低温冷藏对西兰花营养品质和叶绿素荧光特性的影响

Effects of refrigerated storage on phytochemical qualities and chlorophyll fluorescence characteristics of post-harvested broccoli

针对采后西兰花易黄花和品质劣变导致的快速衰老问题,以西兰花品种‘优秀’为试材,对采收后的西兰花进行低温冷藏(4±1)℃处理,以室温贮藏(25±1)℃为对照,分别在第0,2,4,6,8d测定叶绿素、蛋白质、VC、可溶性糖和叶绿素荧光参数。与室温贮藏下的西兰花相比,低温冷藏第4d下花蕾中的Chl a、Chl b、Vc和实际光化学效率Y(II)降低幅度较小,分别为46.7%,53.0%,54.7%和12.2%,而花茎中的Vc和可溶性蛋白则呈现较高幅度的增加,分别为132.3%和91.8%。随着贮藏时间进一步延长,无论是室温贮藏还是低温冷藏下的西兰花色素均开始大幅度分解,花蕾和花茎发生明显的黄花且其营养品质开始变劣。因此,从商品品质和营养品质综合考虑,西兰花采后应进行低温冷藏并在4d之内食用完毕。

Broccoli（Brassica oleracea L.）is perishable and susceptible to senescence after harvest with symptoms of de-greening and quality deterioration.By using the broccoli cultivar‘Youxiu＇as the experiment material,post-harvested fresh broccoli was stored under laboratory refrigerated storage of（4±1）℃for a total period of 8d,with the room temperature storage of（25±1）℃ as the control.The effects of room temperature and refrigerated storage temperature on phytochemical qualities（e.g.chlorophyll content,β-carotene,Vc,soluble sugar and soluble protein）and fluorescence characteristics（e.g.Y（II）,Y（NPQ）,Y（NO））of post-harvested broccoli were investigated and evaluated at the 0,2,4,6and 8th day during the storage.Compared with the room temperature condition,samples stored under laboratory refrigerated condition showed significant（P 0.05）lower losses of chlorophyll a content,chlorophyll b content,Vc and Y（II）in broccoli florets（46.7%,53.0%,54.7% and 12.2%,respectively）andgreater increases of Vc and soluble protein（132.3%and 91.8%,respectively）in broccoli stems during the storage for up to the 4th day.Then,the broccoli was rapidly yellowing as evidenced by greater degradation of chlorophyll.For better phytochemical quality retention,the broccoli should be stored under refrigerated condition and eaten within 4days.