Chiang Mai Journal of Science

     Coffee, a globally popular beverage, undergoes various processing methods such as natural (also known as dry process), washed (also known as wet processed), and honey (also known as pulped natural), impacting bean composition and beverage quality. Microorganisms, especially yeasts, play a crucial role in these processes. We investigated three yeasts’ effects on chemical profiles and antioxidant activity during coffee bean aging. Our findings indicate significant influences of processing method and yeast choice on antioxidant potential and physicochemical properties. Dry-processed beans demonstrated a heightened DPPH scavenging capacity, surpassing other processing methods by approximately 69.21%, while Saccharomycopsis fibuligera fermentation exhibited superior antioxidant activity, outperforming other yeasts by 69.42%. However, no significant impact on SOD-like activity was observed. Coffee bean aging, not yeast or processing method, affected total phenolic content, while total flavonoid content showed temporal variations. Quality and sensory evaluations suggest the potential for specialty-grade coffee. Coffee beans fermented by S. fibuligera using dry methods scored 83.31, while those fermented by Pichia kluyveri with wet methods scored 82.31 in SCAA evaluations. Our study emphasizes the role of specific yeasts in controlled fermentation for enhanced coffee sensory qualities.