Kinetics of Acid Hydrolysis of Defatted Peanut Flour

The kinetics of hydrolysis of defatted peanut flour as affected by treatment at 100, 110 and 120°C in 3N and 5N HCl were determined. Rates of hydrolysis of protein and destruction of reducing sugars were rapid at 120°C and in 5N HCl. About 90% of total amino acids were released after 4 hr. The overall rate of reaction followed second-order kinetics as monitored by the generation of free amino acids over time. This relationship was reliable for all acid and temperature treatment conditions when the extent of hydrolysis was less than 80%. The rate of hydrolysis of peanut protein was about 2.2 times faster for every 10°C increase. Hydrolysis in 3N HCl was about 2.3 times faster than in 3N HCl at the same temperature. The activation energy was =24 kcal mol^?1. The rate of liberation of individual amino acids with respect to temperature and HCl concentration, however, varied.