Effect of enzymatic deamidation on the heat-induced conformational changes in whey protein isolate and its relation to gel properties

Noriko Miwa, Keiichi Yokoyama, Noriki Nio, Kenji Sonomoto

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The effect of protein-glutaminase (PG) on the heat-induced conformational changes in whey protein isolate (WPI) and its relation to gel properties was investigated. The structural properties of WPI treated with PG were examined by several analytical methods. The analysis of the fluorescence spectrum and the binding capacity of a fluorescent probe demonstrated that deamidation prevented the increase in the fluorescence intensity caused by subsequent heat treatment. Measurements of the molecular weight distribution of WPI showed that PG-treated WPI was not likely to polymerize even after heating. This is thought to be due to an increase in electrostatic repulsion between carboxylic acid groups and a decrease in the formation of disulfide bonds, which results in the decrease in heat-induced aggregation. The properties of heat-induced WPI gels were modified by deamidation. PG-treated WPI gels had a soft texture and a high water-holding capacity in the presence of salts.

Original languageEnglish
Pages (from-to)2205-2212
Number of pages8
JournalJournal of Agricultural and Food Chemistry
Volume61
Issue number9
DOIs
Publication statusPublished - Mar 6 2013

Fingerprint

deamidation
whey protein isolate
glutaminase
Glutaminase
Hot Temperature
Gels
gels
heat
Proteins
proteins
Fluorescence
fluorescence
electrostatic interactions
disulfide bonds
binding capacity
carboxylic acids
Carboxylic Acids
Static Electricity
Fluorescent Dyes
water holding capacity

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

Cite this

Effect of enzymatic deamidation on the heat-induced conformational changes in whey protein isolate and its relation to gel properties. / Miwa, Noriko; Yokoyama, Keiichi; Nio, Noriki; Sonomoto, Kenji.

In: Journal of Agricultural and Food Chemistry, Vol. 61, No. 9, 06.03.2013, p. 2205-2212.

Research output: Contribution to journalArticle

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