Seasonal Variation of Glucosinolate Hydrolysis Products in Commercial White and Red Cabbages (Brassica oleracea var. capitata).

Nicole S Wermter,Franziska S Hanschen,Sascha Rohn

doi:10.3390/foods9111682

Abstract

Brassica vegetables contain glucosinolates, which are well-known for their potential to form health-promoting isothiocyanates. Among those crucifers, white and red cabbage are commonly consumed vegetables, exhibiting different glucosinolate and hydrolysis profiles thereof. Regarding the health beneficial effects from these vegetables, more information, especially concerning the seasonal variation of glucosinolate profiles and the formation of their bioactive hydrolysis products in commercial cabbages, is needed. In this study, glucosinolates and glucosinolate hydrolysis product profiles in red and white cabbages from three different food retailers were monitored over six different sampling dates across the selling season in autumn. For the first time, it was shown that, while glucosinolate profiles were similar in each cabbage variety, glucosinolate hydrolysis product profiles and hydrolysis behavior varied considerably over the season. The highest total isothiocyanate concentrations were observed in conventional red (1.66 μmol/g FW) and organic white (0.93 μmol/g FW) cabbages purchased at the first sampling date in September. Here, red cabbage was with up to 1.06 μmol/g FW of 4-(methylsulfinyl)butyl isothiocyanate (sulforaphane), an excellent source for this health-promoting isothiocyanate. Cabbages purchased 11 weeks later in autumn released lower levels of isothiocyanates, but mainly nitriles and epithionitriles. The results indicate that commercial cabbages purchased in early autumn could be healthier options than those purchased later in the year.

Highlights

IntroductionWith a consumption of 5.2 kg/person and year in 2017/2018, red cabbage
With a consumption of 5.2 kg/person and year in 2017/2018, red cabbage (Brassica oleracea var.capitata f. rubra) and white cabbage (Brassica oleracea var. capitata f. alba) are the most consumedBrassicaceae vegetables in Germany, contributing to 5% of total vegetable intake [1]
Most analyzed cabbage heads differed in their regional origin and harvest time (Table 2)

Summary

Introduction

With a consumption of 5.2 kg/person and year in 2017/2018, red cabbage Brassicaceae vegetables in Germany, contributing to 5% of total vegetable intake [1] These vegetables are rich in glucosinolates (GLSs), secondary, sulfurous plant constituents, which are present in vacuoles of plant cells of the Brassicaceae family. The carbon atom, in turn, is linked to a sulfate group and an organic aglycone residue, possessing an alkyl, alkenyl, aryl, or indole group [2]. This organic residue is inherent to the GLS, its chemical properties and its flavor, respectively [4,5].

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