Fermentation Of Grape Research Articles

Impact of fermentation temperature and grape solids content on the chemical composition and sensory profiles of Cabernet Sauvignon wines made from flash détente treated must fermented off-skins

This study investigated the color, phenolic, polysaccharide, volatile and sensory profiles of Cabernet Sauvignon wines made from flash détente (FD) treated musts fermented at different temperatures (16, 24 or 32 °C), with and without suspended grape solids. Low fermentation temperature and low solids content increased the concentration of esters, whereas the opposite conditions increased the concentration of fusel alcohols, polysaccharides and glycerol. Higher fermentation temperatures also increased linalool concentration independent of solids content. Traditional maceration fermentation conditions gave the highest concentration of fusel alcohols and 1-hexanol relative to FD treatments. Pre-fermentation removal of grape solids from FD juice created wines with increased red fruit and confectionery attributes, whereas inclusion of 3.5% grape solids increased dark fruit notes. In comparison, control wines had significantly higher green and savory attributes compared to wines from FD treatments. Research findings demonstrated the potential for FD to be used to create differentiated red wine styles.

Effect of Oxygen and Nitrogen Sparging during Grape Fermentation on Volatile Sulphur Compounds

Elemental sulphur is a common fungicide applied in vineyards before harvest, and has been found toincrease the production of desirable polyfunctional mercaptans, but also H2S and unwanted reductivesulphur aroma compounds. This paper investigates the effectiveness of oxygen and nitrogen sparging,applied during fermentation, on the removal of volatile sulphur compounds in Sauvignon blanc wines.Increasing the amount of elemental sulphur added to grapes after pressing, from nil to 10 to 100 mg/L,led to an increase in the formation of 3-mercaptohexanol (3MH), of 3-mercaptohexyl acetate (3MHA) forthe 10 mg/L additions only, and of some unwanted reductive compounds. Few changes were observed inthe concentrations of aroma compounds when the juices were sparged with nitrogen during fermentation.Additions of oxygen during fermentation led to some decrease in the concentration of polyfunctionalmercaptans for the 10 mg/L sulphur additions, but did not significantly remove reductive aroma compounds.Few differences were observed in the concentration of wine phenolics or of further wine aroma familieswith any of the treatments.

Native Yeasts and Lactic Acid Bacteria Isolated from Spontaneous Fermentation of Seven Grape Cultivars from the Maule Region (Chile).

Grapes are a source of native yeasts and lactic acid bacteria (LAB); however, the microbial make up is dependent on the grape cultivar and the regional growth conditions. Therefore, the aim of this study was to characterize the yeast and LAB in seven grape cultivars cultivated in Chile. Grape juices were fermented at 25 °C for 7 days. Samples were collected to analyze sugar, organic acids, and ethanol. Microbial evolution was measured with culture-dependent and molecular approaches. Then, a native isolated Candida oleophila was selected for further sequential fermentations with Saccharomyces cerevisiae. The grape cultivars in the Maule showed a diversity of non-Saccharomyces yeasts, with a greater diversity observed at the beginning of the fermentation. However, species from the Hansenasporia, Metschnikowia, Torulaspora, Lachancea, and Candida genera were detected after 7 days, suggesting tolerance to environments rich in ethanol, capability may be associated to the terroir studied, which is characterized by torrid weather and antique and traditional vineyards. The alcoholic fermentation negatively impacted the LAB population, and after 7 days only Leuconostoc mesenteroides was isolated. In the sequential fermentations, C. oleophila was able to produce fermented grape juices with <1.5 g/L glucose, 12.5% (v/v) alcohol, and low concentrations of malic (<1.00 g/L) and succinic (2.05 g/L) acids, while acetic acid reached values >0.3 (g/L). To our knowledge this is the first time C. oleophila has been reported as a potential starter culture for wine production. However, more studies are necessary to fully characterize the potential of C. oleophila on wine attributes.

Influence ofSaccharomyces cerevisiaeautochthonousMQ3strain on terpenes during the alcoholic fermentation of Chardonnay dry white wine

Background and Aims Terpenes are major varietal aroma compounds significantly contributing to wine quality and style. Autochthonous microbial starters can promote the formation and release of the terpenes and thus highlight the terroir typicality of wines. This study compared the physicochemical parameters, changes in the terpene concentration, β-D-glucosidase activity and sensory attributes of Chardonnay wines fermented individually by the Saccharomyces cerevisiae autochthonous MQ3 strain isolated from spontaneous fermented grape must and by three commercial S. cerevisiae strains. Methods and Results The evolution of terpenes during alcoholic fermentation was followed with ultrasound-assisted liquid–liquid extraction combined with GC. The physicochemical parameters of wine fermented by the MQ3 strain were significantly different from those of the wines fermented by other yeasts. The pattern of the terpenes detected, including linalool, α-terpineol, farnesol, geraniol, nerol and citronellol, varied during alcoholic fermentation. The MQ3 strain induced greater accumulation of terpenes with increased concentration of α-terpineol, geraniol and (E,E)-farnesol. Besides, the MQ3 strain exhibited an enhanced ability to produce β-D-glucosidase compared to that of the other three strains. With the exception of α-terpineol and (E,E)-farnesol, there was no significant correlation between the concentration of the other terpenoids and β-D-glucosidase activity as shown by Pearson's correlation analysis. Wine produced with the MQ3 strain was characterised by a distinctive complex flavour with enhanced floral and fruity aromas. Conclusions The autochthonous MQ3 strain had a positive effect on the varietal aroma and sensory quality of the wines. Significance of the Study Due to its aroma enhancing ability, the MQ3 strain could be applied to produce quality Chardonnay wine with terroir typicality.

Correlations between Total Antioxidant Capacity, Polyphenol and Fatty Acid Content of Native Grape Seed and Pomace of Four Different Grape Varieties in Hungary.

Grape pomace is a valuable source of various bioactive compounds such as plant-derived polyphenols and polyunsaturated fatty acids (PUFAs). The commercial demand of grape skin and seed powders as nutraceuticals is still growing. However, no distinction is currently made between unfermented native grape seed and grape seed pomace powders regarding their antioxidant activities. Our aim was to find the relationship between the polyphenol and fatty acid content as well as the antioxidant capacity of native and fermented grape seeds of four different grape varieties harvested in the Villány wine region. According to our results, none of the three investigated polyphenols (resveratrol, rutin, quercetin) could be detected in native grape seed samples in correlation with their significantly lower total antioxidant capacities compared to fermented seed samples. Pinot Noir (PN) grape seed pomace samples with the highest resveratrol and oil content showed significantly higher total antioxidant capacity than Cabernet Sauvignon (CS), Syrah (S) and Blue Portugal (BP) samples. Based on the statistical analysis, positive correlation was found between the fatty acid content and the resveratrol concentration in the pomace samples of different grape varieties. In contrast, rutin concentrations were negatively proportional to the fatty acid content of the fermented samples. No significant correlation was found considering the quercetin content of the samples. According to our findings, grape pomace seems a more promising source in the production of nutraceuticals, since it contains polyphenols in higher concentration and exerts significantly higher antioxidant activity than native grape seeds.

Assessment of Antioxidant and Antimutagenic Properties of Red and White Wine Extracts In Vitro.

Wine is an alcoholic beverage of complex composition obtained through the fermentation of grape must. The consumption of wine has already been associated with a multitude of beneficial effects due to its high polyphenolic content. In this study, four Greek emblematic wines from two red (i.e., Xinomavro and Agiorgitiko) and two white (i.e., Assyrtiko and Malagouzia) varieties were analyzed for the estimation of their antioxidant profiles. To address this question, we assessed their ability to scavenge both synthetic and endogenous free radicals, such as DPPH•, ABTS+•, OH•, O2−, their potential reducing power, and their antimutagenic and antigenotoxic properties. All varieties exhibited potent antioxidant activity, as indicated by the results of methods above, with the red wines appearing more effective than the white ones regarding antioxidant capacity. Our small-scale study is the first to reveal that these wine varieties may have the ability to scavenge the most reactive endogenous radicals. In the future, this finding must be accompanied by larger studies to fill a knowledge gap in the scientific literature concerning a holistic approach of the in vitro antioxidant action of plant polyphenolic compounds. Conclusively, we believe that wines possess high bioactivity that allow them to settle in the industry of food additives and medicinal products.

Effects of a Fermented Grape Combined with Specified Fruits and Vegetables or Their Extracts on Anti-aging and Anti-inflammatory Status: A Randomized Controlled Clinical Trial

Vegetables and fruits had antioxidant capacity. Fermented grapes had a higher content of anthocyanins and flavonoids, and reduced skin wrinkles. There were not more clinical studies on whether fermented grapes with fruit and vegetable extracts had anti-aging and anti-inflammatory activities. The current study used fermented grapes beverages made from fermented grapes combined with fruit and vegetable extracts to explore anti-aging and anti-inflammatory. 60 subjects were recruited and divided into a placebo and another fermented grape drinks group. The subjects drank 50 ml , 1 bottle a day for 8 week. After drinking for 8 weeks, a skin test and blood inflammatory factor analysis were performed. Compared to the placebo group, skin brightness, moisture, elasticity was significantly increased by 3.6%, 4.9%, 5.4%, respectively. Fermented grape drinks decreased skin spots, and wrinkles by 7.0%, and 19.0%, respectively. TNF-α (Tumor Necrosis Factor) and IL-6 (Interleukin-6) expression were decreased, also, as a function of fermented grape drinks intakes. This study indicated that fermented grapes combined with fruit and vegetable extracts can significantly improve the brightness, moisture, elasticity, wrinkles, pores, and decrease TNF-α and IL-6 expression.

CHARACTERIZATION, IN-VITRO EVALUATION OF PROBIOTIC POTENTIAL AND ANTAGONISTIC ACTIVITY OF SELECTED LACTIC ACID BACTERIA STRAINS ISOLATED FROM NATURAL ORIGIN AGAINST SOME HUMAN PATHOGENS

Probiotic bacteria have recently become popular for their health-related beneficial effects. In this study, 19 lactic acid bacteria were isolated from breast milk, dairy products, infant stool, vaginal swabs, fermented beverages, and fermented grapes. These isolates were evaluated for their tolerance to gastrointestinal conditions, hydrophobicity, auto-aggregation, and antimicrobial activity. Five isolates, belonging to Pediococcus spp. and Lactobacillus spp., showed potential probiotic features. These isolates were tested for the presence of virulence enzymes and for susceptibility to various antibiotics. The isolates were found to be non-hemolytic and lacked gelatinase and deoxyribonuclease enzymes, however, some antibiotic resistance genes were detected. To ensure the safety of the used probiotics, cell-free supernatants (CFS) of the promising candidates were prepared and its antimicrobial activity before and after neutralization was assessed against standard strains of Candida albicans, Gram-positive, and Gram-negative bacteria. The neutralization of the CFS significantly diminished the antibacterial and antifungal activities of probiotics. Using the time-kill assay, the combination of CFS of Lactiplantibacillus plantarum with gentamicin and ceftazidime was tested against Staphylococcus aureus and Escherichia coli clinical isolates. A significant reduction in log number of survivors was obtained with gentamicin against E. coli and with ceftazidime against both isolates. The anti-biofilm ability of the CFS of the selected probiotics was tested as well. Neutralized CFS caused 26-52% inhibition of S. aureus isolate biofilm formation compared to the control. In conclusion, the five selected isolates could be considered promising probiotic candidates that can be used as biotherapeutics in case of bacterial infection.

A Gas Chromatography-Mass Spectrometry Method for the Determination of Fatty Acids and Sterols in Yeast and Grape Juice

Lipids are essential components of all living cells. In an oenological context, the supply of unsaturated lipids in grape juice allows the yeasts to grow and ferment, despite very low levels of oxygen. The current study proposes a systematic optimization procedure for the analysis of fatty acids and sterols relevant to the grape fermentation process, including both extracellular and intracellular (i.e., yeast cells) lipids. Even though it was extensive, the sample preparation yielded reproducible results for all compounds of interest. The stability of the analyzed compounds was also tested to offer some implementation flexibility for the extensive procedure. The performance parameters (i.e., selectivity, linearity, limit of detection and quantitation, accuracy, and precision) indicated that the method was suitable for future practical implementation. The proof of concept also suggests that the list of compounds of interest can be expanded if additional peaks are identified. Given the large variation in concentrations, the dilution of the matrix needs to be carefully considered in order to ensure that the lipids of interest are still within the dynamic range and not below the limit of detection and/or quantification.

The addition of wine yeast &lt;i&gt;Starmerella bacillaris&lt;/i&gt; to grape skin surface influences must fermentation and glycerol production

Starmerella bacillaris is a non-Saccharomyces yeast recently proposed for grape fermentation in association with Saccharomyces cerevisiae. Due to its high glycerol and moderate volatile acidity production this yeast can contribute to improving wine quality. Some strains have been demonstrated to exhibit antifungal activity against grey mould on grape, which is caused by Botrytis cinerea. The simultaneous presence of these traits in S. bacillaris is of great interest. Indeed, this yeast can be potentially used as a biocontrol agent in vineyards. Research on the ability of S. bacillaris to survive or, even to grow on the surface of grapes is a starting point in the evaluatation of its potential use in vineyards. The preliminary results of our study showed that when applied to the grape surface under laboratory condictions, inoculum sized S. bacillaris with antifungal activity developed and lasted for at least 6 days in high concentrations. In addition, it positively influenced the fermentation process by producing high concentrations of glycerol (average value 4.89 ± 0.47 g/L). Interestingly, a positive effect on wine quality was also observed when the inoculum size was 10 times higher or lower than the reference concentration. When sprayed on the vines in the vineyard and present on the grape skin surface after harvest, S. bacillaris cells can start alcoholic fermentation.

Saccharomyces cerevisiae Gene Expression during Fermentation of Pinot Noir Wines at an Industrially Relevant Scale.

Saccharomyces cerevisiae metabolism produces ethanol and other compounds during the fermentation of grape must into wine. Thousands of genes change expression over the course of a wine fermentation, allowing S. cerevisiae to adapt to and dominate the fermentation environment. Investigations into these gene expression patterns previously revealed genes that underlie cellular adaptation to the grape must and wine environments, involving metabolic specialization and ethanol tolerance. However, the majority of studies detailing gene expression patterns have occurred in controlled environments that may not recapitulate the biological and chemical complexity of fermentations performed at production scale. Here, an analysis of the S. cerevisiae RC212 gene expression program is presented, drawing from 40 pilot-scale fermentations (150 liters) using Pinot noir grapes from 10 California vineyards across two vintages. A core gene expression program was observed across all fermentations irrespective of vintage, similar to that of laboratory fermentations, in addition to novel gene expression patterns likely related to the presence of non-Saccharomyces microorganisms and oxygen availability during fermentation. These gene expression patterns, both common and diverse, provide insight into Saccharomyces cerevisiae biology critical to fermentation outcomes under industry-relevant conditions.IMPORTANCE This study characterized Saccharomyces cerevisiae RC212 gene expression during Pinot noir fermentation at pilot scale (150 liters) using industry-relevant conditions. The reported gene expression patterns of RC212 are generally similar to those observed under laboratory fermentation conditions but also contain gene expression signatures related to yeast-environment interactions found in a production setting (e.g., the presence of non-Saccharomyces microorganisms). Key genes and pathways highlighted by this work remain undercharacterized, indicating the need for further research to understand the roles of these genes and their impact on industrial wine fermentation outcomes.

Effect of calcium alginate coating on the cell retention and fermentation of a fungus-yeast immobilization system

Yeast cell leakage from the matrix is one of the reoccurring inconveniences of most yeast immobilization systems. Yeast biocapsules are a cost-effective, spontaneous immobilization system whereby yeast cells are attached to the hyphae of a filamentous fungus, creating hollow spheres that allow recovery and reutilization. In an attempt to prevent yeast cell leakage from the fungal matrix, we coated the yeast biocapsules with a 0.2% (w/v) alginate layer and evaluated yeast cell immobilization and the potential to ferment synthetic high sugar medium and grape must. We concluded that alginate coating prevents cell leakage from yeast biocapsules but hinders alcoholic fermentation. In grape must fermentations, alginate coating does not affect wine acidity but impacts concentrations of some volatile compounds.

Functional and genomic characterization of Komagataeibacter uvaceti FXV3, a multiple stress resistant bacterium producing increased levels of cellulose

Bacterial cellulose is one of the most promising biomaterials for the development of a wide array of novel biotechnological solutions. Nevertheless, the commercial production of bacterial cellulose is still a challenge and obtaining novel strains presenting increased cellulose biosynthesis and stress resistance properties is of extreme importance.This work demonstrates the increased stress resistance, cellulose production abilities, and overall genomic properties of Komagataeibacter uvaceti FXV3, a novel cellulose-producing and stress resistant strain isolated from a fermented grape must.K. uvaceti FXV3 was able to grow under several stress conditions, including the presence of high concentrations of ethanol (up to 7.5 % v/v), a trait that is not observed in the model strain K. xylinus CECT 7351T. Moreover, K. uvaceti FXV3 produced increased concentrations of cellulose (4.31 mg/mL, 7 days after inoculation-DAI) when compared to K. xylinus CECT 7351T (1.42 mg/mL, 7 DAI). Moreover, the detailed analysis of strain FXV3 genome revealed the presence of several genes involved in cellulose and acetan biosynthesis, quorum-sensing and quenching mechanisms, carbohydrate, amino acid, alcohol and aldehyde metabolism, as well as several other genes involved in stress resistance. Additionally, comparative genomic analysis revealed the increased prevalence of stress resistance genes in K. uvaceti FXV3 when compared to K. xylinus CECT 7351T.Ultimately, this study reveals the increased biotechnological potential of K. uvaceti FXV3 and brings new insights into the genetics behind Komagataeibacter stress resistance and cellulose production abilities.

Isolation and Screening of Wine Yeasts from Grapes in Yalu River Valley China for Fermentation Performance

In order to further explore the diversity of yeast in grape brewing in Yalu River Valley, northern China and to better exploit and utilize the yeast resources in a grape producing area, we investigated soil, grape residue after juice extraction and naturally fermented grape juice samples collected from grape plantations in the Yalu River Valley in this study. Twelve yeast strains were identified using colony and cell morphology and molecular biology. Three Saccharomyces cerevisiae strains from different sources, EN2, BZ1 and EZ2, were selected to determine their acid, Sodium dioxide (SO2), glucose and ethanol tolerance. The results showed that EN2 exhibited significant acid and SO2 tolerance, while BZ1 and EZ2 exhibited significant glucose and ethanol tolerance. These three S. cerevisiae strains showed good growth and fermentation characteristics and could be used as development strains for brewing wine. Results of this study could be useful in breeding, wine yeast-strain research and wine product development.

RNA-seq-based transcriptomic comparison of Saccharomyces cerevisiae during spontaneous and inoculated fermentations of organic and conventional grapes

Viticulture practices influence yeast genetics and phenotypes during wine fermentation by affecting grape quality and yeast microflora attached to grape berries, but the influence is limited understood yet. The aim of this study was to evaluate the impact of organic viticulture on wine quality and yeast transcriptome-wide response, and their associated mechanisms. This work compared the yeast transcriptional response during the spontaneous and inoculated fermentation of grapes from organic and conventional agriculture systems, through genome-wide analysis of gene expression, by Illumina Hiseq sequencing platforms. Transcriptome profiling showed that 991 and 96 differentially expressed genes (DEGs) were detected in spontaneous and inoculated fermentations, respectively, indicating that organic viticulture was more likely to affect yeast transcriptome by influencing yeast microflora rather than grape/juice quality. Several pathways of Saccharomyces cerevisiae had more up-regulated DEGs than down-regulated ones in organic samples and in spontaneous fermentation group, including central carbon metabolism, translation, transport and catabolism, and energy metabolism. Besides, viticulture practices and fermentation modes had specific effects on wine quality. This study could enhance the understanding of yeast transcription changes during the fermentation of different grapes and with different strains, as well as elucidate the effect of viticulture practice on yeast transcriptome and wine quality.

Effect of raw and fermented grape seed on growth performance, antioxidant capacity, and cecal microflora in broiler chickens

Grape seed (GS) is a by-product of the fruit juice and wine industry with the potential to be an alternative to synthetic antioxidants due to its antioxidant activity. Agro-industrial residues can be converted to more effective products by solid-state fermentation. The objective of the study was to investigate the effects of GS and fermented grape seed (FGS) on the growth performance, antioxidant capacity, and cecal microflora in broiler chickens. A total of 128 female broilers were randomly allocated into four treatment groups, each consisting of four replicates of eight birds. Throughout the 42-day feeding period, the birds were fed with soybean-corn based diet (CON), 0.15 g/kg synthetic antioxidant (butylated hydroxyanisole) supplemented diet (AO), 5 g/kg GS supplemented diet (GS), and 5 g/kg FGS supplemented diet (FGS). Dietary GS, FGS, and AO supplementation increased the BW (P < 0.05) and average daily weight gain (ADG, P < 0.05) compared with the CON group in the overall period of 42 days. Dietary FGS also increased the ADG (P < 0.05) in the period of 22–42 days compared with the control group. The pH of the breast meat of the chickens fed GS was higher (P < 0.01) than CON and FGS groups. Dietary FGS and AO decreased the b* value (P < 0.01) of breast meat compared with the CON group. Grape seed had the highest serum glutathione peroxidase (P < 0.05) and catalase (CAT, P < 0.01) levels among the treatment groups. The FGS also increased serum CAT level (P < 0.01) compared with the AO group. Moreover, dietary FGS supplementation increased Lactobacillus spp. (P < 0.05) in the cecum compared with the other treatment groups and decreased Staphylococcus aureus (P < 0.05) compared with the CON and AO groups. The present findings indicate that GS and FGS can be used in broiler diets as alternatives to synthetic antioxidants.

An indigenous Saccharomyces uvarum population with high genetic diversity dominates uninoculated Chardonnay fermentations at a Canadian winery.

Saccharomyces cerevisiae is the primary yeast species responsible for most fermentations in winemaking. However, other yeasts, including Saccharomyces uvarum, have occasionally been found conducting commercial fermentations around the world. S. uvarum is typically associated with white wine fermentations in cool-climate wine regions, and has been identified as the dominant yeast in fermentations from France, Hungary, northern Italy, and, recently, Canada. However, little is known about how the origin and genetic diversity of the Canadian S. uvarum population relates to strains from other parts of the world. In this study, a highly diverse S. uvarum population was found dominating uninoculated commercial fermentations of Chardonnay grapes sourced from two different vineyards. Most of the strains identified were found to be genetically distinct from S. uvarum strains isolated globally. Of the 106 strains of S. uvarum identified in this study, four played a dominant role in the fermentations, with some strains predominating in the fermentations from one vineyard over the other. Furthermore, two of these dominant strains were previously identified as dominant strains in uninoculated Chardonnay fermentations at the same winery two years earlier, suggesting the presence of a winery-resident population of indigenous S. uvarum. This research provides valuable insight into the diversity and persistence of non-commercial S. uvarum strains in North America, and a stepping stone for future work into the enological potential of an alternative Saccharomyces yeast species.

Effect of Raw and Fermented Grape Pomace on the Growth Performance, Antioxidant Status, Intestinal Morphology, and Selected Bacterial Species in Broiler Chicks.

Simple SummaryGrape pomace (GP) is a by-product of fruit juice and wine production. Owing to its biochemical composition and lower cost, GP has the potential to be a feed additive for poultry nutrition. However, its antinutritional compounds limit its usability in broiler diets. Fermentation is an ancient and useful method for the utilization of agricultural residues. The aim of the study was to investigate the effects of GP and Aspergillus niger-fermented grape pomace (FGP) on the growth performance, antioxidant capacity, intestinal morphology, and selected bacterial species in broilers. Dietary GP improved the antioxidant status and intestinal morphology of broiler chickens. Dietary FGP enhanced the growth performance, antioxidant capacity, and selected intestinal bacterial species of broilers. Dietary GP caused worsened growth performance compared with the synthetic antioxidants, although FGP had similar growth performance. The findings demonstrate that FGP can be an alternative to synthetic antioxidants for broiler diets.The effects of raw (GP) and fermented grape pomace (FGP) on the growth performance, some carcass parameters, antioxidant status, intestinal morphology, and selected bacterial species in broiler chicken were investigated in this study. Grape pomace was fermented with Aspergillus niger for 7 d. In total, 140 one-day-old male chicks (Ross 308) were randomly assigned to four treatment groups, with five replicates and seven birds each. Chickens were fed either a basal diet (CON) or the basal diet supplemented with 0.25 g/kg synthetic antioxidants (5% butylated hydroxytoluene, 1% butylated hydroxyanisole, and 11% ethoxyquin) (AO), or 15 g/kg GP (GP), or 15 g/kg FGP (FGP) for 42 d. Dietary GP raised serum glutathione peroxidase (p = 0.031) and superoxide dismutase (p = 0.021) levels, increased ileum lamina muscularis thickness (p = 0.016), and did not affect selected bacterial species in the cecum of broiler chickens. Dietary FGP improved body weight (p = 0.003), increased the serum catalase level (p = 0.032), and decreased the cecal Clostridium perfringens count (p = 0.033) but did not affect the ileal morphology of broiler chickens. The carcass parameters, malondialdehyde level, pH, and color of the breast meat of chickens were not changed by either GP or FGP supplementation. Chickens fed with the synthetic antioxidants had similar growth performance with the chickens fed with FGP but had better body weight (p = 0.003) and feed conversion ratio (p = 0.045) compared with the chickens fed with GP. The obtained results showed that FGP can be used as an alternative to synthetic antioxidants in broiler diets.

Nutritional and flavor properties of grape juice as affected by fermentation with lactic acid bacteria

ABSTRACT Two lactic acid bacteria (LAB) strains of Lactobacillus plantarum 21802 and Lactobacillus brevis 6239 were selected and combined for fermentation of grape juice. The changes of sugars, organic acids, volatiles, phenolic compounds as well as antioxidant capacity of the grape juice were characterized. Results showed that fermentation with LAB led to a slight decrease in sugar content and increased in organic acid content. The sugars were mainly consumed at the initial stage of fermentation, while the malic acid was consumed completely during the fermentation. The contents of total phenolics and flavonoids in grape juice decreased gradually during the fermentation process. As compared with the initial contents in unfermented grape juice, the contents of proanthocyanin B2, rutin, isoquercitrin, rhamnose-3-O-glucoside in the final fermented grape juice were increased by 26.83%, 249.24%, 138.48%, 139.60%, respectively, while the contents of gallic acid, proanthocyanin B1, catechin and epicatechin were decreased by 24.49%, 14.85%, 71.68%, 42.52%, respectively. The mice fed with the fermented grape juice showed higher activity of superoxide dismutase and lower level of malondialdehyde both in serum and liver tissue than those fed with the unfermented grape juice. Fermentation with LAB also enhanced the flavor profile by increasing the total number and content of volatile compounds, especially those of monoterpene alcohols, which are the main and characteristic aroma volatile compounds in Muscat aroma grapes. This research confirmed that fermentation with LAB might be a desirable option for improving the flavor and nutritional attributes of grape juice by altering the ratio of sugar to organic acid, improving the phenolic compounds, enhancing the antioxidant capacity, intensifying of the characteristic aroma and pleasant flavor of the grape juice.

Nata de ceulerpa from sea grape fermentation (Caulerpa racemosa) by Acetobacter xylinum as a functional food rich in vitamin C

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