乳酸菌发酵对红茶饮料营养成分、香气成分及抗氧化活性的影响

以植物乳杆菌菌剂发酵红茶饮料为研究对象,分别采用酒石酸铁比色法、茚三酮比色法和标准碱滴定法测定红茶发酵前后的茶多酚、茶氨酸、咖啡碱及乳酸含量;采用4种不同体外抗氧化模型来考察红茶饮料发酵前后的抗氧化活性;并采用顶空固相微萃取结合气相色谱-质谱联用技术分析红茶发酵前后主要香气成分。结果表明,发酵后红茶饮料茶多酚和咖啡碱含量比发酵前稍有下降,茶氨酸含量较发酵前显著上升(P0.05);对部分自由基的清除能力较发酵前略有下降;醇类和酮类等香气成分在发酵后较发酵前有明显增加,有利于提升红茶的香气品质。

Effects of Lactic Acid Bacterial Fermentation on Nutritional Components,Aroma Components and Antioxidant Activity of Black Tea Beverage

This study determined the contents of tea polyphenols, theanine, caffeine and lactic acid in non-fermented and Lactobacillus plantarum fermented black tea beverage by ferrous tartrate colorimetry, nihydrin colorimetry and alkaline titration. Four in vitro antioxidant models were used to study the antioxidant activity. Also, the major aroma components were analyzed by headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). It was shown that after fermentation, the contents of tea polyphenols and caffeine in black tea beverage decreased slightly but theanine and lactic acid increased significantly (P < 0.05). Moreover, the scavenging capacity against some free radicals declined slightly. The GC-MS analysis showed that the contents of some volatile flavor components such as alcohols and ketone significantly increased after fermentation, contributing to enhancing the aroma quality of black tea.