苦杏仁蛋白的功能特性

采用稀盐溶液浸提及等电点盐析相结合的方法提取制备苦杏仁蛋白，研究pH值、NaCl浓度、蛋白质量浓度和温度等因素对苦杏仁蛋白功能特性(溶解性、持水性、吸油性、乳化性及乳化稳定性、起泡性及起泡稳定性)的影响。结果表明：在等电点pI附近时，苦杏仁蛋白的溶解性、持水性、乳化性及乳化稳定性、起泡性最差；在较低NaCl浓度范围内(0～0.8mol/L)提高NaCl浓度可促进蛋白溶解性、乳化性及乳化稳定性、起泡性及起泡稳定性的提高，而较高的NaCl浓度对蛋白功能特性提高具有抑制作用；当蛋白质量浓度达到一定水平时(3～4g/100mL)，蛋白功能特性(乳化性及乳化稳定性、起泡性及起泡稳定性)提高趋于平缓；在适宜的温度范围内，提高温度可有效提高苦杏仁蛋白各项功能特性，但当温度继续上升，各项功能特性持续降低。

Functional Properties of Bitter Almond Protein

In this study, bitter almond protein was prepared through the combined use of diluted salt solution extraction and isoelectric point-salt precipitation. The effects of pH, NaCl concentration, protein concentration and temperature on functional properties (solubility, water-holding capacity, oil-absorbing capacity, emulsifying capacity, emulsion stability, foaming capacity and foam stability) of bitter almond protein were investigated systematically. The results showed that the solubility, water-holding capacity, emulsifying capacity and emulsion stability, foaming capacity of bitter almond protein were the lowest around isoelectric point (pI 4.1). The solubility, emulsifying properties and foaming properties could be improved with increasing NaCl concentration from 0 to 0.8 mol/L. However, higher level of NaCl concentration had a negative effect on these properties. The emulsifying and foaming properties of bitter almond protein were improved by increasing the protein concentration, but at a level of 3－4 g/100 mL, no obvious change in emulsifying capacity, emulsion stability, foaming capacity or foam stability was observed. Functional properties were significantly improved by suitable heating, but exposure to excessive heat caused a continuous decrease in the various functional properties.