真空冷冻干燥与热风干燥对桑果品质的影响

Effects vacuum freezing drying and hot air drying on qualities of mulberry fruit

研究真空冷冻干燥与热风干燥对不同果桑品种果实品质的影响,为果桑综合开发利用提供依据。以果桑品种大十、台湾72C002和白玉王为研究对象,分析测定热风干燥和真空冷冻干燥后果实中总酸含量、总黄酮含量、总酚含量、花色苷含量及16种氨基酸含量等品质指标的差异和变化,并利用因子分析法对不同品种果实干燥处理前后果实品质进行综合评价。结果显示:3个品种鲜果中总酸含量、总黄酮含量、总酚含量、花色苷含量及总氨基酸含量皆存在显著差异,其中大十果实中总黄酮含量、总酚含量和花色苷含量最高。3个品种果实中花色苷含量、总黄酮含量和总酚含量在真空冷冻干燥处理后皆显著高于热风干燥处理。2种干燥处理对桑果品质指标影响差异由大到小皆为:花色苷>总黄酮>总酚>总酸>总氨基酸。大十和台湾72C002桑果在2种干燥处理后果实综合品质由高到低均为鲜果>真空冷冻干燥>热风干燥,白玉王桑果在2种干燥方式间综合品质差异较小。说明不同干燥方式对果实的营养成分,特别是活性物质含量影响差异较大,且影响程度与品种相关,总体上,真空冷冻干燥更利于保持果实原有品质。

The effects of hot air drying and vacuum freeze drying on fruit quality of different mulberry varieties were studied to provide the basis for the comprehensive development and utilization of fruit mulberry.The fruits of Dashi,Taiwan 72C002 and Baiyuwang were taken as the research objects to detect the differences and changes of quality indices such as total acids content,total flavonoids content,total phenols content,anthocyanin content and 16 kinds of amino acids in fruits after treated by hot air drying and vacuum freeze drying.Factor analysis was applied to comprehensively evaluate the qualities of different fruits before and after drying.The results showed that there were significant differences in total acids content,total flavonoids content,total phenols content,anthocyanin content and total amino acids content between the fresh fruits of three varieties.The fruits of Dashi had the highest content of total flavonoids,total phenols and anthocyanin.The content of anthocyanin,total flavonoids and total phenols in mulberry fruits of three varieties treated with vacuum freeze drying were significantly higher than those treated with hot air drying.The difference in the effects of the two drying treatments on the quality of mulberry fruits was as follows:anthocyanins>total flavonoids>total phenols>total acids>total amino acids.The ranking of comprehensive quality of the fruits of Dashi and Taiwan 72C002 after two drying treatments were both fresh>vacuum freeze drying>hot air drying.The difference of comprehensive quality of Baiyuwang between the two drying methods was small.The results demonstrate that different drying methods show great differences in influencing nutrient content of fruits,especially in the content of active substances.The influence degree of different drying methods on nutrients is related to varieties.In general,vacuum freeze-drying is more conducive in maintaining the original quality of the fruits.