From soil health to tea flavour: Organic fertilisation enhances microbial communities and aroma compounds

Tea processing plays an important role in the formation of tea aroma. In order to explore the composition and variation in aroma during Rizhao green tea processing, gas chromatography-ion mobility spectrometry was employed to investigate the formation and changes of tea aroma in four processing stages. A total of 62 volatile compounds were identified, including alcohols, aldehydes, ketones, esters, terpenes, and oxygen compounds. Relative odor activity value was used to identify 17 characteristic aroma compounds. The main aromatic compounds of chestnut-like aroma were linalool, pentanal, hexanal, heptanal, octanal, nonanal, 2-methylbutanal, 3-methylbutanal, 3-methylthiopropanal, and methyl 2-methylbutanoate. There were significant changes in the volatile components at different processing stages. Samples of tea leaves and green tea had special aroma characteristics, while samples of fixated and rolled leaves had similar aroma compounds. The results are beneficial for the improvement of the flavor and quality of Rizhao green tea. Practical Application. Tea is the world’s most consumed nonalcoholic beverage, with a multitude of health-promoting benefits, such as antioxidant, antiobesity, and antiallergic activities. At present, the research on the aroma compounds of Rizhao green tea mainly focuses on the aroma characteristics of finished tea and the aroma differences of different kinds of commercial tea. This study explored the effects of the processes on aroma compounds, and the results provide a theoretical reference for the improvement of tea processing technology, tea quality control, and evaluation methods.

Bio-augmented Daqu is used to improve the microbial community and physicochemical parameters of fermented grains, thus affecting the flavor and quality of baijiu. This study investigated the effects of bio-augmented Daqu inoculated with Aspergillus niger NCUF413.1 and Saccharomyces cerevisiae NCUF304.1 on the microbial community, aroma compounds, and physicochemical parameters of fermented grains during special-flavor baijiu brewing. Compared with the control group (CG), the utilization of starch and production of ethanol in the inoculated group (IG) increased by 3.55% and 12.59%, respectively. The use of bio-augmented Daqu changed the bacterial communities. For example, Kroppenstedsia was the dominant bacterial genus (the relative abundance was about 22%) in the CG while Lactobacillus was the main dominant genus (the relative abundance was more than 30%) in the IG on days 20-30. Lactobacillus showed a significant positive correlation with the aroma compounds. The use of bio-augmented Daqu increased the aroma compound content - such as the ethyl heptanoate and ethyl hexanoate content. The addition of bio-augmented Daqu with A. niger and S. cerevisiae could change microbial communities, resulting in an increase in the yield of ethanol and the aroma compound content of fermented grains, thus improving the quality of baijiu. © 2022 Society of Chemical Industry.

Tilia has a long history of cultivation and holdshigh ornamental and economic value. The volatile aroma compounds of Tilia flowers have significant characteristics that contribute to their ornamental appeal, and affect the flavor of floral tea. Here, widely targeted metabolomic analyses were conducted to investigate the aroma active compounds in the fresh inflorescences of Tilia cordata Mill. (Tc) and Tilia miqueliana Maxim. (Tm), and in samples prepared by freeze drying, air drying, and oven drying. We identified 442 volatile organic compounds by headspace solid-phase microextraction gas chromatography-mass spectrometry. Terpenoids were the most abundant and diverse group, while heterocyclic compounds were the main contributors to the aroma profile. Notably, 46 aroma compounds were identified as primary contributors to the characteristic aroma of Tilia, including abhexon, 2-isobutyl-3-methoxypyrazine, (Z)-6-nonenal, methyl benzoate, (E)-2-hexenal, 1-hexanol, 2-thiophenemethanethiol, p-cymene, furaneol, and (Z)-4-heptenal. The concentration of volatile organic compounds was higher in Tc than in Tm, indicating a more pronounced aroma character of Tc. For both Tc and Tm, the aroma compounds were better preserved and present at higher concentrations in freeze-dried samples than in air-dried and oven-dried samples. These results provide a foundation for further research on the molecular mechanisms of aroma formation in Tilia flowers and on aroma as a cue for insect pollination. Furthermore, the results provide a basis for the development and commercialization of Tilia floral teas and other related products. © 2025 Society of Chemical Industry.

Synergistic effects of pre-harvest drought and shade on flavor and aroma enhancement in fermented tea: Insights into JA/ABA signaling and metabolic regulation.

Understanding of formation and change of chiral aroma compounds from tea leaf to tea cup provides essential information for tea quality improvement

Multi-omics analysis of the dynamic changes in aroma compounds and microbial communities during the fermentation of Shanxi broomcorn millet Huangjiu.

Comparative evaluation of the effects of natural and artificial inoculation on soybean paste fermentation

Development of analytical “aroma wheels” for Oolong tea infusions (Shuixian and Rougui) and prediction of dynamic aroma release and colour changes during “Chinese tea ceremony” with machine learning

Chapter 33 - Effect of Soil Nutrition on Aroma Compound Formation in Organically Grown Apples (cv. Golden Delicious)

Effect of main taste compounds on the release of methoxyphenolic compounds in Pu-erh tea

This paper presents data related to an article entitled “Green tea flavor determinants and their changes over manufacturing processes” (Han et al., 2016) [1]. Green tea samples were prepared with steaming and pan firing treatments from the tender leaves of tea cultivars ‘Bai-Sang Cha’ (‘BAS’) and ‘Fuding-Dabai Cha’ (‘FUD’). Aroma compounds from the tea infusions were detected and quantified using HS-SPME coupled with GC/MS. Sensory evaluation was also made for characteristic tea flavor. The data shows the abundances of the detected aroma compounds, their threshold values and odor characteristics in the two differently processed tea samples as well as two different cultivars.

Selenium-enriched lactic acid bacteria inoculation enhances the quality of Paocai by imparting the microbiome and metabolome.

ABSTRACTTraditionally fermented Pixian broad bean paste (PBP) is a traditional condiment in China and is recognized to have superior quality than the industrially fermented. This work aimed to identify the dominant microbes and unique aroma compounds in traditionally fermented PBP with respect to those in the industrially fermented one. Results showed that several species of lactic acid bacteria, yeasts, Aspergillus, molds, and Staphylococcus were only detected in traditionally fermented PBP, namely, Leuconostoc lactis, Staphylococcus xylosus, S. succinus, Amylomyces rouxii, Mucor genevensis, Absidia corymbifera, Issatchenkia orientalis, basidiomycete yeast sp., and Metschnikowia pulcherrima. Furthermore, the traditionally fermented PBP contained more compounds that contribute to its aroma than those in industrially fermented PBP. A total of 28 aroma substances only were detected in the traditionally fermented PBP. Among these substances, seven were considered aroma-active compounds, namely, ethyl caprylate, hexadecanoic acid methyl ester, 2-methyl-pyrazine, 2,6-dimethyl- pyrazine, 2-pentyl furan, 2-acetyl furan, and hexadecanoic acid. This work provides useful information on the microbial composition and aroma compounds of PBP that can be used to upgrade the quality of industrially fermented PBP.

Commercial Saccharomyces cerevisiae plays an important role in the traditional winemaking industry. In this study, the correlation of microbial community and aroma compound in the process of alcohol fermentation of Cabernet Sauvignon by four different commercial starters was investigated. The results showed that there was no significant difference in the fermentation parameters of the four starters, but there were differences in microbial diversity among the different starters. The wine samples fermented by CEC01 had higher microbial abundance. GC-MS detected a total of 58 aromatic compounds from the fermentation process by the experimental yeasts. There were 25 compounds in the F6d variant, which was higher than in other samples. The PCA score plot showed that 796 and F15 yeast-fermented wines had similar aromatic characteristic compositions. According to partial least squares (PLS, VIP > 1.0) analysis and Spearman’s correlation analysis, 11, 8, 8 and 10 microbial genera were identified as core microorganisms in the fermentation of 796, CEC01, CECA and F15 starter, respectively. Among them, Leuconostoc, Lactobacillus, Sphingomonas and Pseudomonas played an important role in the formation of aroma compounds such as Ethyl caprylate, Ethyl caprate and Ethyl-9-decenoate. These results can help us to have a better understanding of the effects of microorganisms on wine aroma and provide a theoretical basis for improving the flavor quality of Cabernet Sauvignon wine.

The aroma profile and microbiota structure in oil furu, a Chinese fermented soybean curd