Use of Cow and Buffalo Milk with Different Fat Contents for Production of Kefir Drinks with Kefir Grain and Starter Culture: Their Protein and Tyrosine Contents during Storage

Abstract

In
 this study, cow and buffalo milk with different fat contents were used for the
 production of kefir drinks with kefir grain or kefir culture, and the protein
 and tyrosine contents of kefir drinks were determined during 21 days of storage
 at 4°C. The protein content of samples decreased during storage (P<0.05). Protein
 contents of kefir samples ranged from 3.44 to 4.80% (P<0.05) at the
 beginning and from 3.31 to 4.71% at the last day of storage. Tyrosine content
 of kefir samples increased for the first 14 days of storage, and it decreased
 at the end of storage except for the kefir produced with cow milk (P<0.05). Tyrosine
 contents of samples produced with starter culture were higher than those with
 kefir grains, and the use of cow milk had a significant effect on the tyrosine
 content of kefir samples (P<0.05). At the end of storage, the highest
 tyrosine content (15.80 µg/g) was determined in kefir from cow milk with a 0.5%
 fat content and starter culture, and the lowest (8.04 µg/g) was determined in kefir
 from buffalo milk with a 3% fat content and kefir grain (P<0.05).