Assessment of the production of antioxidants from winemaking waste solids

The Potential of Grape Pomace Varieties as a Dietary Source of Pectic Substances

Grape pomace is one of the most abundant solid by-products generated during winemaking. A lot of products, such as ethanol, tartrates, citric acid, grape seed oil, hydrocolloids, bioactive compounds and dietary fiber are recovered from grape pomace. Grape pomace represents a major interest in the field of fiber extraction, especially pectin, as an alternative source to conventional ones, such as apple pomace and citrus peels, from which pectin is obtained by acid extraction and precipitation using alcohols. Understanding the structural and functional components of grape pomace will significantly aid in developing efficient extraction of pectin from unconventional sources. In recent years, natural biodegradable polymers, like pectin has invoked a big interest due to versatile properties and diverse applications in food industry and other fields. Thus, pectin extraction from grape pomace could afford a new reason for the decrease of environmental pollution and waste generation. This paper briefly describes the structure and composition of grape pomace of different varieties for the utilization of grape pomace as a source of pectin in food industry.

A Review on Stems Composition and Their Impact on Wine Quality

Often blamed for bringing green aromas and astringency to wines, the use of stems is also empirically known to improve the aromatic complexity and freshness of some wines. Although applied in different wine-growing regions, stems use remains mainly experimental at a cellar level. Few studies have specifically focused on the compounds extracted from stems during fermentation and maceration and their potential impact on the must and wine matrices. We identified current knowledge on stem chemical composition and inventoried the compounds likely to be released during maceration to consider their theoretical impact. In addition, we investigated existing studies that examined the impact of either single stems or whole clusters on the wine quality. Many parameters influence stems' effect on the wine, especially grape variety, stem state, how stems are incorporated, when they are added, and contact duration. Other rarely considered factors may also have an impact, including vintage and ripening conditions, which could affect the lignification of the stem.

Antiproliferative and cytotoxic effects of grape pomace and grape seed extracts on colorectal cancer cell lines

Grape pomace is the source of bioactive compounds (anthocyanins, flavonols, flavan-3-ols, and stilbenes) which exhibit antiproliferative actions on cell cultures. We have investigated the antitumoral effects of grape pomace and grape seed extracts on colon cancer cells (Caco-2, HT-29) and fibroblasts. Crude extracts prepared from white and red pomace, and grape seeds, reduced the viability and proliferation of Caco-2. HT-29 cells were resistant to these actions. Purified extracts were then prepared from the same sources and compared with the LDH test; again, all three extracts were active and purified extract from grape seed was the most potent and specific on Caco-2 cells. HT-29 cells were more sensitive to these purified extracts. The biological activity resided almost exclusively in the flavonol and flavan-3-ols subfractions, rather than the anthocyanin subfraction. Preliminary results on the mechanisms involved in these effects revealed downregulation of Myc gene expression in HT-29 and upregulation of Ptg2 in Caco-2 cells.

Natural bioactive compounds from winery by-products as health promoters: a review

The relevance of food composition for human health has increased consumers' interest in the consumption of fruits and vegetables, as well as foods enriched in bioactive compounds and nutraceuticals. This fact has led to a growing attention of suppliers on reuse of agro-industrial wastes rich in healthy plant ingredients. On this matter, grape has been pointed out as a rich source of bioactive compounds. Currently, up to 210 million tons of grapes (Vitis vinifera L.) are produced annually, being the 15% of the produced grapes addressed to the wine-making industry. This socio-economic activity generates a large amount of solid waste (up to 30%, w/w of the material used). Winery wastes include biodegradable solids namely stems, skins, and seeds. Bioactive compounds from winery by-products have disclosed interesting health promoting activities both in vitro and in vivo. This is a comprehensive review on the phytochemicals present in winery by-products, extraction techniques, industrial uses, and biological activities demonstrated by their bioactive compounds concerning potential for human health.

Structural characterization of lignin from grape stalks (Vitis vinifera L.)

The chemical structure of lignin from grape stalks, an abundant waste of winemaking, has been studied. The dioxane lignin was isolated from extractive- and protein-free grape stalks (Vitis vinifera L.) by modified acidolytic procedure and submitted to a structural analysis by wet chemistry (nitrobenzene and permanganate oxidation (PO)) and spectroscopic techniques. The results obtained suggest that grape stalk lignin is an HGS type with molar proportions of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units of 3:71:26. Structural analysis by (1)H and (13)C NMR spectroscopy and PO indicates the predominance of β-O-4' structures (39% mol) in grape stalk lignin together with moderate amounts of β-5', β-β, β-1', 5-5', and 4-O-5' structures. NMR studies also revealed that grape lignin should be structurally associated with tannins. The condensation degree of grape stalks lignin is higher than that of conventional wood lignins and lignins from other agricultural residues.

Evolution of organic matter during the mesophilic composting of lignocellulosic winery wastes

Winery wastes were composted in the laboratory during five months in order to study the composting process of lignocellulosic wastes. In a first experiment, spent grape marc was composted alone, and in a second one, hydrolyzed grape marc, which is the residue generated after the acid hydrolysis of spent grape marc for biotechnological purposes, was composted together with vinification lees. During the composting of spent grape marc, total organic matter did not change, and as total N increased only slightly (from 1.7% to 1.9%), the reduction in the C/N ratio was very low (from 31 to 28). The mixture of hydrolyzed grape marc and lees showed bigger changes, reaching a C/N ratio around 20 from the third month on. Water-soluble organic matter followed the usual trend during composting, showing a progressive decrease in both experiments. Although the mixture of hydrolyzed grape marc and lees presented the highest initial water-soluble carbon concentrations, the final values for both experiments were similar (8.1 g kg(-1) for the spent grape marc, and 9.1 g kg(-1) for the mixture). The analysis of the humification parameters did not allow an adequate description of the composting process, maybe as a consequence of the inherent problems existing with alkaline extractions. The total humic substances, which usually increase during composting as a consequence of the humification process, followed no trend, and they were even reduced with respect to the initial values. Notwithstanding, the fractionation of organic matter into cellulose, hemicellulose and lignin enabled a better monitoring of the waste decomposition. Cellulose and hemicellulose were degraded mainly during the first three months of composting, and the progressive reduction of the cellulose/lignin ratio proved that the main evolution of these wastes took place during the first three months of composting.

Enhancement of poly(3-hydroxybutyrate) thermal and processing stability using a bio-waste derived additive

Poly(3-hydroxybutyrate) (PHB) is a biodegradable polymer, whose applicability is limited by its brittleness and narrow processing window. In this study a pomace extract (EP), from the bio-waste of winery industry, was used as thermal and processing stabilizer for PHB, aimed to engineer a totally bio-based system. The results showed that EP enhanced the thermal stability of PHB, which maintained high molecular weights after processing. This evidence was in agreement with the slower decrease in viscosity over time observed by rheological tests. EP also affected the melt crystallization kinetics and the overall crystallinity extent. Finally, dynamic mechanical and tensile tests showed that EP slightly improved the polymer ductility. The results are intriguing, in view of the development of sustainable alternatives to synthetic polymer additives, thus increasing the applicability of bio-based materials. Moreover, the reported results demonstrated the feasibility of the conversion of an agro-food by-product into a bio-resource in an environmentally friendly and cost-effective way.

Anti-skin cancer properties of phenolic-rich extract from the pericarp of mangosteen (Garcinia mangostana Linn.)

Skin cancers are often resistant to conventional chemotherapy. This study examined the anti-skin cancer properties of crude ethanol extract of mangosteen pericarp (MPEE) on human squamous cell carcinoma A-431 and melanoma SK-MEL-28 lines. Significant dose-dependent reduction in% viability was observed for these cell lines, with less effect on human normal skin fibroblast CCD-1064Sk and keratinocyte HaCaT cell lines. Cell distribution in G(1) phase (93%) significantly increased after 10 μg/ml of MPEE versus untreated SK-MEL-28 cells (78%), which was associated with enhanced p21(WAF1) mRNA levels. In A-431 cells, 10 μg/ml MPEE significantly increased the sub G(1) peak (15%) with concomitant decrease in G(1) phase over untreated cells (2%). In A-431 cells, 10 μg/ml MPEE induced an 18% increase in early apoptosis versus untreated cells (2%). This was via caspase activation (15-, 3- and 4-fold increased caspse-3/7, 8, and 9 activities), and disruption of mitochondrial pathways (6-fold decreased mitochondrial membrane potential versus untreated cells). Real-time PCR revealed increased Bax/Bcl-2 ratio and cytochrome c release, and decreased Akt1. Apoptosis was significantly increased after MPEE treatment of SK-MEL-28 cells. Hence, MPEE showed strong anti-skin cancer effect on these two skin cancer cell lines, with potential as an anti-skin cancer agent.

Recovery and concentration of antioxidants from winery wastes

: Grape and wine byproducts have been extensively studied for the recovery of phenolic compounds with antioxidant activity and a variety of biological actions. The selective recovery and concentration of the phenolic compounds from the liquid phase separated from further diluted winery wastes has been proposed. Adsorption onto non ionic polymeric resins and further desorption with ethanolic solutions was studied. Several commercial food grade resins were screened with the aim of selecting the most suited for the practical recovery of phenolic compounds with radical scavenging activity. Under the optimized desorption conditions (using Sepabeads SP207 or Diaion HP20 as adsorbents and eluting with 96% ethanol at 50 °C) a powdered yellow-light brown product with 50% phenolic content, expressed as gallic acid equivalents, was obtained. The radical scavenging capacity of one gram of product was equivalent to 2–3 g of Trolox.

Influence of postharvest processing and storage on the content of phenolic acids and flavonoids in foods

The review is based on the evaluation of electronically collated data published between 2002 to June 2006. It is based on 325 references dealing with the following subclasses of phenolic compounds: hydroxycinnamic and hydroxybenzoic acids, chalcones, flavanones, flavones, flavonols, monomeric flavanols and anthocyanins. Only publications dealing directly with the effects of storage and postharvest processing on the phenolic acid and flavonoid contents of foods were considered. The expectation that the structural diversity even within each subgroup, and the number of different procedures and of different parameters would make finding homogenous tendencies unlikely, has, in most instances, been confirmed. By adding a database Excel table combined with a focused and unified evaluation, specific additional information was rendered accessible and concise. It holds true for most of the subclasses in question that the effect of storage and food processing on the polyphenol content is negligible in comparison to the differences between different varieties of plants. Variety dependence must always be considered, for all classes of compounds.

Fractionation of antioxidants from autohydrolysis of barley husks

The liquid phase from nonisothermal autohydrolysis of barley husks was extracted with ethyl acetate and redissolved in ethanol to yield a crude extract (denoted BHEAE), which was subjected to further processing to enhance the antioxidant activity. A fractionation method, carried out for characterization purposes, consisted of the extraction of BHEAE with organic solvents of increasing polarity and further fractionation in Sephadex LH-20. Among the tested solvents, ethyl acetate allowed the highest yield, phenolic content, and antioxidant activity. Upon elution with methanol, products with high DPPH radical scavenging capacity (IC50 = 0.22 g/L) were obtained. The major compounds in the isolate were benzoic and cinnamic acids. Adsorption-desorption in commercial polymeric resins was carried out as an alternative strategy for BHEAE refining. This method is more suited for possible scale-up and provided a concentrate with a Trolox equivalent antioxidant capacity of 9 mM, which was obtained at a yield of 18 g/kg of barley husks.

Extraction of polyphenols from white distilled grape pomace: optimization and modelling

Both ethanolic and aqueous extraction were carried out in a laboratory-scale vertical extractor to obtain polyphenols from distilled grape pomace of Vitis vinifera var. "Albariño". An experimental design was performed to analyse the effects of flow (2 ml/min and 4 ml/min) and temperature (40 degrees C and 50 degrees C). Yields of polyphenolics from aqueous extraction were much higher (up to 30-fold) than those of ethanolic extraction, in contrast with previous results obtained by us from batch extraction of different grape varieties. Polyphenols extraction was modelled by application of second Fick's law to spherical particles of 0.5 mm diameter, so obtaining the effective diffusion coefficient as parameter. The mass transfer coefficients were also estimated, giving as result that the external mass transfer resistance was negligible. Correlation coefficients ranged 0.989-0.9999. Effective diffusivity values in water extraction assays were between 0.6x10(-11) m(2)/s and 2.1x10(-11) m(2)/s. Using ethanol as solvent, the effective diffusivity was lower, between 0.1x10(-11) m(2)/s and 0.76x10(-11) m(2)/s.

Separation and HPLC-MS identification of phenolic antioxidants from agricultural residues: almond hulls and grape pomace

Almond hulls and grape pomace are residues abundantly generated by agricultural industries, which could be processed to obtain bioactive products. To this purpose, crude ethanol extracts from both agricultural byproducts were attained and subsequently fractionated in order to obtain an organic/water fraction (FOW). Extracts and fractions were analyzed for antioxidant power and their phenolic components tentatively identified by HPLC-MS. Chromatographic peaks of almond hull extracts showed the occurrence of hydroxybenzoic and cinnamic acid derivatives, with minor presence of flavan-3-ols (ECG, EGCG), whereas the FOW fraction offered the additional presence of epicatechin (EC) and glycosylated flavonols. In the composition for extracts of white and red grape pomace several of these compounds were also detected but basically consisted of glycosylated flavonols (quercetin, kaempferol). As a difference between both grape pomaces, myricetin glycosyde was found in that from the red variety, whereas flavan-3-ols (EC, afzelechin) were only identified in white pomace. When their FOW fractions were analyzed, gallic acid and some hydroxybenzoic acids were additionally detected. Antioxidant activity was assessed by DPPH and TBARS assays. Almond hulls showed inhibition percentages lower than 50% in both assays, while the inhibition percentage ranged from 80% to 90% in pomace extracts. Red grape pomace extract was the most efficient antioxidant, with an EC50 value of 0.91 g/L for TBARS and 0.20 g/L for DPPH. Even appearing as two quite different vegetal matrixes, the composition of phenolics in grape pomace and almond hulls is quite similar, the main difference being the major occurrence of flavonols in grape pomace. This fact could presumably explain the lower antiradical activity of hull extracts.

Evaluation of mesophilic biodegraded grape marc as soil fertilizer

The wine industry generates a large amount of wastes, including grape marc and vinification lees. These substances can be used to produce enzymes or other food additives. Composting could be a successful strategy for the sustainable and complete recycling of grape marc. In this work, the mesophilic biodegradation of grape marc during 60 d under microaerobic conditions using several ratios of seeds, skin, and stem were studied. The presence of Penicillium spp. was detected at the beginning of the composting. Changes in chemical and biological parameters were evaluated. Biodegraded grape marc with stem showed the best organic matter properties (C/N ratio of 14 and N content of 37 g/kg) and a germination index of 155% for the growth of ray grass seeds. The results suggest that the biodegraded of grape marc could be used as fertilizer, especially for ray grass crops.