不同干燥方式对甘薯叶理化特性和抗氧化能力的影响

Effects of different drying methods on physicochemical properties and antioxidant capacity of sweet potato leaves

中文关键词:  甘薯叶  微波干燥  热风干燥  冷冻干燥  抗氧化性

英文关键词:sweet potato leaves  microwave drying  hot air drying  vacuum freeze drying  physicochemical property  antioxidant ability

中文摘要:

      目的 探究3种不同干燥方式(微波干燥、热风干燥、冷冻干燥)对甘薯叶理化特性和抗氧化能力的影响。方法 以新鲜甘薯叶为原料, 探究3种不同干燥方式对甘薯叶基本成分(水分、蛋白质、总膳食纤维、粗脂肪、可溶性糖、总酚、总黄酮和绿原酸含量)、理化特性(色度、微观结构、胆固醇吸附能力、持水力、持油力和葡萄糖吸附能力)和抗氧化活性{1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)自由基清除能力、2,2’-联氮-二(3-乙基-苯并噻唑啉-6-磺酸)二铵盐[2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt, ABTS]自由基抑制率、总还原力和羟基(hydroxyl, OH)清除能力}以及酚类物质的组成等影响。结果 利用热风干燥的甘薯叶水分含量最高, 为7.96 g/100 g; 冷冻干燥含水量最低, 为7.29 g/100 g, 蛋白质含量、粗脂肪、总酚、总黄酮以及绿原酸含量最高, 分别为31.39 g/100 g、3.43 g/100 g、50.73 mg CAE/g DW、18.49 mg RE/g DW、7.05%; 热风干燥的总纤维含量最高, 为28.80 g/100 g。不同干燥方式对甘薯叶理化指标的影响中, 利用冷冻干燥的甘薯叶色泽品质明显优于热风干燥和微波干燥; 热风干燥的胆固醇吸附能力和持油力最强, 分别为0.23 mg/L, 1.54 mL/g; 冷冻干燥的持水力和葡萄糖吸附能力最优, 分别为7.33 g/g和12.00 mmol/g。抗氧化性上, 不同方法测定的抗氧化能力都表现为冷冻干燥>微波干燥>热风干燥。冷冻干燥的总还原力、DPPH·清除能力、·OH清除能力、ABTS+清除率分别高达83.34、41.28、9.17、27.21 mg VC E/g DW。结论 冷冻干燥最适合用来对甘薯叶进行干燥处理。

英文摘要:

      Objective To investigate the effects of 3 kinds of different drying methods (hot air drying, vacuum freeze drying, microwave drying) on physicochemical characteristics and antioxidant capacity of sweet potato leaves. Methods Fresh sweet potato leaves were used as raw materials to explore the effects of three different drying methods on the basic components (moisture, protein, total dietary fiber, crude fat, soluble sugar, total phenol, total flavone and chlorogenic acid contents), physicochemical properties (chroma, microstructure, cholesterol adsorption capacity, water retention, oil retention and glucose adsorption capacity) and antioxidant activities 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt (ABTS) radical inhibition rate, total reducing power and hydroxyl (OH) radical scavenging capacity and the composition of phenolic substances. Results The moisture content of sweet potato leaves using hot air drying was the highest, which was 7.96 g/100 g. While using vacuum freeze drying water content was the lowest, which was 7.29 g/100 g. The content of protein, fat, total phenol, total flavonoids and chlorogenic acid in vacuum freezedrying were the highest, which were 31.39 g/100 g, 3.43 g/100 g, 50.73 mg CAE/g DW, 18.49 mg RE/g DW and 7.05%, respectively. The total fiber content of hot air drying was the highest, which was 28.80 g/100 g. Among the effects of different drying methods on physical and chemical indexes of sweet potato leaves, the color and quality of sweet potato leaves powder using vacuum freeze drying was obviously better than using hot air drying and microwave drying. The cholesterol adsorption capacity and oil holding capacity of hot air drying were the strongest, 0.23 mg/L and 1.54 mL/g, respectively. The optimum hydraulic capacity and glucose adsorption capacity using vacuum freeze drying were best which were 7.33 g/g and 12.00 mmol/g, respectively. In terms of antioxidant capacity, the antioxidant capacity measured by different methods was vacuum freeze drying>microwave drying>hot air drying. The total reducing power, DPPH· scavenging capacity, ·OH scavenging capacity and ABTS+ scavenging rate of vacuum freezedrying were 83.34, 41.28, 9.17 and 27.21 mg VC E/g DW, respectively. Conclusion Vacuum freeze drying which is most suitable for drying sweet potato leaves.