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

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 4°C, 25°C; 10% reconstituted milk at 4°C, 25°C) 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 20°C 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 4°C rehydration temperature showed the best viabilities for yeasts, however, viability was not significantly affected by rehydration media (p>0.05).

Survival and beneficial properties of lactic acid bacteria from raniculture subjected to freeze-drying and storage

“…These sugars replace structural water in membranes after dehydration (Clegg ; Crowe and Crowe ; Chen et al . ) and prevent unfolding and aggregation of proteins by hydrogen bonding with polar groups of proteins (Hanafusa ; Carpenter et al . ).…”

Production of freeze-dried kefir culture using whey

“…A number of publications concerning freeze-drying of a variety of microorganisms are available in the literature (Bekatorou, Koutinas, Psarianos, & Kanellaki, 2001;Boss, Filho, & Vasco de Toledo, 2004;Iconomopoulou, Kanellaki, Psarianos, & Koutinas, 2000;Palmfeldt, & Hahn-Ha¨gerdal, 2000;Palmfeldt, Ra˚dstro¨m, & HahnHa¨gerdal, 2003;Tal, Rijin, & Nussinovitch, 1997). Recently, the effects of sugars on survival of microorganisms present in kefir during freeze-drying were studied (Chen, Lin, & Chen, 2006). Although whey has been extensively used as a fermentation medium for production of a number of products, such as oligonucleotides, single cell protein, potable alcohol, and alcoholic beverages (Athanasiadis, Boskou, Kanellaki, Kiosseoglou, & Koutinas, 2002;Athanasiadis et al, 2004;Belem & Lee, 1999;Hosseini, Shojaosadati, & Towfighi, 2003;Kourkoutas, Dimitropoulou, et al, 2002;Kourkoutas, Psarianos, et al, 2002;Parrondo, Garcia, & Diaz, 2000), to the authors' knowledge, it has never been used as a cryoprotective medium.…”

Process Optimization for a Novel Kefir Candy With High Probiotic Viability

“…After a screening test, preliminary results were obtained revealing that the viabilities of the LAB and yeast survival rates after freeze‐drying were affected by lyoprotectants (galactose, SMP and sucrose). Appropriate ranges for lyoprotectants were also determined by the results of the screening test and the reference by Chen et al. (2006a), which were 0–8% for SMP and 0–7% for both galactose and sucrose.…”

“…After a screening test, preliminary results were obtained revealing that the viabilities of the LAB and yeast survival rates after freeze-drying were affected by lyoprotectants (galactose, SMP and sucrose). Appropriate ranges for lyoprotectants were also determined by the results of the screening test and the reference by Chen et al (2006a), which were 0-8% for SMP and 0-7% for both galactose and sucrose. A three-variable Box Behnken Design (BBD; Box and Behnken 1960), which is a three-level design based on the construction of a balanced incomplete block design, with five replicates at the center point (uncoded and coded levels of the independent variables are given in Table 1, and the experimental results of the design are listed in Table 2), i.e., a set of 17 experiments, was selected to build response surface models.…”