Removal of Glucosinolates from Defatted Rapeseed Meal by Extraction with Aqueous Ethanol

Abstract

Defatted rapeseed meals containing about 120μM glucosinolates/g were extracted with aqueous ethanol (75%). It was found that the extractability of glucosinolates depended on the history of the meal. From expelled, hexane extracted, toasted meal, the greater part of the glucosinolates could be removed by direct extraction with aqueous ethanol. This procedure incompletely extracted glucosinolates from open air desolventized meals. In that case, an incubation step prior to extraction was needed, involving heating of the meal in the presence of water (2g/g) at 40°C for 1h. The use of mustard seed meal (20mg/g) as a source of myrosinase and L-ascorbic acid (3mg/g) during incubation, proved to be essential for the removal of the glucosinolates from meal with a low endogenous myrosinase activity. Under these conditions, more than 99.5% of glucosinolates could be removed.