EFFECT OF PECTINASE, CELLULASE AND NUTRIENT ADDITION ON FERMENTATION OF SWEET POTATO MASHES

Abstract

Addition of either cellulase or pectinase mixture to pre-heated sweet potato mashes at the time of yeast inoculation increased ethanol production up to twice that of untreated mashes, possibly by enhancing the post-heating activity of the native amylase and/or by lowering the viscosity of the mash, thus allowing better mixing and providing more chances for amylase attack on starch granules. With enzyme addition, heating mashes beyond 60°C did not increase ethanol yield. However, ethanol production was higher if enzymes were not added. The use of a common yeast nutrient supplement, corn steep, was detrimental to fermentation.