电子鼻技术与感官审评联用评价山东抹茶香气品质

Evaluation on Aroma Quality of Shandong Matcha by Combining Electronic Nose and Sensory Evaluation Technology

山东抹茶具有“海苔香显著、鲜爽味浓”的品质特征,产品已出口到欧盟、日本等国际市场。为了更好地做好山东抹茶的生产与品质评价,本研究采用扫描电镜对茶道级、一级、二级山东抹茶的粉体形貌进行表征,感官审评3个级别的抹茶及其原料碾茶,并采用电子鼻技术对其香气成分组成进行重点检测与分析。结果表明,山东抹茶颗粒大小均匀,粒度均在10μm以内。以电子鼻检测结果为基础,通过PCA分析和LDA分析可以对不同等级的山东抹茶和碾茶进行较好的区分;通过雷达图能够直观反映抹茶和碾茶的香气特征,即山东抹茶的氮氧化合物、硫化物、萜烯类化合物含量较高,其原料碾茶的氮氧化合物和甲基类化合物含量较高,碾茶加工成抹茶后的香气特征变化不大,说明好的碾茶原料是制成高品质抹茶的重要前提。根据Loadings分析可知,氮氧化合物、硫化物、萜烯类、甲基类化合物可用于区分不同等级碾茶,甲基类、醇类、醛酮类、萜烯类化合物及硫化物、氮氧化合物可用于区分不同等级抹茶。综之,电子鼻技术与感官审评联用可全面准确地评价山东抹茶的香气品质特征,可应用于山东抹茶香气的快速评价。

Shandong matcha has the quality characteristics of“unique aroma of like-seaweed,fresh and strong taste”,and the products have been exported to the European Union,Japan and other international markets.In order to better evaluate the production and quality of Shandong matcha,the scanning electron microscopy was used to characterize the powder morphology of tea ceremony grade,first-grade and second-grade Shandong matcha in this study.The three different grades of Shandong matcha and its raw material tencha were evaluated by sensory evaluation,and their aroma components were detected and analyzed by electronic nose technology.The results showed that the particle size of Shandong matcha was uniform and less than 10μm.Based on the electronic nose detection results,different grades of Shandong matcha and tencha could be distinguished by PCA and LDA analyses.The radar image could directly reflect the aroma characteristics of tencha and matcha.The content of nitrogen oxides,sulfides and terpenes in Shandong matcha were higher,and the nitrogen oxides and methyl components of its raw material tencha were higher,too.The aroma characteristics changed little after tencha was processed into matcha,indicating that good tencha was important prerequisite for making high-quality matcha.According to Loadings analysis,nitrogen oxides,sulfides,terpenes and methyl compounds could be used to distinguish different grades of tencha and methyl groups,alcohols,aldehydes and ketones,terpenes,sulfides and nitrogen oxides could be used to distinguish different grades of matcha.All in all,the combination of electronic nose technology and sensory evaluation could be used to evaluate the aroma quality of Shandong matcha comprehensively and accurately,so it could be used to evaluate the aroma of Shandong matcha rapidly.