Development of a Small Capacity Coconut Charcoal-Fired Peanut Roasting Machine and Performance Evaluation Using a Smartphone-Based Colorimeter Application

This study aimed to design and develop a compact coconut charcoal-fired peanut roasting machine with a 2-kg capacity, investigating the correlation between the roasting chamber temperature and peanut product output through linear regression analysis and correlation. The main components of the designed and developed peanut roasting machine include the frame, heating chamber, roasting chamber, furnace, and driving mechanism. The machine's dimensions are 480 mm x 330 mm x 380 mm, with a furnace capacity of at least 1 kilogram of coconut charcoal. A low-speed motor was employed to drive the roasting chamber. To assess the Maillard browning reaction resulting from the roasting process, a smartphone-based colorimeter application was utilized to measure the CIE L* ideal roasting color. The analysis indicated that as roasting time increased, the roasting chamber temperature also increased at a rate of 1.320, while the CIE L* decreased at a rate of 1.170. Pearson's correlation analysis demonstrated a strong negative correlation between chamber temperature and CIE L*, with an r-value of 94.71% and statistical significance at p = 0.0073. Additionally, when plotting the trends of chamber temperature and CIE L*, the intersection point was observed at 21.8 minutes, indicating that the optimal roasting chamber temperature for the highest rate of temperature increase and CIE L* decrease is 134°C. The developed peanut roaster can roast 2 kg of skinless peanut using 1 kg of coco-shell charcoal and achieve the best roasting color in 22 minutes at 134oC.