不同热泵干燥温度对高良姜干燥品质的对比分析

采用不同的热泵干燥温度(45℃、50℃、55℃、60℃、65℃),并以日晒为对照,对高良姜干燥至水分含量8%±0.5%,分析不同热泵干燥温度对高良姜的色泽、活性物质和挥发性成分的影响。结果表明:50℃干燥的高良姜与日晒干燥的高良姜色泽最为相近,△E为2.16±0.2;50℃干燥的高良姜复水率最高,为2.39±0.03,且复水比随着热泵干燥温度升高而降低的趋势;50℃热泵干燥得到的高良姜总酚和黄酮含量最高,分别为19.33±0.21 mg/g和8.44±0.19 mg/g,热泵温度超过50℃时,总酚和总黄酮的含量随着热泵温度的升高而降低。热泵干燥温度对高良姜素含量的影响不显著,50℃干燥的高良姜素含量为6.29±0.07 mg/g,且热泵干燥的高良姜素含量均大于日晒干燥,日晒干燥高良姜素含量为5.54±0.1 mg/g。日晒、45、50、55、60、65℃干燥高良姜挥发性物质种类分别为81、69、74、78、82和85,烯烃类物质分别为42、39、37、32、34和31,45℃热泵干燥,桉叶油醇的含量最高,为37.41%,且随着热泵温度的升高而降低。综合色泽、品质、风味等比较,50℃是热泵干燥高良姜的最佳温度参数。本文的研究结果为热泵干燥在高良姜干燥条件的控制提供了理论依据。

Comparison of Dried Alpinia officinarum Hance Quality Dried at Different Heat Pump Temperatures

The effects of different heat pump drying temperatures(45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃) on the color, active substances and volatile components of the Alpinia officinalis with a moisture content of 8±0.5% were analyzed through using sun-drying as the control approach. The results showed that the color of Alpinia officinalis dried at 50 ℃ was the closest to that of sun-dried Alpinia officinalis, with the △E as 2.16±0.2 and rehydration rate as 2.39±0.03(the highest). The rehydration ratio decreased with an increase of the heat pump drying temperature;Drying at 50℃ led to the highest contents of total phenols and flavonoids(19.33±0.21 mg/g and 8.44±0.19 mg/g, respectively). When the heat pump temperature exceeded 50 ℃, the contents of total phenols and flavonoids decreased with an increase of the heat pump temperature. The effect of heat pump drying temperature on the content of galangin was not significant. The content of galangin in the Alpinia officinarum dried at 50 ℃ was 6.29±0.07 mg/g, and this content in the Alpinia officinarum dried by heat pump was higher than by sun-dyring(5.54±0.1 mg/g). The Alpinia officinalis dried in the sun, at 45 ℃, at 50 ℃, at 55 ℃, at 60 ℃, and at 65 ℃, respectively, had 81, 69, 74, 78, 82 and 85, types of volatile substances, and 42, 39, 37, 32, 34 and 31 olefin substances. Drying at 45 °C led to the highest content of eucalyptol(37.41%), and the content of eucalyptol decreased with the increase of heat pump temperature. Based on the color, quality and flavor of the dried Alpinia officinalis, the optimum temperature for heat pump drying was 50 ℃. The results reported in this paper provide a theoretical basis for the control of drying conditions of Alpinia officinarum by heat pump.