微波真空干燥对铁皮石斛品质特性影响的研究  

Effect of Microwave Vacuum Drying on Quality Characteristics of Dendrobium officinale

作　　者：林鸿 王为为[1] 郑宝东[1] 郭泽镔[1] LIN Hong;WANG Weiwei;ZHENG Baodong;GUO Zebin(College of Food Science,Fujian Agriculture and Forestry University,Fuzhou,Fujian 350002,China)

机构地区：[1]福建农林大学食品科学学院,福建福州350002

出　　处：《热带作物学报》2020年第7期1459-1468,共10页Chinese Journal of Tropical Crops

基　　金：福建农林大学科技创新专项基金项目(No.CXZX2018062)。

摘　　要：本研究以新鲜铁皮石斛为原料,采用微波真空干燥方法干燥,通过测定铁皮石斛的多糖含量、色泽、多酚氧化酶(PPO)、水分分布状态、组成氨基酸以及多酚的DPPH•和•OH清除率,研究微波真空干燥对铁皮石斛品质特性的影响。结果表明:相比于新鲜样品,当微波强度为9 W/g,干燥后样品的多糖含量最高可达52.21%;氨基酸分析仪分析结果表明,微波真空干燥后铁皮石斛的总游离氨基酸和风味氨基酸含量显著提高。在微波强度9、12、15 W/g下,微波真空干燥的铁皮石斛的PPO活性分别在干燥16、12、6 min后不再存在,表明微波真空干燥能够在较短时间内钝化铁皮石斛的PPO活性,且微波强度越大时间越短。干燥过程的非酶促褐变主要由Maillard反应引起。低场核磁共振结果表明,自由水驰豫时间T23和A23均显著降低。自由基清除能力研究结果表明,铁皮石斛多酚仍具有较强的羟基自由基清除能力。通过观察干燥后样品的微观结构发现,随着微波功率密度的增大,样品孔状结构受到更严重破坏,微波强度越大,铁皮石斛的复水特性越好。The microwave vacuum drying method was used to dry Dendrobium officinale.The effects of microwave vacuum drying on the quality characteristics of D.officinale were studied by measuring the content of polysaccharides,color,polyphenol oxidase(PPO),water distribution,Composition of amino acids and DPPH•and•OH scavenging rates of polyphenols.When the microwave intensity was 9 W/g compared with the fresh sample,the dried sample had the highest polysaccharide content of 52.21%.The content of total free amino acids and flavor amino acids of D.officinale was significantly increased after microwave vacuum drying.PPO activity of D.officinale after microwave vacuum drying at microwave intensity of 9 W/g,12 W/g and 15 W/g was no longer present at the 16th,12th and 6th minutes respectively,indicating that microwave vacuum drying could inactivate PPO activity of D.officinale in a relatively short time,and higher microwave intensity would lead to shorter time.Non-enzymatic browning in drying process was caused by Maillard reaction.The free water relaxation time T23 and A23 decreased significantly.The free radical scavenging ability of D.officinale showed that the hydroxyl radical scavenging ability was still strong.By observing the microstructure of the sample after drying,the pore structure of the sample was seriously damaged with the increase of microwave power density.The rehydration characteristics of D.officinalis showed that higher microwave intensity resulted in better rehydration characteristics.

关 键 词：铁皮石斛 微波真空干燥 氨基酸 多糖 品质特性 

分 类 号：S567[农业科学—中草药栽培]