干燥条件对橘皮颜色与结构性能的影响

Effect of Different Drying Conditions on Color and Texture of Citrus Peels

摘要:

柑橘皮富含经济和药用价值，为寻求更优的干燥方式以实现资源全利用，本文对比研究了真空冷冻、热风、中短波红外干燥橘皮的颜色和结构性能。结果表明：不同干燥条件对橘皮色泽和结构性能影响显著（p<0.05）。褐变引起橘皮总色差值变化，而类胡萝卜素降解导致b值降低；在干燥温度60 ℃~90 ℃范围内，干燥橘皮L值，a值，b值和类胡萝卜素含量随干燥温度升高而降低，ΔE值和褐变度随干燥温度升高而升高。微观结构的改变则为干燥橘皮粗纤维含量、质构参数和干燥效率、复水性等性质研究提供了参考方法，微观结构疏松且未受损伤，孔隙大，分布均匀，则粗纤维含量较高，硬脆度适中，复水性好，反之结构性能较差；较真空冷冻和热风干燥，中短波红外低温干燥（60 ℃~70 ℃）对橘皮的颜色和结构保持最好。本文为橘皮的干燥产业化生产提供了重要理论依据。

Abstract:

Citrus peels have significant economic and medicinal values. To realize the full utilization of citrus fruits, a comparative study was carried out to illustrate the color and textural property of citrus peels dried by freeze drying, hot-air drying, and mid- and short-wave infrared radiation drying. Different drying conditions significantly affected the color and textural property of citrus peels (p < 0.05). The browning reaction caused △E changes in citrus peels, and the degradation of carotenoid led to a decrease in b value. When the drying temperature was in the range of 60 ℃ to 90 ℃, L value, a value, b value, and total carotenoid content of dried citrus peels decreased with increasing temperatures, and △E value and browning index were elevated. The variation of microstructure provided a theoretical basis to further study the crude fiber, textural parameters, drying efficiency, and rehydration of citrus peels. If the microstructure was loose, undamaged, and regular, the dried citrus peels had high crude fiber content, suitable hardness and crispness, and good rehydration. The mid- and short-wave infrared radiation drying at relatively low drying temperatures (60 ℃~70 ℃) gave better color and structural quality compared to that by freeze-drying and hot-air drying. This study provides an important theoretical basis for the industrial production of dried citrus peels.