Potential prebiotic effect of whey protein and spent brewer yeast hydrolysates by enzymes of Cynara cardunculus extract

Biologically active peptides are of particular interest to food science and health since they have demonstrated beneficial physiological roles upon ingestion. These biopeptides can be released and/or activated in vivo during gastrointestinal digestion or otherwise via enzyme-mediated proteolysis throughout food processing. The survival of many bacterial species inhabiting the large bowel depends essentially on the substrates made available to them, most of which come directly from the diet. Some of these substrates can be selectively considered asprebiotics - which are nondigestible food ingredients that can stimulate beneficial bacteria such as lactobacilli or bifidobacteria growth in the colon. Thus, the major objective of this research work was to study the potential prebiotic activity of peptide extracts obtained via hydrolysis of whey proteins from a mixture of milk (cow, ewe and goat) and spent brewer yeast extracts achieved by cardosins present in Cynara cardunculus aqueous extract. The strains tested were probiotic strains viz. Lactobacillus acidophillus Ki and Bifidobacterium lactisBb12 and Frutooligosacharides were used as positive control of prebiotic activity. From whey protein hydrolysates two fractions were tested, the ultrafitration permeate (PM >1000 Da and 20000 Da). Incorporation of the extracts in media without glucose did not produce such good results, but the better activity was obtained for the ultrafiltration permeate of whey hydrolyzate (>1000 and >20000 Da); this result was expected since both extracts stimulate mainly the bacterial growth through the nitrogen compounds: peptides and aminoacids.info:eu-repo/semantics/publishedVersio

Characterization of edible films based on alginate or whey protein incorporated with Bifidobacterium animalis subsp. lactis BB-12 and prebiotics

Recently, edible films were shown to be an effective strategy for the delivery of functional ingredients, such as probiotics and prebiotics. With that in mind, two soluble fibres (inulin and fructooligosaccharides) were selected as prebiotic elements, in whey protein isolate (WPI) and alginate (ALG) matrices plasticized with glycerol and used for the incorporation of Bifidobacterium animalis subsp. lactis BB-12. The results obtained showed that the viability of the B. animalis subsp. lactis BB-12 probiotic strain was maintained within the minimum threshold (10(6) CFU/g) necessary to act as a probiotic throughout 60 days of storage at 23 degrees C. The incorporation of prebiotic compounds improved B. animalis subsp. lactis BB-12 viability, with inulin showing the best performance, as it maintained the viability at 7.34 log CFU/g. The compositional characteristics (biopolymer type and prebiotics addition) of the film forming solutions had no significant impact upon the viability of the probiotic strain. The incorporation of probiotics and prebiotics did not modify the infrared spectra, revealing that the molecular structure of the films was not modified. The moisture content and water solubility decreased positively in WPI- and ALG-based films with the addition of prebiotics compounds. Overall, the results obtained in this work support the use of WPI films containing inulin as a good strategy to immobilize B. animalis subsp. lactis BB-12, with potential applications in the development of functional foods.info:eu-repo/semantics/publishedVersio

Valorisation of protein-rich extracts from spent brewer’s yeast (Saccharomyces cerevisiae): an overview

As one of the main brewing by-products, Saccharomyces cerevisiae extracts (from spent yeast) have been commercialized as food supplement for years. Among their several claims, the application as protein source is highlighted. In fact, their high protein content (about 45–60%) including essential amino acids with high biological value, safety and low cost are primarily responsible for their spreading in agri-food sector. Meanwhile, cosmetic and health sectors have been working on yeast bioactive peptides because of their antihypertensive, antioxidant and antimicrobial properties, among others. Several studies related to valorisation of S. cerevisiae are currently ongoing, aiming to create novel products and optimize production processes. The present review aims to provide an overview from production of protein-rich extracts from S. cerevisiae to their chemical characterisation, detailing protein extraction, isolation and purification processes, as well as characterisation methods for the final extracts. Graphical abstract: [Figure not available: see fulltext.]info:eu-repo/semantics/acceptedVersio

Fish by-products as a source of proteolytic enzymes and bioactive peptides

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Effect of drying technology in Saccharomyces cerevisiae mannans: structural, physicochemical, and functional properties

Mannans are polysaccharides whose physicochemical and biological properties render them commercialization in several products. Since these properties are strongly dependent on production conditions, the present study aims to assess the impact of different drying technologies – freeze (FDM) and spray drying (SDM) – on the structural, physicochemical, and biological properties of mannans from Saccharomyces cerevisiae. Structural analysis was assessed by FT-IR, PXRD and SEM, whereas physicochemical properties were evaluated based on sugars, protein, ash and water contents, solubility, and molecular weight distribution. Thermal behaviour was analysed by DSC, and antioxidant activity by DPPH and ABTS assays. The parameters which revealed major differences, in terms of structural and physicochemical properties regarded morphology (SEM), physical appearance (colour), moisture (3.6 ± 0.1 % and 11.9 ± 0.6% for FDM and SDM, respectively) and solubility (1 mg/mL for FDM and 25 mg/mL for SDM). Nevertheless, these differences were not translated into the antioxidant capacity.info:eu-repo/semantics/publishedVersio

Effect of mannan oligosaccharides extracts in uropathogenic escherichia coli adhesion in human bladder cells

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Fish by-products: a source of enzymes to generate circular bioactive hydrolysates

Fish viscera are usually discarded as waste, causing environmental problems, or as low-value by-products. This study describes a self-sufficient and zero waste approach to obtain enzymes and protein hydrolysates from fish by-products. Firstly, recovery steps of viscera enzymatic extract were applied, and the resulting raw extract was stable at a pH range of 8–9 and at temperatures between 40 and 50 °C. The application of the extracted enzymes and alcalase on fish by-products hydrolysis was also determined. The selected conditions for the enzymatic hydrolysis were 10% (E/S) for 6 h using viscera enzymatic extract and 3% (E/S) for 2 h using alcalase. Fish protein hydrolysates (FPH) proved to have a notable antioxidant capacity with similar activity, ~11 mg ascorbic acid/g dry extract (ABTS assay) and ~150 mg Trolox/g dry extract (ORAC assay). FPH were also able to inhibit the angiotensin-converting enzyme, however, alcalase hydrolysates revealed a higher antihypertensive potential, IC50 of 101 µg of protein/mL. In general, FPH obtained by both enzymes systems maintained these bioactivities after the passage throughout a simulated gastrointestinal tract. The hydrolysates also displayed important technological properties, namely oil absorption capacity (~1 g oil/g sample) and emulsifying property (~40%). Therefore, it will be conceivable to use fish by-products based on a circular economy approach to generate added value compounds for animal and human nutritioninfo:eu-repo/semantics/publishedVersio

Spent yeast valorization for food applications: effect of different extraction methodologies

Over the years, synthetic biology has been growing with the use of engineered yeast strains for the production of sustainable ingredients to meet global healthcare, agriculture, manufacturing and environmental challenges. However, as seen from the brewing industry perspective, these processes generate a substantial amount of spent yeast that contains high nutritional value related to its high protein content, showing its potential to be used as an alternative protein source. Taking into account the rising demand for protein because of the growth in the global population, the present study aims to produce peptide-rich extracts by different potentially scalable and sustainable methodologies in a circular economy approach for the food and nutraceutical industries. The results demonstrated that extraction from genetically modified strains allowed the production of extracts with an excellent nutritional profile and low molecular weight peptides. Furthermore, autolysis was shown to be a potential sustainable approach for this production, though other green metrics need to be explored in order to establish this process at an industrial level.info:eu-repo/semantics/publishedVersio

Purification of bioactive peptides from spent yeast autolysates

Spent brewer’s yeast have been described as an important source for bioactive peptides, with their properties well proven over the years. Besides the brewing sector, growing of large-scale processes on synthetic biology industry has generated a substantial amount of spent engineered yeast with further potential to be valued in a circular economy approach. In line with this perception, in this work, peptide-rich fractions were obtained from spent yeast peptide-rich extract autolysate (“ESY1”), using two different techniques, namely protein ultrafiltration and size-exclusion chromatography (SEC). Both methods allowed the production of different peptide fractions with diverse protein content, molecular weight distribution and peptides sequences. Overall, fractions with higher protein content and more purified reveal higher bioactivities, namely antihypertensive and anticholesterolemic, emphasizing that the purification process is an important step to include in production process of a dietary supplement with these specific features. In addition, significant antioxidant capacity values for peptide fractions purified by SEC were obtained, highlighting their potential use in economic sectors where antioxidant capacity has a massive impact, such as cosmetics.info:eu-repo/semantics/publishedVersio

A step for the valorization of spent yeast through production of iron–peptide complexes — a process optimization study

Given the importance of iron in human nutrition and the significance of waste and by-product valorisation in a circular economy environment, we investigated the effects of protein and iron concentration on the production yield of iron–peptide complexes from spent Saccharomyces cerevisiae. For this purpose, different amounts of protein and iron were used in the complexation process. The results have shown that higher concentrations, although permitting a faster and larger scale process, provide a significantly lower complexation yield, which deems the process less feasible. This is corroborated by fluorescence analysis, which shows a lower degree of complexation with higher protein concentration. In addition, varying the concentration of iron does not change the quality of formed complexes, as evidenced by Fourier transform infrared spectroscopy (FT-IR) analysis. The morphology of all samples was also evaluated using scanning electron microscopy (SEM). Therefore, further studies are needed to optimize the process and to evaluate the best conditions for an economically sound valorization process for iron–peptide complexes. Nonetheless, current results in the development of a new process for the valorisation of spent yeast, in the form of iron-peptide complexes, look promising.info:eu-repo/semantics/publishedVersio