Subcritical water extraction of glucosinolates from mustard (Brassica juncea L.) seed meal

Mustard (Brassica juncea L.) seed meal is known to have a high amount of glucosinolates. Glucosinolates are identified to have anti-viral, anti-cancer, and anti-bacterial properties. Therefore, it is important to extract glucosinolates from mustard seed meal using subcritical water (SW) extraction. However, the study also employs methanol extraction of glucosinolates from the mustard seed meal. Sinigrin is a type of glucosinolates that is focused in this study because it is the most abundant substance in the mustard seed meal. The sinigrin yield from SW extraction is then compared to the result obtained from methanol extraction. SW extraction of sinigrin was performed by varying extraction time (5-15min), extraction temperature (110-140 oC), and solid-to-solvent ratio (1:20-1:40 g/ml). The ANOVA showed that extraction time had a significant effect, while extraction temperature and solid-to-solvent ratio had high significant effect on sinigrin yield. By RSM analysis, the maximum predicted yield of sinigrin (53.01µmol/g seed meal) obtained as an optimum condition of using extraction time (7.4min), extraction temperature (131 oC), and solid-to-solvent ratio (1:33 g/ml). At this condition, the total glucosinolates content of Brassica juncea L. seed meal was 64.18µmol sinigrin equivalent/g seed meal. These results are similar to sinigrin yield (52.467µmol/g seed meal) and total glucosinolates (61.54 µmol sinigrin equivalent/g seed meal) from methanol extraction. However, SW extraction promotes shorter extraction time than the methanol extraction