Improvement mechanism of volatile flavor in fermented tilapia surimi by cooperative fermentation of Pediococcus acidilactici and Latilactobacillus sakei: Quantization of microbial contribution through influence of genus.

Single starter can hardly improve the volatile flavor of fermented fish surimi. In this study, the changes of volatile compounds (VCs) and microbial composition during cooperative fermentation of Latilactobacillus sakei and Pediococcus acidilactici were studied by headspace solid-phase microextraction gas chromatography-mass spectrometry and 16S rRNA gene high-throughput sequencing. During cooperative fermentation, most VCs and the abundance of Latilactobacillus and Lactococcus significantly increased, while Pediococcus, Acinetobacter, and Macrococcus obviously decreased. After evaluation of correlation and abundance of each genus, Latilactobacillus and Lactococcus possessed the highest influence on the formation of volatile flavor during cooperative fermentation. Compared with the natural fermentation, cooperative fermentation with starters significantly enhanced most of pleasant core VCs (odor activity value≥1), but inhibited the production of trimethylamine and methanethiol, mainly resulting from the absolutely highest influence of Latilactobacillus. Cooperative fermentation of starters is an effective method to improve the volatile flavor in the fermented tilapia surimi.

Analysis of ester-producing performance in high-yield ethyl hexanoate yeast and the effect on metabolites in bio- enhanced Daqu, the starter for Baijiu and other traditional fermented foods.

AIMS: Ethyl hexanoate, one of the key flavor compounds in strong-flavor Baijiu. To improve the content of ethyl hexanoate in strong-flavor Baijiu, a functional strain with high yield of ethyl hexanoate was screened and its ester-producing performance was studied. METHODS AND RESULTS: Upon identification, the strain was classified as Candida sp. and designated as ZY002. Under optimal fermentation conditions, the content of ethyl hexanoate synthesized by ZY002 can be as high as 170.56 mg L-1. A fermentation test was carried out using the ZY002 strain bioaugmented Daqu to verify the role of the strain applied to Baijiu brewing. It was found that strain ZY002 could not only improve the moisture and alcohol contents of fermented grains but also diminish the presence of reducing sugar and crude starch. Furthermore, it notably amplified the abundance of flavor compounds. CONCLUSION: In this study, Candida sp. ZY002 with a high yield of ethyl hexanoate provided high-quality strain resources for the actual industrial production of Baijiu.

Exploring the Relationships Between Bacterial Community, Taste-Enhancing Peptides and Aroma in Thai Fermented Fish (Pla-ra).

As a traditional Thai condiment, Pla-ra is used to add flavor and richness to dishes. Nine treatment combinations of Pla-ra formulations created from 3 types of fish (Mor fish, Kradee fish, and Mor + Kradee fish) and 4 different carbohydrate sources (none, rice bran, roasted rice, and rice bran─roasted rice mixture) were studied through a 12 month fermentation period (1, 3, 5, 7, 8, 9, 10, 11, and 12 months). 16S rRNA Next Generation Sequencing (NGS) and LC-MS/MS techniques were used to analyze the microbial diversity and identify taste-enhancing peptides. Descriptive sensory analysis was performed on the extracts of the 108 Pla-ra samples mixed in a model broth. Koku perception and saltiness-enhancing attributes were clearly perceived and dominant in all samples, even though glutamyl peptides, including γ-Glu-Val-Gly, were found at subthreshold levels. The samples from mixed fish and Mor fish fermented with roasted ground rice and rice bran for 12 months had the most typical Pla-ra odors and tastes and had high taste-enhancing activities. NGS analysis revealed the presence of bacteria containing a large number of protease and aminopeptidase genes in the samples. Bacillus spp., Gallicola spp., and Proteiniclasticum spp. correlated well with the generation of glutamyl and arginyl peptides and typical odors in the samples. These results confirmed the typical sensory quality of Pla-ra depended on protein sources, carbohydrate sources, and bacteria communities. Further optimization of the microbial composition found could lead to the development of starter cultures to control and promote flavor development in fermented fish products.

A combination of omics-based analyses to elucidate the effect of NaCl concentrations on the metabolites and microbial dynamics during the ripening fermentation of Pixian-Douban.

The study investigated the effect of different sodium chloride (NaCl) concentrations (10%, 15%, and 20%) on the ripening fermentation of Pixian-Douban, a traditional fermented condiment. The results showed that NaCl affected the dynamics of physicochemical parameters, volatile components, fatty acids, amino metabolites, organic acids, and microbial composition, and their dynamic modes were different. After 253 days fermentation, the 10% NaCl Pixian-Douban had significantly (p < 0.05) higher levels of total organic acids (20,308.25 mg/kg), amino metabolites (28,144.96 mg/kg), and volatiles (3.36 mg/kg) compared to 15% and 20% NaCl Pixian-Douban. Notably, the possible health risk associated with high concentration of biogenic amines in 10% NaCl Pixian-Douban is of concern. Moreover, correlation analyses indicated that the effect of NaCl on the quality of Pixian-Douban may be mainly related to bacteria. This study deepens the knowledge about the role of NaCl in ripening fermentation of Pixian-Douban and contributes to develop low-NaCl Pixian-Douban product.

Mechanism of carbohydrate and protein conversion during sourdough fermentation: An analysis based on representative Chinese sourdough microbiota.

Sourdough fermentation is attracting growing attention because of its positive effects on properties of leavened baked good. However, the changes in dough features and the mechanisms behind them are not well understood, which limits its widespread use. In this study, we assessed the effects of representative lactic acid bacteria in sourdough monoculture or co-culture with yeasts on dough characteristics. Physicochemical analysis identified increased proteolysis and enhanced nutritional properties of co-culture groups. However, a reduction in organic acids contents of co-culture groups compared to monoculture was detected, and this effect was not limited by the yeast species. The RNA sequencing further demonstrated that the presence of yeast enhanced the protein metabolic activity of lactic acid bacteria, while decreased its organic acid biosynthetic activity. Moreover, the proteomic analysis revealed that endogenous metabolic proteins of flour, such as pyruvate kinase, glucosyltransferase and pyruvate dehydrogenase play a key role in carbohydrate metabolism during fermentation. This study uncovered the influence of typical microorganisms and endogenous enzymes on dough characteristics based on different aspects. Bacteria-mediated consumption of proteins and increased proteolysis in co-culture groups may underlie the improved digestibility and nutritional effects of sourdough fermented products, which provides an important basis for nutrient fortified bread making with multi-strain leavening agent.

Identification, Characterization, and Receptor Binding Mechanism of New Umami Peptides from Traditional Fermented Soybean Paste (Dajiang).

Dajiang, a traditional Chinese condiment, is made from fermented soybeans. It is highly popular among consumers as a result of its delicious umami flavor, which mainly originates from umami peptides. To examine the mechanism of umami taste in Dajiang, we selected Dajiang samples with strong umami taste and subjected them to purification and identification analysis using ethanol precipitation, gel chromatography, reversed-phase high-performance liquid chromatography, and ultraperformance liquid chromatography-tandem mass spectrometry. Subsequently, on the basis of toxicity and umami prediction analysis, we screened, synthesized, and characterized three novel bean umami peptides in Dajiang: TLGGPTTL, 758.4174 Da; GALEQILQ, 870.4811 Da; and HSISDLQ, 911.4713 Da. Their sensory threshold values were 0.25, 0.40, and 0.17 mmol/L, respectively. Furthermore, molecular docking results showed that hydrogen-bonding and hydrophobic interactions are important interaction forces in the binding of umami peptide to taste receptors. Ser147 and Glu148 of the T1R3 taste receptor are important amino acid residues for binding of the three umami peptides. This study uncovers the mechanism of umami-peptide-driven flavor in fermented soybean products.

[Distribution of vitamin K_2 content in Chinese traditional fermented soybean products].

OBJECTIVE: To determine the content of vitamin K_2 in different types of fermented bean products and analyze the difference of vitamin K_(2 )content. METHODS: A total of 98 kinds of typical fermented bean products were included in Chinese traditional fermented bean products(Douchi, Sufu, soybean paste). Process, region, sales volume, raw materials and flavor were considered, and the content of vitamin K_2 in fermented bean products was determined by high performance liquid chromatography. RESULTS: Chinese bean fermented foods generally contained vitamin K_2, and the subtype menaquinone-7(MK-7)was the main one. The content of vitamin K_2 in Douchi was the highest(437.55 µg/100 g), the content of vitamin K_2 in Sufu and Soybean paste were lower(7.48 µg/100 g and 2.47 µg/100 g). The content of vitamin K_2 in bacterial Douchi was higher than that in Mucor type and Aspergillus oryzae type which were 403.94, 232.98 and 81.00 µg/100 g(P<0.05). Soybean type Douchi was higher than that in black bean type of Douchi which were 610.41, 178.08 µg/100 g(P<0.05), and the content of vitamin K_2 in dry Douchi was higher than the content of vitamin K_2 in water Douchi which were 1 517.45 µg/100 g, 297.58 µg/100 g(P<0.05). However, there were no significant difference in the content of vitamin K_2 in Soybean paste and Sufu in different types and regions(P > 0.05). CONCLUSION: Vitamin K_2 is widely contained in Chinese fermented bean products, and its content is mainly affected by fermentation microorganisms and processing technology.

Sourdough Fermentation Improves the Antioxidant, Antihypertensive, and Anti-Inflammatory Properties of Triticum dicoccum.

The fermentation process has been widely used to improve plant-based foods' nutritional and nutraceutical properties. This study aimed to investigate and compare the impact of sourdough fermentation on the bioactive content and profile, antioxidant and antihypertensive activities, as well as the anti-inflammatory properties of fermented (FS) and non-fermented (NFS) flour from Tuscan Triticum dicoccum wheat (spelt) on tumor necrosis factor-alpha (TNF-α)-inflamed human intestinal epithelial cells (HT-29). FS showed significantly higher total phenolic and flavonoid content, in vitro and ex vivo antioxidant activities, and ACE-inhibitory activities than NFS. Gallic acid was identified by HPLC-DAD as the most representative polyphenol, followed by rutin, trans-ferulic acid, iso-quercitrin, and quercetin, in the fermented spelt sample. Instead, rutin and gallic acid were identified as the predominant compounds in the non-fermented ones. Moreover, FS exhibited a better protective effect on inflamed HT-29 cells by significantly counteracting the TNFα-induced alterations, lowering the expression of IL-8, COX-2, and ICAM-1 inflammatory mediator while enhancing antioxidant enzyme HO-1 gene expression. In conclusion, sourdough fermentation positively affected the nutraceutical and functional properties of spelt, which may represent a valuable ingredient for the formulation of functional foods and a key product for managing hypertension and inflammatory intestinal diseases.

Evaluation of vegetable sauerkraut quality during storage based on convolution neural network.

Vegetable sauerkraut is a traditional fermented food. Due to oxidation reactions that occur during storage, the quality and flavor in different periods will change. In this study, the quality evaluation and flavor characteristics of 13 groups of vegetable sauerkraut samples with different storage time were analyzed by using physical and chemical parameters combined with electronic nose. Photographs of samples of various periods were collected, and a convolutional neural network (CNN) framework was established. The relationship between total phenol oxidative decomposition and flavor compounds was linearly negatively correlated. The vegetable sauerkraut during storage can be divided into three categories (full acceptance period, acceptance period and unacceptance period) by principal component analysis and Fisher discriminant analysis. The CNN parameters were fine-tuned based on the classification results, and its output results can reflect the quality changes and flavor characteristics of the samples, and have better fitting, prediction capabilities. After 50 epochs of the model, the accuracy of three sets of data namely training set, validation set and test set recorded 94%, 85% and 93%, respectively. In addition, the accuracy of CNN in identifying different quality sauerkraut was 95.30%. It is proved that the convolutional neural network has excellent performance in predicting the quality of Szechuan Sauerkraut with high reliability.

Analysis of Oligosaccharides in Korean Fermented Soybean Products by the Combination of Mass Spectrometry and Gas Chromatography.

Doenjang (fermented soybean paste) and ganjang (soy sauce) are traditional fermented foods that are widely consumed in Korea. The oligosaccharides found in soybean and its fermented foods have great potential to improve the quality of foods; however, their structural details have not been well studied. In this study, we used advanced mass spectrometry and gas chromatography to analyze oligosaccharides and their monomeric composition in two fermented soybean products. In both foods, oligosaccharides with a degree of polymerization ranging from 3 to 7 were found. Their constituent monosaccharides were characterized; galactose, xylose, arabinose, and rhamnose were the predominant constituents of the oligosaccharides, and fucose, fructose, mannose, glucose, and N-acetylglucosamine were also found. The great structural diversity of the oligosaccharides found suggests that soybean carbohydrates are hydrolyzed and/or transformed during fermentation and may yield novel oligosaccharides.

Characteristics of changes in volatile organic compounds and microbial communities during the storage of pickles.

The variations of volatile organic compounds (VOCs) and microbial communities of three pickles during storage at 4°C for one week were analyzed by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), high-throughput sequencing, and Spearman correlation analysis. A total of 50 VOCs were identified from three pickles. During storage, most alcohols, aldehydes, ketones, and esters decreased, while acids increased, and sulfides, alkenes, and phenols were relatively equal. Firmicutes, Cyanobacteria, and Proteobacteria were the predominant bacterial phyla, and Weissella, Streptophyta, Leuconostoc, Bacillariophyta, and Lactobacillus were the predominant bacterial genera in three pickles. The bacterial diversity level significantly decreased during storage (P < 0.05). Spearman correlation coefficient indicated that Leuconostoc, Lactobacillus, and Weissella were highly correlated with the flavor of pickles, while Bacillariophyta and Streptophyta were highly correlated with the flavor formation of pickles during storage. These results could contribute to a better understanding of the impact of bacteria in flavor formation during pickle storage.

Dynamics of microbial communities, flavor, and physicochemical properties of pickled chayote during an industrial-scale natural fermentation: Correlation between microorganisms and metabolites.

Pickled chayote is a Chinese fermented vegetable with unique flavors and is favored by local consumers. However, little is known about its quality changes and microbial community succession during fermentation and the relationship between microbes and quality. In the work, the physicochemical quality attributes (pH, acidity, nitrite, texture, and color) and flavor properties (sugars, organic acids, free amino acid [FAA], and volatiles) were investigated. The results revealed that organic acids, FAAs, and key volatiles (esters, terpenes, alcohols, and phenols) significantly increased during fermentation. Lactobacillus was the dominant bacterial genus with Lactobacillus alimentarius being the prevalent species; Kazachstania and Pichia were dominant fungal genera with Kazachstania humilis and Pichia membranifaciens being the prevalent species. The microbial metabolic network found that bacteria (L. alimentarius, L. futsaii, and L. paralimentarius) and fungi (K. humilis and P. membranifaciens) played significant roles in the physicochemical changes and flavor production of pickled chayote.

Dynamic correlations between major enzymatic activities, physicochemical properties and targeted volatile compounds in naturally fermented plain sufu during production.

Dynamic changes and correlations between physicochemical properties, 14 targeted volatile compounds (TVCs) and six groups of enzyme activities during eight production stages of naturally fermented plain sufu were explored. Multiple factor analysis was used to discriminate between and group the samples into three clusters: cluster I comprised tofu and pehtze; cluster II comprised dried pehtze and salted pehtze; cluster III involved the aging stages. Clusters I and II were characterised by higher enzyme activities, while cluster III was characterised by the presence of diverse TVCs. Protease and esterase were strongly correlated with most of the TVCs. Esterase, in particular, contributed to the formation of three high molecular weight esters, namely, ethyl dodecanoate, ethyl (Z)-9-octadecenoate and ethyl (Z, Z)-9,12-octadecadienoate. The enzymes found contributed to the texture and flavour of naturally fermented sufu and will provide a good guide and control for using the enzymes directly to ripen sufu products.

Microbial toxins in fermented foods: health implications and analytical techniques for detection.

Recently, demand for fermented foods has increased due to their improved nutritional value, taste, and health-promoting properties. Worldwide consumption of these products is increasing. Fermented foods are generally safe for human consumption. However, some toxins, primarily biogenic amines (putrescine, phenylethylamine, histamine, tyramine, and cadaverine), mycotoxins (fumonisins, aflatoxins, ochratoxin A, zearalenone, and trichothecenes), and bacterial toxins (endotoxins, enterotoxins, and emetic toxins) can be produced as a result of using an inappropriate starter culture, processing conditions, and improper storage. These toxins can cause a multitude of foodborne illnesses and can lead to cardiovascular aberration and adverse gastrointestinal symptoms. Analytical techniques are in use for the detection of toxins in fermented foods for monitoring and control purposes. These include culture, chromatographic, immunoassays, and nano sensor-based techniques. These detection techniques can be used during the production process and along the food chain. On an industrial scale, HPLC is widely used for sensitive quantification of toxins in fermented foods. Recently, biosensor and nano sensor-based techniques have gained popularity due to accuracy, time efficiency, and simultaneous detection of multiple toxins. Other strategic methods being investigated for the removal of toxins from fermented foods include the use of specific starter cultures for bio-preservation, aflatoxin-binding, and biogenic amine-degradation agents that may help to appropriately manage the food safety concerns associated with fermented foods.

Avaliação da interação entre leveduras isoladas de kombucha e bactérias probióticas / Evaluation of the interaction between isolated kombucha yeasts and probiotic bacteria

Um dos maiores desafios no desenvolvimento de produtos probióticos é entender como os microrganismos interagem entre si e com o hospedeiro. Quando falamos em alimentos fermentados tradicionais, este obstáculo aumenta porque a matriz alimentar já possui um microbioma intrínseco. No entanto, também é conhecido que muitos microrganismos podem interagir e cooperar para sobreviver quando condições de estresse são encontradas. Assim, o objetivo deste trabalho foi isolar leveduras de quatro diferentes kombuchas em distintos momentos fermentativos e verificar a influência que leveduras isoladas de kombucha têm na manutenção da viabilidade da bactéria probiótica Bifidobacterium animalis subsp. lactis HN019 em condições de aerobiose. Meyerozyma guilliermondii, Candida albicans, Rhodotorula mucilaginosa e Pichia membranifaciens foram leveduras encontradas nas kombuchas, das quais as duas últimas favoreceram a manutenção da alta viabilidade de HN019 em cocultura por 14 dias. Observou-se a viabilidade da bactéria acima de 9 log ao longo de todo o experimento, o que não foi observado em monocultura. Ademais, utilizou-se de análise de autoagregação, hidrofobicidade, atividade enzimática de proteases e fosfolipases das leveuras para analisar seu potencial patogênico. Observou-se que R. mucilaginosa demonstrou características semelhantes à Saccharomyces cerevisiae subsp. boulardii, e sua interação benéfica com HN019 reforça a possibilidade de que esta levedura seja uma chave para a inserção da bactéria em uma kombucha probiótica. Análises metabólicas foram realizadas e encontrou-se uma vasta diversidade de dipeptídeos, principalmente os compostos de prolina, durante a cocultura da bactéria com as leveduras. Tais dipeptídeos apresentam importantes mecanismos de ação no controle biológico e quorum sensing de bactérias e leveduras, e supostamente regulam a manutenção das relações mutualísticas entre ambos microrganismo

One of the biggest challenges in the development of probiotic products is to understand how microorganisms interact with each other and with the host. When we talk about traditional fermented foods, this obstacle increases because the food matrix already has an intrinsic microbiome. However, it is also known that many microorganisms can interact and cooperate to survive when stressful situations are encountered. Thus, the objective of this work was to isolate yeasts from four different kombuchas at different fermentation times and to verify the influence that yeasts isolated from kombucha have on maintaining the viability of the probiotic bacterium Bifidobacterium animalis subsp. lactis HN019 under aerobic conditions. Meyerozyma guilliermondii, Candida albicans, Rhodotorula mucilaginosa and Pichia membranifaciens were yeasts found in kombuchas, of which the last two favored the maintenance of HN019 high viability in co-culture for 14 days. Bacteria viability above 9 log was observed throughout the experiment, which was not observed in monoculture. In addition, analysis of autoaggregation, hydrophobicity, enzyme activity of proteases and phospholipases of yeasts was used to analyze their pathogenic potential. It was observed that R. mucilaginosa demonstrated characteristics similar to Saccharomyces cerevisiae subsp. boulardii, and its beneficial interaction with HN019 reinforces the possibility that this yeast is a key to the insertion of the bacterium in a probiotic kombucha. Metabolic analysis were performed and a wide diversity of dipeptides, mainly proline-based, was found during the co-culture of the bacteria with the yeasts. Such dipeptides have important mechanisms of action in the biological control and quorum sensing of bacteria and yeast, and supposedly regulate the maintenance of mutualistic relationships between both microorganism

Antioxidant and tyrosinase inhibitory activities of traditional fermented Rosa from Dali Bai communities, Northwest Yunnan, China.

Traditional fermented Rosa (TFR) is a typical food and medical product among the Dali Bai people, and its popularity is growing. A few studies have looked into TFR's medicinal advantages, linked germplasm resources, traditional processing procedures, and functional food qualities. Our goal was to look into Rosa's traditional processing, examine the dominant strains in TFR, and prove how these strains affected antioxidant and tyrosinase inhibitory activities. We used a snowball selection strategy to pick 371 informants for a semi-structured interview, supplemented with direct observations and sample collection. A microbial strain was isolated and identified from a TFR sample collected in the field. We synthesized TFR in the lab using the traditional way. Both of 2, 2-diphenyl-1 picrylhydrazyl (DPPH) free radical scavenging and tyrosinase inhibitory properties of the fermented solution of Rosa 'Dianhong' have been tested in this study. Altogether 15 species belonging to the genus Rosa, which are utilized in herbal medicine and fermented foods. Rosa 'Dianhong' was the Bai community's principal species with considerable cultural value and consumption. Raw Rosa petals included 15 major flavonoids and phenols, which were identified as TFR's active components. TFR-1 was discovered to be the dominating microbial strain in TFR, increasing total phenolic and flavonoid content in the fermented solution of Rosa 'Dianhong' by 0.45 mg GAE/ml and 0.60 mg RE/ml, respectively, after 30 days. TFR-1 also exhibited promising activity in terms of DPPH free radical scavenging and tyrosinase inhibition. TFR showed potent antioxidant and free-radical scavenger properties and is beneficial in skincare and nutrition, according to the findings. TFR's medicinal and edible properties suggest that it could be used as a cosmetic or nutraceutical product.

Evaluation of the Relationship among Biogenic Amines, Nitrite and Microbial Diversity in Fermented Mustard.

Biogenic amines (BAs) and nitrites are both considered harmful compounds for customer health, and are closely correlated with the microorganisms in fermented mustard (FM). In this study, BAs and nitrite contents in fifteen FM samples from different brands were analyzed. The concentrations of cadaverine in one sample and of histamine in one sample were above the toxic level. Moreover, five FM samples contained a high level of nitrite, exceeding the maximum residue limit (20 mg/kg) suggested by the National Food Safety Standard. Then, this study investigated bacterial and fungal communities by high-throughput sequencing analysis. Firmicutes and Basidiomycota were identified as the major bacteria and fungi phylum, respectively. The correlations among microorganisms, BAs and nitrite were analyzed. Typtamine showed a positive correlation with Lactobacillus and Pseudomonas. Cadaverine and nitrite is positively correlated with Leuconostoc. Furthermore, thirteen strains were selected from the samples to evaluate the accumulation and degradation properties of their BAs and nitrite. The results indicated that the Lactobacillus isolates, including L. plantarum GZ-2 and L. brevis SC-2, can significantly reduce BAs and nitrite in FM model experiments. This study not only assessed the contents of BAs and nitrite in FM samples, but also provided potential starter cultures for BAs and nitrite control in the FM products industry.

Mineral content, fatty acid composition, and volatile compounds of gluten-free tarhana formulated with different cereal and pulse flours.

This research was intended to determine the effect of different cereal and pulse flours and commercial gluten-free flour on the mineral content, fatty acid composition, and volatile compounds of the gluten-free tarhana (cereal-based fermented dry soup). In order to produce the gluten-free tarhana, white bean (BF), chickpea (CF), commercial gluten-free (GWF), yellow lentil (LF), and rice (RF) flours were used. The Mg, K, Al, and Mn contents of tarhanas obtained using different pulse and cereal flours were found to be quite high compared to tarhanas produced with commercial GWF. The utilization of different cereal and pulse flours in the tarhana formulation resulted in an increase in the percentage (30.37-51.47%) of the total polyunsaturated fatty acid (TPUFA). The highest (452.4 µg/g) and the lowest (241.17 µg/g) total concentration of all compounds were detected in BF and GWF, respectively. The highest number (21) of compounds belonged to terpenes and terpenoids, followed by acids, hydrocarbons, alcohols, aldehydes, esters, ketones, and alkanes. PRACTICAL APPLICATION: This study shows that cereal and pulse flours can be used to produce acceptable tarhana with improved nutritional quality in terms of mineral and fatty acid contents. The results of the current study may be useful and applicable to food manufacturers producing gluten-free products for celiac patients.

In vitro protein digestibility and physico-chemical properties of lactic acid bacteria fermented beverages enriched with plant proteins.

The objective of this study was to develop probiotic beverages, enriched with plant proteins, with high nutritional value. A rice-based beverage fermented with a specific probiotic formulation comprised Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R and Lactobacillus rhamnosus CLR2 has been enriched with a combination of pea and rice proteins (PR) or pea and hemp proteins (PH) at 13 and 11% total protein, respectively. These protein associations have been selected because their amino acid ratio was >1, as recommended by the FAO. The beverage enriched with protein significantly increased its viscosity by more than 10 times thanks to the enrichment, while the fermentation reduced it by 50% for PR and 20% for PH. In vitro protein digestibility results showed that the protein enrichment and the fermentation treatment significantly increased digestibility values of the beverages with value of 72.7% for fermented PR beverage and 61.4% for unenriched fermented control beverage (p ≤ 0.05). Peptide profiles of PR and PH enriched beverages indicated that the fermentation led to a reduced level of high molecular weight (HMW) peptides of about 60% and an increase of low molecular weight (LMW) peptides by over 50%. Therefore, both the fermentation and the enrichment in protein increased the nutritional value of the rice-based beverages. PRACTICAL APPLICATION: Good quality of probiotics formulation and high-protein products are in increasing demand and plant proteins as an alternative of animal protein are popular. This study has permit to develop rice-based commercial probiotic beverages enriched in a combination of pea and rice or pea and hemp proteins in order to obtain a complete protein in terms of amino acids composition. The lactic acid fermentation and the enrichment with a plant protein combination led to a better protein digestibility of beverage.

Chemical Constitution and Antimicrobial Activity of Kombucha Fermented Beverage.

Kombucha is a traditional beverage of sweetened black tea fermented with a symbiotic association of acetic acid bacteria and yeasts. In this study, kombucha fermented beverage (KFB) appeared to include nine chemical groups (alcohols, acids, lactones, condensed heterocyclic compounds, antibiotics, esters, aldehydes, fatty acids, and alkaloids) of many bioactive metabolites, as elucidated by gas chromatography-mass spectrometry (GC-MS) and IR spectra. The fermented metabolic components of KFB seem collectively to act in a synergistic action giving rise to the antimicrobial activity. Four types of kombucha preparations (fermented, neutralized, heat-treated and unfermented) were demonstrated with respect to their antimicrobial activity against some pathogenic bacterial and fungal strains using agar well diffusion assay. KFB exerted the strongest antimicrobial activities when compared with neutralized and heat-treated kombucha beverages (NKB and HKB). Staphylococcus aureus ATCC6538 (S. aureus) and Escherichia coli ATCC11229 (E. coli) were the organisms most susceptible to the antimicrobial activity of kombucha beverage preparations. Finally, the KFB preparation showed remarkable inhibitory activity against S. aureus and E. coli bacteria in a brain heart infusion broth and in some Egyptian fruit juices (apple, guava, strawberry, and tomato). These data reveal that kombucha is not only a prophylactic agent, but also appears to be promising as a safe alternative biopreservative, offering protection against pathogenic bacteria and fungi.