Determination of Isothiocyanate-Protein Conjugates in a Vegetable-Enriched Bread

Abstract

Vegetables of the plant order Brassicales are believed to have health-promoting properties, as they provide high contents of glucosinolates (GLS) and deriving from these, enzymatically and heat-induced breakdown products, such as isothiocyanates (ITC). Besides their positive physiological effects, ITC are electrophilic and can undergo reactions with food components such as proteins. Following the trend of improving traditional food products with GLS-rich ingredients, interactions of ITC with proteins can diminish the properties of both components—protein’s value and functionality as well as ITC’s bioactivity. In vegetable-enriched bread, where cresses (Lepidium sativum L. or Tropaeolum majus L.) are added to the initial dough, together with benzyl cyanide, benzyl isothiocyanate (BITC) is formed during the baking process. The aim of the present study was to investigate the possible migration behavior of the GLS breakdown products and the formation of ITC-wheat protein conjugates. After the baking process, the breads’ proteins were enzymatically hydrolyzed, and the ITC-amino acid conjugates analyzed using a LC-ESI-MS/MS methodology. In all samples, BITC-protein conjugates were detected as thiourea derivatives, while formation of dithiocarbamates could not be detected. The study showed that GLS and their breakdown products such as ITC migrate into the surrounding food matrix and undergo reactions with proteins, which could in turn lead to modified protein properties and reduce the bioavailability of ITC and lysine.

Impact of Different Plant Constituents on the Thermal Stability of Glucosinolates.

“…The formation of TUs in food by GLS-derived ITCs was reported previously. In these studies, formation of protein adducts after reaction of ITCs with lysine side chains in various foods such as curd with sprouts or vegetable-enriched bread was described (Krell, Cvancar, Poloczek, Hanschen, & Rohn, 2021;Kühn, von Oesen, Hanschen, & Rohn, 2018). Further, also arginine side chains of proteins form TUs with ITCs (Kawakishi & Kaneko, 1987).…”

Benzyl isothiocyanate improves the prognosis of Aspergillus fumigatus keratitis by reducing fungal load and inhibiting Mincle signal pathway

“…Studies revealed that BITC treatment reduced the lipid components in the conidia and hyphae of A. ochraceus and that BITC could covalently bind to aminophospholipids and phosphatidylethanolamine in the cell membrane ( Clemente et al, 2016 ; Nakamura et al, 2019 ). In addition, ITCs can react with nucleophiles such as thiol groups in proteins ( Krell et al, 2021 ). The mechanism of BITC damage to cell membranes may be involved in a reaction with lipid components and proteins on the cell membrane.…”

High-Performance Thin-Layer Chromatography-Immunostaining as a Technique for the Characterization of Whey Protein Enrichment in Edam Cheese

“…Pronase E digestion was performed according to Kühn et al (2018) and Krell et al (2021) [ 55 , 56 ]. A total of 2 mL of a PBS buffer (pH 7.4) was added to the lyophilizates of the 0.5 mL supernatants (c.f.…”