Optimization of pH for extracting sinapates from mustard varieties using green technology

Abstract

Mustard seeds contain higher levels of phenolic compounds, especially sinapine, compared to many other oilseeds. Due to their rich bioactive composition, mustard seeds have considerable potential in food and pharmaceutical industries as antimicrobials, antioxidants, and chemoprotective agents. The yields of phenolic compounds, particularly the formation of canolol, could be substantially enhanced by modifying the pre-treatment conditions and extraction techniques. To achieve this, there is a need for innovative green technology methods to minimize environmental damage. This novel approach involved pre-heating by sautéing, and adjusting the pH of the extract to acid, alkaline or neutral conditions using safe household ingredients, such as vinegar and sodium bicarbonate. The treated whole or crushed seeds were then extracted by pressurized heating at 115 °C at 10.2 psi, and the extractability of the phenolic compounds was assessed.Statistical analysis of selected mustard varieties showed an interesting trend in which pH affected the mustard endogenous phenolic compound profile, in which neutral pH proved to be superior to acid and alkaline treatment Among the selected varieties, both yellow and black mustard had competitive amounts of sinapine, sinapic acid, and canolol. Sinapic acid and canolol were predominant in crushed black mustard seeds (2.71± 0.0.8 and 2.61± 0.35 mg/g DW, respectively) (p < 0.05). Meanwhile, crushed yellow mustard prevailed in sinapine concentration (385 ± 49.47 mg/g DW).Overall, on the basis of electrostatic interactions between the solvent and the extractants, using water with the combination of preheat treatment and pressure was an alternative green extraction method to optimize the extraction of phenolic compounds from Oriental, black, and yellow mustard seeds.