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

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.

Young Shoots of White and Red Headed Cabbages Like Novel Sources of Glucosinolates as Well as Antioxidative Substances

“…The natural glucosinolates content in vegetables varies in accordance with genotype, plant developmental step, soil, and cultivation conditions and other ecophysiological influences, and also by storage conditions. Additionally, glucosinolates level vary over the growth season and several studies reported higher glucosinolates levels in Brassica oleracea plants grown in spring compared to plants grown in autumn [ 18 ].…”

“…Hassini et al [ 21 ] reported that total glucosinolates content depended significantly on the variety, being higher in red than in white cabbage sprouts. In a study by Wermter et al [ 18 ] red cabbage heads at full maturity produced higher levels of glucosinolates compared to white cabbage heads. According to Bell and Wagstaff [ 22 ] the white headed cabbage and red headed cabbage are widely consumed and studied crops but has modest total glucosinolates concentrations compared to those of other Brassica crops.…”

“…Wermter et al [ 18 ] monitored the variation of glucosinolates levels and the formation of their bioactive hydrolysis products in commercial red and white cabbage heads obtained from three local retailers in Germany and linked the data with the cultivation practices and post-harvest storage conditions. These authors reported that in the heads of the analyzed white and red cabbage cultivars, a total of 12 chemically different glucosinolates were detected.…”

“…The main glucosinolates were allyl glucosinolate (Allyl), 3-butenyl glucosinolate (3But), 2-hydroxy-3-butenyl glucosinolate (2OH3But), 3-(methylsulfinyl) propyl glucosinolate (3MSOP), 4-(methylsulfinyl) butyl glucosinolate (4MSOB), and indol-3-ylmethyl glucosinolate (I3M). In a study of Wermter et al [ 18 ] the two major glucosinolates detected in white cabbage at full maturity were 3-(methylsulfinyl) propyl glucosinolate and allyl glucosinolate, while red cabbage was often the richest in -hydroxy-3-butenyl glucosinolate and 4-(methylsulfinyl)butyl glucosinolate. Bell and Wagstaff [ 22 ] concluded that red cabbage contains similar total glucosinolates content to white cabbages but differs in the relative amounts present within leaf tissues, e.g., it contains greater concentrations of glucoraphanin and gluconapin and less sinigrin.…”

Determination of Isothiocyanate-Protein Conjugates in a Vegetable-Enriched Bread

“…The extraction started with frozen bread powder that was allowed to heat to room temperature after adding the first round of methylene chloride. GLS breakdown products were extracted and analyzed with gas chromatography-mass spectrometry (GC-MS) using the extraction protocol described by Wermter et al and the GC-MS protocol described by Hanschen et al, except that the transfer line temperature was set to 250 • C [31,32].…”