Effects of caseinate deamidation on transglutaminase-induced glucosamine conjugation and cross-linking as well as properties of the treated caseinates

• Published in: CYTA: journal of food 2015-07, Vol.13 (3), p.400-407
• Main Authors: Yao, Xin-Tong, Zhao, Xin-Huai
• Format: Article
• Language: English
• Subjects: caseinate; caseinato; conjugación de glucosamina; Conjugation; cross-linking; Crosslinking; deamidación; deamidation; entrecruzamiento; functional properties; Glucosamine; glucosamine conjugation; Hydrophobicity; propiedades funcionales; Proteins; Solubility; transglutaminasa; transglutaminase
• ISSN: 1947-6337; 1947-6345
• DOI: 10.1080/19476337.2014.988647

Caseinate was treated by diluted HCl solution to achieve degrees of deamidation of 16.6% and 28.1%, which resulted in lower surface hydrophobicity. Two deamidated caseinates were treated by transglutaminase and glucosamine to carry out glucosamine conjugation and cross-linking, to generate two modified caseinates (glucosamine-conjugated and cross-linked deamidated caseinates). Two modified caseinates contained less glucosamine (6.9-9.8 versus 12.6 g/kg protein) and higher reactable -NH 2 (0.54-0.56 versus 0.51 mol/kg protein) than the glucosamine-conjugated and cross-linked caseinate, declaring they were less glycated and less cross-linked than caseinate. Two modified caseinates had better solubility in pH 3.0-9.0, higher water- and oil-binding and emulsion stability but lower emulsifying activity than caseinate; however, they also exhibited better solubility and emulsifying activity than the counterpart. It is thus concluded that HCl-induced deamidation was powerful enough to control transglutaminase-induced glucosamine conjugation and cross-linking as well as functional properties of the treated caseinates.