蒸制断生后真空冷冻干燥对天麻质量的影响

Effects of steaming on quality of vacuum freeze dried Gastrodia elata Bl.

目的:提高真空冷冻干燥天麻的天麻素含量。方法:采用蒸制后再真空冷冻干燥的方法对天麻进行干燥,考察天麻的外观及微观结构,测定天麻复水率、多糖和天麻素含量及不同干燥工艺下天麻粉末在模拟胃肠液中的溶出量与溶出率。结果:与鲜天麻直接真空冷冻干燥相比,天麻经蒸制后再真空冷冻干燥其外观和切面微观结构无显著变化。95℃蒸制4 min后再真空冷冻干燥,其天麻素含量和复水率分别为0.875%和502%,显著高于鲜天麻直接冷冻干燥(0.280%和362%)和120℃蒸制4 min后再真空冷冻干燥(0.775%和466%),但3个干燥工艺下天麻的多糖含量无显著差异。热风干燥天麻及真空冷冻干燥天麻粉末的红外指纹图谱谱峰位置相近,峰形相似,说明天麻成分无显著变化。不同工艺干燥天麻的天麻素在模拟胃液和肠液中的溶出率无显著差异。结论:天麻经95℃蒸制4 min后再进行真空冷冻干燥可在保持其外观和微观形态的条件下显著提高天麻素含量和复水率,天麻真空冷冻干燥生产中可对该工艺进行适当修正以推广应用。

OBJECTIVE To improve content of gastrodin of vacuum freeze dried （VFD） Gastrodia elata BI. METHODS VFD was performed for steamed Gastrodia elata Bl. Appearance and microstructure were observed. Rehydration rate, gastrod- in and polysaccharides content were measured. In artificial gastric and intestinal solution, dissolution quantity （mg·g^-1 ） and rate （%） of Gastrodia elata B1. powder were also measured to compare different drying technologies. RESULTS No signifi- cant difference was observed in appearance and microstructure of steamed Gastrodia elata B1 between direct VFD of fresh Gast- rodia elata B1 and steamed Gastrodia elata B1. However, gastrodine content and rehydration ratio were 0. 875% and 502% in 95℃ steamed then VFD treated Gastrodia elata 131, higher than VFD （0. 280% and 362%） and 120℃ steamed then VFD Gast- rodia elata B1 （0. 775% and 466%）. Contents of polysaccharides showed no marked difference of 3 VFD process. FTIR spec- tra showed that the characteristic peaks were closely positioned and a spectrum was analogous between hot air drying treatment and VFD treatment. It showed that components of dried Gastrodia elata B1. Could not be changed by processing in present study. The dissolution quantity （mg·g^-1） and rate （%） in gastric and intestinal solution of Gastrodia elata B1. powder were the same for the processes in this study. CONCLUSION Compared with VFD, content of gastrodin and rehydration ratio can be increased by process of steaming at 95℃ for 4 min, while there is no significant variation in appearance, microstructure and components. This process can be extended and applied with appropriate readjustment.