Functional Properties of Microorganisms in Fermented Foods

Studies on dietary fiber and nutrient bioavailability have gained an increasing interest in both human and animal nutrition. Questions are increasingly being asked regarding the faith of nutrient components such as proteins, minerals, vitamins, and lipids after feed formulation. The aim of this review is to evaluate the evidence with the perspective of fiber usage in feed formulation. The consumption of dietary fiber may affect the absorption of nutrients in different ways. The physicochemical factors of dietary fiber, such as fermentation, bulking ability, binding ability, viscosity and gel formation, water-holding capacity and solubility affect nutrient absorption. The dietary fiber intake influences the different methods in which nutrients are absorbed. The increase in the total fiber content of the diet may delay the glycemic response. Soluble fiber decreased blood glucose content whereas purified insoluble fiber has a little or no effect on the blood glucose levels after a meal. Dietary fiber and prebiotics influence the host animal well-being by regulating blood glucose or insulin levels, stool bulking effects, increasing the acidity of the gut, constructive synthesis of short chain fatty acids (SCFAs), decreasing intestinal transit time, stimulating the growth of intestinal microbes, and increasing blood parameters. Previous studies suggest that fiber affects the bioavailability of nutrients, and maintains the host wellness.

Legumes are valued worldwide as a sustainable and inexpensive meat alternative and are considered the second most important food source after cereals. Legumes are nutritionally valuable, providing proteins (20-45%) with essential amino acids, complex carbohydrates (±60%) and dietary fibre (5-37%). Legumes also have no cholesterol and are generally low in fat, with ±5% energy from fat, with the exception of peanuts (±45%), chickpeas (±15%) and soybeans (±47%) and provide essential minerals and vitamins. In addition to their nutritional superiority, legumes have also been ascribed economical, cultural, physiological and medicinal roles owing to their possession of beneficial bioactive compounds. Research has shown that most of the bioactive compounds in legumes possess antioxidant properties, which play a role in the prevention of some cancers, heart diseases, osteoporosis and other degenerative diseases. Because of their composition, legumes are attractive to health conscious consumers, celiac and diabetic patients as well as consumers concerned with weight management. The incorporation of legumes in diets, especially in developing countries, could play a major role in eradicating proteinenergy malnutrition especially in developing Afro-Asian countries. Legumes could be a base for the development of many functional foods to promote human health.

This study aimed to investigate in vitro and in vivo the probiotic characteristics of lactic acid bacteria (LAB) isolated from Korean traditional fermented foods. Caenorhabditis elegans  (C. elegans) was used for analytical assays of fertility, chemotaxis, life-span, worm-killing and bacterial colonization in the intestinal lumen of the worm. All 35 strains of LAB reduced fertility and slowed development in the worms. The worm-killing assay showed that LAB significantly increased the lifespan (P < 0.05) and reduced the susceptibility to virulent PA14; however, the heat-killed LAB did not. The bacterial colonization assay revealed that LAB proliferated and protected the gut of the worm against infection by Pseudomonas aeruginosa PA14. In addition, specific LAB Pediococcus acidilactici(P. acidilactici DM-9), Pediococcus brevis (L. brevis SDL1411), and Pediococcus pentosaceus (P. pentosaceus SDL1409) strains showed acid resistance (66–91%), resistance to pepsin (64–67%) and viability in simulated intestinal fluid (67–73%) based on in vitro probiotic analyses. Taken together, these results suggest that C. elegans may be a tractable model for screening efficient probiotics.