Infrared drying of wine grape pomace

The objective of this study was to determine the effects of infrared drying on the quality of dried wine grape pomace and related drying kinetics, with the aim to find a better way to dry it.Four drying methods including solar drying, infrared drying, intermittent infrared drying and two- stage drying ( infrared drying and convective drying) were studied. Drying characteristics, sterilizing efficacy, effects on pomace 's polyphenols and proanthocyanidins content as well as the micro- structure of dried grape seed were determined. The results revealed infrared drying had the highest drying rate; except for solar drying and IR9min- CD55℃, all the other drying methods had a good sterilizing ability.The content of polyphenols and proanthocyanidins decreased after drying and infrared drying created a comparatively small damage to these two substances.Through the scanning electron microscope, many small holes were found on the grape seeds' surface dried by infrared drying, less or no holes were found on that dried by solar drying or convective drying.In conclusion, infrared drying is a good way to dehydrate wine grape pomace with high drying quality.