Influence of Shading Cultivation on Free Amino Acid, Sinigrin, and Allyl Isothiocyanate Contents of Leaf Mustard (Brassica juncea var. cernua)

Abstract

Leaf mustard (Brassica juncea var. cernua) is cultivated well in Okinawa Prefecture. The Okinawa region belongs to a subtropical climate and the cultivation of leaf mustard requires sunshade treatment. In this investigation, leaf mustard was cultivated under shading material and chemical components were compared with those with no shading. About 53% of sunshine was shaded by the material. Edible parts were subjected to the analysis of the content of free amino acids, sinigrin and allyl isothiocyanate using high-performance liquid chromatography. Many contents of leaf mustard cultivated with the no shading treatment were higher than those cultivated with shading. The flesh weight and dry matter rate of leaf mustard cultivated with no shading were also higher than those cultivated with shading. This suggested that cultivation of leaf mustard with shading was able to control the texture and content of various flavorful chemical components.