Metabolic Profiling of Glucosinolates, Anthocyanins, Carotenoids, and Other Secondary Metabolites in Kohlrabi (Brassica oleracea var. gongylodes)

Abstract

We profiled and quantified glucosinolates, anthocyanins, carotenoids, and other secondary metabolites in the skin and flesh of pale green and purple kohlrabis. Analysis of these distinct kohlrabis revealed the presence of 8 glucosinolates, 12 anthocyanins, 2 carotenoids, and 7 phenylpropanoids. Glucosinolate contents varied among the different parts and types of kohlrabi. Glucoerucin contents were 4-fold higher in the flesh of purple kohlrabi than those in the skin. Among the 12 anthocyanins, cyanidin 3-(feruloyl)(sinapoyl) diglucoside-5-glucoside levels were the highest. Carotenoid levels were much higher in the skins than the flesh of both types of kohlrabi. The levels of most phenylpropanoids were higher in purple kohlrabi than in pale green ones. trans-Cinnamic acid content was 12.7-fold higher in the flesh of purple kohlrabi than that in the pale green ones. Thus, the amounts of glucosinolates, anthocyanins, carotenoids, and phenylpropanoids varied widely, and the variations in these compounds between the two types of kohlrabi were significant.

Profiling Polyphenols in Five Brassica Species Microgreens by UHPLC-PDA-ESI/HRMSn

“…The major ones are cy 3-(feruloyl)(sinapoyl) diglucoside-5-glucoside, cy 3-(feruloyl) diglucoside-5-glucoside and cy 3-(sinapoyl)(sinapoyl) diglucoside-5-glucoside (31). In our study, the acylated anthocyanins with one malonyl group attached to the hexose of C-5 and other aromatic groups (caffeic, p -coumaric, sinapic or ferulic acid) attached to the C-3 glycosidic substituent were found.…”

Functional Ingredients From Brassicaceae Species: Overview and Perspectives

“…chinensis), and kohlrabi (Brassica oleracea var. ganglyoides) [38,39]. Kale is considered the richest cruciferous source of this compound, surpassing cabbage in about 40 times [35].…”

Glucosinolates in Food

“…Depending on the cultivar, kohlrabi may be purple, red, or white-green in the skin, but the flesh is always white. GLS content varies among the different parts of the kohlrabi (skin and flesh), and generally the red varieties have a higher total content of GLSs than the green ones [81,91,92]. Beside these differences among varieties (ranging from 50 to 784 mg/100 gFW), GLS content data demonstrate that kohlrabi possesses a very high total GLS content, with a mean value of 295.5 mg/100 g FW ( Table 2).…”