Bioprospecting for Bioactive Peptide Production by Lactic Acid Bacteria Isolated from Fermented Dairy Food

With rapidly ageing populations, the world is experiencing unsustainable healthcare from chronic diseases such as metabolic, cardiovascular, neurodegenerative, and cancer disorders. Healthy diet and lifestyle might contribute to prevent these diseases and potentially enhance health outcomes in patients during and after therapy. Fermented dairy foods (FDFs) found their origin concurrently with human civilization for increasing milk shelf-life and enhancing sensorial attributes. Although the probiotic concept has been developed more recently, FDFs, such as milks and yoghurt, have been unconsciously associated with health-promoting effects since ancient times. These health benefits rely not only on the occurrence of fermentation-associated live microbes (mainly lactic acid bacteria; LAB), but also on the pro-health molecules (PHMs) mostly derived from microbial conversion of food compounds. Therefore, there is a renaissance of interest toward traditional fermented food as a reservoir of novel microbes producing PHMs, and “hyperfoods” can be tailored to deliver these healthy molecules to humans. In FDFs, the main PHMs are bioactive peptides (BPs) released from milk proteins by microbial proteolysis. BPs display a pattern of biofunctions such as anti-hypertensive, antioxidant, immuno-modulatory, and anti-microbial activities. Here, we summarized the BPs most frequently encountered in dairy food and their biological activities; we reviewed the main studies exploring the potential of dairy microbiota to release BPs; and delineated the main effectors of the proteolytic LAB systems responsible for BPs releaseWith rapidly ageing populations, the world is experiencing unsustainable healthcare from chronic diseases such as metabolic, cardiovascular, neurodegenerative, and cancer disorders. Healthy diet and lifestyle might contribute to prevent these diseases and potentially enhance health outcomes in patients during and after therapy. Fermented dairy foods (FDFs) found their origin concurrently with human civilization for increasing milk shelf-life and enhancing sensorial attributes. Although the probiotic concept has been developed more recently, FDFs, such as milks and yoghurt, have been unconsciously associated with health-promoting effects since ancient times. These health benefits rely not only on the occurrence of fermentation-associated live microbes (mainly lactic acid bacteria; LAB), but also on the pro-health molecules (PHMs) mostly derived from microbial conversion of food compounds. Therefore, there is a renaissance of interest toward traditional fermented food as a reservoir of novel microbes producing PHMs, and “hyperfoods” can be tailored to deliver these healthy molecules to humans. In FDFs, the main PHMs are bioactive peptides (BPs) released from milk proteins by microbial proteolysis. BPs display a pattern of biofunctions such as anti-hypertensive, antioxidant, immuno-modulatory, and anti-microbial activities. Here, we summarized the BPs most frequently encountered in dairy food and their biological activities; we reviewed the main studies exploring the potential of dairy microbiota to release BPs; and delineated the main effectors of the proteolytic LAB systems responsible for BPs release

Survival and bioactivities of selected probiotic lactobacilli in yogurt fermentation and cold storage: New insights for developing a bi-functional dairy food

In previous work , we demon strated that two probiotic strains, name ly Lactobacillus casei PRA205 and Lactobacillus rhamnosus PRA331, produce fermented milks with potent angiotensin-converting enzyme (ACE)-inhibitory and antioxidant activities. Here, we tested these strains for the survivability and the release of antihypertensive and antioxidant peptides in yogurt fermentation and cold storage. For these purposes three yogurt batches were compared: one prepared using yogurt starters alone (Lactobacillus delbrueckii subspecies bulgaricus 1932 and Streptococcus thermophilus 99), and the remaining two containing either PRA205 or PRA331 in addition to yogurt starters. Despite the lower viable counts at the fermentation end compared to PRA331, PRA205 overcame PRA331 in survivability during refrigerated storage for 28 days, leading to viable counts (>108 CFU/g) higher than the minimum therapeutic threshold (106 CFU/g). Analyses of in vitro ACE-inhibitory and antioxidant activities of peptide fractions revealed that yogurt supplemented with PRA205 displays higher amounts of antihypertensive and antioxidant peptides than that produced with PRA331 at the end of fermentation and over storage. Two ACE-inhibitory peptides, Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP), were identified and quantified. This study demonstrated that L. casei PRA205 could be used as adjunct culture for producing bi-functional yogurt enriched in bioactive peptides and in viable cells, which bring health benefits to the host as probiotics

Next-generation sequencing and its potential impact on food microbial genomics

Recent efforts of researchers to elucidate the molecular mechanisms of biological systems have been revolutionized greatly with the use of high throughput and cost-effective techniques such as next generation sequencing (NGS). Application of NGS to microbial genomics is not just limited to predict the prevalence of microorganisms in food samples but also to elucidate the molecular basis of how microorganisms respond to different food-associated conditions, which in turn offers tremendous opportunities to predict and control the growth and survival of desirable or undesirable microorganisms in food. Concurrently, NGS has facilitated the development of new genome-assisted approaches for correlating genotype and phenotype. The aim of this review is to provide a snapshot of the various possibilities that these new technologies are opening up in area of food microbiology, focusing the discussion mainly on lactic acid bacteria and yeasts associated with fermented food. The contribution of NGS to a system level understanding of food microorganisms is also discussed

Peptidomic study of casein proteolysis in bovine milk by Lactobacillus casei PRA205 and Lactobacillus rhamnosus PRA331

Lactobacilli contain different cell envelope proteinases (CEPs) responsible for the hydrolysis of caseins and the release of various bioactive peptides. In this work, we explored the CEP activity of Lactobacillus casei PRA205 and Lactobacillus rhamnosus PRA331 whole cells towards β-, αS1-, κ- and αS2-caseins in bovine milk. Mass spectrometry analysis of fermented milk hydrolysates identified a total of 331 peptides, which were mainly derived from β-caseins (59.0 and 60.1% for PRA205 and PRA331, respectively). Analysis of αS1-casein (f1–23) cleavage site specificity congruently supports that Lb. casei PRA205 and Lb. rhamnosus PRA331 exhibited a mixed-type CEPI/III activity. PRA205 and PRA331 CEPs also showed cleavage site specificity toward β-casein. These CEPs cleaved the peptide bond preferentially when hydrophobic or negatively charged amino acids were present. 13.5% and 13.7% of peptides released by Lb. casei PRA205 and Lb. rhamnosus PRA331 CEPs were found to have 100% homology with previously identified bioactive peptides

Sensory analysis of traditional balsamic vinegars: current state and future perspectives

Quality evaluation of traditional balsamic vinegar (TBV) is primarily based on sensory analysis. For every TBV batch, official sensory panels give a final score, which determines its assessment into quality and price categories. Therefore, an effective and objective sensory analysis is a core aspect in TBV production and marketing and it should fulfill at least two conditions: i) the panelists have been properly trained on the TBV features; ii) the panelists have to be free from any psychological and physical conditions which might affect human judgments. Traditionally, a panel of trained members assesses the TBV sensory attributes evaluating visual, olfactory, gustatory and trigeminal features at the same time. The result is that visual appearance significantly affects the subsequent stages of the sensory analysis, and even the olfactory and gustatory sensations will greatly affect each other. The aim of this work was to review the procedures for the sensory analysis of TBV and to define a set of TBV attributes. A new assessment questionnaire has been proposed to establish the appropriate sensory vocabulary for a complete description of TBV sensory properties

Fermentation strategy to produce high gluconate vinegar

Gluconic acid is a non-volatile acid that has many applications in food, pharmaceutical and cleaning fields. Gluconic acid has been detected as main oxidation product of Acetobacter and Gluconobacter strains growing on grape must, and it plays an important role in Traditional Balsamic Vinegar. Commonly, high gluconate vinegars have a greater physical stability and a greater preference by consumers because are perceived less pungent. In fact, gluconic acid reduces the pH and increases fixed acidity of the vinegar without increasing the sensation of pungency typical of acetic acid. Its taste is acid but mild sweet and, therefore, gluconic acid has influence on the sensory complexity of the vinegar. The aim of this work is to set up a fermentation procedure that improves the quality of balsamic vinegar by using selected yeasts and acetic acid bacteria strains able to oxidize glucose in grape must-based media having a different sugars concentration. In particular, Saccharomycodes ludwigii UMCC 297 and Acetobacter pasteurianus UMCC 1754 strains were chosen as selected starter cultures for small-scale fermentation of cooked grape must, to evaluate the physical-chemical parameters affecting gluconic acid production in the obtained vinegar. The strains used and the control of all production process have been fundamental for obtaining the vinegar with the desired characteristics

Impact of Spontaneous Fermentation and Inoculum with Natural Whey Starter on Peptidomic Profile and Biological Activities of Cheese Whey: A Comparative Study

Fermentation is a promising solution to valorize cheese whey, the main by-product of the dairy industry. In Parmigiano Reggiano cheese production, natural whey starter (NWS), an undefined community of thermophilic lactic acid bacteria, is obtained from the previous day residual whey through incubation at gradually decreasing temperature after curd cooking. The aim of this study was to investigate the effect of fermentation regime (spontaneous (S) and NWS-inoculated (I-NWS)) on biofunctionalities and release of bioactive peptides during whey fermentation. In S and I-NWS trials proteolysis reached a peak after 24 h, which corresponded to the drop out in pH and the maximum increase in lactic acid. Biological activities increased as a function of fermentation time. NWS inoculum positively affected antioxidant activity, whilst S overcame I-NWS in angiotensin-converting enzyme (ACE) and DPP-IV (dipeptidyl peptidase IV) inhibitory activities. Peptidomics revealed more than 400 peptides, mainly derived from β-casein, κ-casein, and α-lactalbumin. Among them, 49 were bioactive and 21 were ACE-inhibitors. Semi-quantitative analysis strongly correlated ACE-inhibitory activity with the sum of the peptide abundance of ACE-inhibitory peptides. In both samples, lactotripeptide isoleucine-proline-proline (IPP) was higher than valine-proline-proline (VPP), with the highest content in S after 24 h of fermentation. In conclusion, we demonstrated the ability of whey endogenous microbiota and NWS to extensively hydrolyze whey proteins, promoting the release of bioactive peptides and improving protein digestibility

Hybridization of saccharomyces cerevisiae sourdough strains with cryotolerant saccharomyces bayanus nbrc1948 as a strategy to increase diversity of strains available for lager beer fermentation

The search for novel brewing strains from non-brewing environments represents an emerging trend to increase genetic and phenotypic diversities in brewing yeast culture collections. Another valuable tool is hybridization, where beneficial traits of individual strains are combined in a single organism. This has been used successfully to create de novo hybrids from parental brewing strains by mimicking natural Saccharomycescerevisiae ale 7 Saccharomyceseubayanus lager yeast hybrids. Here, we integrated both these approaches to create synthetic hybrids for lager fermentation using parental strains from niches other than beer. Using a phenotype-centered strategy, S. cerevisiae sourdough strains and the S. eubayanus 7 Saccharomyces uvarum strain NBRC1948 (also referred to as Saccharomyces bayanus) were chosen for their brewing aptitudes. We demonstrated that, in contrast to S. cerevisiae 7 S. uvarum crosses, hybridization yield was positively affected by time of exposure to starvation, but not by staggered mating. In laboratory-scale fermentation trials at 20 \ub0C, one triple S. cerevisiae 7 S. eubayanus 7 S. uvarum hybrid showed a heterotic phenotype compared with the parents. In 2 L wort fermentation trials at 12 \ub0C, this hybrid inherited the ability to consume efficiently maltotriose from NBRC1948 and, like the sourdough S. cerevisiae parent, produced appreciable levels of the positive aroma compounds 3-methylbutyl acetate (banana/pear), ethyl acetate (general fruit aroma) and ethyl hexanoate (green apple, aniseed, and cherry aroma). Based on these evidences, the phenotype-centered approach appears promising for designing de novo lager beer hybrids and may help to diversify aroma profiles in lager beer