Journal
JOURNAL OF DAIRY RESEARCH
Volume 69, Issue 4, Pages 541-553Publisher
CAMBRIDGE UNIV PRESS
DOI: 10.1017/S0022029902005721
Keywords
TTIs; milk fat; kinetics; alkaline phosphatase; lactoperoxidase; beta-lactoglobulin
Ask authors/readers for more resources
In the context of identifying intrinsic time temperature integrators (TTIs) for evaluating heat processing of milk, the extent to which milk fat content has an effect on alkaline phosphatase (ALP) and lactoperoxidase (Lpo) inactivation and on beta-lactoglobulin (beta-lg) denaturation kinetics was studied. Inactivation and denaturation kinetics were analysed in whole, semi-skimmed and skimmed milk. In previous experiments (isothermal and non-isothermal heating conditions), heat inactivation of ALP and Lpo and heat denaturation of beta-lg were found to follow first order kinetics. This allowed experimental design to be simplified. Data analysis was performed by non-linear regression and results were evaluated by construction of joint confidence regions. The possible effect of milk fat was illustrated by temperature time tolerance (TTT-) diagrams. Although initial ALP activity was lower in skimmed milk compared with semi-skimmed or whole milk, kinetics were comparable and fat content did not seem to substantially affect the ALP test result for pasteurized milk. Unlike ALP, Lpo inactivation and beta-lg denaturation kinetics differed significantly in milk with different fat content. Differences between Lpo inactivation kinetics were relatively small and acceptable in the context of quantifying the process impact. Denaturation of beta-lg, on the other hand, seemed to be enhanced at higher milk fat content (> 72 degreesC).
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available