Kefir is a fermented milk beverage and known to have positive effects on gut microbial diversity and human health. In this study, digested and undigested kefir samples were compared for changes in their antihypertensive, antidiabetic, antioxidant and antimicrobial activities. Results showed that the amount of total phenolic substances, 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH) activity, and the angiotensin-converting enzyme inhibitor (ACE-I) activity increased from 43.76 AE 0.005 mg gallic acid equivalents (GAE)/L, 4.20 AE 0.55%, and 9.91 AE 3.90% in undigested kefir to 668.16 AE 3.332 mg GAE/ L, 63.06 AE 0.64%, and 98.88 AE 0.42% in digested kefir, respectively. While the dipeptidyl peptidase IVinhibitory (DPPIV-I) activity of undigested kefir increased by 19.11 AE 7.35% after digestion, the optical density of the ferric-reducing antioxidant power (FRAP) decreased from 1.188 AE 0.05 to 0.278 AE 0.009, and the protein amount decreased from 101.4 mg L À1 to 12.42 mg L À1 in digested kefir. No antimicrobial effect was observed in undigested kefir, whereas, digested kefir samples were active, but only against Escherichia coli. These results show that the gastrointestinal digestion processes of kefir generally increase the number of bioactive molecules, and the digestion process must be taken into account to determine the biological capability of foods.
Human dipeptidylpeptidase IV (hDPPIV) is an enzyme that is in hydrolase class and has various roles in different parts of human body. Its deficiency may cause some disorders in the gastrointestinal, neurologic, endocrinological and immunological systems of humans. In the present study, hDPPIV enzyme was expressed on Spodoptera frugiperda (Sf9) cell lines as a host cell, and the expression of hDPPIV was obtained by a baculoviral expression system. The enzyme production, optimum multiplicity of infection, optimum transfection time, infected and uninfected cell size and cell behavior during transfection were also determined. For maximum hDPPIV (269 mU mL -1 ) enzyme, optimum multiplicity of infection (MOI) and time were 0.1 and 72 h, respectively. The size of infected cells increased significantly (P \ 0.001) after 24 h post infection. The results indicated that Sf9 cell line was applicable to the large scale for hDPPIV expression by using optimized parameters (infection time and MOI) because of its high productivity (4.03 mU m L -1 h -1 ).
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.