HEAT‐INDUCED GELATION OF PEANUT PROTEIN/WHEY PROTEIN BLENDS

ABSTRACT Whey protein concentrate dispersions formulated at 7.5% or more of protein formed strong gels when heated at temperatures above 80°C. Quantitative gel strength calculated from penetration force data generally increased with heating temperature to 110°C. Increasing pH from 7.0 to 9.0 generally decreased the gel strength of whey protein concentrate. At a total protein concentration of 10%, gel strength was lower when peanut flour protein was 25% or more of a mixture with whey protein. Only weak gels were formed with heating protein blends formulated with peanut protein at greater than 50% of total protein. Sodium chloride (up to 0.5M) and calcium chloride (up to 30 mM) increased gel strength of whey protein and blended systems, but decreased gel strength of dispersions containing only peanut flour. Calcium chloride at 30 mM destroyed gelation ability of peanut flour causing protein precipitation. Gel strength of whey protein increased with moderate cysteine addition and was maximum at a level of 25 mM cysteine. Addition of 100 mM cysteine dramatically reduced whey protein gel strength. Cysteine addition decreased gel strength of peanut flour dispersions and had a varied effect on blended protein systems.