Effects of tea polyphenol intake (0.4 g/volunteer, 3 times per day, for four weeks) on fecal microflora, bacterial metabolites, and pH were investigated using eight healthy human volunteers. Counts for Clostridium perfringens and other Clostridium spp. were significantly decreased during the tea polyphenol intake periods. Percentage of volunteers having C. perfringens in their feces decreased significantly, but not for other Clostridium spp. Percentage of Bifidobacterium spp. (the acid forming bacteria) in total counts and the content of volatile fatty acids including acetic and propionic acids increased significantly, which might have reduced the fecal pH. However, the tea polyphenols had no effect on fecal enzyme activities, ammonia, or putrefactive products. Two weeks after discontinuing the intake, the microflora counts and their biological parameters appeared to have returned to normal.
The antioxidant activity of casein calcium peptides in several in vitro assay systems was investigated. Casein calcium peptides were prepared by the microbial enzymic hydrolysis of casein calcium. The main peak of the molecular mass distribution of the peptides was about 3 kDa. Casein calcium peptides showed strong antioxidant activity with the beta-carotene bleaching method, and they also showed scavenging activity against radicals such as superoxide radicals, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and hydroxyl radicals. Antioxidant activity was increased with an increasing peptide concentration. Casein calcium peptides also showed strong antioxidant activity against lipid oxidation in ground beef homogenates. These results suggest that casein calcium peptides are a suitable natural antioxidant that prevents the lipid oxidation of meat and related food ingredients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.