Determination And Comparision Of Glucosinolate Content In Various Broccoli And Cauliflower Cultivars

Glucosinolates(GS) are a group of plant secondary metabolites mainly found in the cruciferae vegetables.Glucosinolates and their degradation products have various bioactivities,such as flavor-forming,killing pest and pathogen,causing high-grade animal's anti-cancer.Sulphoraphane,the cognate isothiocyanate of glucoraphanin,has strong anti-cancer effect.There are various factors that affect the profile and content of glucosinolates on the plants,including plant species and varieties,development stages and present organs,cultivation and environment conditions(such as,temperature,light,water, mine nutrition,planting date),storage conditions,methods of processing and cooking.This paper studied content of glucoraphanin(RAA) and sulforaphane(SUL) in different organs(curd,stem and leaf) of various broccoli and cauliflower cultivars,selected cultivars with high natural antic-cancer functional components lever,thus it provides the theory for enhancing the levels of functional component in cruciferous vegetables through conventional breeding or genetic engineering to improve the chemopreventive properties and extracting functional component from plant offal's,such as stem and leaf.The result showed that RAA content in curd of broccoli and cauliflower varied significantly among cultivars,and 'Lvbaoshi' and 'Baoshihua' contained the highest RAA lever respectively(9.956 and 0.501μmol·g^-1DW).The Mean RAA content in broccoli was 36.6 folds as that in cauliflower.The Mean total GS content of broccoli and cauliflower was 24.924 and 23.28μmol·g^-1DW.RAA content of cauliflower had a positive and significant linear relationship with the harvest date of the curd(days from transplant to harvest),but we didn't find significant relationship between RAA and total GS content of broccoli or total GS content of cauliflower to days from transplant to harvest.RAA content in stem and leaf of broccoli and cauliflower varied significantly among cultivars.For broccoli,RAA content in stem ranged from 0.124 to 4.03μmol·g^-1DW,and ranged from 0.017 to 1.251μmol·g^-1Dw in leaf.For cauliflower,RAA content in stem ranged from 0.018 to 1.325μmol·g^-1DW,and ranged from 0.069 to 1.628μmol·g^-1DW. Relative percentage of RAA content in stem and leaf of broccoli was 61.12%and 71.51% than that in curd,respectively.Relative percentage of RAA content in stem and leaf of cauliflower was 15.08%and 40.18%higher than that in curd,respectively.Among three organs of broccoli,the curd had the highest content of SUL(2.672μtmol·g^-1DW),then was the stem(1.044μmol·g^-1DW),the content of the leaf was lowest (0.429μmol·g^-1DW).For cauliflower,the leaf had the highest content of SUL(0.47μmol·g^-1 DW),then was the curd(0.106μmol·g^-1DW),the content of the stem was lowest (0.097μmol·g^-1DW).The conversion rate that glucoraphanin was hydrolyzed by myrosinase to produces sulforaphane was higher in curd and leaf(higher than 45%) and lower in stem(37.1%and 38.6%) for broccoli and cauliflower.