Effect of postharvest desiccation at high temperature on soluble sugar changes of two supersweet sweet corn cultivars

The alteration in the soluble sugar contents of two commercial cultivars of sweet corn, Zea mays L. Supersweet Jubilee and Sweetie, desiccated at 60°C was determined. The loss of kernel moisture under field condition was gradual, but was rapid under laboratory condition at 60°C. Constant dry weight of kernels was reached after 24 h. In both cultivars, postharvest desiccation at 60°C significantly increased raffinose and fructose contents over those of non-desiccated control. Sucrose content of kernels, however, was significantly decreased by desiccation in both cultivars. In cv. Supersweet Jubilee, raffinose, sorbitol, fructose and glucose were significantly increased in kernels contained in plastic bags held at 60°C compared with naked desiccation at 60°C. In cv. Sweetie, however, only fructose and glucose contents were increased and not raffinose, sorbitol or sucrose. It was concluded that high temperature desiccation had a profound effect on sweet corn soluble sugars which may be associated with their cell membrane protecting role.