Controlling (bio)chemical conversions of health-related plant-based compounds by processing: The case of Brussels sprouts and leek

Brussels sprouts and leek are suppliers of multiple health-related compounds, yet understudied on how processing impacts their concentration. In this study, the plant tissue structure was altered by processing to direct endogenous enzyme-substrate interactions. For this, both conventional and novel processing techniques were employed. Heating intact vegetables prior to high shear mixing resulted in relatively good preservation of health-related compounds, attributed to a prompt inactivation of endogenous enzymes. Oppositely, high shear mixing prior to heating facilitated over 82% conversion for both vitamin C, S-alk(en)yl-L-cysteine sulfoxides (ACSOs) and glucosinolates. Pulsed electric field (PEF) treatment prior to heating, resulted in ±25% ACSOs conversion, yet no glucosinolates conversion. PEF treatment effectiveness is attributed to substrate-enzyme localization in the matrix and cell size. Vitamin K1 remained relatively stable during all treatments. It was postulated that higher concentrations of vitamin C protect carotenoids against oxidation pointing to interaction effects among health-related compounds.Industrial relevance textThis research paper gives more insight into how (the sequence of) commonly used pretreatments (e.g. heating, mixing) and more innovative pretreatments (e.g. pulsed electric field) can have an impact on the health potential of vegetables. The considered vegetables (Brussels sprouts and leek) are highly industrial relevant and insights may be extrapolated to other vegetables of these large plant families. By understanding which (bio)chemical reactions can occur during certain pretreatments (e.g. degradation or potential formation of health-related compounds), industry can perform pretreatments more thoughtfully and consequently steer the health potential of vegetable products. Pulsed electric fields are currently not commonly used in vegetable processing. However, this processing technique can enable certain enzymatic conversions, of which some could result in formation of health beneficial compounds, without losing the vegetable structure. Therefore, applying pulsed electric fields in the vegetable processing industry could have large potential. The aim of this research is to open the door to more research on pulsed electric fields applied on vegetables, so the vegetable industry becomes acquainted with using this technique.