Functional food obtained from fermentation of broccoli by-products (stalk): Metagenomics profile and glucosinolate and phenolic compounds characterization by LC-ESI-QqQ-MS/MS. (1st November 2022) - Salas-Millán, José-Ángel
Abstract: This research revalues broccoli stalk by-product as a novel fermented health food, using its autochthonous microbiota. Broccoli stalk slices were packed into glass jars, brine was added (6% w/v), and two dressings were studied: garlic, and mustard seeds. No dressing was used as control. Natural fermentation was carried out at 25 °C for 6 days followed by a further 6 days storage at 4 °C. The identification of individual glucosinolates and phenolic compounds was performed by LC-ESI-QqQ-MS/MS. At day 3, the highest content in functional compounds such as glucoerucin and indolic glucosinolates as glucobrassicin, 4-methoxy-glucobrassicin and 4-hidroxy-glucobrassicin, and phenolic acids and flavonoids as sinapic acid, 4-O-feruloyl quinic acid and quercetin-3-O-diglucoside was found. At day 6, the broccoli stalks reached the maximum counts in lactic acid bacteria (>8 log cfu g −1 ), remaining stable until day 12 at 4 °C, including as the main genera Lactobacillus and Leuconostoc . Metagenomic analysis identified 1009 bacteria genera; Latilactobacillus sakei was the most predominant lactic acid bacteria species, followed by Lactobacillus curvatus, Leuconostoc kimchi and Leuconostoc carnosum . This is an example of a vegan and functional food product, based on a circular economy model, using broccoli by-products. Highlights: Fermented broccoli stalk provided a functional novel product. This product is an example of revaluing by-products that promote a circular economy. Latilactobacillus sakei subsp. carnosus is the principal LAB in fermented broccoli stalk. Mustard dressing increases the nutritional value by its high content in phenolic compounds. On day 3, fermented stalks showed a high content in functional compounds.