Abstract:

Yellow pigment in flowers of Buddleja officinalis Maxim was extracted by water with the assistance of ultrasound. The effects of ultrasound power, extraction time, water-to-solid ratio on the yield of yellow pigments (expressed as the absorbance of extract at 435 nm) were studied by conducting single factor tests. Then Box-Behnken experimental design involving the above 3 factors at 3 levels was employed, and coupled with response surface analysis to optimize the extraction conditions. Results showed that ultrasound treatment accelerated the extraction of yellow pigment. The optimum extraction conditions were as follows: ultrasound power 800 W, extraction time 24 min, the ratio of water to solid 27:1. Under such conditions, the theoretical absorbency of Buddleja officinalis Maxim yellow pigment can reach 0.257, while the experimental value is 0.259, with a relative stand error 0.78% to the theoretical value. The yield of yellow pigment reached up to 5.95% .

Key words: ultrasound-assisted extraction, Buddleja officinalis Maxim yellow pigment, response surface