Effect of bean maturity and roasting temperature on chemical content of robusta coffee

Abstract

This study aims to determine the effect of roasting temperature on chemical content of coffee beans at various fruit maturity. Robusta coffee was obtained from Karawang Regency, West Java. After picking, sortation, and drying in the sun to 10% moisture content, the coffee beans were roasted at 190°C, 200°C, 210°C for 12 minutes. Physical properties observed were weight loss during the roasting. The chemical content observed were water, caffeine, fat, chlorogenic acid and ash before and after roasting. Chemical content analysis was performed using gravimetric methods, soxhlet extraction, and UV-Vis spectrophotometry. The color, aroma and flavor of roasted bean were conducted by organoleptic test. The results obtained, the ripe coffee bean with roasting temperature of 210°C is the best, which gives the lowest yield. The unripe green beans have the highest water content. The roasting temperature did not provide a significant difference in fat, caffeine, chlorogenic acid, and ash content. Organoleptic test results (color and aroma) showed that the mature beans with roasting temperature of 200-210°C were the most preferred, while the coffee brew most preferred was overripe bean with the roasting temperature of 200°C.