Influence of chemical treatment of mustrad-cake on its glucosinolate content and myrosinase activity

Finely ground mustard-cake was treated with copper sulphate and ferrous sul phate solutions individually at 0.25, 0.50, 0.75, 1.00% (w/w) levels after adjusting pH ( 4, 5, 6, 7) maintaining 25% moisture followed by drying at 6 0 degreesC till complete drying. Both the chemicals were also mixed homogen eously as such with mustard-cake at the above mentioned levels. Cu and Fe c ontent in untreated, 1% copper sulphate and 1% ferrous sulphate treated-cak e was 38.25, 2592.38, 38.49 and 582.39, 580.85, 2690.30 ppm respectively. T otal glucosinolate content of mustard-cake (42.3 +/- 0.03 mmol/g), comprisi ng 3 butenyl isothiocyanate and 5 vinyl oxazolidine 2 thione (OZT), was red uced more pronouncely as a result of treatment with either of the chemical than their supplementation, Lowest glucosinolate content was recorded as 1. 22 +/- 0.11 and 14.82 +/- 0.10 mmol/g after treatment with 1% copper sulpha te and 1% ferrous sulphate at pH 4. Copper sulphate treatment was more effi cient than ferrous sulphate treatment irrespective of the level of chemical . In none of the chemically treated and supplemented mustard-cake samples, OZT and nitriles were detected. Myrosinase activity of mustard-cake was dra stically reduced in copper sulphate treated -cake ( pH 5) than in ferrous s ulphate treated cake.