Understanding infrared drying behavior of shea (Vitellaria paradoxa) fruit by-product for the production of value-added products

In this study, the effect of different infrared (IR) drying temperatures (60, 80, 100, and 120 °C) on drying kinetics and quality attributes of shea fruit peel and pulp was investigated.The results showed that drying time decreased with an increase in temperature, with shorter drying time required for the peel at the same temperature than the pulp. The Logarithmic and Page models were the best in describing the drying process of the shea fruit peel and pulp, respectively. Moisture diffusivity increased from 1.01 × 10⁻⁹ to 3.56 × 10⁻⁹ m²/s and 1.10 × 10⁻⁹ to 4.75 × 10⁻⁹ m²/s for the peel and pulp, respectively, as the drying temperature increased from 60 to 120 °C. The activation energy was 23.47 kJ/mol for the peel and 27.19 kJ/mol for the pulp. The rehydration ratio (RR) and CIE-L*a*b* color values were influenced (p < 0.05) by the drying temperature with lower total color change (∆E) values observed at 60 °C and 80 °C. However, an increase in IR drying temperature did not significantly (p > 0.05) influence the calcium and magnesium contents of the dried shea fruit components. Drying of the peel and pulp above 80 °C reduced ß-carotene content, total phenol content (TPC), and total antioxidant activity (TAA) while the highest potassium, vitamin C, and total flavonoid content (TFC) retention were observed at 120 °C. The study suggests IR drying of shea fruit peel and pulp at 60 to 80 °C for efficient drying and maintenance of color, ß-carotene content, TPC, TAA, and higher RR. Where, fast drying, vitamin C and TFC are of interest, drying of shea fruit components at 120 °C is recommended.