COLORIMETRIC ANALYSIS OF BOURBON ARABICA COFFEE BEANS

The color of coffee beans is a determining factor in the quality of the product, influencing its acceptance in the market. Specialty coffee is characterized by a bluish-green hue, while fermented coffee may exhibit a lighter coloration acquired over storage time, which can compromise its commercial value. The Cerrado Mineiro region is an internationally recognized hub for excellence in the production of specialty coffees, reinforcing the importance of research that evaluates factors contributing to its market appreciation. This study analyzed the color variation in Coffea arabica Bourbon variety coffee beans subjected to different processing methods and fermentation times after one year of storage. Samples of Natural Coffee and Pulped Coffee (PC) were evaluated, fermented in dry and submerged conditions, with collections at 24, 48, 72, and 96 hours, in addition to the control sample. Color was analyzed using a Delta Vista colorimeter with Delta Color's i7 Software, determining the parameters L* (lightness), a* (variation on the green-red axis), and b* (variation on the yellow-blue axis). Based on these measurements, ΔE was calculated, representing the color change of fermented beans compared to the control sample (without induced fermentation). The data were statistically analyzed using Minitab18 software through one-way ANOVA and Tukey’s test. The results showed that fermentation significantly affected the coloration of the beans, with statistical differences observed in Natural Coffee. In dry fermentation, 96 hours presented a significantly greater color change than 48 hours, indicating a substantial increase in chromatic variation within that period. In submerged fermentation, 96 hours was statistically different from 24 hours, demonstrating that the beans' coloration intensified over immersion time. As for Pulped Coffee, the beans’ coloration did not present statistically significant differences between times, either in dry or submerged fermentation, as all samples remained within the same grouping in Tukey’s test. Natural Coffee showed greater sensitivity to chromatic changes than Pulped Coffee, suggesting that the peel and mucilage enhance color variation. These data reinforce that fermentation methods influence the appearance of beans, a decisive factor in the market acceptance of specialty fermented coffee.