Effects of solution spraying during hot air drying on drying rate, surface hardening and browning of fresh-cut Japanese pear

Three types of solutions (distilled water, aqueous ascorbic acid solution and aqueous citric acid solution) were sprayed periodically on the surface of fresh-cut Japanese pear during hot air drying at 40, 50 and 60 °C. The effects of solution spraying on the drying kinetics, the surface hardening, and the sample discoloration were investigated. The drying rates of the sprayed samples increased 58-63, 16-19 and 20-22% in comparison with those of the non-sprayed samples at 40, 50 and 60 °C, respectively. The hardness of the sprayed samples decreased 12-24% and 2-9% compared to that of the non-sprayed samples, and the total color difference (ΔE) was 27-44 and 20-33% less compared the non-sprayed samples at 40 and 50 °C, respectively.