[Chemical mechanisms involved in slow fire processing and pulverization of Brassica juncea]

This article dealed with the effects of processing method and duration on the major bioactive components (sinigrin and sinapine thiocyanate) in Brassica juncea. The contents of sinigrin and sinapine thiocyanate in decoctions of raw and processed B. juncea were determined and compared by high performance liquid chromatography on a Alltima C18 column (4.6 mm x 250 mm, 5 microm) at 35 degrees C with the acetonitrile-0.1% phosphoric acid as the mobile phrase in gradient elution. The detection wavelength of sinigrin and sinapine thiocyanate was set at 227 nm and 326 nm, and the flow rate was 1.0 mL x min(-1). It was found that with the extended processing duration, the contents of sinigrin and sinapine thiocyanate first increased and then decreased: i.e., 0-2 minutes they increased gradually (for sinigrin, by 9.65% in processed products and 356. 10% in powder; for sinapine thiocyanate, by 12.82% in processed products and 3.41% in powder), and achieved their highest content at 2 min; then, decreased during the next 5 minutes (for sinigrin, by 80.35% in processed products and 82.09% in powder; for sinapine thiocyanate, by 14.29% in processed products and 17.54% in powder), suggesting that processing duration could significantly affect the contents of bioactive components in B. juncea, enzymatic hydrolysis of sinigrin when the seed is crushed in the present of moisture may be responsible for the content change. It is recommended that the slow fire should be the best processing method and the raw seed could be used directly in the water extracts related industrial production.