Search

This study investigated the effect of lactic acid bacteria (LAB) fermentation on the chemical profile of autoclaved broccoli puree, using 7 broccoli-derived LAB isolates (named F1-F5, BF1 and BF2). The total concentrations of glucosinolates (glucoiberin, progoitrin and glucoraphanin) and 10 major phenolics significantly increased from trace level and 289 μg total phenolics/g dry weight (DW) respectively in autoclaved broccoli to 55 to ∼359 μg/g DW and 903 to ∼3105 μg/g DW respectively in LAB fermented broccoli puree. Differential impacts of LAB isolates on the chemical composition of autoclaved broccoli were observed, with the major differences being the significant increase in phloretic acid after fermentation by F1-F5 and an elevated glucoraphanin level in ferments by F1 and BF2. LAB fermentation is a promising way to increase the content of glucosinolates and polyphenolic compounds in broccoli, making the ferments attractive for use as functional ingredients or as a whole functional food.

Phlorizin ( 1 ) was anaerobically incubated with human intestinal bacteria and five biotransformation products ( 2 – 6 ) were obtained. Their structures were elucidated as phloretin ( 2 ), phloroglucinol ( 3 ), phloretic acid ( 4 ), 2,3,4-trihydroxybenzenepropanoic acid ( 5 ), and phloretic acid methyl ester ( 6 ) on the basis of their spectroscopic data. Using high-performance liquid chromatography equipped with a diode array detector, chromatographic separation of 1 – 4 was performed on an analytical C 18 column. The time course of the biotransformation was studied to probe into the biotransformation mechanism of 1 by human intestinal flora. The abilities of isolated strains to transform 1 were also investigated in order to find an optimal transformation strain. In addition, the inhibitory activity of parent compound 1 and its three main biotransformation products 2 – 4 on mushroom tyrosinase was estimated. The result showed that 2 has better inhibitory effect on tyrosinase activity than 1 .