Influence of season and fermentation conditions on glucosinolates, vitamin C and ascorbigen content in Brassica oleracea var. capitata cv. Taler.

Abstract

Recent epidemiological study has shown that high sauerkraut consumption dunng adolescence and adulthood contributes toa decreased risk ofbreast cancer. The anticarcinogenic activity of fermented cabbage is linked with the presence of glucosinolates (GLS) derivativ.es. By means of enzymatic and non-enzymatic transformations which occur dunng cabbage processing, GLS release a number of bilogocally active products. Ascorbigen- product of the reaction of indol3-carbinol (GLS glucobrassicin breakdown product) and ascorbic acid has been found the most abundant GLS derivative of all identified in sauerkraut. Ascorbigen content in fermented cabbage depend on the content of native glucobrassicin of the raw material. Environmental factors su eh as the harvest season play an important role in the GLS content in raw cabbage. Therefore, fermentation of glucobrassicin-rich cabbage is favorable and highly advised. Moreover, fermentation conditions used to produce sauerkraut may influence the formation of ascorbigen. For this reason, this study deals with the effect ofharvest season and different fermentation conditions on GLS, ascorbigen and ascorbic acid content. GLS content in fresh white cabbage (Brasszca oleracea var. capitata cv. Taler) harvested during summer orwinter and after fermentation was deterrnined by HPLC following enzymatic desulfatation. Cabbages were subjected to different fermentation conditions consisting of the combination of low (0.5%) or high (1.5%) sodium addition with natural or induced fermentation using Leuconostoc mesenteroides or Lactobacillus plantarum as starter cultures. The content of ascorbic acid and ascorbigen were analyzed jointly for cabbage and juice at O and 7 days of fermentation by captilary electrophoresis and HPLC, respectively. The results showed that GLS content varied depending on the harvest season. The content of ascorbigen increased sharply after cabbage fermentation whilst ascorbic acid decrease, and the content of these bioactive compounds depended also on the process conditions used.