Effects of starch concentration on calcium-enhanced black bullhead catfish protein gels.

Calcium-enhanced protein recovered from black bullhead catfish was used to develop gels containing increasing amounts of potato starch (0-20 g/kg protein paste) and the effects of starch on functional, textural, and color properties were tested. Energy required to unfold protein groups was greater with the addition of 5 g starch/kg protein paste. Gels containing starch were harder, chewier, and less springy ( p  < .05) than gels without starch. For most measurements, regression analysis showed that increasing the starch concentration beyond 5 g/kg did not contribute to further significant textural changes. Torsional shear stress and strain along with Kramer shear force increased as the concentration of starch increased ( R 2  = .79, .79, and .53, respectively). The addition of ≥10 g starch/kg protein paste resulted in darker gels and gels got darker as more starch was added ( R 2  = .71). Results showed no benefit to increasing starch concentration in gels beyond 5 g starch/kg protein paste.