光照对鲜青花椒干燥过程中叶绿素降解的影响

Chlorophyll Breakdown in Green Prickleyash with Illumination during Drying

以鲜青花椒为原材料,研究在3种单色光黄光、蓝光、紫外光以及日光(复合光)对鲜青花椒干燥过程中色泽和叶绿素及其衍生物含量的变化,以确定光照对鲜青花椒干燥过程中叶绿素降解的影响。结果表明:在整个干燥过程中,鲜青花椒果皮的绿色逐渐褪去,并逐渐变暗;其中,紫外光作用最显著,能使鲜青花椒由绿色转变为褐色;同时,鲜青花椒的叶绿素均有不同程度的降解,其中紫外光干燥能使叶绿素a和叶绿素b降解57.94%;光照会引起叶绿素衍生物的代谢紊乱,包括脱镁叶绿素a、脱镁叶绿酸a和焦脱镁叶绿酸a,在紫外光和日光照射的干燥中,还会产生少量焦脱植基叶绿素a、焦脱镁叶绿素a以及C132-OH脱镁叶绿酸a等褐色衍生物,这些衍生物的积累可能是造成青花椒色泽劣变的主要原因。

The effect of light on chlorophyll breakdown in green prickleyash during drying was investigated by examining changes in peel color and the contents of chlorophylls and their derivatives. The results showed the green color of the peel faded and chlorophylls underwent degradation. The peel color changed from brilliant green to brown and the content of chlorophylls decreased by 57.94% after UV illumination. The metabolism of some derivatives such as pheophorbide a, pheophytin a and pyropheophorbide a was disordered because of the illumination. In addition, the contents of pyropheophytin a, pyrochlorophyllide a and C132-OH-pheophytin a increased slightly, and the browning might contribute to the deterioration of peel color.