Ethanol recovery from solid state fermented apple pomace and evaluation of physico-chemical characteristics of the residue

Abstract

127-132In view of the growing demand of ethanol the identification of resources and development of economical methods for its extraction are very essential. Fermented apple pomace has been identified as a rich source of ethanol especially for the Himalayan region where apple is grown at large scale. There are various methods of alcohol recovery from solid state fermented apple pomace (hot water extraction followed by distillation, vacuum distillation, hydraulic pressure and direct steam distillation) hence, present study was carried out to standardize an efficient and economical method. The physico-chemical characteristics of dried apple pomace residue after the recovery of ethanol by different methods were also evaluated for knowing loss of nutrients during extraction of ethanol. For present study two types of solid state fermented (SSF) apple pomace, obtained by two treatments (one by Saccharomyces cerevisiae and other by Candida utilis and Kloeckera spp. as sequential interactive co-cultures) were used. Out of different methods of alcohol recovery tried, steam distillation method gave the highest separation efficiency while hydraulic pressing gave the lowest separation efficiency. Evaluation of some of the physico-chemical characteristics of dried apple pomace after recovery of ethanol by different methods indicated that steam distillation resulted in minimum nutritional loss, viz. crude and soluble proteins, reducing and total sugars. The maximum nutritional loss took place in hydraulic pressing, wherein the base of distillate was not added back to the pomace, prior to drying. Steam distillation method of ethanol recovery from fermented apple pomace was the best since it gave the dried pomace with minimum loss of nutrients