Enzymatic digestion and in vitro fermentation of oat fractions by human lactobacillus strains

Applicable Strains, Processing Techniques and Health Benefits of Fermented Oat Beverages: A Review

Based on the high nutrients of oat and the demand of health-conscious consumers for value-added and functional foods, fermented oat beverages have great market prospects. This review summarizes the applicable strains, processing techniques and health benefits of fermented oat beverages. Firstly, the fermentation characteristics and conditions of the applicable strains are systematically described. Secondly, the advantages of pre-treatment processes such as enzymatic hydrolysis, germination, milling and drying are summarized. Furthermore, fermented oat beverages can increase the nutrient content and reduce the content of anti-nutritional factors, thereby reducing some risk factors related to many diseases such as diabetes, high cholesterol and high blood pressure. This paper discusses the current research status of fermented oat beverages, which has academic significance for researchers interested in the application potential of oat. Future studies on fermenting oat beverages can focus on the development of special compound fermentation agents and the richness of their taste.

Production of Xylooligosaccharide from Cassava Pulp’s Waste by Endo-β-1,4-D-Xylanase and Characterization of Its Prebiotic Effect by Fermentation of Lactobacillus acidophilus

This study explores the production of prebiotic xylooligosaccharide (XOS) from cassava pulp waste and its effectiveness for the growth of Lactobacillus acidophilus (L. acidophilus). We successfully produced and characterized XOS from cassava pulp xylan using a Bacillus sp. endo-β-1,4-D-xylanase. The XOS was added to modify the MRS medium (MRSm) in various concentrations (0, 1, 3 and 5%) in which the L. acidophilus was inoculated. The growth of L. acidophilus was observed every 12 h for 2 days, and the fermentation products were analyzed for pH, sugar content, and short-chain fatty acids (SCFA) in terms of types and amount. The study showed that L. acidophilus grew well in MRSm. The optimum XOS concentration in MRSm was 5%, indicated by the highest growth of L. acidophilus (8.61 log CFU mL−1). The profile of SCFA products is 14.42 mM acetic acid, 0.25 mM propionic acid, 0.13 mM isobutyric acid, 0.41 mM n-butyric acid, 0.02 mM n-valeric acid, 0.25 mM isovaleric acid, and 25.08 mM lactic acid.

Oat Yogurts Enriched with Synbiotic Microcapsules: Physicochemical, Microbiological, Textural and Rheological Properties during Storage

The aim of this study was to evaluate the influence of synbiotic microcapsules on oat yogurt’s properties. For this study, four different microcapsules were added into the oat yogurt and the modifications were studied for 28 days. Microbiological analysis was used to analyze the effect of different factors on the microencapsulated probiotic population in the product. Those factors are: the technological process of obtaining microcapsules; the type of prebiotic chicory inulin (INU), oligofructose (OLI) and soluble potato starch (STH); the prebiotic concentrations in the encapsulation matrix; the technological process of obtaining yogurt; and the yogurt storage period, gastric juice action and intestinal juice action. The experimental data show that oat yogurt containing synbiotic microcapsules has similar properties to yogurt without microcapsules, which illustrates that the addition of synbiotic microcapsules does not change the quality, texture or rheological parameters of the product. Oat yogurt with the addition of synbiotic microcapsules can be promoted as a functional food product, which, in addition to other beneficial components (bioactive compounds), has in its composition four essential amino acids (glycine, valine, leucine and glutamine acids) and eight non-essential amino acids (alanine, serine, proline, asparagine, thioproline, aspartic acid, glutamic acid and α-aminopimelic acid). After 28 days of storage in refrigerated conditions, the cell viability of the microcapsules after the action of the simulated intestinal juice were: 9.26 ± 0.01 log10 cfu/g, I STH (oat yogurt with synbiotic microcapsules—soluble potato starch); 9.33 ± 0.01 log10 cfu/g, I INU, 9.18 ± 0.01 log10 cfu/g, I OIL and 8.26 ± 0.04 log10 cfu/g, IG (oat yogurt with microcapsules with glucose). The new functional food product provides consumers with an optimal number of probiotic cells which have a beneficial effect on intestinal health.

Impact of Yeast-Derived β-Glucans on the Porcine Gut Microbiota and Immune System in Early Life

Piglets are susceptible to infections in early life and around weaning due to rapid environmental and dietary changes. A compelling target to improve pig health in early life is diet, as it constitutes a pivotal determinant of gut microbial colonization and maturation of the host’s immune system. In the present study, we investigated how supplementation of yeast-derived β-glucans affects the gut microbiota and immune function pre- and post-weaning, and how these complex systems develop over time. From day two after birth until two weeks after weaning, piglets received yeast-derived β-glucans or a control treatment orally and were subsequently vaccinated against Salmonella Typhimurium. Faeces, digesta, blood, and tissue samples were collected to study gut microbiota composition and immune function. Overall, yeast-derived β-glucans did not affect the vaccination response, and only modest effects on faecal microbiota composition and immune parameters were observed, primarily before weaning. This study demonstrates that the pre-weaning period offers a ‘window of opportunity’ to alter the gut microbiota and immune system through diet. However, the observed changes were modest, and any long-lasting effects of yeast-derived β-glucans remain to be elucidated.

Harnessing Microbes for Sustainable Development: Food Fermentation as a Tool for Improving the Nutritional Quality of Alternative Protein Sources

In order to support the multiple levels of sustainable development, the nutritional quality of plant-based protein sources needs to be improved by food technological means. Microbial fermentation is an ancient food technology, utilizing dynamic populations of microorganisms and possessing a high potential to modify chemical composition and cell structures of plants and thus to remove undesirable compounds and to increase bioavailability of nutrients. In addition, fermentation can be used to improve food safety. In this review, the effects of fermentation on the protein digestibility and micronutrient availability in plant-derived raw materials are surveyed. The main focus is on the most important legume, cereal, and pseudocereal species (Cicer arietinum, Phaseolus vulgaris, Vicia faba, Lupinus angustifolius, Pisum sativum, Glycine max; Avena sativa, Secale cereale, Triticum aestivum, Triticum durum, Sorghum bicolor; and Chenopodium quinoa, respectively) of the agrifood sector. Furthermore, the current knowledge regarding the in vivo health effects of fermented foods is examined, and the critical points of fermentation technology from the health and food safety point of view are discussed.

Marine prebiotics: Polysaccharides and oligosaccharides obtained by using microbial enzymes

Utilization of marine algae has increased considerably over the past decades, since biodiversity within brown, red and green marine algae offers possibilities of finding a variety of bioactive compounds. Marine algae are rich sources of dietary fibre. The remarkable positive effects of seaweed dietary fibre on human body are related to their prebiotic activity over the gastrointestinal tract (GIT) microbiota. However, dietary modulation of microorganisms present in GIT can be influenced by different factors such as type and source of the dietary fibre, their molecular weight, type of extraction and purification methods employed, composition and modification of polysaccharide and oligosaccharide. This review will demonstrate evidence that polysaccharides and oligosaccharides from marine algae can be used as prebiotics, emphasizing their use in human health, their application as food and other possible applications. Furthermore, an important approach of microbial enzymes employment during extraction, modification or production of those prebiotics is highlighted.

Comparison of Volatile and Nonvolatile Compounds in Rice Fermented by Different Lactic Acid Bacteria

The production of rice-based beverages fermented by lactic acid bacteria (LAB) can increase the consumption of rice in the form of a dairy replacement. This study investigated volatile and nonvolatile components in rice fermented by 12 different LABs. Volatile compounds of fermented rice samples were analyzed using gas chromatography-mass spectrometry (GC-MS) combined with solid-phase microextraction (SPME), while nonvolatile compounds were determined using gas chromatography-time-of-flight/mass spectrometry (GC-TOF/MS) after derivatization. The 47 identified volatile compounds included acids, aldehydes, esters, furan derivatives, ketones, alcohols, benzene and benzene derivatives, hydrocarbons, and terpenes, while the 37 identified nonvolatile components included amino acids, organic acids, and carbohydrates. The profiles of volatile and nonvolatile components generally differed significantly between obligatorily homofermentative/facultatively heterofermentative LAB and obligatorily heterofermentative LAB. The rice sample fermented by Lactobacillus sakei (RTCL16) was clearly differentiated from the other samples on principal component analysis (PCA) plots. The results of PCA revealed that the rice samples fermented by LABs could be distinguished according to microbial strains.

Oats as a matrix of choice for developing fermented functional beverages

Development of oat-based fermented beverages started in Europe in the past 30 years with the rise of the functional foods market. It is based on the increasing consumer demand for health drinks and value added foods and on the scientific insights on the nutrition composition of oats. The main health effects of oats are attributed to their high β-glucan content, which is proved to lower blood cholesterol and the intestinal absorption of glucose thus preventing diseases like cardiovascular injury, dyslipidemia, hypertension, inflammatory state and diabetes type 2. Another important role of β- glucan is its prebiotic function in the gastrointestinal tract, supporting the growth of beneficial microbial groups. The slowly digestible fraction of oat starch has a functional role as it moderates the glycaemic response. Oats are also a valuable source of highquality proteins, unsaturated lipids and antioxidants. In addition, oats are appropriate for people suffering from celiac disease because they do not contain gluten. Oat grain processing involves several steps, including thermal processes aiming to prevent oat products from rapid enzymatic deterioration and ensure storage stability. Oat drinks are formulated through processing oat with a liquid ingredient. Further, this matrix is inoculated with lactic acid bacteria to produce a fermented beverage. In some, drinks, probiotic lactic acid bacteria were used to increase product functional value. Thus, the ancient concept of cereal-based fermented foods is implemented into development of new functional oat-based fermented beverages and several products are already marketed in Europe as healthy, fast and convenient supplementary foods.

The Extract of Soybean Protein Increases Slow-Myosin Heavy Chain Expression in C2C12 Myotubes

Skeletal muscle is composed of four types of fibers in mammals; oxidative slow-twitch type I, oxidative fast-twitch IIA, and glycolytic fast-twitch IIB and IIX/D. In this study using C2C12 myotubes, an extract of soybean protein significantly upregulated mRNA level of myosin heavy chain 7 (Myh7), the predominant isoform expressed in oxidative slow-twitch type I and downregulated mRNA levels of Myh4, the predominant isoform expressed in glycolytic fast-twitch IIB. Similarly, its hydrolysate prepared using digestive enzyme also significantly increased Myh7 expression. In contrast, no significant change was observed in Myh4 mRNA level after the hydrolysate treatment. These findings suggest that dietary intake of the soybean protein extract may increase oxidative slow-twitch fiber in skeletal muscle.

Volatile Compounds Produced by Lactobacillus paracasei During Oat Fermentation

This study investigated the profiles of volatile compounds produced by Lactobacillus paracasei during oat fermentation using gas chromatography-mass spectrometry coupled with headspace solid-phase microextraction method. A total of 60 compounds, including acids, alcohols, aldehydes, esters, furan derivatives, hydrocarbons, ketones, sulfur-containing compounds, terpenes, and other compounds, were identified in fermented oat. Lipid oxidation products such as 2-pentylfuran, 1-octen-3-ol, hexanal, and nonanal were found to be the main contributors to oat samples fermented by L. paracasei with the level of 2-pentylfuran being the highest. In addition, the contents of ketones, alcohols, acids, and furan derivatives in the oat samples consistently increased with the fermentation time. On the other hand, the contents of degradation products of amino acids, such as 3-methylbutanal, benzaldehyde, acetophenone, dimethyl sulfide, and dimethyl disulfide, decreased in oat samples during fermentation. Principal component analysis (PCA) was applied to discriminate the fermented oat samples according to different fermentation times. The fermented oats were clearly differentiated on PCA plots. The initial fermentation stage was mainly affected by aldehydes, whereas the later samples of fermented oats were strongly associated with acids, alcohols, furan derivatives, and ketones. The application of PCA to data of the volatile profiles revealed that the oat samples fermented by L. paracasei could be distinguished according to fermentation time.

Extrusion of barley and oat influence the fecal microbiota and SCFA profile of growing pigs

The effect of extrusion of barley and oat on the fecal microbiota and the formation of SCFA was evaluated using growing pigs as model system. The pigs were fed a diet containing either whole grain barley (BU), oat groat (OU), or their respective extruded samples (BE and OE).

Cereal β-glucan alters nutrient digestibility and microbial activity in the intestinal tract of pigs, and lower manure ammonia emission: a meta-analysis

Cereal β-glucan may be detrimental in pig production because of negative effects on nutrient digestibility, but they may act as functional ingredients by stimulating the intestinal microbiota. This study primarily aimed to investigate relations between dietary β-glucan and nutrient digestibility, intestinal fermentation, and manure NH3 emission in weaned, growing, and finishing pigs. Effects of dietary xylose, NDF, and CP, and pig BW on animal responses were also evaluated. A meta-analytical approach, accounting for inter- and intraexperiment variations, was used to compute prediction models. Data from 26 studies including 107 different dietary treatments with appropriate dietary and physiological measurements were used to parameterize these models. Dietary β-glucan inclusion ranged from 0 to 6.7%. Increasing dietary β-glucan reduced apparent ileal (AID) and total tract digestibility (ATTD) of CP and energy (R(2) = 0.12 to 0.29; P < 0.05), whereas the ATTD of DM was reduced by 10% up to a threshold β-glucan of 3.5%, above which the response became asymptotic (R(2) = 0.34; P < 0.01). Increasing dietary NDF content decreased ATTD of DM and energy, and increasing xylose concentration reduced ATTD of energy and CP (R(2) = 0.24 to 0.85; P < 0.05). Broken-line model indicated that cecal total VFA and butyrate concentrations increased up to a threshold of 2.5 and 1.4% β-glucan in the diet, respectively, above which these responses became asymptotic (R(2) = 0.77 to 0.96; P < 0.05). Ileal butyrate was negatively and colonic iso-butyrate was positively linked to increasing β-glucan concentration (R(2) = 0.17 to 0.41; P < 0.05). Greater β-glucan concentration were negatively related (R(2) = 0.86; P < 0.01) to NH3 emission, indicating a reduction in NH3 emission by one-half with 6% β-glucan. Backward elimination analysis indicated that greater BW of pigs counteracted (P < 0.05) the negative effect of β-glucan on AID of CP and energy and ATTD of DM and CP. Pig BW also enhanced effects of β-glucan on cecal total VFA, colonic iso-butyrate, ileal butyrate, and NH3 emission (P < 0.05). Dietary CP potentiated (P < 0.01) the β-glucan effects on cecal total VFA, cecal butyrate, and colonic iso-butyrate. In conclusion, this study indicates that β-glucan can stimulate cecal butyrate and ameliorate manure NH3 emission, thereby decreasing nutrient digestibility. Because greater BW ameliorates β-glucan effects, finishing diets may be formulated to contain more β-glucan than weaner diets.