Drying Hot Red Chilies: A Comparative Study of Solar-Gas-Fired, Tunnel, and Conventional Dryers

Drying extends the shelf life of crops; thus, dryers with good designs will help them dry to an optimum level. The present research work was carried out to assess and compare the performance of conventional (CD), solar tunnel (STD), and solar-cum gas-fired dryers (SGD) for drying hot chilies. The Sanam variety of hot chilies was used in this study. Samples were dried using CD, STD, and SGD methods. The drying process was conducted over three days, from 9:00 to 17:00 daily. Results showed significant differences among the drying methods in temperature, relative humidity, and moisture content reduction (p < 0.0001). The SGD consistently outperformed the other methods, achieving the highest temperature (55 °C) and lowest relative humidity (17%), compared to the STD (44 °C, 23%) and CD (34 °C, 31%). The SGD demonstrated superior efficiency, reducing moisture content from 70% to 9.36% in just 36 h, while the STD required 50 h (to 11.37%) and CD took 84 h (to 9.63%). ANOVA and post hoc analyses revealed that the SGD significantly outperformed both the STD (p = 0.0412) and CD (p = 0.0018) in moisture content reduction. Additionally, the SGD and STD better preserved the color of hot chili samples compared to CD, as determined by the Essential Oil Association (EOA) method. It is concluded that the SGD is the most technically suitable method for drying hot chilies, offering improved efficiency and quality retention. It is recommended to use an SGD for optimal results in hot pepper drying.