不同干燥方式对茶树花品质的影响

Effect of different drying methods on quality of tea plant flowers

茶树花与茶鲜叶的生化成分大体一致,富含茶多酚、茶多糖、游离氨基酸、超氧歧化酶(SOD)和咖啡碱等生物活性成分,具有极高的开发利用价值。研究探讨真空冷冻干燥、恒温烘箱烘干和微波干燥等干燥方法对茶树花干花品质的影响,结果表明:(1)真空冷冻干燥的茶树花干花更好保存了茶树花的外形、香气和色泽;烘干茶树花外形相对自然,色泽加深,甜香较高;微波干燥的茶树花干花外形皱缩、色泽偏暗,甜香高长,带火功香。(2)真空冷冻干燥的茶树花干花水浸出物含量、可溶性糖、茶多糖、茶多酚、茶皂素和游离氨基酸含量最高;微波干燥茶树花干花的水浸出物含量、茶多糖、茶多酚高于烘干茶树花,可溶性糖含量低于烘干茶树花干花;3种加工方式的茶树花干花的咖啡碱与总黄酮含量无显著性差异。

The biochemical components of tea plant flowers are in general accord with tea leaves. Tea plant flowers are rich in biological active components, such as tea polyphenols, tea polysaccharides, free amino acid, superoxide dismutase（SOD） and caffeine, which have high value for development and utilization. Study on effects of drying methods, including vacuum freeze drying, oven drying and microwave drying, on quality of tea plant flowers. Results show that：（1） Tea plant flower by vacuum freeze drying can keep its nature color, aroma, taste and shape; tea plant flowers by oven drying have a relative natural appearance, color and lustre are deeper than tea plant flower by vacuum freeze drying, and sweet smell is high; tea plant flower by microwave drying has shrivelled shape, dark color and sweet with caramelized smell.（2） Tea plant flower by vacuum freeze drying have the highest content of water extraction, soluble sugar, tea polysaccharide, tea polyphenols, tea saponin and free amino acid content; the water extract, tea polysaccharide and tea polyphenols content by microwave drying is higher than the oven drying ones, but the soluble sugar content was lower; there were no significant difference on caffeine and total flavonoids content.