Development of a Scalable Extraction Process for Anthocyanins of Haskap Berry (Lonicera caerulea)

Haskap (Lonicera caerulea) berry is rich in anthocyanins, particularly cyanidin-3-O-glucoside (C3G). In this investigation, a response surface methodology was applied to optimize the anhydrous ethanol-based extraction parameters to obtain the maximum yield of anthocyanins from haskap berry and to compare the recovery of anthocyanins from different extraction methods. The central composite design was employed to study the effect of three independent variables (X_A = ultrasonic bath power, X_B = extraction temperature, and X_C = extraction time) which were found to significantly affect the response variable total anthocyanin content (TAC) and fit to the second-order polynomial model. The optimum process parameters of X_A = 536 W, X_B = 62.3 °C, and X_C = 63.5 min provided a predicted TAC of 16.5 mg C3G equivalence (C3GE)/g dry weight (DW), which was experimentally validated with 16.1 mg of C3GE/g DW. The optimized ultrasonication-assisted extraction process using anhydrous ethanol was also effective in recovering quercetin glycosides, catechin, procyanidin B2, and iridoids, as determined by ultra-pressure liquid chromatography-mass spectrometry. Though the anthocyanin recovery was the highest (17.6 mg of C3GE/g DW) when a deep eutectic solvent consisting of citric acid and D-(+)-maltose was used, this solvent system has limitations when preparing dehydrated extracts for industrial applications. This study concludes that the effective extraction of anthocyanins and other phytochemicals from haskap berries can be performed using food-grade anhydrous ethanol.