Optimization of Ultrasonic-assisted Extraction Protein from the Physalis pubescens L. Seeds

The Physalis pubescens L. seeds defatted as materials, the extraction rate of protein as index, on the basis of single factor experiments, such as ultrasonic power, extraction temperature, extraction time and extraction solution pH, the optimal extraction conditions were optimized by orthogonal experiment, and the solubility, emulsibility and foamability properties of the protein were analyzed. The extraction conditions of protein from Physalis pubescens L. seeds by ultrasonic-assisted alkali-soluble acid-precipitation method were optimized by orthogonal experiment. The solubility, emulsibility and foamability of the protein were analyzed. The results showed that the influence order of various factors on the extraction rate of protein was as follows: Extraction temperature>ultrasonic power>extraction solution pH>extraction time. When solid-liquid ratio was 1:15(g/mL), the optimum conditions of protein from Physalis pubescens L. seeds by ultrasound-assisted treatment were as follows: The extraction temperature 50 ℃, the extraction power 300 W, the pH of the extract solution 9.0, and the extraction time 50 min. Under this condition, the extraction rate of protein from Physalis pubescens L. seeds could reach 90.45%±0.16%. The protein from Physalis pubescens L. seeds extracted by ultrasonic-assisted method had the best solubility and emulsification when pH was 10.0, with the nitrogen solubility index (NSI) of 58.32% and the emulsification ability of 68.94 m²/g, and the foaming characteristic of the protein was the best at pH7.0, which was 43%. The extraction process can efficiently extract the protein from Physalis pubescens L. seeds, which provides a theoretical basis for the further application of the protein.