不同干燥方式对火龙果花品质特性的影响

Effects of different drying methods on quality of pitaya flowers

对比分析了自然干燥、鼓风干燥、热泵干燥、真空干燥、真空冷冻干燥以及微波真空干燥6种干燥方式对火龙果花还原糖、可溶性固形物、Vc、氨基酸组分、黏度、复水性和外观质量的影响。结果表明不同干燥方式对火龙果花品质影响差异明显:自然干燥、鼓风干燥和真空干燥火龙果花品质较差;微波真空干燥时间最短,但花的氨基酸总量、黏度和复水性较差、花褐变较严重;热泵干燥综合品质较好;而真空冷冻干燥品质最佳,色泽与新鲜花色泽相近。进而得出,真空冷冻干燥可以开发高品质火龙果干花,热泵干燥适合大批量干燥火龙果花。干燥后的火龙果花可溶性固形物、氨基酸含量高,并含有7种人体必需氨基酸,谷氨酸、天冬氨酸、丙氨酸和丝氨酸含量较高,从而使火龙果花呈鲜甜味。

Natural drying,hot air drying,heat pump drying,vacuum drying,vacuum freeze drying and microwave vacuum drying were used on pitaya flower.Reducing suger,soluble solids,vitamin C,amino acid composition,viscosity,rehydration capability and appearance quality of the drying pitaya flower were analyzed in the present study.The results showed that different drying methods obviously influenced pitaya flower quality.Pitaya flower quality was poorer by natural drying,hot air drying and vacuum drying.Microwave vacuum drying exhibited the shortest drying time,but total amino acid,viscosity and rehydration capability were low with the serious browning.Comprehensive quality was good by heat pump drying.Pitaya flower quality by vacuum freeze drying was the best with the similar color to fresh flower.Thus,vacuum freeze drying could process high quality dry pitaya flowers,and heat pump drying was suitable for mass production of dry pitaya flower.The contents of soluble solids and total amino acids in dry pitaya flower were high,containing 7 kinds of essential amino acids.Glutamic acid,aspartic acid,alanine and serine contents were high,which gave umami and sweetness qualities to pitaya flower.