Culture Conditions Optimization of Tibetan Kefir Grains by Response Surface Methodology

Tibetan kefir grains are naturally-existing yogurt starter and have some unique benefits. In this study, response surface analysis was used to optimize their biomass production. Results showed that optimal culture conditions were skim milk concentration, 41.6%; temperature 30.05°C; inoculation amount, 1.86%; time, 20 h and shaker rotating speed, 0r/min, at which the growth rate was 14.33%, 39.4% more than initial. In addition skim milk concentration, temperature and inoculation amount were proved to be significant factors on biomass production.