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Stability and Activity of β‐Galactosidase in Sonicated Cultures of Lactobacillus delbrueckii ssp. bulgaricus 11842 as Affected by Temperature and Ionic Environments
Author(s) -
Kreft M.E.,
Jelen P.
Publication year - 2000
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2000.tb10613.x
Subject(s) - sonication , lactose , hydrolysis , chemistry , lactobacillus , lactobacillaceae , lactobacillus delbrueckii subsp. bulgaricus , ionic strength , phosphate buffered saline , chromatography , food science , biochemistry , fermentation , organic chemistry , aqueous solution
Stability of β‐galactosidase and related lactose hydrolyzing activity in sonicated cultures of Lactobacillus bulgaricus 11842 was investigated in the presence of Na + or K + ions. After sonication in Na + or K + buffers at various pH levels, cultures were held at various temperatures, before adding test lactose solutions. Hydrolysis was monitored by cryoscopy. Cultures sonicated in K + buffer had higher activity and stability than those in Na + buffer; both were highest at pH 6 and 7. Stability was unaffected at pH 6 and 7 below 56 °C. Holding at 61 °C for 60 min caused 70% activity loss with K + ions at pH 6 and 7, while with Na + , activity loss was almost complete.