Shelf-Life Estimation of Robusta Ground Coffee Roasted with Different Machines Using the Accelerated Shelf-Life Testing (ASLT) Method

Abstract This study aimed to evaluate the shelf life of Robusta ground coffee roasted using three different types of roasting machines: Drum Roaster, Hot Air Roaster, and Hot Air Roaster with a spiral movement system. The Accelerated Shelf Life Testing (ASLT) method combined with the Arrhenius model was employed to estimate the degradation rate of quality based on the increase in free fatty acid (FFA) content. Ground coffee samples were stored at 25°C, 35°C, and 45°C, and shelf life was calculated under the assumption of zero-order kinetics. The results demonstrated significant variation in shelf life across roasting methods. Coffee roasted with the spiral-equipped hot air roaster exhibited the longest shelf life up to 155.72 weeks at 25°C, followed by the standard hot air roaster (134.97 weeks) and drum roaster (103.78 weeks). The combination of convective and conductive heat transfer in the spiral system contributed to improved thermal stability, reduced moisture content, and slower lipid degradation. These findings suggest that the choice of roasting technology has a direct impact on product stability and shelf life.