“金花”菌的鉴定及接种发酵六堡茶的品质变化

Identification of“Golden Flower”Fungi and Quality Changes of Fermented Liupao Tea Inoculated with Them

从六堡茶渥堆茶样中分离得到4株“金花”菌,将其分别命名为LB-22、LB-32、LB-35和LB-55。根据菌落形态特征、光学显微镜结构特征和内源转录间隔区(internal transcribed spacer,ITS)序列比对分析,结合系统发育分析,最终将4株“金花”菌分别鉴定为芒果青霉(Penicillium manginii)、赤曲霉(Aspergillus ruber)、间型曲霉(A.intermedius)和阿姆斯特丹曲霉(A.amstelodami)。以苍梧群体种六堡毛茶为原料,将4株“金花”菌接种至灭菌六堡毛茶进行固态发酵,通过感官审评、生化成分检测结合主成分分析(principal component analysis,PCA),探讨4株“金花”菌对发酵后的六堡茶感官品质和主要理化成分的影响。结果表明,经过“金花”菌发酵,六堡茶滋味由浓强转变为醇厚,香气由毛火气变成陈香、木质香和菌花香,汤色由黄绿明亮变为红浓明亮。PCA和聚类分析显示了4株“金花”菌发酵处理组和对照组(未接种“金花”菌,CK)具有显著差异。与CK相比,LB-22、LB-32、LB-35、LB-55发酵组的总黄酮、总游离氨基酸、茶多酚、茶红素、儿茶素类(表儿茶素、儿茶素没食子酸酯、儿茶素、表没食子儿茶素没食子酸酯、没食子儿茶素没食子酸酯、表儿茶素没食子酸酯)和总儿茶素含量极显著降低(P<0.01),各发酵组的茶褐素含量极显著升高(P<0.01)。本研究为“金花”菌在六堡茶中的应用提供了参考,可为金花六堡茶产业化研究、产品定向开发提供理论依据。

Four“Golden Flower”fungi were isolated from the pile-fermentation process of Liupao tea,and named LB-22,LB-32,LB-35 and LB-55,respectively.Based on colony morphological characteristics,optical microscopic structural characteristics,internal transcribed spacer(ITS)sequence alignment and analysis and phylogenetic analysis,the four strains were identified as Penicillium manginii,Aspergillus ruber,A.intermedius and A.amstelodami.The four“Golden Flower”fungi were separately inoculated into sterilized raw Liupao tea from the Cangwu variety group for solid-state fermentation.The effects of these fungi on the sensory quality and major physicochemical properties of fermented Liupao tea were investigated through sensory evaluation,biochemical component detection and principal component analysis(PCA).The results showed that the taste of Liupao tea changed from heavy and strong to mellow and thick after fermentation by“Golden Flower”fungi,the aroma changed from coarse-fired to stale,woody and arohid,and the color of tea infusion changed from bright yellow-green to bright,intense red.PCA and hierarchical cluster analysis(HCA)showed clear distinction between“Golden Flower”fungi fermented tea and the unfermented control.Compared with the control group,the contents of flavonoids,total free amino acids,tea polyphenols,thearubigin,catechin(EC,CG,C,EGCG,GCG and ECG)and total catechin significantly decreased in the fermented groups(P<0.01),whereas the contents of theabrownins significantly increased(P<0.01).This study provides a reference for the application of“Golden Flower”fungi in Liupao tea,and offers a theoretical basis for research on the industrialization and product development of“Golden Flower”fungi fermented Liupao tea.