Applications of Wine Pomace in the Food Industry: Approaches and Functions

Non-Extractable Polyphenols from Food By-Products: Current Knowledge on Recovery, Characterisation, and Potential Applications

Non-extractable polyphenols (NEPs), or bound polyphenols, are a significant fraction of polyphenols that are retained in the extraction residues after conventional aqueous organic solvent extraction. They include both high molecular weight polymeric polyphenols and low molecular weight phenolics attached to macromolecules. Current knowledge proved that these bioactive compounds possess high antioxidant, antidiabetic, and other biological activities. Plant-based food by-products, such as peels, pomace, and seeds, possess high amount of NEPs. The recovery of these valuable compounds is considered an effective way to recycle food by-products and mitigate pollution, bad manufacturing practice, and economic loss caused by the residues management. The current challenge to valorise NEPs from plant-based by-products is to increase the extraction efficiency with proper techniques, choose appropriate characterising methods, and explore potential functions to use in some products. Based on this scenario, the present review aims to summarise the extraction procedure and technologies applied to recover NEPs from plant-based by-products. Furthermore, it also describes the main techniques used for the characterisation of NEPs and outlines their potential food, pharmaceutical, nutraceutical, and cosmetic applications.

Extraction of Antioxidants from Winemaking Byproducts: Effect of the Solvent on Phenolic Composition, Antioxidant and Anti-Cholinesterase Activities, and Electrochemical Behaviour

Extraction solvent is a very important factor in the recovery of antioxidants from natural matrices. In this study, the effect of three solvents (ethanol, ethanol/water and water) on the phenolic composition, antioxidant and anti-cholinesterase activities and electrochemical behaviour of four winemaking byproducts (seeds, skins, stems, and pomace) was evaluated. Phenolic composition was determined by the Folin-Ciocalteu method and ultra-high-performance liquid chromatography (UHPLC), antioxidant activity by the capacity to scavenge 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radicals, anti-cholinesterase activity by the Ellman's method, and electrochemical behaviour by cyclic voltammetry. Eight phenolic compounds were quantified with higher content in water/ethanol extracts (e.g., epicatechin in pomace: 17 mg/100 g vs. 7 and 6 mg/100 g in ethanol and water extracts, respectively), although there were some exceptions (e.g., gallic acid in seeds was most abundant in water extracts). Moreover, the highest total phenolic content (TPC) and antioxidant activity were found in ethanol/water extracts (between 2 and 30-fold the values of the other extracts). Overall, the most active extracts in inhibiting both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were ethanol/water and ethanol extracts from seeds (between 31.11 and 53.90%). The electrochemical behaviour allowed for differentiating the extracts depending on the solvent and the byproduct. Our findings indicate that winemaking byproducts represent a source of phenolic compounds with antioxidant and anti-cholinesterase activities and suggest that cyclic voltammetry is a promising technique to evaluate the phenolic extraction process from these byproducts.

Potential of grape byproducts as functional ingredients in baked goods and pasta

Wine making industry generates high quantities of valuable byproducts that can be used to enhance foods in order to diminish the environmental impact and to obtain more economic benefits. Grape byproducts are rich in phenolic compounds and dietary fiber, which make them suitable to improve the nutritional value of bakery, pastry, and pasta products. The viscoelastic behavior of dough and the textural and the sensory characteristics of baked goods and pasta containing grape byproducts depend on the addition level and particle size. Thus, an optimal dose of a finer grape byproducts flour must be found in order to minimize the negative effects such as low loaf volume and undesirable sensory and textural characteristics they may have on the final product quality. In the same time, an enrichment of the nutritional and functional value of the product by increasing the fiber and antioxidant compounds contents is desired. The aim of this review was to summarize the effects of the chemical components of grape byproducts on the nutritional, functional, rheological, textural, physical, and sensory characteristics of the baked goods and pasta. Further researches about the impact of foods enriched with grape byproducts on the human health, about molecular interactions between components, and about the effects of grape pomace compounds on the shelf life of baked goods and pasta are recommended.

Eco-Conversion of Two Winery Lignocellulosic Wastes into Fillers for Biocomposites: Vine Shoots and Wine Pomaces

Two winery residues, namely vine shoots (ViSh) and wine pomace (WiPo), were up-cycled as fillers in PHBV-based biocomposites. Answering a biorefinery approach, the impact of a preliminary polyphenols extraction step using an acetone/water mixture on the reinforcing effect of fillers was assessed. Biocomposites (filler content up to 20 wt%) were prepared by melt-mixing and compared in terms of final performance (thermal, mechanical and barrier). It was shown that the reinforcing effect was slightly better in the case of vine shoots, while it was not significantly affected by the pre-treatment, demonstrating that these two winery residues could be perfectly used as fillers in composite materials even after an extraction process to maximize their potential of valorization.

Antioxidant, Anti-Inflammatory and Antiproliferative Effects of the Vitis vinifera L. var. Fetească Neagră and Pinot Noir Pomace Extracts

The pathophysiology of inflammation and oxidative stress generated during different types of cancers and anticancer treatments is well documented. Traditionally, grape pomace is used for animal feed, organic fertilizers, ethanol production or is disposed as waste. Because grape pomace is a rich source of antioxidant compounds, the purpose of the study was to evaluate the antioxidant, anti-inflammatory, and antiproliferative effects of fresh and fermented grape pomace extracts of two Vitis vinifera L. varieties Fetească neagră and Pinot noir cultivated in Romania. Firstly, grape pomace phytochemical analysis and in vitro antioxidant tests were performed. Secondly, the effect of a seven-day pretreatment with grape pomace extracts on the turpentine oil-induced inflammation in rats was assessed by measuring total oxidative status, total antioxidant response, oxidative stress index, malondialdehyde, total thiols, nitric oxide and 3-nitrotyrosine. Thirdly, the antiproliferative properties were evaluated on human lung carcinoma (A549), human breast adenocarcinoma (MDA-MB-231), murine melanoma (B164A5), and keratinocyte (HaCat) cell lines. Fetească neagră and Pinot noir grape pomace extracts have a rich content of polyphenols and in vitro antioxidant effect. Fermented samples had higher polyphenol content, but fresh samples had better antioxidant activity. Pretreatment with grape pomace extracts reduced inflammation-induced oxidative stress in a concentration-dependent way, fresh samples being more efficient. The malignant cells' proliferation was inhibited by all grape pomace extracts, fermented Fetească neagră extracts having the strongest effect. Conclusion: fresh and fermented pomace extracts of Vitis vinifera L. varieties Fetească neagră and Pinot noir cultivated in a Romanian wine region have antioxidant, anti-inflammatory and antiproliferative effects.

From winery waste to bioactive compounds and new polymeric biocomposites: A contribution to the circular economy concept

The paper aims at optimising and validating possible routes toward the full valorisation of grape agrowaste to produce bioactive molecules and new materials. Starting from Merlot red pomace, phenol complex mixtures were successfully extracted by using two different approaches. Extracts obtained by solvent-based (SE) technique contained up to 46.9 gGAeq/kgDW of total phenols. Depending on the used solvent, the prevalence of compounds belonging to different phenol families was achieved. Pressurized liquid extraction (PLE) gave higher total phenol yields (up to 79 gGAeq/kgDW) but a lower range of extracted compounds. All liquid extracts exerted strong antioxidant properties. Moreover, both SE and PLE extraction solid residues were directly exploited (between 5 and 20% w/w) to prepare biocomposite materials by direct mixing via an eco-friendly approach with PHBV polymer. The final composites showed mechanical characteristics similar to PHVB matrix. The use of pomace residues in biocomposites could therefore bring both to the reduction of the cost of the final material, as a lower amount of costly PHBV is used. The present research demonstrated the full valorisation of grape pomace, an agrowaste produced every year in large amounts and having a significant environmental impact.

Integrated biorefinery approach to valorize winery waste: A review from waste to energy perspectives

The ever-increasing environmental crisis, depleting natural resources, and uncertainties in fossil fuel availability have rekindled researchers' attention to develop green and environmentally friendlier strategies. In this context, a biorefinery approach with a zero-waste theme has stepped-up as the method of choice for sustainable production of an array of industrially important products to address bio-economy challenges. Grape winery results in substantial quantities of solid organic and effluent waste, which epitomizes an increasing concentration of pollution problems with direct damage to human health, economy and nature. From the perspective of integrated biorefinery and circular economy, winery waste could be exploited for multiple purpose value-added products before using the biomass for energy security. This review covers state-of-the-art biorefinery opportunities beyond traditional methods as a solution to overcome many current challenges such as waste minimization in grape leaves, stems, seeds, pomace, wine lees, vinasse etc. and the biosynthesis of various high-value bioproducts viz., phenolic compounds, hydroxybenzoic acids, hydroxycinnamic acids, flavonoids, tartaric acids, lignocellulosic substrates etc.. The critical discussion on the valorization of winery waste (solid, liquid, or gaseous) and life cycle assessment was deployed to find a sustainable solution with value added energy products in an integrated biorefinery approach, keeping the environment and circular economy in the background.

Effect of Experimental Parameters on the Extraction of Grape Seed Oil Obtained by Low Pressure and Supercritical Fluid Extraction

Grape seeds are an important byproduct from the grape process. The objective of this work was to evaluate the effect of experimental parameters (temperature and time of pretreatment with ultrasound) to obtain grape seed oil using low pressure (Soxhlet-Sox and Bligh Dyer-BD) and high pressure (supercritical carbon dioxide-SFE) methods. The best condition for pretreatment of samples was 30 min of sonication at 30 °C before extraction by Sox or BD. Ultrasound pretreatment was efficient to increase oil extraction yield by 32.10 (Sox), 20.31 (BD) and 12.54% (SFE), depending on the extraction method used as well as, and certainly influenced the total phenolic concentration in 311 (Sox), 234 (BD), and 184 (SFE)%. Ten fatty acids were identified in the oils, the major ones being 18:2ω-6cis (linoleic 52.39%-63.12%), 16:0 (palmitic 20.22%-26.80%) and 18:0 (stearic 8.52%-13.68%). The highest epicatechin concentration was identified in the BD sample: 30-30 (150.49 ± 5.98mg/kg), which presented a concentration of ≥3 times compared to the control (56.68 ± 1.81mg/kg). Ultrasound pretreatment also contributed positively (56% and 99% increase) in the α-tocopherol content of the SFE: 30-30 and BD: 30-30 samples, respectively. The results indicate that the ultrasound pretreatment is a suitable technology to improve the quality of the oil from the grape seed.

Glycerol as Alternative Co-Solvent for Water Extraction of Polyphenols from Carménère Pomace: Hot Pressurized Liquid Extraction and Computational Chemistry Calculations

Glycerol is a co-solvent for water extraction that has been shown to be highly effective for obtaining polyphenol extracts under atmospheric conditions. However, its efficacy under subcritical conditions has not yet been studied. We assessed different water-glycerol mixtures (15%, 32.5%, and 50%) in a hot pressurized liquid extraction system (HPLE: 10 MPa) at 90 °C, 120 °C, and 150 °C to obtain extracts of low molecular weight polyphenols from Carménère grape pomace. Under the same extraction conditions, glycerol as a co-solvent achieved significantly higher yields in polyphenols than ethanol. Optimal extraction conditions were 150 °C, with 32.5% glycerol for flavonols and 50% for flavanols, stilbenes, and phenolic acids. Considering gallic acid as a model molecule, computational chemistry calculations were applied to explain some unusual extraction outcomes. Furthermore, glycerol, methanol, ethanol, and ethylene glycol were studied to establish an incipient structure-property relationship. The high extraction yields of gallic acid obtained with water and glycerol solvent mixtures can be explained not only by the additional hydrogen bonds between glycerol and gallic acid as compared with the other alcohols, but also because the third hydroxyl group allows the formation of a three-centered hydrogen bond, which intensifies the strongest glycerol and gallic acid hydrogen bond. The above occurs both in neutral and deprotonated gallic acid. Consequently, glycerol confers to the extraction solvent a higher solvation energy of polyphenols than ethanol.

Biotransformation of grape pomace from Vitis labrusca by Peniophora albobadia LPSC # 285 (Basidiomycota)

Grape pomace from Vitis labrusca is an important sub-product of the "American table wine" industry. It is recalcitrant to degradation, and its accumulation is a serious problem with negative environmental impacts. We analyzed the ability of five white-rot fungi to transform this residue in-vitro. Mass loss and phenol removal in grape pomace treated with each fungus were compared after 30-day solid-state fermentation. Since Peniophora albobadia isolate LPSC 285 was the fungus that showed the highest degradative ability and the lowest free phenol levels in the residue transformed, we selected this fungus to monitor its effect on this residue after 30, 60, and 90 days of incubation. We analyzed mass loss of the residue caused by the fungus activity and its chemical changes using Fourier transform infrared spectroscopy. After 90 days of incubation, Peniophora albobadia isolate LPSC 285 reduced grape pomace mass by 20.48%, which was associated with degradation of polysaccharides and aromatic structures. We concluded that Peniophora albobadia LPSC # 285 isolate is a promising fungus to transform grape pomace from Vitis labrusca under solid-state fermentation conditions.

The Dissipation of Cyazofamid and Its Main Metabolite CCIM During Wine-Making Process

Few studies have focused on the residues of cyazofamid and its main metabolite CCIM (4-chloro-5-p-tolylimidazole-2-carbonitrile) in the wine making process, which is crucial to evaluate the potential food risk of cyazofamid and CCIM. In this work, detailed study has been conducted on the evaluation of the fate of cyazofamid and its main metabolite CCIM during the wine-making process. The targeted compounds cyazofamid and CCIM were separated and determined by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) and processing procedure including washing, peeling, fermentation, and clarification. Results showed that residues of cyazofamid and CCIM decreased significantly in wine processing. The dissipation of cyazofamid in the fermentation process followed the first-order of kinetics, and the half-life of cyazofamid was 46.2-63.0 h, whereas, the residues of CCIM, in the three treatments, decreased with time elapse. The processing factors (PFs) were all less than one in different processing processes, and the PFs ranges of cyazofamid and CCIM were 0.003-0.025 and 0.039-0.067 in three treatments in the overall process. The outcome indicated that the whole process could significantly reduce the residues of cyazofamid and CCIM in red and white wines. The results might provide more precise risk assessments of cyazofamid in the wine-making process.

Utilization of Grape Seed Extract as a Natural Antioxidant in the Technology of Meat Products Inoculated with a Probiotic Strain of LAB

Grape seeds have been evaluated for use as food ingredients with stabilizing effects in meat technology. A pork neck, inoculated with probiotic monoculture (Lactobacillus rhamnosus LOCK900), was used as the matrix. The study compared the antioxidant potential of grape seed extract to sodium ascorbate. Three experimental variants of the products were prepared: With grape seed extract, with sodium ascorbate, and without additives. The meat ripened for two months, and during this period of time biophysicochemical analyses (product color, pH, number of lactic acid bacteria, content of free fatty acids, and thiobarbituric acid reactive substances) were carried out. It was found that the extract inhibited lipid hydrolysis occurring in the neck (1% of oleic acid) and limited oxidative processes (0.46 mg MDA kg-1), with efficacy similar to that of sodium ascorbate (0.9% of oleic acid and 0.53 mg MDA kg-1, respectively). No limitation of the desired lactic acid bacteria growth (approximately 7 log cfu g-1) was noticed in the meat samples with the extract. The results are optimistic because they indicate that not only is it possible to produce fermented pork neck inoculated with probiotic, but there are also no obstacles to utilizing grape seed extract as a natural antioxidant in this technology.

Sangiovese cv Pomace Seeds Extract-Fortified Kefir Exerts Anti-Inflammatory Activity in an In Vitro Model of Intestinal Epithelium Using Caco-2 Cells

Inflammatory bowel disease and food allergies are a growing topic in the field of nutrition science. Polyphenols, which are the most important secondary metabolites of plants, demonstrated to modulate the expression and/or production of numerous proteins, but also to regulate the intestinal ecosystem. In this context, our aim was the investigation of protective effects against the gastrointestinal mucosa of fortified milk kefir obtained by adding seeds extract from Sangiovese cv. Pomace. Methods: An ultrasound-assisted method was used to obtain the extracts. All the extracts were assayed for the antioxidant activity. The best extract was used as an additive of fermented milk kefir to obtain a fortified final product. Kefir samples were analyzed by NMR spectroscopy. The efficiency of the barrier functions was evaluated by measuring trans-epithelial electric resistance (TEER) using a voltmeter. Results: the enriched kefir (Ksgn) possesses higher antioxidant performances compared to the unfortified sample (Kwht). Kwht and Ksgn did not alter Caco-2 TEER in basal condition.

Fungal transformation and reduction of phytotoxicity of grape pomace waste

Grape pomace (GP) from Vitis labrusca, the main byproduct from "American table wine" production, is recalcitrant to degradation, and its accumulation is a serious problem with negative environmental impacts. In this work, transformation of grape pomace using a steam pretreatment followed by incubation of GP during a 90-day period with six different fungi were evaluated. Several fungi tested reduced the phytotoxicity of water-soluble fraction (WSFd) from steam-pretreated GP after 90 days' incubation to lettuce and tomato seeds. U. botrytis caused the largest effective phytotoxicity reduction of WSFd (used in the concentration range of 10-1.25% p/v) and was the only fungus causing the removal of monoaromatic compounds. Therefore, this procedure with U. botrytis effectively reduces the availability of phytotoxic monoaromatic compounds in GP, which opens a way for the development of guidelines for the management of these wastes and their potential use as organic amendments in agricultural soil.

Bacterial Cellulose: Production, Modification and Perspectives in Biomedical Applications

Bacterial cellulose (BC) is ultrafine, nanofibrillar material with an exclusive combination of properties such as high crystallinity (84%-89%) and polymerization degree, high surface area (high aspect ratio of fibers with diameter 20-100 nm), high flexibility and tensile strength (Young modulus of 15-18 GPa), high water-holding capacity (over 100 times of its own weight), etc. Due to high purity, i.e., absence of lignin and hemicellulose, BC is considered as a non-cytotoxic, non-genotoxic and highly biocompatible material, attracting interest in diverse areas with hallmarks in medicine. The presented review summarizes the microbial aspects of BC production (bacterial strains, carbon sources and media) and versatile in situ and ex situ methods applied in BC modification, especially towards bionic design for applications in regenerative medicine, from wound healing and artificial skin, blood vessels, coverings in nerve surgery, dura mater prosthesis, arterial stent coating, cartilage and bone repair implants, etc. The paper concludes with challenges and perspectives in light of further translation in highly valuable medical products.

Application of the Just-About-Right Scales in the Development of New Healthy Whole-Wheat Muffins by the Addition of a Product Obtained from White and Red Grape Pomace

The aim of this study was to evaluate the adequacy of sensory attributes, by the use of just-about-right (JAR) scales and penalty analysis, of new healthy whole-wheat muffins with high fibre content due to the addition of two products obtained from white and red grape pomace. Furthermore, the nutritional, colour and texture properties of the muffins were evaluated. For that, five formulations of whole-wheat muffins were studied: a control muffin made with 100% whole-wheat flour and muffins made with 10 and 20% of white and red grape pomace product, respectively. The incorporation of grape pomace products in the recipe led to muffins with "high-fibre content", which would imply healthy properties in these muffins. The hardness and chewiness increased whereas the springiness, cohesiveness, resilience and colour parameters decreased when the grape pomace products were incorporated. The sensory analysis indicated high levels of acceptability of the muffins that incorporated white and red grape pomace products at concentrations of 10%. The penalty analysis showed that none of the attributes evaluated affected the acceptability of the new muffins significantly; only the darker colour of the muffins caused by the red grape pomace product could affect the acceptability, although this fact was not clearly demonstrated.

Effects of feeding increasing levels of grape (Vitis vinifera cv. Pinotage) pomace on lamb shelf-life and eating quality

The study evaluated shelf-life and sensory quality of meat from lambs fed finisher diets containing increasing levels of grape pomace (GP; 0, 5, 10, 15 and 20% GP/kg DM). Color, antioxidant activity and lipid oxidation of the longissimus lumborum were evaluated on different storage times (days 1, 3, 5, 7 and 9) post-slaughter using overwrapped air-permeable packaging. Treatments 0, 10 and 20% GP/kg DM were used for evaluation of protein oxidation and microbial counts on days 1, 5 and 7, while a trained panel assessed the sensory quality on day 1. Diet neither influenced meat color nor sensory quality. Diet × day interactions were observed for antioxidant activity, lipid and protein oxidation. Overall, the 20% GP/kg-diet finished lamb meat had the highest antioxidant activity and the lowest total viable bacterial counts, lipid and protein oxidation values during the shelf-life period. The 20% GP/kg DM in lamb diets, therefore, improved lamb meat shelf-life without negatively affecting sensory quality.

Grape Seed Polyphenols and Fatty Acids of Autochthonous Prokupac Vine Variety from Serbia

Grape pomace (grape skin, seeds, and stems) represents a valuable source of bioactive compounds, thus the interest in making use of these wine waste products is increasing. Prokupac is an autochthonous Serbian variety of black grape with a long tradition in production of red wine. Identification of the superficial polyphenolic compounds by LC/MS revealed presence of 19 compounds including hydroxybenzoic acid derivatives, ellagic acid derivatives, flavan-3-ol monomers, proanthocyanidins, and flavonols. Catechin and epicatechin together with proanthocyanidins were the most abundant compounds and the highest content of phenolic compounds was determined in Prokupac clones 43/1, 40/1, and 40/2. Grape seed oil consisted of dominantly UFA (87-95 %) where methyl linoleate was the most abundant in all samples (69-81 %). Palmitic (3-8 %) and stearic acid (2-4 %) methyl esters were dominant SFA. Prokupac clone 43/3 was the most abundant in UFA (95 %) with the lowest percentage of SFA (5 %), while clones 41/1 and 43/5 had the lowest percentage of UFA (87 %) and the highest content of SFA (13 %). Favorable chemical profile of Prokupac clone seeds implicates its potential to be used as a raw material in further processing and possibility to be included as one of the quality parameters in further selection of the most interesting Prokupac clone.

Grape peel (Syrah var.) jam as a polyphenol-enriched functional food ingredient

In this study, we evaluated the effects of the storage time on the physicochemical properties, bioactive compound content, and antioxidant capacity of jam prepared from grape peel extract to explore its potential as a supplementary food and/or functional ingredient. The ethanolic extract from Syrah var. grape peel exhibited high bioactive compound concentrations and antioxidant activity. The jam stability (prepared with 8.9% of extract) at 14°C was evaluated at 0, 15, 30, 45, and 60 days. The jam was found to contain high concentrations of polyphenolic compounds (137.0 ± 3.2 mg of gallic acid equivalent/100 g), total flavonoids (128.5 ± 23.0 mg of equivalent/100 g), and total anthocyanins (92.5 ± 4.0 mg of cyanidin equivalent/100 g). However, a large reduction in the flavonoid (70%-90%), anthocyanin (29%-35%), and phenolic (23%-30%) content was observed during storage. The free radical-scavenging activity (DPPH-), ferric reducing antioxidant power (FRAP), and β-carotene-linoleic acid assays revealed the great antioxidant potential of the jam prepared from grape peel extract, which exhibited significant levels of radical-neutralizing activity, especially as determined by the DPPH method with EC50 values ranging from 2.3 ± 0.1 to 3.9 ± 0.1 µg/ml. High R 2 values (p > 0.90) were obtained for the correlation between the DPPH results and the concentrations of the compounds of interest. In summary, the high bioactive compound contents and antioxidant capacity of the jam produced from grape peel suggest that it may provide health benefits as a source of natural antioxidants upon incorporation to several food industry products.

Citric acid production from the integration of Spanish-style green olive processing wastewaters with white grape pomace by Aspergillus niger

This study aimed to optimize an integrated simple process for citric acid production using Spanish-style green olive processing wastewaters enriched with sugars from white grape pomace and the robust Aspergillus niger B60. Mild mixing of equal quantities of the above streams governed satisfactory amount of appropriate carbon sources (equimolar mixture of glucose and fructose, 111.5 g/L) in the sugar-enriched wastewater and its neutralization. Various nutrients and fermentation conditions were investigated and maximum citric acid content (85 g/L) and yield (0.56 g/g) were obtained in liquid surface culture after minimum regulation by adding sucrose and NH₄NO₃ (100 g/L and 1.1 g/L, respectively). Scale-up experiments (5 L-scale) verified findings from small scale (250 mL). The chemical oxygen demand value and phenolic content of the treated wastewater were reduced by 78% and 64%, respectively. Findings support the potential for clustering the respective enterprises in a biorefinery plant for citric acid fermentation.

Optimizing the extraction process of natural antioxidants from chardonnay grape marc using microwave-assisted extraction

The aim of this work was to extract phenolic compounds from Chardonnay grape marc employing a microwave-assisted extraction (MAE). Firstly, the effect of solvent concentration (30-60%), solid mass (1.0-2.0 g) and extraction time (5-15 min) on the recovery of phenolic content and antioxidant capacity was evaluated using a response surface methodology (RSM). The optimal parameters found by RSM were 48% ethanol for the solvent content, 10 min for the extraction time, and 1.77 g for the solid mass. The extraction was carried out at room temperature to increase scaling-up opportunities at industrial level. It was found that the phenolic profile was mainly composed of flavanols, such as procyanidins, catechin and epicatechin. Furthermore, the polyphenols obtained by MAE showed a DPPH· inhibition value of 87 ± 5% and the total phenolic content was 1.21 ± 0.04 mg GAE/mL. Finally, it was observed that the degradation temperature of the extract (≈ 200 °C) was above the temperature commonly used for the manufacture of protein films by thermo-mechanical processes. This highlights the potential use of this extract as a bioactive additive in protein film forming formulations for food and pharmaceutical applications.

Hydrothermal synthesis of magnetic nanocomposite from biowaste matrix by a green and one-step route: Characterization and pollutant removal ability

This study aimed to produce an industrial waste-based novel magnetic nanocomposite (Fe@GPHC) by a facile and one-step hydrothermal carbonization (HTC) method. In order to characterize of Fe@GPHC, X-ray fluorescence spectroscopy (XRF), Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), Vibrating-sample magnetometer (VSM), and elemental (ultimate) analyses were applied. Characterization results showed that during the HTC process, the Fe nanoparticles (FeNPs) were successfully incorporated on biowaste matrix. In addition, the Fe@GPHC was used to test its adsorptive property. For this, methylene blue (MB) and methyl orange (MO) were selected as a simulated pollutant. A batch method was used to perform the adsorption experiments. The maximum adsorption capacity of Fe@GPHC was 11 mg g^-1 and 8.9 mg g^-1 for MB and MO, respectively. This study provides a feasible and simple approach to design and synthesis of high-performance functional magnetic material in a cost-effective way.

Food Preservative Capabilities of Grape (Vitis vinifera) and Clementine Mandarin (Citrus reticulata) By-products Extracts in South Africa

The drive towards sustainable food systems coupled with increased consumer sophistication have prompted innovation in waste valorization. Grape and citrus processing by-products, abundant in the Mediterranean and tropical regions, respectively, are expanding and are sustainable sources of bioactive phytochemicals that can be used as natural preservatives for foods. Phytochemical composition, antioxidant, and antimicrobial properties of extracts from grape pomace (GPE), seeds (GSE), and clementine mandarin peel and pulp (MPE) grown in South Africa were analyzed. Total phenols and carotenoids were highest in GPE followed by GSE and MPE (p ≤ 0.05). Flavonoids and anthocyanins were higher (p ≤ 0.05) in GPE and GSE compared to MPE. The GSE had the highest proanthocyanidins content followed by GPE and MPE (p ≤ 0.05). Ascorbic acid was only detected in MPE, which also had the highest titratable acidity and lowest pH values (p ≤ 0.05). The GSE had the highest antioxidant potency composite index followed by GPE and MPE (p ≤ 0.05). The order of antimicrobial activity of the extracts was MPE > GSE > GPE (p ≤ 0.05). Current findings show that GSE is a potential antioxidant while MPE holds promise as an antimicrobial for the food industry.

Effect of cranberry pomace extracts isolated by pressurized ethanol and water on the inhibition of food pathogenic/spoilage bacteria and the quality of pork products

Ethanol and water extracts were prepared from defatted cranberry pomace by pressurized liquid extraction and tested in bacterial cultures of L. monocytogenes, B. thermospacta, P. putida, lactic acid bacteria (LAB), aerobic mesophilic bacteria (AMB), and pork meat products. Anthocynanins (glucosides, galactosides and arabinosides of cyanidin and peonidins), phenolic compounds and organic acids (quinic, chlorogenic, malic and citric acids; procyanidin B3, myricetin and quercetin derivatives) were determined in the extracts. The extracts effectively inhibited the growth of tested bacteria at higher than 3.3% concentration. The effect of 2% ethanol extract additive on the inhibition of the same bacteria was also determined in non-inoculated and inoculated with bacteria pork slurry, pork burgers, and cooked ham. The results showed a significant growth inhibition of pathogenic L. monocytogenes and some other species in pork slurry, burgers and cooked ham with cranberry pomace ethanol extract as compared with the control samples. The extract also effectively inhibited the formation of oxidation indicator malondialdehyde in meat products. Slight impact of extract on some physico-chemical properties of meat products such as pH, metmyoglobin content was also observed, while it did not have significant influence on water activity. Extract addition imparted some color changes; however, it did not have negative effect on the overall sensory quality of burgers and cooked ham. High effectiveness of extract additive against pathogenic L. monocytogenes and some other tested bacteria in pork slurry, burgers and cooked ham during refrigerated storage for 16, 16 and 40 days, respectively, suggest that ethanol extract of defatted cranberry pomace may be a promising natural ingredient of meat products for increasing their microbiological safety and improving oxidative stability.

Recovery of phenolic antioxidants from Syrah grape pomace through the optimization of an enzymatic extraction process

Phenolic compounds are highly valuable products that remain trapped in grape pomace, an abundant winery by-product. Therefore, efficient extraction procedures of these compounds represent a route for grape pomace valorisation. Here we performed a screening of the factors affecting the aqueous enzymatic extraction of phenolic compounds from Syrah grape pomace, including the following independent variables: temperature, pH, pectinase, cellulase and tannase; and a subsequent optimization through response surface methodology. At the optimal region, the enzymatic treatment enhanced the extraction yield of phenolics by up to 66% and its antioxidant capacity by up to 80%, reducing the incubation time and enzyme doses in respect to previous studies. We found that tannase raises the antioxidant capacity of the extract by the liberation of gallic acid, while cellulose favours the liberation of p-coumaric acid and malvidin-3-O-glucoside. We also tested the procedure in different grape pomace varieties, verifying its wide applicability.

Bio-poly(butylene succinate) and Its Composites with Grape Pomace: Mechanical Performance and Thermal Properties

Biocomposites from bio-based poly(butylene succinate) (BioPBS) and grape pomace (GP) were made by melt extrusion-injection molding. Grape pomace is a low value byproduct from the wine industry that can be utilized as a filler to increase its value and to decrease the amount of polymer required in a composite blend. Experiments were performed with up to 50% grape pomace by weight. Composites were also compatibilized with in situ manufactured maleic anhydride-grafted BioPBS (MA-g-BioPBS). Flexural and impact strength were improved with the addition of GP up to the addition of 50 wt % GP, suggesting that at this loading the formulation reached threshold performance. The blend of (57:40:3) BioPBS/GP/MA-g-BioPBS showed the best overall performance in terms of a balance of both mechanical properties and thermal properties. The increase in impact resistance confirmed that the GP acted as a reinforcing phase. The addition of 3 wt % MA-g-BioPBS in samples containing 40 wt % of grape pomace resulted in improvements of 28.4 and 59% in flexural and impact strengths, respectively, compared to neat BioPBS. Heat distortion temperature increased with the addition of grape pomace by 14.3% in a blend combination of 57% BioPBS, 40% grape pomace, and 3% MA-g-BioPBS compared to neat BioPBS. Scanning electron microscopy results show improved interfacial adhesion with the addition of MA-g-BioPBS and thermogravimetric analysis results prove that the GP is thermally stable under the processing conditions. This study shows that GP can be successfully incorporated into a BioPBS matrix to create biocomposites with improved thermal and mechanical properties.

DETERMINATION OF THE CHEMICAL COMPOSITION OF GRAPE SEED POWDERS BY GC-MS ANALYSIS

Substantiation of the expedience of using of natural antioxidants for inhibiting of oxidative and hydrolytic rancidity in confectionary industry is an urgent direction. The offered way of solving the problem is to use a fat-less grape seed powder, a product, obtained as wastes of vine-making as a source of antioxidants. For this aim, there were realized experimental studies of water-alcohol extracts (ethanol, isopropanol) by the method of gas chromatography with mass-spectroscopic detection (CG-MS) of the chemical composition of grape seed powders under industrial conditions. The obtained data allowed to establish that the studied extracts contain an essential amount of phenol compounds of the different origin: aromatic acids – gallic and egallic acids; resveratrol; flavonoids – quercetin and its derivatives, catechine, epicatechine, campferol and others alongside with esters of fatty acids. These components are strong antioxidants, and their introduction to a grape seed powder must favor inhibition of the oxidizing process of fats in fat-containing confectionary products, so increasing shelf-life of products.

Citrus and Winery Wastes: Promising Dietary Supplements for Sustainable Ruminant Animal Nutrition, Health, Production, and Meat Quality

Citrus and grapes are the most widely grown fruits globally, with one-third of total production used for juice and wine making. The juice and winemaking processes generate large quantities of solid organic wastes including citrus pulp and grape pomace. These fruit wastes pose serious economic, environmental, and social challenges, especially in low-to-middle-income countries due to financial, technological, and infrastructural limitations. They are, however, rich in valuable compounds which can be utilized in the ruminant livestock industry as novel, economical, and natural sources of cellulose, polyunsaturated fatty acids, and phytochemicals, which have nutritional, anthelmintic, antioxidant, and antimicrobial properties. Despite citrus and grape fruit wastes having such potential, they remain underexploited by the livestock industry in low-to-middle-income countries owing to lack of finance, skills, technology, and infrastructure. Inclusion of these fruit wastes in ruminant diets could combine the desirable effects of enhancing animal nutrition, health, welfare, production, and meat quality attributes with the prevention of challenges associated with their disposal into the environment. The current review explores the valorization potential of citrus and winery wastes as dietary supplements to sustainably enhance ruminant animal nutrition, health, welfare, production, and meat quality.

Influence of different by-products addition on sensory and physicochemical aspects of Primosale cheese

Food industry produces considerable amounts of by-products that represent a severe problem from both economic and pollution points of view. The bioactive compounds still present in food by-products offer the possibility to re-use them to develop added value products. In the current work some by-products were incorporated into curd during production of Primosale cheese. Specifically, two concentrations (i.e., 50 and 100 g Kg-1) of flours from different by-products (i.e., red and white wine grape pomace; tomato peel, broccoli and artichokes by-products), as source of dietary fibres and bioactive compounds were tested. The swelling and water retention capacity of flours, in addition to physicochemical characteristics of cheese (cheese weight loss, dry substance in the whey, cheese moisture content and pH), bioactive compounds (total phenolic compounds, total flavonoids and antioxidant activity) and sensory profile were evaluated. Results highlighted that addition of by-products to Primosale cheese improved the nutritional properties and some sensory attributes such as friability and adhesiveness. Among the tested by-products, the most attractive result was obtained for Primosale cheese with artichoke by-products.

Grape pomace (Vitis vinifera L. cv. Pinotage) supplementation in lamb diets: Effects on growth performance, carcass and meat quality

This study investigated the effects of feeding graded levels of sun-dried red grape pomace (GP; 0, 5, 10, 15 and 20%) on growth, carcass and meat physico-chemical quality attributes of Dohne Merino lambs for 42 days. Dry matter intake increased quadratically with a critical value (i.e., optimum inclusion level) of 11.3% GP (P ≤ 0.05). Diet exhibited similar quadratic responses for average daily gain, live, hot and cold carcass weights with optimum inclusion levels at 9.6, 9.7, 12, 2 and 12.1, respectively (P ≤ 0.05). Overall, meat quality traits were not negatively affected by GP inclusion (P > .05). Gross profit was influenced by diet, with an optimum inclusion level at 12.2% (quadratic; P ≤ 0.05). Overall, inclusion of 12.2% GP in lamb finishing diets at the expense of oat bran and wheat bran middlings improved lamb productivity, without compromising meat quality.

Obtaining Multiple Coproducts from Red Grape Pomace via Anthocyanin Extraction and Biogas Production

Red grape pomace (RGP), a byproduct of red wine production, is an abundant food processing waste stream in California, rich in both anthocyanins, a class of red-blue pigments, and lignocellulose. Extraction of anthocyanins and biofuel production from RGP have been investigated independently, but no research has examined employing both strategies together for maximal valorization. In this study, anthocyanins were most effectively extracted from RGP at 80 °C. Convection- and vacuum-oven drying of the pomace were found to decrease anthocyanin yield, whereas lyophilization did not significantly affect yield. Fermentable sugars were successfully separated from the crude extract via solid-phase extraction. Ionic liquid pretreatment of RGP was determined to be a nonviable option for application to anaerobic digestion. Extraction reduced biomethane output, but supplementation with the aqueous fraction of the extract mitigated much of this difference, indicating sequential extraction and fractionation of anthocyanins from RGP can minimize the impact on biofuel yields.

Fruit peels as sources of non-extractable polyphenols or macromolecular antioxidants: Analysis and nutritional implications

Despite increasing interest in the relevance of non-extractable polyphenols (NEPP) or macromolecular antioxidants as food bioactive compounds, most studies on their presence in foods focus mainly on the edible part of specific fruits, but their potential presence in fruit peels is usually ignored. The aim of this study was to evaluate NEPP content in the peels from ten common fruits. The results showed that NEPP made up more than half of the total polyphenol contents in half of the studied samples. HPLC analysis showed that NEPP were constituted by phenolic acids, flavanols and flavonols. Also, it was found that peels accounted for >40% of total NEPP in the fruit in four of the samples analysed. These results should encourage both the use of fruit peels in the fruit industry as ingredients and the consumption of whole fruits given the significant presence of NEPP in fruit peels.

Intestinal Absorption and Antioxidant Activity of Grape Pomace Polyphenols

The absorption and antioxidant activity of polyphenols from grape pomace (GP) are important aspects of its valorization as a feed additive in the diet of weaned piglets. This study aimed to evaluate the presence of polyphenols from GP both in vitro in IPEC cells and in vivo in the duodenum and colon of piglets fed with diets containing or not 5% GP and also to compare and correlate the aspects of their in vitro and in vivo absorption. Total polyphenolic content (TPC) and antioxidant status (TAS, CAT, SOD and GPx enzyme activity, and lipid peroxidation-TBARS level) were assessed in duodenum and colon of piglets fed or not a diet with 5% GP. The results of UV-Vis spectroscopy demonstrated that in cellular and extracellular medium the GP polyphenols were oxidized (between λmax = 276 nm and λmax = 627.0 nm) with the formation of o-quinones and dimers. LC-MS analysis indicated a procyanidin trimer possibly C2, and a procyanidin dimer as the major polyphenols identified in GP, 12.8% of the procyanidin trimer and 23% of the procyanidin dimer respectively being also found in the compound feed. Procyanidin trimer C2 is the compound accumulated in duodenum, 73% of it being found in the colon of control piglets, and 62.5% in the colon of GP piglets. Correlations exist between the in vitro and in vivo investigations regarding the qualitative evaluation of GP polyphenols in the cells (λmax at 287.1 nm) and in the gut (λmax at 287.5 nm), as oxidated metabolic products. Beside the presence of polyphenols metabolites this study shows also the presence of the unmetabolized procyanidin trimers in duodenum and colon tissue, an important point in evaluating the benefic actions of these molecules at intestinal level. Moreover the in vivo study shows that a 5% GP in piglet’s diet increased the total antioxidant status (TAS) and decreased lipid peroxidantion (TBARS) in both duodenum and colon, and increased SOD activity in duodenum and CAT and GPx activity in colon. These parameters are modulated by the different polyphenols absorbed, mainly by the procyanidin trimers and catechin on one side and the polyphenols metabolites on the other side.

Effects of in vitro gastrointestinal digestion on phenolic compounds and antioxidant activity of different white winemaking byproducts extracts

The effect of in vitro gastrointestinal digestion on phenolic composition and antioxidant activity of different white winemaking byproducts extracts (grape pomace and its parts: seeds, skins and stems) was evaluated. Fourteen individual phenolic compounds were evaluated by UHPLC. The antioxidant activity was measured by DPPH and ORAC assays. Differences on phenolic profile and antioxidant activity were observed depending on the digestion phase, the type of byproduct, the phenolic group and the antioxidant activity assay. In general, digestion had a reducing effect on TPC and antioxidant activity; however, ORAC values of seed and stem extracts increased after digestion and some recovery indexes of the phenolic groups were very high. Results indicate that extracts from white winemaking byproducts are a reliable source of bioaccessible antioxidant compounds, which could be used as functional food ingredients.

Technologies for enhancement of bioactive components and potential health benefits of cereal and cereal-based foods: Research advances and application challenges

Cereal grains are a major source of human food and their production has steadily been increased during the last several decades to meet the demand of our increasing world population. The modernized society and the expansion of the cereal food industry created a need for highly efficient processing technologies, especially flour production. Earlier scientific research efforts have led to the invention of the modern steel roller mill, and the refined flour of wheat has become a basic component in most of cereal-based foods such as breads and pastries because of the unique functionality of wheat protein. On the other hand, epidemiological studies have found that consumption of whole cereal grains was health beneficial. The health benefit of whole cereal grain is attributed to the combined effects of micronutrients, phytochemicals, and dietary fibre, which are mainly located in the outer bran layer and the germ. However, the removal of bran and germ from cereal grains during polishing and milling results in refined flour and food products with lower bioactive compounds and dietary fibre contents than those from whole grain. Also, the level of bioactive compounds in cereal food is influenced by other food preparation procedures such as baking, cooking, extrusion, and puffing. Therefore, food scientists and nutritionists are searching for strategies and processing technologies to enhance the content and bioavailability of nutrients, bioactive compounds, and dietary fibre of cereal foods. The objective of this article was to review the research advances on technologies for the enhancement of bioactive compounds and dietary fibre contents of cereal and cereal-based foods. Bioactivities or biological effects of enhanced cereal and cereal-based foods are presented. Challenges facing the application of the proposed technologies in the food industry are also discussed.