Abstract
Age gelation is a major quality defect in ultra-high-temperature (UHT) pasteurized milk during extended storage. Changes in plasmin (PL)-induced sedimentation were investigated during storage (23 °C and 37 °C, four weeks) of UHT skim milk treated with PL (2.5, 10, and 15 U/L). The increase in particle size and broadening of the particle size distribution of samples during storage were dependent on the PL concentration, storage period, and storage temperature. Sediment analysis indicated that elevated storage temperature accelerated protein sedimentation. The initial PL concentration was positively correlated with the amount of protein sediment in samples stored at 23 °C for four weeks (r = 0.615; p < 0.01), whereas this correlation was negative in samples stored at 37 °C for the same time (r = −0.358; p < 0.01) due to extensive proteolysis. SDS-PAGE revealed that whey proteins remained soluble over storage at 23 °C for four weeks, but they mostly disappeared from the soluble phase of PL-added samples after two weeks’ storage at 37 °C. Transmission electron micrographs of PL-containing UHT skim milk during storage at different temperatures supported the trend of sediment analysis well. Based on the Fourier transform infrared spectra of UHT skim milk stored at 23 °C for three weeks, PL-induced particle size enlargement was due to protein aggregation and the formation of intermolecular β-sheet structures, which contributed to casein destabilization, leading to sediment formation.
Subject
Chemistry (miscellaneous),Analytical Chemistry,Organic Chemistry,Physical and Theoretical Chemistry,Molecular Medicine,Drug Discovery,Pharmaceutical Science
Reference33 articles.
1. UHT Milk Processing and Effect of Plasmin Activity on Shelf Life: A Review
2. Mordor Intelligence Global UHT Milk Market–Market-Growth, Trends, and Forecast (2020–2025)https://www.mordorintelligence.com/industry-reports/global-uht-milk-market
3. Effect of Homogenization Pressure on Plasmin Activity and Mechanical
Stress-Induced Fat Aggregation of Commercially Sterilized Ultra High Temperature
Milk during Storage
4. Age Gelation of UHT Milk—A Review
5. Age-gelation of UHT milk: Changes that occur during storage, their effect on shelf life and the mechanism by which age-gelation occurs;McMahon,1996
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