Physical alterations of soybean during accelerated and natural aging

The aim of the present study was to investigate the effect of accelerated aging (M) and natural aging (NA) on the physical characteristics of soybeans (Glycine max). Soybeans from two cultivars (Coodetec 214 and BRS 267) were stored under AA (30 degrees C and 84% RH up to nine months), NA (ambient temperature and RH, fluctuation in the period = 17.3 at 24.5 degrees C and 59 at 93% RH, up to 18 months), and control conditions (-20 degrees C and 47% RH). Scanning electron micrographs (SEM) of the hull and cotyledons, the water sorption rate (S) during hydration and equilibrium moisture content (X-eq), the color of the grains and ground soybeans, and the hardness of cooked soybeans were analyzed. After storage of AA and NA, the surface of the palisade cells of the cotyledons became wrinkled and wilted; the browning of the hull, the ground soybeans, and the hardness of the cooked soybeans increased for both cultivars. It was observed that the increase of S and decrease of X-eq were more pronounced in Coodetec 214 than BRS 267. (C) 2013 Elsevier Ltd. All rights reserved.