Drying kinetics and quality assessment of refractance window dried beetroot

Abstract

Thin-layer drying of red beetroot having slice thicknesses of 0.5, 1, and 1.5 mm was carried out using a solar-assisted continuous refractance window dryer at 75, 80, and 85 C drying temperatures for 30, 45, and 60 min. The drying kinetics including moisture ratio, drying rate, and moisture diffusivity was observed to understand the drying behavior of beetroot. The moisture ratio was fitted to the drying models for thinlayer modeling of the beetroot drying. The drying operation reduced the firmness and water activity of the fresh beetroot; however, the antioxidant properties of dried beetroot increased with drying treatment. The minimum alteration was observed with a color difference and hue angle of dried slices. Process optimization was carried out to obtain the ideal drying conditions, which indicated the use of a dryer at 85 C temperature, 0.5 mm slice thickness, and 60 min exposure time with a desirability value of 0.874. Practical applicationsFourth-generation drying technology refractance window drying dried the beet root slices without case hardening and improve its antioxidant properties. Dried beetroot contains carotenoids, vitamins, nitrates, flavonoids, and various minerals that have antioxidant, anti-inflammatory, anticarcinogenic, and hepato-protective activities.Dried beetroot flakes or powder is useful for the development of different functional foods that have anti-diabetic, cardiovascular disease lowering, hypertensive, and wound healing benefits.