真空微波干燥对南瓜片主要类胡萝卜素的影响

利用C30柱及高效液相色谱-二极管阵列检测-大气压化学电离串联质谱方法，对南瓜片中主要类胡萝卜素进行了定性、定量检测，研究了真空微波干燥条件对南瓜片中类胡萝卜素组成及含量的影响。结果表明：真空微波干燥南瓜片总类胡萝卜素含量显著高于热风干燥（P＜0.05）。微波强度对南瓜片中类胡萝卜素的影响最大，其次是真空度和切片厚度。随着微波强度的增加，南瓜片总类胡萝卜素含量显著减少（P＜0.05），增大真空度和切片厚度在一定程度上提高了干样总类胡萝卜素的含量。与此同时南瓜片中类胡萝卜素主要组分α-、β-胡萝卜素和叶黄素含量随微波强度增加而减少，随真空度和切片厚度增加而增加；而β-胡萝卜素各顺式异构体随真空度增加而减少，但随切片厚度增加含量变化不明显。由此可见，增大真空度和切片厚度有利于提高类胡萝卜素保留率，而高微波强度使类胡萝卜素含量下降。

Effect of Vacuum Microwave Drying on the Main Carotenoids of Pumpkin

The effect of vacuum microwave drying conditions on the main carotenoids in pumpkin slices were investigated by
high performance liquid chromatography atmospheric with a C30 column and diode array detection coupled with atmospheric
pressure chemical ionization-tandem mass spectrometry (C30-HPLC-DAD-(APCI) MS/MS) technique. The results showed
that the total carotenoid content of vacuum microwave dried pumpkin was significantly (P < 0.05) higher than that of the
hot air dried one. Microwave intensity had the most evident influence on the carotenoids in pumpkin, followed by vacuum
degree and the thickness of pumpkin slices. By increasing microwave intensity, total carotenoid content was significantly
decreased, whereas it was increased by increasing either vacuum degree or slice thickness. Meanwhile, the contents of
α-, β- carotene and lutein decreased with the increase in microwave intensity, but increased with the increase in vacuum
degree or slice thickness. The contents of all β-carotene cis-isomers decreased with the increase in vacuum degree, but they did not
change significantly with the increase in slice thickness. These results collectively indicate that increasing vacuum degree or slice
thickness is beneficial to retain carotenoids, but too high microwave intensity results in decreased content of carotenoids.