In this study the intermittent infrared assisted heat pump was used to longan drying,and the drying charac-teristics,color change,rehydration properties,antioxidant activity and volatile profiles of longan under different drying conditions were measured.The results indicated that intermittent infrared assisted heat pump drying could dramatically shorten drying time and improved the comprehensive quality of dried longan.Specifically,the intermittent infrared assist-ed heat pump drying time of longan was reduced 25％-28.6％and the rehydration rate was increased 2.65％-8.21％when compared with the single heat pump drying.Total color change of the intermittent infrared assisted heat pump dried lon-gan was lower than the single heat pump dried longan coupled with more uniformity color distribution of dried longan pulp surface.Moreover,the higher ferric reducing antioxidant power,4.42％-17.95％,was also observed in intermittent infrared assisted heat pump dried longan.The types or content of alcohols,aldehydes,ketones,and esters in longan were increased after drying,and(E)-6,10-dimethyl-5,9-undecadien-2-one,1-octanol,and ethyl caprate were only de-tected in intermittent infrared assisted heat pump dried longan,which indicated that intermittent infrared assistant effec-tively enriched the volatile profiles of dried longan.In general,60 ℃ heat pump drying coupled with 2 min every 5 min intermittent infrared was the best assisted drying scheme in all the selected methods,which is benefit to improve the qualities and volatile profiles formation of longan.
维普
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