云南大叶种晒青毛茶提取物对产毒黄曲霉生长及产毒的影响

Effect of Yunnan Large-Leaf Camellia Sinensis Extract on Growth and Aflatoxin Production of Aspergillus flavus

摘要:

普洱茶在发酵过程中，微生物组成十分复杂，尤其是黑曲霉等霉菌起到主要作用，因此一些消费者担心普洱茶在发酵过程中受到黄曲霉毒素（AFS）的污染。本文通过测定菌落直径、孢子萌发及菌丝体干重等方法研究云南大叶种茶提取物对产毒黄曲霉AS3.4408生长的影响；采用紫外荧光法和HPLC法研究云南大叶种茶提取物对产毒黄曲霉AFS生物合成的影响；并将产毒黄曲霉AS3.4408接种到云南大叶种茶叶中，检测茶叶中的AFS含量，以求对普洱茶的安全性进行评估。研究表明，云南大叶种茶提取物对产毒黄曲霉AS3.4408菌落的生长及产毒均具有显著的抑制作用，且存在明显的剂量依赖关系；将产毒黄曲霉AS3.4408接种到云南大叶种茶叶中，菌株生长良好，但茶叶基质经HPLC检测，未检测到黄曲霉毒素B1、B2、G1和G2，表明云南大叶种茶中的某种（些）成分对黄曲霉毒素的生物合成具有抑制作用。

Abstract:

Various microbes are involved in the fermentation of pu-erh tea. , among themAspergillus niger plays a crucial role in this process. Therefore, some consumers worry about the contamination of pu-erh tea with aflatoxins (AFs). In this study, the effect of Yunnan large-leaf Camellia sinensis extract on the growth of A. flavus AS3.4408 was studied by measuring the colony diameter, spore germination, and mycelial dry weight. The effect of Yunnan large-leaf Camellia sinensis extract on the biosynthesis of AFs was studied using ultraviolet fluorescence analysis and HPLC. Tea containing Yunnan large-leaf Camellia sinensis extract was inoculated with A. flavus AS3.4408 and the AF content in the tea was measured in order to evaluate the safety of pu-erh tea. The results showed that the growth and AF production of A. flavus AS3.4408 were significantly inhibited by the Yunnan large-leaf Camellia sinensis extract in a dose-dependent manner. After A. flavus AS3.4408 was inoculated into the tea containing the Yunnan large-leaf Camellia sinensis extract, the strain grew well. However, the AF B1, B2, G1 and G2 were not detected by HPLC, indicating that AF biosynthesis was inhibited by some components of Yunnan large-leaf Camellia sinensis.