In this work, the effect of drying conditions on pear slices' physicochemical properties was determined. The factors investigated were drying temperature, air velocity, and addition of ascorbic acid. An analysis of variance indicated that the factors affected (P ≤ .05) the response variables significantly. The lowest drying time resulted at 60°C, 3 m s⁻¹, at 0%, and 1% of ascorbic acid concentration. At these drying conditions, the final moisture content in pear samples was 0.14 g H₂O g d s⁻¹. The water activity of the pear samples was in the range from 0.27 to 0.39. A low value of 6.36 of color difference was obtained at 50°C, 1 m s⁻¹, and 0% of ascorbic acid. During the drying process, the lightness in pear samples increases as the air velocity and the drying temperature increases. The highest hue values (from 54.66° to 63.27°) resulted in dried pear samples without ascorbic acid; therefore, the dried pear slices tended to yellowness. Chroma results ranged from 19.51 to 21.41 and from 14.96 to 19.16 in pear slices with and without ascorbic acid. Therefore, the color of the pear slices resulted in grayish-yellow. An increment in sugar content was observed from an initial value of 18°Brix to values from 37.5 to 48.7°Brix. This behavior is because the sugar core is concentrated in large amounts during the drying process as the residual water content decreases.

中文翻译：

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过程变量对梨片（梨）干燥动力学和颜色特性的影响

在这项工作中，确定了干燥条件对梨切片理化性质的影响。研究的因素是干燥温度、风速和抗坏血酸的添加。方差分析表明，这些因素 显着影响 ( P ≤ .05) 响应变量。最短的干燥时间是在 60°C、3 m s ^-1、0% 和 1% 的抗坏血酸浓度下。在这些干燥条件下，梨样品中的最终水分含量为 0.14 g H ₂ O g d s ^-1。梨样品的水分活度在 0.27 到 0.39 的范围内。在 50°C、1 m s ^-1下获得了 6.36 的低色差值和 0% 的抗坏血酸。在干燥过程中，梨样品的亮度随着风速和干燥温度的增加而增加。最高的色调值（从 54.66° 到 63.27°）导致干梨样品不含抗坏血酸；因此，干燥的梨片趋于发黄。含和不含抗坏血酸的梨片的色度结果范围为 19.51 至 21.41 和 14.96 至 19.16。因此，梨片的颜色为灰黄色。观察到糖含量从 18°Brix 的初始值增加到 37.5 到 48.7°Brix 的值。这种行为是因为糖核在干燥过程中随着残留水含量的降低而大量浓缩。