Effect of fermentation on non-water infrared refractance window drying of Malabar spinach

Abstract

The Malabar spinach was fermented and dried using novel non-water infrared refractance window drying (IR-RWD). The sample fermented for 48 h with a 3 % salt and 3 % sucrose solution (SS) was selected as the best pretreatment condition for drying because it enhanced the total carotenoid (TC), total phenolic content (TPC), and total flavonoid content (TFC) while significantly reducing the antinutrient factors. During drying, the optimized product resulted in 67.53 % chlorophyll retention, 0.75 mg g⁻¹ TC, 20.79 mg GAE g⁻¹ TPC, and 1.97 mg QE g⁻¹ TFC. The XRD and SEM of the dried product showed alterations in the crystalline structure with porous and round-shaped particles. The Page model described well the drying data with R² values of more than 0.991. Thus, the sugar-supported fermentation combined with non-water IR-RWD resulted in high-quality dried Malabar spinach showing a promising future as sustainable, nutritious, and convenient foods.