Physicochemical and Microbiological Characteristics of Robusta Coffee Processed Using Wet Fermentation Method with and Without S. Cerevisiae Starter Culture

Fermentation is utilized in washed coffee to expedite the degradation of mucilage, thereby altering the coffee's quality.The study investigated the fermentation process of de-pulped Robusta coffee beans with and without Saccharomyces cerevisiae.This research purpose was to investigate the effects of fermentation on the physicochemical (moisture, ash, color, total phenolic content, DPPH radical scavenging, and caffeine content) and microbiological (total plate count (TPC), total yeast (TY)) characteristics of de-pulped Robusta coffee produced, using two fermentation conditions (with and without S. cerevisiae starter culture) and varying the duration of fermentation (24, 48, and 72 h).The data was analyzed using ANOVA and Duncan' post hoc test, while the relationship between dependent variables and treatments was quantified using principal component analysis (PCA) and hierarchical clustering analysis (HCA).Results showed that the moisture, pH caffein, and total phenolic content of the coffee fermented with and without S. cerevisiae starter culture were 1.02-1.32%; 4.12 to 4.23; 4.03-9.50ppm; and 350.89-444.08 (GAE mg/100 mL), respectively.The TPC and TY gradually increased with fermentation time, while both parameters were higher in fermentation without S. cerevisiae.The PCA revealed that moisture positively correlated with phenolics and caffeine, while negatively correlated with DPPH.The HCA revealed that coffee fermented with and without S. cerevisiae starter culture varied significantly.