College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China; Key Laboratory of Ministry of Education for Tea Science, College of Horticulture, Hunan Agricultural University, Changsha 410128, China.
College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China.
Food Res Int. 2024 Dec;197(Pt 1):115219. doi: 10.1016/j.foodres.2024.115219. Epub 2024 Oct 22.
Eurotium cristatum is the primary fungus in Fu brick tea (FBT) and plays a crucial role in its special flavor. This study investigated the effect of inoculation with different E. cristatum strains (i.e., ZJ, GX, GZ, HN, and SX) on the microbial communities and volatile organic compounds (VOCs) of FBT. A total of 113 VOCs were identified in all samples, with the concentration of VOCs (alcohols, aldehydes, and ketones) significantly higher in GXE FBT than in other samples. The core VOCs of GXE (19), GZE (16), HNE (19), SXE (15), and ZJE (13) FBT were identified using orthogonal partial least squares discriminant analysis and relative odor activity value (ROAV) analysis. Methional (a27), butanal (a41), 1-octen-3-one (a69), and ethyl acetate (a77) were key markers for inoculated FBTs, and 1-octen-3-ol, dimethyl disulfide, and acetoin-M were the specific markers of HNE. Linalool and (E)-2-octenal were particularly prominent in GXE, and isoamyl acetate-D was an important aroma component of GZE. Differences in microbial diversity were observed among the different inoculated fermented FBTs, and E. cristatum inoculation remarkably influenced the richness and diversity of bacterial communities. The VOCs were closely associated with fungi and bacteria, and 19 potentially dominant microorganisms (10 fungal and 9 bacterial genera) correlated with VOCs were identified. Among them, Aspergillus (fungi) and Pseudomonas (bacteria) exerted the greatest role. The FBT inoculated with E. cristatum from ZJ had the highest content of theaflavins and theabrownins, which intensified the red and yellow colors of the tea. E. cristatum greatly decreased the free amino acids and fatty acids, contributing to the aroma formation of FBT. Therefore, inoculating FBT with E. cristatum remarkably influenced the microbial communities and improved its flavor profile. This work provides a theoretical foundation on the role of E. cristatum in the formation and regulation of FBT flavor.
冠突散囊菌是茯砖茶（FBT）中的主要真菌，对其特殊风味起着至关重要的作用。本研究调查了接种不同冠突散囊菌菌株（ZJ、GX、GZ、HN 和 SX）对 FBT 微生物群落和挥发性有机化合物（VOCs）的影响。在所有样品中共鉴定出 113 种 VOCs，其中 GXE FBT 中 VOCs（醇、醛和酮）的浓度明显高于其他样品。通过正交偏最小二乘判别分析和相对气味活度值（ROAV）分析，确定了 GXE（19）、GZE（16）、HNE（19）、SXE（15）和 ZJE（13）FBT 的核心 VOCs。甲硫醛（a27）、丁醛（a41）、1-辛烯-3-酮（a69）和乙酸乙酯（a77）是接种 FBT 的关键标记物，1-辛烯-3-醇、二甲基二硫和乙酰基-M 是 HNE 的特有标记物。芳樟醇和（E）-2-辛烯醛在 GXE 中尤为突出，乙酸异戊酯-D 是 GZE 的重要香气成分。不同接种发酵 FBT 之间的微生物多样性存在差异，冠突散囊菌接种显著影响了细菌群落的丰富度和多样性。VOCs 与真菌和细菌密切相关，鉴定出 19 种与 VOCs 相关的潜在优势微生物（10 种真菌属和 9 种细菌属）。其中，曲霉菌（真菌）和假单胞菌（细菌）的作用最大。用 ZJ 冠突散囊菌接种的 FBT 茶黄素和茶褐素含量最高，使茶叶的红色和黄色加深。冠突散囊菌大大降低了游离氨基酸和脂肪酸的含量，有助于 FBT 的香气形成。因此，用冠突散囊菌接种 FBT 显著影响了微生物群落，改善了其风味特征。这项工作为冠突散囊菌在茯砖茶风味形成和调控中的作用提供了理论基础。
