Proteolysis of yogurts made from ultra-high-pressure homogenized milk during cold storage

• Published in: Journal of dairy science Vol. 92; no. 1; pp. 71 - 78
• Main Authors: Serra, M., Trujillo, A.J., Guamis, B., Ferragut, V.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.01.2009; American Dairy Science Association; Am Dairy Sci Assoc; Elsevier
• Subjects: Amino Acids - analysis; Animal productions; Biological and medical sciences; capillary electrophoresis; casein; Caseins - analysis; cold storage; Cold Temperature; Food Handling; Food industries; Food Technology - methods; free amino acids; Fundamental and applied biological sciences. Psychology; high pressure treatment; homogenized milk; Hydrogen-Ion Concentration; hydrophobicity; Milk and cheese industries. Ice creams; Milk Proteins - metabolism; Nitrogen - analysis; nitrogen content; peptides; Peptides - analysis; Pressure; protein composition; protein content; proteolysis; skim milk; storage time; temperature; temporal variation; Terrestrial animal productions; ultra-high pressure homogenization; Vertebrates; yogurt; Yogurt - analysis; yogurt; ultra-high pressure homogenization; proteolysis; capillary electrophoresis; Physical dressing; Cold; Capillary electrophoresis; Dairy product; Homogenization; Yogurt; High pressure; Warehousing; Proteolysis; Dairy industry; Food preservation; Homogenized milk
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2008-1416

Proteolysis was investigated in yogurts made from milk that was ultra-high-pressure homogenized at 200 or 300MPa and at 30 or 40°C and compared with those produced from heat-treated milk containing 3% skim milk powder. To evaluate changes in the protein fraction, samples were analyzed at d 1, 7, 14, 21, and 28 of storage for residual caseins, peptides, and total free amino acids. Results showed that yogurts from heat-treated milk and 300 MPa-treated milk presented similar levels of residual caseins, as well as similar profiles of soluble peptides and total free amino acids. On the contrary, greater amounts of hydrophobic peptides were detected in yogurts made from 200MPa-treated milk at both 30 and 40°C, especially at the end of storage. In all treatments studied, caseins were hydrolyzed and hydrophobic peptides were increased during storage, as reflected by the increase in soluble nitrogen at the end of the storage.