Optimisation of ultrasonic-assisted extraction of phenolic compounds, antioxidants, and anthocyanins from sugar beet molasses

Response surface methodology was used to optimise experimental conditions for ultrasonic-assisted extraction (UAE) of functional components from sugar beet molasses. The central composite design (CCD) was used for the optimisation of extraction parameters in terms of total phenolic contents, antioxidant activities and anthocyanins. Result suggested the optimal conditions obtained by RSM for UAE from sugar beet molasses were as follows: HCl concentration 1.55–1.72 mol/L, ethanol concentration 57–63% (v/v), extraction temperature 41–48 °C, and extraction time 66–73 min. In the optimal conditions, the experimental total phenolic contents were 17.36 mg GAE/100 mL, antioxidant activity was 16.66 mg TE/g, and total anthocyanins were 31.81 mg/100 g of the sugar beet molasses extract, which were well matched the predicted values. Teen compounds, i.e. gallic acid, vanillin, hydroxybenzoic acid, syringic acid, cyanidin-3-O-rutinoside, cyanidin-3-O-glucoside, catechin, delphinidin-3-O-rutinoside, delphinidin-3-O-glucuronide and ferulic acid were determined by HPLC-DAD-MS/MS in sugar beet molasses.