知识与财富的链接
该文以自然风干的桑叶为对照,研究红外干燥及热风干燥对桑叶的干燥效率及其对氢氧化钠、明胶、氢氧化钠-明胶和明胶-氢氧化钠4种方法去除桑叶涩味的影响,并通过分析单宁、黄酮和多酚的含量变化探究其与涩味的相关性。试验结果表明,105 ℃红外干燥效率最高（干燥时间为1.53 h）,60 ℃红外干燥结合明胶-氢氧化钠（infrared 60 ℃-gelatin-sodium hydroxide,ID60-GS）组桑叶的涩味比相同条件下自然风干的桑叶涩味响应值减少2.50。成分分析结果表明,ID60-GS组比自然风干组贡献涩味的单宁含量降低74.36%,黄酮含量减少56.69%,多酚含量减少80.67%。综上,105 ℃红外干燥是最高效的干燥方法,干燥时间最短且水分流失量最多;60 ℃红外干燥结合明胶-氢氧化钠是去除涩味最有利的方法。
In this paper,the effects of infrared and hot air drying on the drying efficiency of mulberry leaves and on the removal of astringency of mulberry leaves by four methods of sodium hydroxide,gelatin,sodium hydroxy+ gelatin,and gelatin+ sodium hydroxide were investigated using naturally air-dried mulberry leaves as the control.The correlation between them and astringency was researched by analyzing the changes in the contents of tannin,flavonoids,and polyphenols. The experimental results showed that the highest drying efficiency（the drying time of 1.53 h）was achieved under infrared drying at 105 ℃,and the astringency response of mulberry leaves treated with gelatin+sodium hydroxide under infrared drying at 60 ℃（ID60-GS）was 2.50 lower than that of the naturally air-dried mulberry leaves. The results of the component analysis showed that the content of tannin contributing to astringency was reduced by 74.36% in the ID60-GS group compared with the naturally air-dried group;flavonoid content was decreased by 56.69%;polyphenol content was reduced by 80.67%. In conclusion,infrared drying at 105 ℃ was the most efficient drying method,with the shortest drying time and the most water loss. Infrared drying at 60 ℃ combined with gelatin + sodium hydroxide was the most favorable method to remove astringency.
