Abstract:

In this study, the extraction conditions for improved yield of polyphenols from haskap berries (Lonicera caerulea
L.) were optimized using single factor experiments and response surface methodology involving three independent variables
at three different levels. The optimum conditions for polyphenol extraction were determined as follows: the extraction
solvent was 50% ethanol with a solvent to solid ratio of 1:25 (g/mL), and the extraction was performed at 40 ℃ with a
microwave power of 500 W for 90 min. Under these conditions, the extraction yield of polyphenols from haskap berries was
7.52 mg/g. In addition, the extracted polyphenols had a strong scavenging capacity against superoxide anion, 1,1-diphenyl-
2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ehtylbenzothiazoline-6-sulfonic acid) diammonium salt radical (ABTS+·) free
radicals. Highly significant positive correlation was found between total polyphenol content and superoxide anion or DPPH
free radical scavenging capacity (P < 0.01) and the correlation with ABTS+· free radical scavenging capacity was positive
significantly (P < 0.05).

Key words: Lonicera caerulea L., polyphenols, ultrasonic-assisted extraction, response surface methodology, antioxidant capacity