Department of Flavor Chemistry, Institute of Food Science and Biotechnology, University of Hohenheim, Fruwirthstraße 12, 70599 Stuttgart, Germany.
Institute of Food Science and Technology, College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China.
Molecules. 2022 Apr 13;27(8):2503. doi: 10.3390/molecules27082503.
Submerged fermentation of green tea with the basidiomycete resulted in a pleasant chocolate-like and malty aroma, which could be a promising chocolate flavor alternative to current synthetic aroma mixtures in demand of consumer preferences towards healthy natural and 'clean label' ingredients. To understand the sensorial molecular base on the chocolate-like aroma formation, key aroma compounds of the fermented green tea were elucidated using a direct immersion stir bar sorptive extraction combined with gas chromatography-mass spectrometry-olfactometry (DI-SBSE-GC-MS-O) followed by semi-quantification with internal standard. Fifteen key aroma compounds were determined, the most important of which were dihydroactinidiolide (odor activity value OAV 345), isovaleraldehyde (OAV 79), and coumarin (OAV 24), which were also confirmed by a recombination study. Furthermore, effects of the fermentation parameters (medium volume, light protection, agitation rate, pH, temperature, and aeration) on the aroma profile were investigated in a lab-scale bioreactor at batch fermentation. Variation of the fermentation parameters resulted in similar sensory perception of the broth, where up-scaling in volume evoked longer growth cycles and aeration significantly boosted the concentrations yet added a green note to the overall flavor impression. All findings prove the robustness of the established fermentation process with for natural chocolate-like flavor production.
在担子菌的作用下对绿茶进行深层发酵，产生了一种令人愉悦的巧克力般的麦芽香气，这可能是一种有前途的巧克力风味替代品，可以替代当前需求消费者对健康天然和“清洁标签”成分的合成香气混合物。为了了解这种巧克力香气形成的感官分子基础，使用直接浸入式搅拌棒吸附萃取结合气相色谱-质谱-嗅觉（DI-SBSE-GC-MS-O）法对发酵绿茶中的关键香气化合物进行了阐明，并通过内标进行半定量。确定了十五种关键香气化合物，其中最重要的是二氢猕猴桃内酯（气味活度值 OAV 345）、异戊醛（OAV 79）和香豆素（OAV 24），这也通过重组研究得到了证实。此外，还在分批发酵的实验室规模生物反应器中研究了发酵参数（培养基体积、避光、搅拌速度、pH 值、温度和通气）对香气特征的影响。发酵参数的变化导致了培养液相似的感官感知，其中体积的放大导致了更长的生长周期，而通气显著提高了浓度，但却给整体风味印象增添了一丝绿色调。所有发现都证明了所建立的发酵工艺的稳健性，可用于生产天然的巧克力风味。
