Chemical and Proteolysis-Derived Changes during Long-Term Storage of Lactose-Hydrolyzed Ultrahigh-Temperature (UHT) Milk
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- 作者：Therese Jansson ; Hanne B. Jensen ; Ulrik K. Sundekilde ; Morten R. Clausen ; Nina Eggers ; Lotte B. Larsen ; Colin Ray ; Henrik J. Andersen ; Hanne C. Bertram
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2014
- 出版时间：November 19, 2014
- 年：2014
- 卷：62
- 期：46
- 页码：11270-11278
- 全文大小：451K
- ISSN：1520-5118
文摘
Proteolytic activity in milk may release bitter-tasting peptides and generate free amino terminals that react with carbohydrates, which initiate Maillard reaction. Ultrahigh temperature (UHT) heat treatment inactivates the majority of proteolytic enzymes in milk. In lactose-hydrolyzed milk a 尾-galactosidase preparation is applied to the milk after heat treatment, which has proteolytic side activities that may induce quality deterioration of long-term-stored milk. In the present study proteolysis, glycation, and volatile compound formation were investigated in conventional (100% lactose), filtered (60% lactose), and lactose-hydrolyzed (<1% lactose) UHT milk using reverse phase high-pressure liquid chromatography鈥搈ass spectrometry, proton nuclear magnetic resonance, and gas chromatography鈥搈ass spectrometry. Proteolysis was observed in all milk types. However, the degree of proteolysis was significantly higher in the lactose-hydrolyzed milk compared to the conventional and filtered milk. The proteins most prone to proteolysis were 尾-CN and 伪s1-CN, which were clearly hydrolyzed after approximately 90 days of storage in the lactose-hydrolyzed milk.