Microwave-assisted Extraction Technology and Functional Properties of Protein from Amygdalus communis L. Seed Kernel

The protein was extracted from almond (Amygdalus communis L.) seed kernel by microwave-assisted alkaline extraction and acid precipitation method. Based on single factor test, the effect of microwave power, microwave time, extracted pH, extracted temperature and solid/liquid ratio (W/V) on the extraction rate of protein were studied according to L₁₆(4⁵) orthogonal test. The results showed that the optimum microwave-assisted extracting conditions of protein from almond seed kernel were microwave power 300 W, microwave time 180 s, extracted pH9.5, extracted temperature 50 ℃ and solid/liquid ratio 1:25 g/mL. The extraction rate of protein was 46.69% under the above optimal extracting conditions. Compared with commonly extracted methods, the functional properties of almond seed kernel protein by microwave-assisted were improved, such as solubility, water holding capacity, oil holding capacity, emulsifying ability and foaming ability were increased by 15.35%, 26.07%, 26.22%, 30.61% and 20.53%, respectively. the emulsion stability and foam stability were slightly decreased by 1.05% and 13.29%, respectively. It was concluded that microwave-assisted treatment would be favor to increase the extraction rate and improve functional properties of almond seed kernel protein.