Effect of processing and preservation on L-ascorbic acid content in commercially cultivated jute leaves

Vitamin C, also known as ascorbic acid is essential nutrients that cannot produce in human body and meet up through diet. Jute leaves contain L-ascorbic acid. The amount of L-ascorbic is unknown in different varieties developed by Bangladesh Jute Research Institute. L-ascorbic acid content is affected by cooking or processing and preservation. Therefore, the experiment was conducted to investigate the content of vitamin C in the fresh jute leaves as well as the effect of cooking and preservation methods on L-ascorbic acid content in jute leaves. Fresh jute leaves of different varieties contain different amount of L-ascorbic acid 0.39g/10g to 0.64g/10g in Corchorus olitorius and 0.64g/10g to 0.92g/10g in Corchorus capsularis. C. capsularis contain more amount of L-ascorbic acid than the C. olitorius. Jute leaves of C. olitorius retain 95% L-ascorbic acid and C. capsularis retain 62% L-ascorbic acid after 15 min of boiling. Vinegar soaking leaves release more L- ascorbic acid by 5 min than the fresh leaves and then the L-ascorbic acid content was reduced by 15 min in both the species. Spraying vinegar treatment releases more L-ascorbic acid and increasing up-to 30 min treatment. Both oven dried and cold dried leaves retain small amount of L-ascorbic acid. L-ascorbic acid content was reduced in preserved jute leaf tea and soup powder also in both species. Usually, leafy vegetables are cooked before consumption and sometimes preserved vegetables are consumed when fresh vegetables may not available. So, this study may be useful to know the actual intake of L-ascorbic acid from the processed or preserved jute leaves.