Effect of puff cooking on structure and chemical properties of several lignocellulosic agrowastes.

Abstract

Agrowastes (rice husks, rice straw and peanut husks) were treated by puff cooking at a pressure of 6 or 12 kg/cm2 prior to enzymatic hydrolysis. The puff cooking treatment resulted in a decrease in the relative content of hemicellulose and morphological changes. Components such as lignin and sugar were easily extracted with water or methanol from rice husks and rice straw treated at the pressure of 12 kg/cm2. The amount of lignin removed with NaClO2 solution increased with increasing pressure applied for puff cooking. The degrees of enzymatic hydrolysis of rice straw and husks were also increased with increasing pressure applied for puff cooking, which simultaneously caused increases in the weight ratios of glucose as well as reducing sugar to the total sugar in the hydrolysates. However, in the case of peanut husks, little or no effect of puff cooking treatment on enzymatic hydrolysis or the degree of extraction of the components with water or methanol was observed.