EFFECT OF ADDITION OF SO2 ON SOLID-STATE FERMENTATION OF APPLE POMACE

Addition of up to 150 ppm of sulphur dioxide (SO2) in solid-state ferm entation (SSF) of apple pomace by Candida utilis and Torula utilis, an d 200 ppm in case of Saccharomyces cerevisiae generally enhanced the e thanol concentration, fermentation efficiency and decreased the reduci ng sugars. But 250 ppm and above of SO2 proved inhibitory to all the y easts tried. The titrable acidity remained similar except for a small increase in the treatment with 300 ppm of SO2. The yeast count decreas ed after 200 ppm of SO2. Bacterial and fungal contamination was the hi ghest at 50 ppm and decreased after this level. The yeast counts at 15 0-200 ppm of SO2 after 96 h of SSF of apple pomace were quite comparab le with those obtained in the steam-sterilized treatment prior to inoc ulation, Addition of 150-200 ppm of SO2 can be used as a practical alt ernative to sterilization in solid-state fermentation of apple pomace.