1- Fars Research Center for Agriculture and Natural Resource, Zarghan, Shiraz, Islamic Republic Iran.
2- Department of Food Science, College of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran
Abstract: (6171 Views)
Crude Enzyme (beta-galactosidase) Extract (CEE) was produced by Lactobacillus ssp.
bulgaricus CHR Hansen Lb-12 and was applied in sterile milk which had been processed
through Ultra High Temperature method (UHT milk), for hydrolyzing lactose. Lactosehydrolyzed
milk was also produced by a pure and commercially available betagalactosidase
(Maxilact). Optimum quantities of CEE and Maxilact enzyme, for
producing lactose-hydrolyzed milk, during 6 hours of processing, were 0.418 and 0.512 U
ml-1, respectively. Using more than 0.418 U ml-1 CEE resulted in unacceptable acidity.
Acidity of lactose-hydrolyzed milk produced through 0.418 U ml-1 of CEE was
significantly increased from 15 to 17 ºD, while enhancement of acidity in lactosehydrolyzed
milk produced through Maxilact enzyme was not significant. Total count of
lactose-hydrolyzed milk by 0.418 U ml-1 CEE, after 6 hours of processing was significantly
increased from 5 to 30 CFU (Colony Forming Unit). Sensory evaluation of lactosehydrolyzed
milk and ordinary UHT milk (as control) did not show any significant
differences with respect to acceptability of sweetness, taste, aftertaste and color.
Received: 2011/02/5 | Accepted: 2011/02/5 | Published: 2011/02/5