连翘叶速溶茶制备及多种功能成分分析

Preparation of Instant Tea from Forsythia suspensa Leaves and Analysis of Its Various Functional Components

【目的】研究连翘叶速溶茶的制备工艺及功能成分,为连翘资源高附加值利用提供了理论依据和新的方法。【方法】以连翘叶速溶茶得率为指标,对连翘叶水提工艺进行优化;分别以阴干、炒制杀青、杀青发酵的连翘叶为原料,制备连翘叶速溶茶粉FSL-D、FSL-G、FSL-B,并分析其理化性质和功能成分。【结果】1)连翘叶速溶茶的最佳提取工艺为料液比1∶20.14 g·mL^(-1)、提取时间180 min、提取温度90℃,连翘叶速溶茶的平均得率为15.30%。2)FSL-D、FSL-G和FSL-B溶解时间分别为50.04、55.19和46.46 s,均达到了行业标准;FSL-B味道更好且不易结块。功能成分分析表明,3种速溶茶蛋白质含量均在11%以上,总酚含量为3.22%,总黄酮含量为4.44%,总糖含量为47.76%;其中FSLG中连翘脂苷A含量较高,为19.96%。3)连翘叶多糖的抗氧化试验结果表明,多糖分子量越大,抗氧化效果越好;红外光谱结果表明,抗氧化活性与O-H伸缩振动峰、C=O键的伸缩振动峰及-C-H弯曲振动峰活性减弱相关。【结论】以杀青发酵的连翘叶为原料,制备的连翘叶速溶茶(FSL-B)品质较好。

【Objective】This study aims to investigate the preparation technique and analyze the functional components of instant tea from Forsythia suspensa leaves,in order to provide a new idea and scientific basis for high value-added utilization of forsythia resources.【Method】The water extraction process of F.suspensa leaves was optimized with the yield of the instant tea as an indicator.Three kinds of instant tea powder,FSL-D,FSL-G and FSL-B,were prepared from dried,fried,and fermented leaves of F.suspensa,respectively.The physical and chemical properties and functional components were tested to further identify the optimal raw materials for preparing the instant tea.【Results】1)The optimal extraction process for instant tea from F.suspensa leaves was solid-liquid ratio of 1∶20.14 g·mL^(−1),extraction temperature of 90℃and extraction time of 180 min,under which the average yield of instant tea from F.suspensa leaves was 15.30%.2)The dissolving time of FSL-D,FSL-G and FSL-B was 50.04,55.19 and 46.46 s,respectively,which all meet the industry standard.The hygroscopic property test and sensory evaluation indicated that FSL-B was less prone to agglomerate during storage and had a better taste.Active components analysis indicated that the protein content,the total phenolic content,the total flavonoids content and the total polysaccharides content of the three kinds of instant tea were all above 11%,3.22%,4.44%,and 47.76%,respectively.The content of forsythia glycoside A in FSL-G was relatively high,at 19.96%.3)The antioxidant experiment of polysaccharides from F.suspensa leaves showed that the larger the molecular weight of the polysaccharides,the better the antioxidant effect.The infrared spectrum test showed that the antioxidant activity was related to the weakening of O-H stretching vibration peak,C=O bond stretching vibration peak,and C-H bending vibration peak activity.【Conclusion】The high quality instant tea(FSL-B)can be obtained from the fermented F.suspensa leaves.This research not only provides theoretical basis for the study of forsythia leaf products,but also improves the economic value of forsythia,which is of great significance to promote the development of forsythia economic forest.