Influence of glucosinolates and native enzymes on the nutritional value of low-glucosinolate rapeseed meal.

This study attempted to find out whether the low content of glucosinolates in the seed of the rapeseed cultivar Bronowski significantly affects the nutritional value of the seed meal. Glucosinolates were extracted from unheated meal with cold acetone, a process giving rise to only a slight inactivation of enzymes. Mice fed with a diet containing this meal as the protein source showed similar growth, feed intake and protein efficiency ratio to mice fed with heat-treated meal. When glucosinolates were added to the acetone-extracted meal, bringing them to about the same amount as before the acetone extraction, the growth response of the mice was as poor as that of mice fed with unheated, unextracted meal. Thus, even such low amounts of glucosinolates as found in Bronowski seed meal significantly affect the nutritional value of the diet as long as the appropriate enzymes are present. Besides myrosinase, other enzymes influencing the hydrolysis of glucosinolates appear to exist in the meal.