Effects of different factors of ultrasound treatment on the extraction yield of the all-trans-β-carotene from citrus peels

The effects of different factors, including the material’s particle size, the extraction solvent, solid/solvent ratio, temperature, extraction time, the electrical acoustic intensity, liquid height and duty cycle of ultrasound exposure on the extraction yield of all-trans-β-carotene from citrus peels by ultrasound-assisted extraction (UAE) were investigated. The extraction yield was significantly affected by particle size. Dichloromethane caused the degradation of all-trans-β-carotene extracted during UAE. Ethanol showed a pronounced higher extraction yield during UAE in comparison with classical extraction (CE). The extraction yield of UAE had a peak value at 25 °C. In comparison with classical extraction, the extraction yield of UAE did not easily arrive at equilibrium. The extraction yield increased first, then decreased, then slightly increased with an increase in electrical acoustic intensity. The extraction yield of UAE decreased with increased liquid height. The extraction yield increased with increased duty cycle until equilibrium was achieved.