Quality variation of wine grape pomace dried by infrared drying or during storage without drying

To study the characteristic of quality variation during wine grape pomace's storage and the possibility to apply infrared drying to wine grape pomace's dehydration, the quality of wine grape pomace was evaluated.The pomace were dried by solar drying after being stored for 0, 1, 3, 5 or 7d, for the pomace dried after being stored for1 d, grape seed and grape skin ultramicro- pulverised powder were made, for the other pomace, the grape skin ultramicro-pulverised powder were made; some pomace were dried by infrared drying after being stored for 1d, and the grape skin and grape seed ultramicro- pulverised powder were made. The content of microorganism ( yeast, mould and bacteria) , 8 kinds of phenolic acid and fungaltoxin ( patulin and ochratoxin A) of ultramicropulverised powder was determined. It was found that with the storage time prolonged, the content of yeast increased at first and decreased in the next, the content of microorganism and fungaltoxin increased and the content of phenolic acid decreased. The ultramicro- pulverised powder which were stored for 1d and dried by infrared drying possessed less microorganism which meant that infrared drying owned a good sterilizing effect; the phenolic acid met with some loss and no influence was found for fungaltoxin.In conclusion, wine grape pomace should be dried immediately after separated from wine making process and infrared drying could be a proper way for their dehydration.