Effect of protective agents, freezing temperature, rehydration media on viability of malolactic bacteria subjected to freeze-drying.
OBJECTIVE
The effects of protective agents, rehydration media and freezing temperature on the viabilities of Lactobacillus brevis and Oenococcus oeni H-2 when subjected to freeze-drying were investigated.


RESULTS
Several protectants and rehydration media were tested to improve the survival after freeze-drying. The cells were also frozen at -65 and -20 degrees C to check the effect of freezing temperature on the viability.


CONCLUSIONS
The best protectant and rehydration medium to obtain the highest viability after freeze-drying varied with the species of bacteria. Yeast extract (4.0%) and sodium glutamate (2.5% ) gave maximum viability of L. brevis and O. oeni (67.8% and 53.6% respectively). The highest survival of L. brevis and O. oeni were obtained when rehydrated with 10% sucrose and MGY medium respectively. When the bacterial cells were frozen quickly (-65 degrees C) than slowly (-20 degrees C), L. brevis and O. oeni both showed increased viability after freeze-drying.


CONCLUSIONS
The viabilities of L. brevis and O. oeni after freeze-drying were shown to be strain specific and dependent on protective agents, rehydration media and freezing temperature.
Zhao
G
G
Alcoholic Beverage Research Institute, Hebei University of Science and Technology, Shijiazhuang, Hebei, China.
Zhang
G
G
D000596:Amino Acids / Q000494:pharmacology; D002470:Cell Survival; D003080:Cold Temperature; D003470:Culture Media; D005285:Fermentation; D005516:Food Microbiology; D005612:Freeze Drying / Q000379:methods*; D006095:Gram-Positive Cocci / Q000187:drug effects / Q000502:physiology*; D007778:Lactobacillus / Q000187:drug effects / Q000502:physiology*; D012970:Sodium Glutamate / Q000494:pharmacology; D013395:Sucrose / Q000494:pharmacology; D014920:Wine / Q000382:microbiology*; D015003:Yeasts
D000596:Amino Acids; D003470:Culture Media; D013395:Sucrose; D012970:Sodium Glutamate