Effect of the Freeze-Drying Process on the Physicochemical and Microbiological Properties of Mexican Kefir Grains

Processes

Guadalupe Luna-Solano¹  AliciaÁgueda Conde-Islas¹  Denis Cantú-Lozano¹  GaloRafael Urrea-García¹  Maribel Jiménez-Fernández² 

[1] Instituto Tecnológico de Orizaba, División de Estudios de Posgrado e Investigación, Oriente 9 No. 852 Orizaba, Veracruz 94320, Mexico;Instituto de Ciencias Básicas, Universidad Veracruzana, Dr. Luis Castelazo s/n. Col. Industrial Animas Xalapa, Veracruz 91000, Mexico;

关键词: freeze-drying;    operating parameters;    properties;    kefir grains;    probiotic;   

DOI  :  10.3390/pr7030127

来源: DOAJ

【 摘 要 】

The purpose of this study was to investigate how the properties of Mexican kefir grains (MKG) are affected by the operating parameters used in the freeze-drying process. The factors investigated were the freezing time (3–9 h), freezing temperature (−20 to −80 °C), pressure (0.2–0.8 mbar), and lyophilization time (5–20 h). The maximum range of change and one-way analysis of variance showed that lyophilization time and freezing time significant affects (p < 0.05) the response variables, residual moisture content and water activity, and pressure had a significant effect on the color difference and survival rate of probiotic microorganisms. The best drying conditions were a freezing time of 3 h, a freezing temperature of −20 °C, a pressure of 0.6 mbar, and a lyophilization time of 15 h. Under these conditions, we obtained a product with residual moisture content below 6%, water activity below 0.2, and survival rates above 8.5 log cfu per gram of lactic acid bacteria and above 8.6 log for yeast.

【 授权许可】

Unknown