烫漂预处理结合不同干燥方式对刺梨活性物质及抗氧化活性的影响

Effects of blanching pretreatment combined with different drying methods on active substances and antioxidant activity of Rosa roxburghii Tratt

中文关键词:  刺梨  干燥方式  烫漂  活性物质  抗氧化活性

英文关键词:Rosa roxburghii Tratt  drying methods  blanching  active substances  antioxidant activity

中文摘要:

      目的 探究不同干燥方式结合烫漂预处理对刺梨中主要活性物质及抗氧化活性的影响。方法 以刺梨鲜果为对象, 首先对其烫漂预处理, 再分别采用微波干燥、热风干燥、真空冷冻干燥进行初加工, 再测定刺梨的褐变度及其中游离酚、结合酚、黄酮、维生素C (vitamin C, VC)、多糖含量, 最后评价刺梨对2,2’-联氮-二(3-乙基-苯并噻唑啉-6-磺酸)二铵盐阳离子自由基清除能力、1,1-二苯基-2-三硝基苯肼自由基清除能力。结果 与热风干燥和微波干燥相比, 真空冷冻干燥条件下刺梨中游离酚[(139.26±2.94) mg/g]、多糖[(21.47±0.41) mg/g]和VC [(18.87±0.86) mg/g]的含量相对较高; 但是烫漂处理显著降低了真空冷冻干燥中刺梨的结合酚和多糖含量, 还升高了刺梨的褐变度。而烫漂联合热风干燥、微波干燥处理, 不仅实现了刺梨的护色, 还显著减少了刺梨中VC的流失。结论 刺梨在真空冷冻干燥后品质最佳, 但应避免过多的预处理联合加工; 而相比工艺成本较高的真空冷冻干燥, 热风干燥和微波干燥辅以烫漂也能使刺梨产品达到较好的外观品质。该研究结果可为较高价值的刺梨初加工乃至精深加工提供参考。

英文摘要:

      Objective To explore the effects of different drying methods combined with blanching pretreatment on the main active substances and antioxidant activity in Rosa roxburghii Tratt. Methods The fresh fruit of Rosa roxburghii Tratt was first blanched and pretreated, followed by microwave drying, hot air drying, and vacuum freeze-drying for initial processing. The browning degree, free phenols, bound phenols, flavonoids, vitamin C (VC), and polysaccharide content of Rosa roxburghii Tratt were measured, the antioxidant activity of Rosa roxburghii Tratt was evaluated by 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt cation free radical scavenging ability and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging ability. The fresh fruit of Rosa roxburghii Tratt was first blanched and pretreated, followed by microwave drying, hot air drying, and vacuum freeze-drying for initial processing. The browning degree, free phenols, bound phenols, flavonoids, vitamin C (VC), and polysaccharide content of Rosa roxburghii Tratt were measured, and the scavenging ability of Rosa roxburghii Tratt to 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt cation radical and 1,1-diphenyl-2-picrylhydrazyl radical was evaluated. Results Compared with hot air drying and microwave drying, the content of free phenols [(139.26±2.94) mg/g], polysaccharides [(21.47±0.41) mg/g], and VC [(18.87±0.86) mg/g] in Rosa roxburghii Tratt under vacuum freeze-drying conditions was relatively higher; the blanching pretreatment did not affect the antioxidant activity of Rosa roxburghii Tratt, however, blanching treatment significantly reduced the content of bound phenols and polysaccharides in Rosa roxburghii Tratt during vacuum freeze-drying, and also increased the browning degree of Rosa roxburghii Tratt. The combination of blanching, hot air drying, and microwave drying not only achieved the color protection of Rosa roxburghii Tratt, but also significantly reduced the loss of VC in Rosa roxburghii Tratt. Conclusion Rosa roxburghii Tratt has the best quality after vacuum freeze-drying, but excessive pretreatment combined processing should be avoided; compared to vacuum freeze-drying with higher process costs, hot air drying and microwave drying combined with blanching can also achieve better appearance quality of Rosa roxburghii Tratt products. The research results can provide reference for the initial processing and even deep processing of high-value Rosa roxburghii Tratt.