气调过程中O_(2)含量对西兰花叶绿素降解的影响

Effects of O_(2) Content on the Chlorophyll Degradation in Broccoli Heads Under Controlled Atmospheres

以西兰花为试材,采用气调处理的方法,以自然空气为对照(CK),设置20%O_(2)+20%CO_(2)、50%O_(2)+20%CO_(2)、80%O_(2)+20%CO_(2)的气体比例,研究了20℃贮藏条件下O_(2)对西兰花的贮藏品质和叶绿素降解的影响,阐明O_(2)促进西兰花黄化的作用机制,以期为研究高O_(2)条件下叶绿素的降解调控提供参考依据。结果表明:高O_(2)比例降低了西兰花体内叶绿素、维生素C以及可溶性蛋白质含量;气调处理中O_(2)比例提高能够促进叶绿素b还原酶编码基因(BoNYC1)、滞绿蛋白编码基因(BoSGR)、脱镁叶绿素酶编码基因(BoPPH)、脱镁叶绿酸a氧化酶编码基因(BoPaO)、红色叶绿素降解产物还原酶编码基因(BoRCCR)表达水平,尤其是BoSGR、BoPPH和BoRCCR相对表达量高峰提前出现,促进了叶绿素分解代谢,加速了西兰花黄化进程。其中,O_(2)促进叶绿素降解过程中BoPPH基因表达可能是促进黄化的主要原因,SGR则通过互作影响BoPPH表达。

Taking broccoli as test materials, the air conditions of 20%O_(2)+20%CO_(2),50%O_(2)+20%CO_(2)and 80%O_(2)+20%CO_(2)were employed as treatments, natural air was set as control(CK).During storage at 20 ℃,the storage quality of broccoli florets and the relative expression of genes related to chlorophyll degradation were determined.To explore the effects of O_(2)on the degradation of broccoli chlorophyll in controlled atmosphere.The results of this experiment could provide a theoretical basis for the regulation of chlorophyll degradation under high O_(2)conditions.The results showed that with the increase of O_(2)ratio, the chlorophyll b reductase encoding gene(BoNYC1),the chlorophyll encoding gene(BoSGR),the pheophytinase encoding gene(BoPPH),the pheophorbide a oxidase encoding gene(BoPaO),red chlorophyll degradation product reductase encoding gene(BoRCCR) expression levels and their relative expression peaks appeared earlier, which promoted chlorophyll catabolism and accelerated the yellowing process of broccoli.Among them, O_(2)promoted the gene expression of BoPPH in the process of chlorophyll degradation, which may be the main reason for promoting yellowing, SGR interacted the expression of BoPPH.