Chemical Changes and Amylase Activity of Freshly Shelled Southern Peas, Vigna sinensis1

Abstract

Abstract Southern peas were held under conditions simulating those which exist at the processing plant. Freshly shelled peas were held in small cylinders up to 3 days at 7°-10° and 24°-27°C before they were frozen. Samples, taken from the upper and lower positions of the cylinders, were analyzed for starch and maltose content, total acidity, and amylase activity. During the holding period the starch content decreased, the maltose content rose initially and remained stable, total acidity increased, and amylase activity decreased. Peas held at 7°-10°C had less starch degradation, higher maltose accumulation, lower total acidity, but higher amylase activity than peas held at 24°-27°C. Position in the cylinder did not influence the starch content, but peas from the upper position (higher oxygen tension) had a higher maltose content, higher total acidity, and lower amylase activity. Significant correlation coefficients were found between total acidity and amylase activity (r = -0.93), starch content and amylase activity (r = 0.84), and starch and maltose contents (r = -0.58).