Some factors affecting pectinase production from apple pomace in solid-state cultures

Abstract Some factors affecting pectinase production from apple pomace in solid-state culture (medium composition, inoculum size, temperature and type of apple pomace used) were investigated. To obtain high enzymatic activities, apple pomace requires the addition of an adequate level of organic nitrogen components like those present in peptone, yeast extract or corn-steep. Inoculum size is not critical and optimum temperature for the fermentation process is 30°C. In connection with apple-pomace quality, the sugar concentration is the most important parameter which controls pectinase yields. By using Granny Smith pomace mixtures, containing 4% of sugars, production as high as 1300 U g−1 was attained in 36 h of culture. Pectinase levels ranging from 1000 to 2000 U litre−1 of juice for 1 to 3 h were necessary to achieve clarification in three different apple juices.