Author(s)

Bowen Zhu ¹

Affiliation(s)

¹ HD Beijing School, Beijing, China

Corresponding Author

Bowen Zhu

ABSTRACT

Yunnan, China's primary Arabica coffee-producing region, faces a critical sensory challenge: its dominant Catimor variety, accounting for over 90% of plantings, typically exhibits nutty and caramel notes but lacks sweetness and complex flavor layers [1]. Chemical analyses have identified that Yunnan coffee beans are characterized by insufficient levels of fruity and sweet aroma compounds such as ethyl propionate, while containing higher levels of furans and pyrazines associated with woody or earthy undertones[2]. Sensory studies using descriptive analysis of 25 representative samples further confirm these limitations, noting that Yunnan coffee frequently lacks intricate flavor profiles, with "sweet" attributes ranking low among 57 identified sensory descriptors[3]. Compounding this issue, small-scale processors rely on traditional processing methods due to limited access to advanced fermentation equipment, restricting technical interventions for flavor enhancement[4]. To address these flavor-related quality issues, this study explored a low-cost solution: improving sensory attributes through anaerobic fermentation with commercial microbes. Three anaerobic groups (3 biological replicates each) were designed: spontaneous fermentation (Group A), commercial lactic acid bacteria (LAB, Group B), commercial yeast (Group C); traditional sun-drying (Group D) was the control. High-throughput sequencing, LC-MS metabolomics, and double-blind SCAA sensory evaluations (by 5 CQI Q Graders) were used for analysis. Results showed commercial microbes reshaped microbial communities: on day 15, Group A had Levilactobacillus / Wickerhamomyces, Group B had Lactiplantibacillus / Lentilactobacillus, and Group C had increasing Saccharomyces. LC-MS revealed distinct metabolite profiles (e.g., organic acids, phenolics) in anaerobic groups. Sensory scores: samples fermented without anaerobic conditions scored significantly lower than all anaerobic treatments in flavor, aftertaste and overall aspect respectively, compaired with samples from LAC treatment group . Among the treatment groups, Group B exhibited the best performance in flavor balance, cleanliness, and aftertaste, followed by Group A, while Group C scored slightly lower but remained significantly superior to the sample fermented without anaerobic conditions. Although no significance statistically, decreased total score can be observed in non-anaerobic group when compared with samples from A, B and C group, from 83.05~82.5 in fermented group A, B and C, to 81.65 in average in non-anaerobic group. This method—commercial microbes + simple sealed containers, no sterilization (preserving terroir via native microbiota)—is easy and low-cost, ideal for small-scale processors. It provides a feasible way to improve Yunnan coffee's quality and economic value.

KEYWORDS

Yunnan Arabica Coffee; Anaerobic Fermentation; Commercial Microbes; Sensory Quality; Small-Scale Processors; Microbial Community; Metabolomics

CITE THIS PAPER

Bowen Zhu, Anaerobic Fermentation with Commercial Microbes for Enhanced Sensory Quality of Yunnan Arabica Coffee: A Practical Approach for Small-Scale Processors. Advances in Food Science and Human Nutrition (2025) Vol.7: 65-76. DOI: http://dx.doi.org/10.23977/afshn.2025.070110.

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