Exploitation of grape marc as functional substrate for lactic acid bacteria and bifidobacteria growth and enhanced antioxidant activity

Safety Evaluation of a Novel Potentially Probiotic Limosilactobacillus fermentum in Rats

Limosilactobacillus (L) fermentum (strains 139, 263, 296) is a novel probiotic mixture isolated from fruit processing by-products. The use of this formulation has been associated with improvements in cardiometabolic, inflammatory, and oxidative stress parameters. The present study evaluated the safety of a potential multi-strain probiotic by genotoxicity (micronucleus assay) and subchronic toxicity study (13-week repeated dose). In the genotoxicity evaluation, L. fermentum 139, 263, 296 did not increase the frequency of micronuclei in erythrocytes of rats of both sexes at doses up to 1010 CFU/mL. In the subchronic toxicity study, the administration of L. fermentum did not promote adverse health effects, such as behavioral changes, appearance of tumors, changes in hematological and biochemical parameters. In addition, higher doses of L. fermentum 139, 263, 296 have been shown to reduce the levels of pro-inflammatory cytokines. Administration of potentially probiotic L. fermentum did not promote adverse health effects in rats and could be evaluated as a potential probiotic for humans.

Grape Pomace-Advances in Its Bioactivity, Health Benefits, and Food Applications

From a circular economy perspective, the appropriate management and valorization of winery wastes and by-products are crucial for sustainable development. Nowadays, grape pomace (GP) has attracted increasing interest within the food field due to its valuable content, comprising nutritional and bioactive compounds (e.g., polyphenols, organic and fatty acids, vitamins, etc.). Particularly, GP polyphenols have been recognized as exhibiting technological and health-promoting effects in different food and biological systems. Hence, GP valorization is a step toward offering new functional foods and contributing to solving waste management problems in the wine industry. On this basis, the use of GP as a food additive/ingredient in the development of novel products with technological and functional advantages has recently been proposed. In this review, we summarize the current knowledge on the bioactivity and health-promoting effects of polyphenolic-rich extracts from GP samples. Advances in GP incorporation into food formulations (enhancement of physicochemical, sensory, and nutritional quality) and information supporting the intellectual property related to GP potential applications in the food industry are also discussed.

Uncovering the promising role of grape pomace as a modulator of the gut microbiome: An in-depth review

Grape pomace is the primary wine coproduct consisting primarily of grape seeds and skins. Grape pomace holds immense potential as a functional ingredient to improve human health while its valorization can be beneficial for industrial sustainability. Pomace contains bioactive compounds, including phenols and oligosaccharides, most of which reach the colon intact, enabling interaction with the gut microbiome. Microbial analysis found that grape pomace selectively promotes the growth of many commensal bacteria strains, while other types of bacteria, including various pathogens, are highly sensitive to the pomace and its components and are inactivated. In vitro studies showed that grape pomace and its extracts inhibit the growth of pathogenic bacteria in Enterobacteriaceae family while increasing the growth and survival of some beneficial bacteria, including Bifidobacterium spp. and Lactobacillus spp. Grape pomace supplementation in mice and rats improves their gut microbiome complexity and decreases diet-induced obesity as well as related illnesses, including insulin resistance, indicating grape pomace could improve human health. A human clinical trial found that pomace, regardless of its phenolic content, had cardioprotective effects, suggesting that dietary fiber induced those health benefits. To shed light on the active components, this review explores the potential prebiotic capacity of select bioactive compounds in grape pomace.

Spontaneous fermentation improves the physicochemical characteristics, bioactive compounds, and antioxidant activity of acerola (Malpighia emarginata D.C.) and guava (Psidium guajava L.) fruit processing by-products

This study aimed to investigate the effects of spontaneous fermentation on physicochemical characteristics, bioactive compounds, and antioxidant activity of acerola and guava fruit industrial by-products. Viable cell counts of lactic acid bacterial (LAB) in acerola and guava by-products were ≥ 5.0 log CFU/mL from 24 h up to 120 h of fermentation. Fermented acerola and guava by-products had increased luminosity and decreased contrast. Contents of total soluble solids and pH decreased, and titrable acidity increased in acerola and guava by-products during fermentation. Ascorbic acid contents decreased in acerola by-product and increased in guava by-product during fermentation. Different phenolic compounds were found in acerola and guava by-products during fermentation. Fermented acerola and guava by-products had increased contents of total flavonoids, total phenolics, and antioxidant activity. The contents of total flavonoids and total phenolics positively correlated with antioxidant activity in fermented acerola and guava by-products. These results indicate that spontaneous fermentation could be a strategy to improve the contents of bioactive compounds and the antioxidant activity of acerola and guava by-products, adding value and functionalities to these agro-industrial residues.

Up-Cycling Grape Pomace through Sourdough Fermentation: Characterization of Phenolic Compounds, Antioxidant Activity, and Anti-Inflammatory Potential

Despite its appealing composition, because it is rich in fibers and polyphenols, grape pomace, the major by-product of the wine industry, is still discarded or used for feed. This study aimed at exploiting grape pomace functional potential through fermentation with lactic acid bacteria (LAB). A systematic approach, including the progressively optimization of the grape pomace substrate, was used, evaluating pomace percentage, pH, and supplementation of nitrogen and carbon sources. When grape pomace was used at 10%, especially without pH correction, LAB cell viability decreased up to 2 log cycles. Hence, the percentage was lowered to 5 or 2.5% and supplementations with carbon and nitrogen sources, which are crucial for LAB metabolism, were considered aiming at obtaining a proper fermentation of the substrate. The optimization of the substrate enabled the comparison of strains performances and allowed the selection of the best performing strain (Lactiplantibacillus plantarum T0A10). A sourdough, containing 5% of grape pomace and fermented with the selected strain, showed high antioxidant activity on DPPH and ABTS radicals and anti-inflammatory potential on Caco2 cells. The anthocyanins profile of the grape pomace sourdough was also characterized, showing qualitative and quantitative differences before and after fermentation. Overall, the grape pomace sourdough showed promising applications as a functional ingredient in bread making.

Development of Functional Fermented Dairy Products Containing Taiwan Djulis (Chenopodium formosanum Koidz.) in Regulating Glucose Utilization

Taiwan djulis (Chenopodium formosanum Koidz.) is a plant native to Taiwan and is a grain rich in nutrients, vitamins, and minerals with antioxidant properties. This paper aimed to use appropriate processing technology and incorporate probiotics, thus combining Taiwan’s high-quality milk sources to develop Taiwan djulis fermented dairy products. Later, FL83B cells have used to evaluate the glucose utilization ability after the administration of djulis. We first screened Lactiplantibacillus plantarum and combined it with the traditional yogurt strains Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus for cultivation. Further, the fermentation process was optimized where 7.5% djulis and an inoculum of 107 colony forming unit/mL were fermented at 40 °C for 18 h. Compared to fermented milk without djulis, the analysis of various nutrients and active ingredients showed that free radical scavenging abilities of DPPH and ABTS reached 2.3 and 2.0 times (752.35 ± 29.29 µg and 771.52 ± 3.79 µg TE/g, respectively). The free phenol content increased 2.5 times (169.90 ± 14.59 mg gallic acid/g); the total flavonoid content enhanced 4.8 times (3.05 ± 0.03 mg quercetin/g), and the gamma-aminobutyric acid content was 3.07 ± 0.94 mg/g. In a co-culture of mouse liver cells with fermented products, 100 ppm ethanol extract of fermented products effectively improved glucose utilization with increased glucose transporter expression. This functional fermented dairy product can be developed into the high value added local agricultural products and enhance multiple applications including medical and therapeutic fields.

Supplementation of Labneh with Passion Fruit Peel Enhanced Survival of E. coli Nissle 1917 during Simulated Gastrointestinal Digestion and Adhesion to Caco-2 Cells

Passion fruit peel powder (PFPP) was used to supplement the probiotic labneh to increase the activity of Escherichia coli Nissle 1917 (EcN) during production and storage. Labneh was manufactured with PFPP (0.5% and 1%) and analyzed at 0, 7, and 15 days of cold storage for postacidification and sensory properties and viability of EcN, survival of EcN to simulated gastrointestinal tract stress, and adhesion potential of EcN to Caco-2 cells. Acidification kinetics during fermentation showed that supplementation with PFPP reduced the time needed to decrease pH and reach the maximum acidification rate. PFPP addition contributed to postacidification of labneh during storage. PFPP had a beneficial effect (p < 0.05) on counts of EcN in labneh during different storage periods. Consumer preference expectations for labneh enriched with PFPP (0.5% and 1%) were higher than those for the control. PFPP provided a significant protective action for EcN during simulated gastrointestinal transit and had a positive effect on EcN adhesion to Caco-2 cells in vitro, although this decreased during storage with labneh. Labneh supplementation with PFPP can be recommended because of the positive effect on EcN viability and the high nutritional value, which may increase the appeal of the product to consumers.

Current Options in the Valorisation of Vine Pruning Residue for the Production of Biofuels, Biopolymers, Antioxidants, and Bio-Composites following the Concept of Biorefinery: A Review

Europe is considered the largest producer of wine worldwide, showing a high market potential. Several wastes are generated at the different stages of the wine production process, namely, vine pruning, stalks, and grape marc. Typically, these residues are not used and are commonly discarded. Portugal generates annually approximately 178 thousand metric tons of wine production waste. In this context, the interest in redirecting the use of these residues has increased due to overproduction, great availability, and low costs. The utilization of these lignocellulosic biomasses derived from the wine industry would economically benefit the producers, while mitigating impacts on the environment. These by-products can be submitted to pre-treatments (physical, chemical, and biological) for the separation of different compounds with high industrial interest, reducing the waste of agro-industrial activities and increasing industrial profitability. Particularly, vine-pruning residue, besides being a source of sugar, has high nutritional value and may serve as a source of phenolic compounds. These compounds can be obtained by bioconversion, following a concept of biorefinery. In this framework, the current routes of the valorisation of the pruning residues will be addressed and put into a circular economy context.

Targeting the Gut Microbiota for Remediating Obesity and Related Metabolic Disorders

The rate of obesity is rapidly increasing and has become a health and economic burden worldwide. As recent studies have revealed that the gut microbiota is closely linked to obesity, researchers have used various approaches to modulate the gut microbiota to treat the condition. Dietary composition and energy intake strongly affect the composition and function of the gut microbiota. Intestinal microbial changes alter the composition of bile acids and fatty acids and regulate bacterial lipopolysaccharide production, all of which influence energy metabolism and immunity. Evidence also suggests that remodeling the gut microbiota through intake of probiotics, prebiotics, fermented foods, and dietary plants, as well as by fecal microbiota transplantation, are feasible methods to remediate obesity.

Evaluation and Application of Different Cholesterol-Lowering Lactic Acid Bacteria as Potential Meat Starters

ABSTRACT

A total of 115 isolates of lactic acid bacteria were screened from traditional fermented foods in Guizhou Province, People's Republic of China. The cholesterol removal rates of 86 isolates ranged from 7.29 to 25.66%, and 18 isolates showed a cholesterol removal rate of more than 15%. According to the results of physiological and biological tests, 13 isolates were selected to determine the fermentation performance; 9 isolates-MT-4, MT-2, PJ-15, SR2-2, SQ-4, SQ-7, ST2-2, ST2-6, and NR1-7-had high tolerance of bile salt and acid and had a survival rate of more than 96% under pH 3.0 and 0.3% bile salt. ST2-2, SR2-2, NR1-7, SQ-4, and MT-4 had high survival rate in different concentrations of NaCl and NaNO2 under different temperatures. According to BLAST comparison results of the 16S rRNA sequence in the GenBank database and the genetic distance of the 16S rRNA sequence with an ortho-connected algorithm, SR2-2, NR1-7, and ST2-2 were identified as Lactobacillus plantarum, MT-4 was identified as Lactobacillus pentosus, and SQ-4 was identified as Lactobacillus paraplantarum. Moreover, strains SQ-4 and MT-4 were added to fermented beef. Results showed that the fermented beef had delicious taste and was popular to consumers because of its proper pH, pleasant colors, high viable cell count, and suitable content of bound and immobilized water. These results provide a basis for the development of new starter formulation for the production of high-quality fermented meat products.

HIGHLIGHTS

Cultivation media for lactic acid bacteria used in dairy products

This review aims to familiarize the reader with research efforts on the cultivation media of lactic acid bacteria (LAB). We have also included a brief discussion on standard ingredients used in LAB media and chemically defined media as related to bacterial growth requirements. Recent research has focused on modifying standard media for the enumeration, differentiation, isolation, and identification of starter cultures and probiotics. Even though large numbers of these media have been developed to serve dairy microbial control, they have failed to provide consistent results. The research consequently points to the need to develop a reliable lactobacilli growth medium for the dairy industry.

Effects of Quercetin and Resveratrol on in vitro Properties Related to the Functionality of Potentially Probiotic Lactobacillus Strains

The ability of probiotics to exert benefits on host has been associated with different physiological functionalities in these microorganisms, namely cell surface hydrophobicity, autoaggregation, coaggregation with pathogens, antagonistic activity against pathogens and ability to survive the exposure to gastrointestinal conditions. This study assessed the effects of different concentrations of quercetin (QUE) and resveratrol (RES) on the ability of six potentially probiotic Lactobacillus strains to tolerate different pH values and bile salt concentrations, to autoaggregate, coaggregate with and antagonize pathogens and survive the exposure to simulated gastrointestinal conditions. QUE and RES presented low inhibitory effects on all tested Lactobacillus strains, with minimum inhibitory concentration (MIC) ranging from 512 to >1024 μg/mL. In most cases, QUE and RES at all tested concentrations (i.e., MIC, 1/2 MIC, and 1/4 MIC) did not affect the tolerance of the Lactobacillus strains to acidic pH and bile salts. QUE increased cell surface hydrophobicity of most of the tested Lactobacillus strains and increases or decreases in cell surface hydrophobicity varied in the presence of different RES concentrations among some strains. QUE and RES increased the ability of tested Lactobacillus strains to autoaggregate and coaggregate with pathogens. QUE and RES did not negatively affect the antagonistic activity of the tested Lactobacillus strains against pathogens and did not decrease their survival rates when exposed to in vitro gastrointestinal conditions. In a few cases, the ability of some tested Lactobacillus strains to antagonize pathogens, as well as to survive specific steps of the in vitro digestion was increased by QUE and RES. QUE exerted overall better protective effects on the measured in vitro properties of tested Lactobacillus strains than RES, and L. fermentum and L. plantarum strains presented better responses when treated with QUE or RES. These results showed that probiotic Lactobacillus strains could present low susceptibility to QUE and RES. Combined use of QUE and RES with probiotic Lactobacillus could improve their functionalities on the host; however, the concentration of these polyphenols should be carefully selected to achieve the desirable effects and vary according to the selected probiotic strain.

Piacentinu Ennese PDO Cheese as Reservoir of Promising Probiotic Bacteria

Piacentinu Ennese is a protected designation of origin (PDO) cheese produced in the surrounding area of Enna (Sicily, Italy), using raw ewe's milk without the addition of any starter cultures. In the present study, the Lactobacillus population of Piacentinu Ennese PDO cheese was in vitro screened in order to select promising probiotic strains to be further used in humans. One hundred and sixty-nine lactic acid bacteria (LAB) were isolated from 90 days ripened cheeses and identified by Rep-PCR genomic fingerprinting, using the (GTG)5-primer, and by MALDI-TOF MS. One hundred and thirteen (113) isolates belonging to QPS-list species were characterized for both safety and functional properties. All tested isolates were considered safe because none showed either gelatinase, DNase, mucinase, or hemolytic activity. Tolerance to lysozyme, bile salts, and acidic conditions, along with ability to survive under simulated gastrointestinal digestion, were observed. In addition, based on antimicrobial activity against pathogens, cell surface characteristics, Caco-2 adhesion abilities, and anti-inflammatory potential, it was possible to confirm the strain-dependent functional aptitude, suggesting that Piacentinu Ennese PDO cheese may be considered a precious source of probiotic candidates.

Changes Over the Fermentation Period in Phenolic Compounds and Antioxidant and Anticancer Activities of Blueberries Fermented by Lactobacillus plantarum

This study determined the effects of blueberry fermentation by Lactobacillus plantarum on antioxidant and anticancer activities. The fermented blueberries extracted with 80% ethanol (FBE) showed increased superoxide dismutase-like activity, increased scavenging of DPPH and alkyl radicals, and increased antiproliferative activity against human cervical carcinoma HeLa cells by inducing apoptosis. Seven representative phenolic compounds (malvidin 3-O-glucopyranoside, gallic acid, protocatechuic acid, catechol, chlorogenic acid, syringic acid, and epigallocatechin) in FBE were measured by high-performance liquid chromatography at different fermentation times. The content of each phenolic compound in the FBE was dependent on the fermentation period. Protocatechuic acid and catechol levels increased significantly with fermentation time. Of these three major compounds (protocatechuic acid, catechol, and chlorogenic acid), catechol showed the most significant anticancer activity when HeLa cells were treated with each of these three compounds alone or mixed in various ratios. Pearson's product-moment correlation analysis revealed that the increases in antioxidant and anticancer activities following blueberry fermentation were positively correlated with the phenolic acids present in FBE. PRACTICAL APPLICATION: Blueberries fermented with a tannase-producing lactic acid bacteria (LAB), Lactobacillus plantarum showed higher antioxidant activities and antiproliferative activities against human cervical carcinoma HeLa cells than did raw blueberries. L. plantarum fermentation biotransformed blueberry polyphenols into active phenol metabolites with strong antioxidant and antiproliferative activities. Our results suggest that fermented blueberries are rich in phenolic acids, which are a promising source of natural antioxidants and anticancer drugs and can be used as additives in food, pharmaceuticals, and cosmetic preparations.

Composition and Characteristics of Yam Juice Fermented by Lactobacillus plantarum and Streptococcus thermophilus

In this study, Lactobacillus plantarum (LP), alone or in combination with Streptococcus thermophilus, was used to ferment yam juice. Changes in the composition (phenols, organic acids, reducing sugars and volatile substances) and functional characteristics (antioxidative activity and ability to regulate the intestinal flora) of yam juice during fermentation were investigated. The results showed that the total phenolic (TP) content increased from 201.27 to 281.27 and 285.77 μg/mL for LP- and L. plantarum and S. thermophilus (LPST)-fermented yam juice, respectively. The antioxidative activity of yam juice improved significantly after fermentation, highly correlating with its TP content. In addition, LP- or LPST-fermented yam juice had positive effects on members of the human intestinal flora, improving the activity of Bifidobacterium and inhibiting the growth of Escherichia coli. Sensory analysis showed that LPST-fermented yam juice had a highest score. The results of this study showed that fermented yam juice can serve as a healthy beverage for consumers with low immunity or an imbalance of the intestinal flora.

Sustainable wineries through waste valorisation: A review of grape marc utilisation for value-added products

Grapes are one of the most cultivated fruits worldwide, with one third of total production used in winemaking. Both red and white winemaking processes result in substantial quantities of solid organic waste, such as grape marc (pomace) and stalks, which requires suitable disposal. Grape marc accounts for approximately 10-30% of the mass of grapes crushed and contains unfermented sugars, alcohol, polyphenols, tannins, pigments, and other valuable products. Being a natural plant product rich in lignocellulosic compounds, grape marc is also a promising feedstock for renewable energy production. However, despite grape marc having such potential, advanced technologies to exploit this have not been widely adopted in wineries and allied industries. This review covers opportunities beyond traditional composting and animal feed, and examines value-added uses via the extraction of useful components from grape marc, as well as thermochemical and biological treatments for energy recovery, fuel or beverage alcohol production, and specialty novel products and applications such as biosurfactants and environmental remediation. New advances in relevant technology for each of these processes are discussed, and future directions proposed at both individual producer and regional facility scales, including advanced processing techniques for integrated ethanol production followed by bioenergy generation from the spent marc.

Potential interactions among phenolic compounds and probiotics for mutual boosting of their health-promoting properties and food functionalities - A review

Several foods are rich sources of phenolic compounds (PC) and their beneficial effects on human health may be increased through the action of probiotics. Additionally, probiotics may use PC as substrates, increasing their survival and functionality. This review presents available studies on the effects of PC on probiotics, including their physiological functionalities, interactions and capability of surviving during exposure to gastrointestinal conditions and when incorporated into food matrices. Studies have shown that PC can improve the adhesion capacity and survival of probiotics during exposure to conditions that mimic the gastrointestinal tract. There is strong evidence that PC can modulate the composition of the gut microbiota in hosts, improving a variety of biochemical markers and risk factors for chronic diseases. Available literature also indicates that metabolites of PC formed by intestinal microorganisms, including probiotics, exert a variety of benefits on host health. These metabolites are typically more active than parental dietary PC. The presence of PC commonly enhances probiotic survival in different foods. Finally, further clinical studies need to be developed to confirm in vitro and experimental findings concerning the beneficial interactions among different PC and probiotics.