Lactic-fermented cereal gruels with improvedin vitroprotein digestibility

Gut health benefits and associated systemic effects provided by functional components from the fermentation of natural matrices

Recently, the role of the gut microbiota in metabolic health, immunity, behavioral balance, longevity, and intestine comfort has been the object of several studies from scientific communities. They were encouraged by a growing interest from food industries and consumers toward novel fermented ingredients and formulations with powerful biological effects, such as pre, pro, and postbiotic products. Depending on the selected strains, the operating conditions, the addition of suitable reagents or enzymes, the equipment, and the reactor configurations, functional compounds with high bioactivity, such as short-chain fatty acids, gamma-aminobutyric acid, bioactive peptides, and serotonin, can be enhanced and/or produced through fermentation of several vegetable matrices. Otherwise, their formation can also be promoted directly in the gut after the dietary intake of fermented foods: In this case, fermentation will aim to increase the content of precursor substances, such as indigestible fibers, polyphenols, some amino acids, and resistant starch, which can be potentially metabolized by endogenous gut microorganisms and converted in healthy molecules. This review provides an overview of the main functional components currently investigated in literature and the associated gut health benefits. The current state of the art about fermentation technology as a promising functionalization tool to promote the direct or indirect formation of gut-health-enhancing components was deepened, highlighting the importance of optimizing microorganism selection, system setups, and process conditions according to the target compound of interest. The collected data suggested the possibility of gaining novel functional food ingredients or products rich in functional molecules through fermentation without performing additional extraction and purification stages, which are needed when conventional culture broths are used.

Sweetpotato-based infant foods produce porridge with lower viscosity and aflatoxin level than cereal-based complementary blends

The viscosity, protein, and total aflatoxins contents in orange-fleshed sweetpotato (OFSP) and cereal-based commercial complementary formulations and the effect of dilution on the protein content of the formulations were investigated. Standard procedures were used for the determination of these parameters. Over 80% of the formulations had a viscosity above the recommended consistency of 1000-3000 cP for feeding young children. The consistency of OFSP-legume porridge was significantly (2392.5 cP; p < 0.001) lower, about 1.7 and 3.4 times than cereal-only and cereal-legume blends, respectively. All the complementary flours, except the cereal-only, met the proposed protein requirement of 6 to 11 g per 100 g for feeding children aged 6 to 23 months on an as-is basis. However, the protein content in the porridges on an as-would-be-eaten basis was about 6% lower than the as-is basis value. About 38% of the complementary foods had total aflatoxin level above the acceptable limit of 10 ppb, mainly in blends containing peanuts, maize, or both. Adding more water to meet the required thickness of cereal-only and cereal-legume porridges diluted the protein content. More efforts are needed from regulatory bodies and all stakeholders to ensure complementary foods are safe in terms of mycotoxin levels, particularly those containing maize, peanut, or both as ingredients.

A Novel Millet-Based Probiotic Fermented Food for the Developing World

Probiotic yogurt, comprised of a Fiti sachet containing Lactobacillus rhamnosus GR-1 and Streptococcus thermophilus C106, has been used in the developing world, notably Africa, to alleviate malnutrition and disease. In sub-Saharan African countries, fermentation of cereals such as millet, is culturally significant. The aim of this study was to investigate the fermentation capability of millet when one gram of the Fiti sachet consortium was added. An increase of 1.8 and 1.4 log CFU/mL was observed for S. thermophilus C106 and L. rhamnosus GR-1 when grown in 8% millet in water. Single cultures of L. rhamnosus GR-1 showed the highest μ_max when grown in the presence of dextrose, galactose and fructose. Single cultures of S. thermophilus C106 showed the highest μ_max when grown in the presence of sucrose and lactose. All tested recipes reached viable counts of the probiotic bacteria, with counts greater than 10⁶ colony-forming units (CFU)/mL. Notably, a number of organic acids were quantified, in particular phytic acid, which was shown to decrease when fermentation time increased, thereby improving the bioavailability of specific micronutrients. Millet fermented in milk proved to be the most favorable, according to a sensory evaluation. In conclusion, this study has shown that sachets being provided to African communities to produce fermented milk, can also be used to produce fermented millet. This provides an option for when milk supplies are short, or if communities wish to utilize the nutrient-rich qualities of locally-grown millet.

Development of sprouted wheat based probiotic beverage

Present study was carried out to evaluate the potential of Lactobacillus acidophilus (L. acidophilus) for development of wheat based probiotic beverage and to optimize the proportion of different ingredients viz. sprouted wheat flour, sprouted wheat bran, oat and stabilizer using response surface methodology. Acidity, pH and probiotic count of samples prepared with L. acidophilus NCDC-14 was higher than that of L. acidophilus NCDC-16 culture. Being more compatible, L. acidophilus NCDC-14 was selected for this study. Acidity (in terms of lactic acid), pH and probiotic count of the different samples ranged from 0.21 to 0.45 %, 4.0 to 4.9, and 8.30 to 10.95 log10 cfu mL(-1), respectively. Probiotic count increased with increasing amount of sprouted wheat and oat. Optimized levels for sprouted wheat flour, oat, wheat bran and guar gum were 7.86, 5.42, 1.42 and 0.6 g, respectively per 100 mL of water. Optimized probiotic beverage provided 13.19 % total solids, 1.19 % protein, 0.33 % fat, 0.10 % ash, 0.42 % crude fibre, 1.45 mg iron, calcium 15.74 mg, 11.56 % carbohydrates, 54 kcal calories and 10.43 log10 cfu mL(-1) probiotic count. Thus, Lactobacillus acidophilus NCDC-14 can be used for development of potentially probiotic beverage with sprouted wheat and oat.

Significance of coarse cereals in health and nutrition: a review

This review assesses the nutritional attributes of coarse cereals and also their utilization as food and as formulated foods. These cereals are laden with phytochemicals including phenolic acids, tannins, anthocyanins, phytosterols, avenenathramides and policosanols. They possess high antioxidant properties in vitro than staple cereals and fruits by different purported pathways. There are also some anti-nutritional factors that may be reduced by certain processing treatments. Several epidemiological studies show that these cereals are helpful in reducing several kinds of chronic diseases like cancers, cardiovascular diseases, type II diabetes and various gastrointestinal disorders. Being coarse in nature, they cannot replace our staple cereals, but can be used in different proportions with rice and wheat to formulate various nutritional products. They can be used to make porridges, biscuits, cakes, cookies, tortillas, bread, probiotic drinks, ladoo, ghatta, flakes and several fermented foods. The coarse cereals also have good potential in manufacturing bioethanol, paper, oil and biofilms.

Proteolytic activities in togwa, a Tanzanian fermented food

Proteolytic activities were investigated in sorghum-based togwa prepared by natural fermentation and using starter cultures previously isolated from the native product, i.e., Lactobacillus brevis, Lactobacillus cellobiosus, Lactobacillus fermentum, Lactobacillus plantarum, Pediococcus pentosaceus, and Issatchenkia orientalis in coculture with either L. brevis or L. plantarum. Both proteinase and aminopeptidase activities were substantially higher in naturally fermented togwa than in those with starters (14-30%, 12-70%, respectively). A variable but substantial part of the proteinase activity followed the particulate fraction of togwa; aminopeptidase activity was mainly in that fraction. The breakdown of relatively high molecular mass protein (64 kDa) in togwa was detected by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE); the products were mainly in the 14-30 kDa range. Reversed-phase fast-protein liquid chromatography (RP-FPLC)-protein/peptide patterns changed during fermentation with some variation between togwa of different cultures. Supplementation of gruel with malt increased the concentration of total protein [from 9.5% to 11.0% (w/w) on dry weight basis)] and of most of the free amino acids. Fermentation had no effect on total protein content; however, the concentration of most of the amino acids was reduced, except for the proline content that increased. Natural fermentation also increased the concentration of glutamic acid and ornithine. Fermentation by P. pentosaceus increased aspartic acid, while L. cellobiosus, L. fermentum, and L. brevis in coculture with I. orientalis increased the concentration of citrulline.

Application of cereals and cereal components in functional foods: a review

The food industry is directing new product development towards the area of functional foods and functional food ingredients due to consumers' demand for healthier foods. In this respect, probiotic dairy foods containing human-derived Lactobacillus and Bifidobacterium species and prebiotic food formulations containing ingredients that cannot be digested by the human host in the upper gastrointestinal tract and can selectively stimulate the growth of one or a limited number of colonic bacteria have been recently introduced into the market. The aim of these products is to affect beneficially the gut microbial composition and activities. Cereals offer another alternative for the production of functional foods. The multiple beneficial effects of cereals can be exploited in different ways leading to the design of novel cereal foods or cereal ingredients that can target specific populations. Cereals can be used as fermentable substrates for the growth of probiotic microorganisms. The main parameters that have to be considered are the composition and processing of the cereal grains, the substrate formulation, the growth capability and productivity of the starter culture, the stability of the probiotic strain during storage, the organoleptic properties and the nutritional value of the final product. Additionally, cereals can be used as sources of nondigestible carbohydrates that besides promoting several beneficial physiological effects can also selectively stimulate the growth of lactobacilli and bifidobacteria present in the colon and act as prebiotics. Cereals contain water-soluble fibre, such as beta-glucan and arabinoxylan, oilgosaccharides, such as galacto- and fructo-oligosaccharides and resistant starch, which have been suggested to fulfil the prebiotic concept. Separation of specific fractions of fibre from different cereal varieties or cereal by-products, according to the knowledge of fibre distribution in cereal grains, could be achieved through processing technologies, such as milling, sieving, and debranning or pearling. Finally, cereal constituents, such as starch, can be used as encapsulation materials for probiotics in order to improve their stability during storage and enhance their viability during their passage through the adverse conditions of the gastrointestinal tract. It could be concluded that functional foods based on cereals is a challenging perspective, however, the development of new technologies of cereal processing that enhance their health potential and the acceptability of the food product are of primary importance.