Latent heat of vaporization for selected foods and crops

Abstract

The equation for latent heat of vaporization was estab lished based on published equilibrium moisture content curves for main crops and selected foods. For moisture content (mc) above 0.2 db, there is little difference between the heat of vaporization from the grain kernels, hfg*, and that of free water, hfg. Below 0.2 db, this difference increases significantly for grains such as corn and rice. For the other grains (wheat, barley, bean, peanut kernel, soybean, sorghum), the ratio of hfg*/hfg increases at moisture contents below 0.12 db. There is a significant difference in hfg*/hfg results between durum wheat and soft or hard wheat. The latent heat of vaporization of free water is not significantly different from the latent heat of vaporization of water for celery, cloves, and eggs above 0.10 mc db and above 0.15 mc db for chamomile tea and horse radish. The hfg*/hfg ratios for starchy gels are 1.35 to 1.50, which were the highest of the tested crops and foods, for the moisture range between 0.11 and0.16db.