Modification of heat-induced whey protein gels by basic amino acids

Various amino acids have been studied as gelation enhancers. This study investigated the effect of histidine, lysine, and arginine on gelling properties of heat-induced whey protein isolate (WPI) gels at different pHs. Basic amino acids modified WPI gels in a pH- and amino acid-dependent manner. Hardness and gumminess of the WPI gel was improved by arginine at pH 7.59 while springiness was enhanced by histidine at pHs 7.59 and 9.74 and by lysine at pH 7.59 (P < 0.05). At pH 2.0, WPI formed a weak gel. Lysine and arginine facilitated beta-lactoglobulin cross-linking at pH 2.0 and reduced protein leach out from the gel (P < 0.05). At pH 5.2, WPI formed a particulate gel with poor water holding capacity (WHC). Lysine improved WHC of the WPI gel at pH 5.2 by changing the structure of the gel network. At pHs away from 5.2, basic amino acid treatments resulted in a more uniform and porous gel matrix and a greater WHC (P < 0.05). In conclusion, different basic amino acids may be applied as WPI gel enhancers depending on the pH and desired attributes of the product.