Functional Properties of Hydrolysates from Proteolysis of Heat‐denatured Whey Protein Isolate

Abstract

Heat-denatured whey protein isolate was hydrolyzed with trypsin, ␣-chymotrypsin, Alcalase or Neutrase to 2.8, 4.3, 6.0 or 8.0% degree of hydrolysis. Hydrolysates were fractionated by ultrafiltration and freezedried. Protein content of retentates showed little variation but permeates differed with enzyme. Surface hydrophobicity increased with hydrolysis but was not linear except for ␣-chymotrypsin. Ultrafiltration increased solubility and the permeates and retentates had better solubility than hydrolysates. Retentates had higher emulsifying activity index than hydrolysates while permeates did not form stable emulsions. Permeates formed stable foams but hydrolysates and retentates showed poor foaming characteristics. Specificity of the enzyme, and degree of hydrolysis influenced the functional properties of the peptides. Fractions generated by trypsin, at all levels of hydrolysis generally had higher solubility, emulsifying properties and foaming properties. Permeates from Alcalase hydrolysis had the best foam capacity but low foam stability.

Nutritional evaluation of caseins and whey proteins and their hydrolysates from Protamex

“…It altered their structure and exposed previously buried hydrophobic regions to the aqueous environment. The enhanced solubility of sodium caseinate and WPC hydrolysates was also due to their smaller molecular size (data not shown) as confirmed by Chobert et al(1988b) and Mutilangi et al(1996). Although Protamex is an endopeptidase with a broad specificity to hydrophobic amino acids, it attacked WPC 80 and sodium caseinate at specific sites.…”

Enzymatic hydrolysis of whey and casein protein- effect on functional, rheological, textural and sensory properties of breads

“…It altered their structure and exposed previously buried hydrophobic regions to the aqueous environment. The enhanced solubility of casein and WPC hydrolysates was also due to their smaller molecular size as confirmed by Chobert et al (1988b) and Mutilangi et al (1996).…”

Antioxidative activity of protein hydrolysate produced by alcalase hydrolysis from shrimp waste (Penaeus monodon and Penaeus indicus)

“…In general, proteins were vulnerable to heat treatment, leading to the aggregation of protein and exposure of hydrophobic domain (Sikorski and Naczk 1981). Low MW fish protein hydrolysates were influenced by heat treatment minutely, whereas proteins with second, tertiary and quarternary structure were affected greatly by heat (Mutilangi et al 1996). The antioxidant activity slightly decreased after being heated for 30 min but the activity remained after heating for up to 120 min, in which 80% activity was still retained.…”