Improving the nutritional properties of Brassica L. vegetables by spontaneous fermentation

Abstract

Introduction. Brassica L. vegetables are rich in fiber, minerals, and bioactive compounds. Lactic fermentation can improve their nutritional value. The goal of this study was to evaluate phytase, calcium, phytic acid, total phenolic content, and antioxidants during spontaneous fermentation of white cabbage, red cabbage, and Chinese cabbage.
 Study objects and methods. The research featured samples of water extract, methanol extract, and brine. The procedure involved monitoring lactic bacteria and pH during cabbage fermentation. Diphenyl-1-picrylhydrazyl radical (DPPH) scavenging assay and cupric reducing antioxidant capacity (CUPRAC) assay were used to measure the antioxidant activity and Folin-Ciocalteau method to determine total phenolic content in the water and methanol extracts. In the brine samples, we studied calcium, phytic acid, and phytase activity.
 Results and discussion. The samples of white and red cabbage displayed the highest phytase activity on days 5–10 and had a maximal decrease of phytic acid and increase of calcium concentration, while in Chinese cabbage these processes occurred gradually throughout the fermentation. The total phenolic content in the brine and extracts was very similar for all the cultivars throughout the fermentation process. A continuous release from the solid phase to brine could be observed during the first ten days of fermentation. DPPH and CUPRAC assays revealed a similar phenomenon for the total phenolic content. The antioxidant capacity decreased in the water and methanol extracts and increased in the brine. At the end of fermentation, the red cabbage samples demonstrated a significant increase in the total phenolic content and total antioxidant activity, which was less prominent in the Chinese cabbage. The samples of white cabbage, on the contrary, showed a decrease in these parameters.
 Conclusion. Fermentation made it possible to increase the concentration of free calcium in white, red, and Chinese cabbages, as well as improve the antioxidant capacity of red and Chinese cabbages.

Assessment of the bioaccessibility of phenolic compounds and antioxidant activity in raw and pickled white cabbage and gherkins

“…The DPPH antioxidant activity of raw and pickled cabbages is 9.68 and 9.33 mg TE/100 g (P > 0.05), respectively, and no change is observed after the brining process, similar to results reported in the literature (Girgin et al, 2015). Differently, in a previous research, the DPPH antioxidant activity of white cabbage increased on day 1 and then lowered through fermentation, probably due to the passage of antioxidant compounds to the brine (Parada et al, 2022). After in vitro digestion, DPPH antioxidant activity is found to remain unaffected by in vitro digestion of raw and pickled cabbage.…”

“…In a previous study (Sayın et al, 2015), the fermentation process was found to increase TPC initially and then decrease the TPC of white cabbage. In another spontaneous fermentation study, fermentation decreased the TPC of white cabbage (Parada et al, 2022). Sauerkraut production was found to increase TPC and some individual phenolics (Ciska et al, 2005a;Tlais et al, 2022).…”

Effects of brining and standardized drying on the composition, shelf stability, microbial safety and antioxidant status of four wild edible vegetables

“…The TFC increase was 55% in ST, 95% in TP, 70% in TT and 25% in JZ as compared to their respective raw samples. Although peculiar, such increase in the concentrations of bioactive compounds have also been reported in carrots, 41 daikon radish and red cabbage ferment mix, 42 dried g fruit juice fermented using LAB culture, 43 in individually fermented red, white and Chinese cabbage with 3% salt at 18 °C for 30 days, 21 and in market pickled commercial chayote. 25 Moreover, Irakoze et al (2023) reported such increase in fermented African Black Nightshade and African Spider Plant.…”

“…Brining also helps in the preservation of nutrients and antioxidant compounds. 20,21 Such basic processing techniques ensure the 'organic status' of WEVs, promoting good health and well-being of the consumers. Besides, they show potential to boost the economic livelihoods of the forestdwelling tribal populations, fostering holistic sustainable communities.…”