TITLE:
Influence of Freezing and Freeze Drying on Intracellular Enzymatic Activity and Autolytic Properties of Some Lactic Acid Bacterial Strains
AUTHORS:
S. Kandil, M. El Soda
KEYWORDS:
Freeze-Drying, Freezing, Intracellular Enzymes, Lactic Acid Bacteria, Viability, Autolysis
JOURNAL NAME:
Advances in Microbiology,
Vol.5 No.6,
June
3,
2015
ABSTRACT: Lactic acid bacteria
possess several interesting properties of great economic importance. Improvement
and stabilization of these industrially important features are an active
research area at the present time. The objectives of this work are to study the
effect of freezing and freeze-drying on the survival rate, autolytic activity
and intracellular enzymatic activity of the main species of lactic acid
bacteria used in the dairy industry. The article focused on several
characteristics that were not well covered in the past. The obtained results
revealed that both preservation methods have a significant effect on viability,
autolytic activity and intracellular enzymatic activity. After six months of
storage we found that frozen cultures exhibited higher survival rate, higher
rate of intracellular enzymatic activity and lower rate of autolysis. The
impact of conservation treatments was only strain specific in the case of survival
rate. The results obtained lead to the selection of the best preservation
method for the selected cultures based on survival rate, autolytic activity and
intracellular enzymatic activity.