Comparative study on infrared radiation and hot air convective drying of coconut: Effect on oil quality features

Appropriately dried coconut kernel, or copra, is imperative for oil production to ensure consistent quality, taste, aroma, and nutritional properties of the resultant coconut oil. This research assesses the effects of different drying techniques—hot air drying (HAD), infrared drying (ID), and infrared-assisted hot air drying (IAHAD)—on the quality profile of coconut oil extracted from copra. Coconut kernels were subjected to radiation and convective hot-air drying methods at varying temperatures (50 °C, 60 °C, and 70 °C). The fresh oil sample extracted from copra using different drying techniques exhibited zero peroxide value, indicating high quality. Among the methods, IAHAD at 60 °C was remarkable for producing the highest-grade copra, resulting in superior quality oil with exceptional preservation of essential nutrients. The physical and biochemical properties of the coconut oil produced using IAHAD at 60 °C included specific gravity, refractive index, moisture content, antioxidant capacity, and total phenolic content, all indicating enhanced oil quality.