The Effects of Freeze Drying and Rehydration on Survival of Microorganisms in Kefir

Chen, Hsi-Chia; Lin, Chin-Wen; Chen, Ming-Ju

doi:2006.19.1.126

Article

Animal Products

Asian-Australasian Journal of Animal Sciences 2006;19(1): 126-130.
https://doi.org/10.5713/ajas.2006.126 Published online December 6, 2005.

The Effects of Freeze Drying and Rehydration on Survival of Microorganisms in Kefir

Hsi-Chia Chen, Chin-Wen Lin, Ming-Ju Chen

Abstract

The purpose of this research was to study the effect of freeze drying on the microorganisms in kefir. Influences of lyoprotectants and rehydrated media (water at 4째C, 25째C; 10% reconstituted milk at 4째C, 25째C) on the viability of lactic acid bacteria and yeasts in freeze-dried kefir were investigated. Kefir was made from cow milk which was inoculated with 5% kefir grains, and incubated at 20째C for 20 h. Lyoprotectants (galactose, lactose, maltose, sucrose and trehalose) were added independently before dehydration of kefir by freeze drying. Results indicated significant loss in viability of microorganisms in kefir after freeze-drying. Addition of 10% galactose or 10% sucrose as lyoprotectants significantly increased the survival rates of both lactic acid bacteria and yeasts (p<0.05). The 4째C rehydration temperature showed the best viabilities for yeasts, however, viability was not significantly affected by rehydration media (p>0.05).

Keywords: Kefir; Freeze-drying; Lyoprotectant