DEVELOPING AND EVALUATING A VALUE-ADDING PROCESSING TECHNOLOGY FOR ROBUSTA COFFEE BEANS FOR SMALL-SCALE FARMERS

Abstract

Robusta coffee farmers in the Laplae District of Uttaradit Province are unable to add value to their crops due to a lack of appropriate processing technology. As a result, they are forced to sell their coffee at low prices, which are often kept artificially low by intermediaries. The objectives of this study were to 1) investigate post-harvest handling practices for coffee beans and 2) develop and evaluate the effectiveness of processing technologies suitable for smallholder farmers, including a hulling machine and a coffee roaster. A contextual analysis revealed that 95% of farmers in the area typically sell their crops as raw coffee beans for only 8 to 12 Baht per kilogram. To assess the performance of the hulling machine, the gap between the abrasive stone and rubber units was adjusted to three levels (2, 3, and 4 mm), while maintaining a constant shaft speed of 24 rpm. The results showed that the 2 mm gap produced the highest average percentage of unbroken beans (58.5%). However, this difference was not statistically significant when compared with the 3 mm and 4 mm settings. Roasting experiments demonstrated that roast levels (light, medium, and dark) had a statistically significant effect on the weight of the beans after roasting (P-value < 0.001). Roast level also significantly affected bean moisture content (P-value = 0.009). Light roast beans exhibited the highest average moisture content (8.20%), followed by medium roast (7.88%) and dark roast (7.26%). In conclusion, the developed technologies show strong potential to enable farmers to process their coffee locally, thereby increasing product value, improving income, and promoting the development of a sustainable community-level coffee processing industry.