, Sensory, and Aromatic Profile Were Affected?

There is a growing need for gluten-free bakery products with an improved nutritional profile. Currently, gluten-free baked goods deliver low protein, fiber, and mineral content and elevated predicted glycaemic index (pGI). Olive cake (OC), a by-product from virgin olive oil extraction, is an excellent natural source of unsaturated fatty acids, dietary fiber and bioactive molecules, including polyphenols and tocopherols. In this framework, this study aimed at using two selected lactic acid bacteria and a yeast for increasing the antioxidant features and the phenol profile of the gluten-free breadsticks fortified with OC with the perspective of producing a functional food. Control (CTR) samples were prepared and compared with fermented ones (fCTR). Samples were added with either non-fermented OC (nfOC) or fermented for 12 and 20 h (fOC-12 and fOC-20). Our results showed that the predicted glycemic index (pGI) was influenced by both OC addition and sourdough fermentation. In fact, the lowest value of pGI was found in fOC-12, and hydrolysis index and pGI values of samples with OC (fOC-12 and nfOC) were statistically lower than fCTR. Both OC addition and fermentation improved the total phenol content and antioxidant activity of breadsticks. The most pronounced increase in hardness values was observed in the samples subjected to sourdough fermentation as evidenced both from texture profile analysis and sensory evaluation. Moreover, in most cases, the concentration of the detected volatile compounds was reduced by fermentation. Our work highlights the potential of OC to be upcycled in combination with fermentation to produce gluten-free breadsticks with improved nutritional profile, although additional trials are required to enhance textural and sensory profile.

Food Loss and Food Waste for Green Cosmetics and Medical Devices for a Cleaner Planet

To stay wealthy in a world where all can live in prosperity and wellbeing, it is necessary to develop sustainable growth at net zero emissions to stop climate change, neutralizing both risks and diseases such as the COVID-19 pandemic and inequalities. Changing the worldwide use of the great quantity of food loss and waste can help to move in this direction. At this purpose, it seems useful to transform food waste into richness, extracting and using its content in natural ingredients and biopolymers to make new sustainable products and goods, including cosmetics and medical devices. Many of these ingredients are not only bioactive molecules considered of interest to produce these consumer products but are also useful in reducing the environmental footprint. The active agents may be obtained, for example, from waste material such as grapes or olive pomace, which include, among others natural polymers, phythosterols, vitamins, minerals and unsaturated fatty acids. Among the polymers, chitin and lignin have shown particular interest because biodegradable, nontoxic, skin- and environmentally friendly ingredients can be obtained at low cost from food and forestry waste, respectively. According to our experience, these polymers may be used to make nanocomposites and micro-nanoparticles that encapsulate different active ingredients, and which may be embedded into gel and non-woven tissues to realize advanced medications and smart cosmeceuticals. However, to utilize food waste in the best possible way, a better education of both industry and the consumer is considered necessary, introducing all to change the ways of production and living. The consumer has to understand the need to privilege, food, cosmetics and goods by selecting products known to be effective that also have a low release of carbon dioxide. Thus, they must pay heed to purchasing cosmetics and medical devices made by natural ingredients and packaged by biodegradable and/or reusable containers that are possibly plastic free. Conversely, the industry must try to use natural raw materials obtained from waste by changing their actual production methods. Therefore, both industry and the consumer should depart from the linear economy, which is based on taking, making, and producing waste, to move into a circular economy, which is based on redesigning, reducing, reusing and recycling. Some examples will report on the possibility to use natural polymers, including chitin and lignin, to produce new cosmeceutical tissues. These innovative tissues, to be used as biodegradable carriers for making smart cosmetics and medical devices, may be produced at zero waste to save our health and the planet biodiversity.

Olive Pomace and Pâté Olive Cake as Suitable Ingredients for Food and Feed

Olive oil extraction generates several by-products that represent an environmental issue, mainly for Mediterranean countries where olive oil is mostly produced. These by-products represent an ecological issue for their phenolic components, such as oleuropein, hydroxytyrosol, and tyrosol. However, olive oil by-products can be treated and properly exploited in different fields for their health-promoting properties, and they represent great potential for the food and beverage, cosmetic, and pharmaceutical industries. Furthermore, recovery and treatment processes can contribute to efficient waste management, which can enhance the sustainability of the olive oil industry, and in turn, lead to relevant economic benefits. The solid waste, i.e., olive pomace, could be considered to be a suitable matrix or primary resource of molecules with high added value due to their high phenolic content. Olive pomace, at different moisture contents, is the main by-product obtained from two- or three-phase extraction systems. A commonly used centrifugal extraction system, i.e., a multiphase decanter (DMF), does not require the addition of water and can generate a new by-product called pâté or olive pomace cake, consisting of moist pulp that is rich in phenols, in particular, secoiridoids, without any trace of kernel. Although several reviews have been published on olive wastes, only a few reviews have specifically focused on the solid by-products. Therefore, the aim of the present review is to provide a comprehensive overview on the current valorization of the main solid olive oil by-products, in particular, olive pomace or pâté olive cake, highlighting their use in different fields, including human nutrition.

Enrichment of Refined Olive Oils with Phenolic Extracts of Olive Leaf and Exhausted Olive Pomace

Refined olive oils (ROOs) are commonly enriched with synthetic antioxidants. Antioxidant extracts obtained from natural products can be used to improve the stability of these oils. In this study, ROOs were enriched through the addition of phenolic extracts from olive leaves (OLs) and exhausted olive pomace (EOP). In addition to replacing synthetic antioxidants with natural ones, this results in the valorization of these olive-derived biomasses. The most suitable method for mixing and enriching refined oils was probe-type ultrasonication using lecithin as the emulsifier. Thereafter, the change in the content of antioxidant compounds and the antioxidant capacity of the oils at 25, 35, and 45 °C were studied over 28 and 50 days of storage. The experimental results were fitted using a pseudo-first-order kinetic model. The oxidative stability index of the ROO enriched with a 2 g/L OL extract (70 h) was higher than that of a commercial ROO (46.8 h). Moreover, the oxidative stability index of the refined olive pomace oil (ROPO) enriched with a 2 g/L EOP extract (44.1 h) was higher than that of a commercial ROPO (38.9 h). In addition, the oxidative stabilities and antioxidant capacities of the oils were significantly correlated.

Influence of genetic and interannual factors on bioactive compounds of olive pomace determined through a germplasm survey

Olive mill wastes, generated in the extraction of virgin olive oil (VOO), are of important concern for the industry owing to the produced volume and polluting load, mainly associated with the presence of organic compounds. Among them, it is worth mentioning bioactive compounds, mainly phenols and triterpenes, which could be potentially isolated for further use in the cosmetic, pharmaceutical, or food industries. This research analyzed the olive pomace after extraction of VOO from fruits harvested of 43 international olive cultivars during three consecutive seasons. The cultivar was identified as the most determinant factor to explain the variability in the relative concentration of phenols and terpenic acids in the extracts. In addition, the characterization of olive pomace extracts allowed clustering cultivars according to the profile of bioactive compounds. Finally, we identified the components responsible for the observed discrimination that was explained according to biosynthetic metabolic pathways.

Extraction, Purification and In Vitro Antioxidant Activity Evaluation of Phenolic Compounds in California Olive Pomace

Olive pomace (OP) is a valuable food byproduct that contains natural phenolic compounds with health benefits related to their antioxidant activities. Few investigations have been conducted on OP from the United States while many studies on European OP have been reported. OP of Arbequina, the most common cultivar from California, was collected and extracted by water, 70% methanol and 70% ethanol, followed by purification using macroporous absorbing resin. Results showed that the extractable total phenolic content (TPC) was 36–43 mg gallic acid equivalents (GAE)/g in pitted, drum-dried defatted olive pomace (DOP), with major contributions from hydroxytyrosol, oleuropein, rutin, verbascoside, 4-hydroxyphenyl acetic acid, hydroxytyrosol-glucoside and tyrosol-glucoside. Macroporous resin purification increased TPC by 4.6 times the ethanol crude extracts of DOP, while removing 37.33% total sugar. The antioxidant activities increased 3.7 times Trolox equivalents (TrE) by DPPH and 4.7 times TrE by ferric reducing antioxidant power (FRAP) in the resin purified extracts compared to the ethanol crude extracts. This study provided a new understanding of the extraction of the bioactive compounds from OP which could lead to practical applications as natural antioxidants, preservatives and antimicrobials in clean-label foods in the US.

Elderberry Stalks as a Source of High-Value Phytochemical: Essential Minerals and Lipophilic Compounds

Elderberry (Sambucus nigra L.) consumption has been growing in the last years, generating a large number of stalks (~10% of the berries bunch) that are still under-valorized. This study focused on the evaluation of elderberry stalks as a source of high-value phytochemicals. In this vein, the essential mineral content and lipophilic composition were analyzed for the first time. In addition, the polar fraction was evaluated regarding its total phenolic content (TPC) and antioxidant activity by both 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assays. The lipophilic fraction was mainly composed of triterpenic acids (2902.20 mg kg−1 of dry weight (dw)), fatty acids (711.73 mg kg−1 dw) and sterols (288.56 mg kg−1 dw). Minor amounts of long-chain aliphatic alcohols and other components were also detected. Ursolic acid (2265.83 mg kg−1 dw), hexadecanoic acid (219.85 mg kg−1 dw) and β-sitosterol (202.74 mg kg−1 dw) were the major lipophilic components verified. The results of this study also indicated that elderberry stalks might be used as a natural source of essential minerals, particularly calcium, iron and potassium, which are known to play important roles in various body functions. The analysis of the polar fraction also showed that elderberry stalks present TPC as high as elderberry themselves as well as considerable antioxidant activity (1.04 and 0.37 mmol TE g−1 of extract, against respectively ABTS and DPPH radicals). These results highlight the potential of elderberry stalks as a natural source of high-value phytochemicals that may be explored in several fields.

Effects of Sargassum thunbergii Extract on Skin Whitening and Anti-Wrinkling through Inhibition of TRP-1 and MMPs

Sargassum thunbergii has been traditionally used as an edible and medicinal material in oriental countries. However, the skin-whitening and anti-wrinkling effects of S. thunbergii have not yet been investigated. This study was conducted to establish optimal extraction conditions for the production of bioactive compounds with antioxidant activity as well as skin-whitening and anti-wrinkle effects using ultrasound-assisted extraction (UAE) in S. thunbergii. The extraction time (5.30~18.7 min), extraction temperature (22.4~79.6 °C), and ethanol concentration (0.0~99.5%), which are the main variables of the UAE, were optimized using a central composite design. Quadratic regression equations were derived based on experimental data and showed a high coefficient of determination (R2 > 0.85), demonstrating suitability for prediction. The optimal UAE condition for maximizing all dependent variables, including radical scavenging activity (RSA), tyrosinase inhibitory activity (TIA), and collagenase inhibitory activity (CIA), was identified as an extraction time of 12.0 min, an extraction temperature of 65.2 °C, and ethanol of 53.5%. Under these conditions, the RSA, TIA, and CIA of S. thunbergii extract were 86.5%, 88.3%, and 91.4%, respectively. We also confirmed S. thunbergii extract had inhibitory effects on the mRNA expression of tyrosinase-related protein-1, matrix metalloproteinase-1, and matrix metalloproteinase-9, which are the main genes of melanin synthesis and collagen hydrolysis. Liquid chromatography-tandem mass spectrometry was used to identify the main phenolic compounds in S. thunbergii extract, and caffeic acid was identified as a major peak, demonstrating that high value-added ingredients with skin-whitening and anti-wrinkling effects can be produced from S. thunbergii and used for developing cosmetic materials.

Valorisation of food agro-industrial by-products: From the past to the present and perspectives

Food agro-industrial by-products mainly include peels, seeds, stems, bagasse, kernels, and husk, derived during food processing. Due to their overproduction and the lack of sustainable management, such by-products have been conventionally rejected and wasted in landfills, being the principal strategy for their treatment, but nowadays, this strategy has been associated with several environmental, social and economic issues. Hence, we focused on the use of different consolidated biotechnological processes and methodologies as suitable strategies for food by-products management and valorisation, highlighting them as potential bioresources because they still gather high compositional and nutritional value, owing to their richness in functional and bioactive molecules with human health benefits. Food by-products could be utilised for the development of new food ingredients or products for human consumption, promoting their integral valorisation and reincorporation to the food supply chain within the circular bioeconomy concept, creating revenue streams, business and job opportunities. In this review, the main goal was to provide a general overview of the food agro-industrial by-products utilised throughout the years, improving global sustainability and human nutrition, emphasising the importance of biowaste valorisation as well as the methodologies employed for the recovery of value-added molecules.

Applications of bioactive compounds extracted from olive industry wastes: A review

The wastes generated during the olive oil extraction process, even if presenting a negative impact for the environment, contain several bioactive compounds that have considerable health benefits. After suitable extraction and purification, these compounds can be used as food antioxidants or as active ingredients in nutraceutical and cosmetic products due to their interesting technological and pharmaceutical properties. The aim of this review, after presenting general applications of the different types of wastes generated from this industry, is to focus on the olive pomace produced by the two-phase system and to explore the challenging applications of the main individual compounds present in this waste. Hydroxytyrosol, tyrosol, oleuropein, oleuropein aglycone, and verbascoside are the most abundant bioactive compounds present in olive pomace. Besides their antioxidant activity, these compounds also demonstrated other biological properties such as antimicrobial, anticancer, or anti-inflammatory, thus being used in formulations to produce pharmaceutical and cosmetic products or in the fortification of food. Nevertheless, it is mandatory to involve both industries and researchers to create strategies to valorize these byproducts while maintaining environmental sustainability.

Health benefits of first and second extraction drum-dried pitted olive pomace

Olive pomace (OP) is the main by-product of olive oil extraction. After pit and skin removal, OP pulp has high concentrations of dietary fiber and phenolics with high antioxidant capacity. This study evaluated mice health benefits of drum-dried pitted OP pulp obtained after first and second oil extraction. Fresh OP was steam blanched, then pits and skins separated in a pulper/finisher, and pulp drum-dried and milled. OP was characterized by proximate analysis, total soluble phenolics (TSP), individual phenolics, and dietary fiber. Drum-dried pitted OP from first and second extraction was formulated at 10% and 20% in a high fat mice diet. Low fat (5%) and high fat (18%) control diets were also used for comparison. First extraction OP had higher TSP than OP from second extraction. Hydroxytyrosol was the main phenolic in OP. Mice weight gain was lower for the four OP diets compared to high and low-fat control diets. Fecal protein was high for all OP diets, indicating poor protein retention in mice, possibly by phenolics binding of protein and enzymes. Liver weight and adipose tissue were lower in mice consuming the four high fat OP diets compared to high fat control diet. Also, there was no effect on blood glucose by OP in diets. Mice gut microbiota analysis indicated that Actinobacteria decreased in the OP diets compared to the two control diets while Bacteroidetes increased, indicating a positive correlation with reduced body fat and weight. Drum-dried pitted OP is a novel agricultural by-product with its bioactive compounds having the potential to be incorporated in feeds and foods providing health benefits. PRACTICAL APPLICATION: Drum-dried pitted olive pomace can be produced from first or second olive oil extraction byproducts to be used as a shelf-stable healthy food or feed supplement.

Olive Pomace Phenolic Compounds Stability and Safety Evaluation: From Raw Material to Future Ophthalmic Applications

Nowadays, increasing interest in olive pomace (OP) valorization aims to improve olive's industry sustainability. Interestingly, several studies propose a high-value application for OP extracts containing its main phenolic compounds, hydroxytyrosol and oleuropein, as therapy for ocular surface diseases. In this work, the stability and accessibility of OP total phenolic and flavonoid content, main representative compounds, and antioxidant activity were assessed under different pretreatment conditions. Among them, lyophilization and supercritical CO₂ extraction were found to increase significantly most responses measured in the produced extracts. Two selected extracts (CONV and OPT3) were obtained by different techniques (conventional and pressurized liquid extraction); Their aqueous solutions were characterized by HPLC-DAD-MS/MS. Additionally, their safety and stability were evaluated according to EMA requirements towards their approval as ophthalmic products: their genotoxic effect on ocular surface cells and their 6-months storage stability at 4 different temperature/moisture conditions (CPMP/ICH/2736/99), together with pure hydroxytyrosol and oleuropein solutions. The concentration of hydroxytyrosol and oleuropein in pure or extract solutions was tracked, and possible degradation products were putatively identified by HPLC-DAD-MS/MS. Hydroxytyrosol and oleuropein had different stability as standard or extract solutions, with oleuropein also showing different degradation profile. All compounds/extracts were safe for ophthalmic use at the concentrations tested.

Chemical Composition and Antimicrobial Activity of a New Olive Pomace Functional Ingredient

Olive pomace, an olive oil processing byproduct, can be upcycled and meet the current demand for natural and sustainable food ingredients. In this work, a patented process was used to obtain a functional ingredient from different olive pomaces. The nutritional, chemical and antioxidant profiles, as well as the antimicrobial activity against S. aureus, E. coli and C. albicans, were investigated for the first time. The amount of phenolics ranged between 3.1 and 3.8 g gallic acid eq./100 g in all samples and flavonoids between 2.0 and 3.2 g catechin eq/100 g. No significant differences were found regarding the antioxidant activity. The total fat varied between 5 and 11%, α-tocopherol being the major vitamer and oleic acid the main fatty acid. The protein and ash contents were 1–4% and 10–17%, respectively. The functional ingredient with a higher hydroxytyrosol content (220 mg/100 g) also presented the best minimal inhibitory concentration against the tested bacteria. No activity against C. albicans was verified. This new functional ingredient presents the potential to be used as a natural preservative or as a nutritional profile enhancer. Moreover, it can be an advantageous ingredient in food products, since it comprises specific lipid and hydrophilic bioactive compounds usually not present in other plant extracts.

Whole or Defatted Sesame Seeds (Sesamum indicum L.)? The Effect of Cold Pressing on Oil and Cake Quality

Whole sesame seeds and sesame oil, which is obtained after cold pressing the seeds, are foodstuffs globally consumed due to their nutritional characteristics. The press cake that remains from the oil extraction process can be ground to form a defatted flour that can be incorporated into the human diet, contributing to the valorisation of this product. The nutritional comparison between the whole seeds and the press cake reveals the potential of this by-product to be incorporated in the formulation of diverse foodstuff, since it is richer than the seeds in proteins (30%) and fibre (25%) and still contains a proportion of oil (32%) with a fatty acid pattern characterized by the abundance of unsaturated fatty acids. The protein fraction of both the seeds and the cake shows a balanced composition regarding amino acid composition, with all the essential amino acids included. On the other hand, the oil obtained by cold pressing is shown as a high-quality oil, where the predominant fatty acids are oleic (42.66%) and linoleic (41.25%), which are essential fatty acids because they are not synthetised in the organism and must be obtained through the diet. In addition, it is rich in vitamin E, especially in γ-tocopherol, that was the main isomer found. Regarding these results, all products (sesame seeds, oil and press cake) are components suitable to be included in a healthy diet.

Phenolic Compounds from Irradiated Olive Wastes: Optimization of the Heat-Assisted Extraction Using Response Surface Methodology

Olive pomace, an environmentally detrimental residue generated during olive oil extraction, contains bioactive compounds in demand by the food industry. To valorize this waste product a suitable yield for the extraction process is required. Heat-assisted extraction of bioactive compounds from olive pomace was optimized by a circumscribed central composite design and response surface methodology. Our previous studies indicated that irradiation could improve 2.4-fold the extractability of the main phenolic compounds from olive pomace. The effect of extraction time, temperature and solvent concentration on the yield of polyphenols from irradiated olive pomace at 5 kGy was tested. Hydroxytyrosol-1-β-glucoside, hydroxytyrosol, tyrosol and caffeic acid were quantified by High Performance Liquid Chromatography to calculate the total polyphenol content. The optimal general conditions by RSM modeling were extraction time of 120 min, temperature of 85 °C, and 76% of ethanol in water. Using these selected conditions, 19.04 ± 1.50 mg/g dry weight, 148.88 ± 8.73 mg/g extract of total polyphenols were obtained, representing a yield of 13.7%, which was consistent with the value predicted by the model. This work demonstrated the potential of residues from the olive oil industry as a suitable alternative to obtain compounds that could be used as ingredients for the food industry.

Encapsulation of Olive Pomace Extract in Rocket Seed Gum and Chia Seed Gum Nanoparticles: Characterization, Antioxidant Activity and Oxidative Stability

The aim of this study was to determine the potential use of rocket seed and chia seed gum as wall materials, to encapsulate and to prevent degradation of olive pomace extract (OPE) in polymeric nanoparticles, and to characterize olive pomace extract-loaded rocket seed gum nanoparticles (RSGNPs) and chia seed gum nanoparticles (CSGNPs). The phenolic profile of olive pomace extract and physicochemical properties of olive pomace, rocket seed gum (RSG), and chia seed gum (CSG) were determined. The characterization of the nanoparticles was performed using particle size and zeta potential measurement, differential scanning calorimeter (DSC), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), encapsulation efficiency (EE%), in vitro release, and antioxidant activity analyses. Nanoparticles were used to form oil in water Pickering emulsions and were evaluated by oxitest. The RSGNPs and CSGNPs showed spherical shape in irregular form, had an average size 318 ± 3.11 nm and 490 ± 8.67 nm, and zeta potential values of −22.6 ± 1.23 and −29.9 ± 2.57, 25 respectively. The encapsulation efficiency of the RSGNPs and CSGNPs were found to be 67.01 ± 4.29% and 82.86 ± 4.13%, respectively. The OPE-RSGNP and OPE-CSGNP presented peaks at the 1248 cm⁻¹ and 1350 cm⁻¹ which represented that C-O groups and deformation of OH, respectively, shifted compared to the OPE (1252.53 cm⁻¹ and 1394.69 cm⁻¹). The shift in wave numbers showed interactions of a phenolic compound of OPE within the RSG and CSG, respectively. In vitro release study showed that the encapsulation of OPE in RSGNPs and CSGNPs led to a delay of the OPE released in physiological pH. The total phenolic content and antioxidant capacity of RSGNPs and CSGNPs increased when the OPE-loaded RSGNPs and CSGNPs were formed. The encapsulation of OPE in RSGNPs and CSGNPs and the IP values of the oil in water Pickering emulsions containing OPE-RSGNPs and OPE-CSGNPs were higher than OPE, proving that OPE-loaded RSGNPs and CSGNPs significantly increased oxidative stability of Pickering emulsions. These results suggest that the RSG and CSG could have the potential to be utilized as wall materials for nanoencapsulation and prevent degradation of cold-pressed olive pomace phenolic extract.