液压压榨澳洲坚果粕蛋白质提取工艺优化及其组成分析与功能性质

以液压压榨澳洲坚果粕为原料,采用碱溶酸沉法提取蛋白质,通过单因素与正交试验确定最佳提取条件,并对其组成与功能性质进行研究。结果表明:澳洲坚果粕蛋白质提取工艺各因素对提取率影响的主次顺序依次为料液比、碱溶p H值、提取时间、提取温度,且均达到了极显著水平(P0.01),最佳提取工艺条件为:料液比1∶50(g/m L)、碱溶p H 9、提取时间2 h、提取温度40℃。在此条件下提取率达到95.40%,纯度为65.46%。澳洲坚果粕蛋白质中清蛋白、球蛋白、醇溶蛋白、谷蛋白质量分数依次为:7.29%、14.58%、14.95%、63.18%。澳洲坚果粕蛋白质的等电点约为5.0。在适宜的p H值条件下,澳洲坚果粕蛋白质具有较好的溶解性、乳化性、乳化稳定性与泡沫稳定性,起泡性相对较差。在70℃温度条件下,吸油性达到最大值,为50.10%。

Extraction,Composition Analysis and Functional Properties of Protein Isolate from Hydraulic Expeller-Pressed Macadamia Nut Meal

The extraction of protein from hydraulic?expeller-pressed macadamia nut meal by alkali dissolution and acid precipitation was optimized using one-factor and orthogonal array design methods. The composition and functionality of the protein extract were evaluated. The results showed that alkaline pH, extraction time and temperature all had highly significant effects on extraction efficiency (P < 0.01), and these factors could be ranked in decreasing order of significance: alkaline pH, extraction time and temperature. The optimal extraction conditions were determined as follows: solid-to-liquid ratio, 1:50 (g/mL); pH value, 9.0; extraction time, 2 h; and extraction temperature, 40 ℃. Under these conditions, the yield and purity of protein extracted from macadamia nut meal were up to 95.40% and 65.46%, respectively. Albumin, globulin, gliadin and glutenin accounted for 7.29%, 14.58%, 14.95%, and 63.18% of the total proteins extracted from macadamia nut meal, respectively. The isoelectric point of the protein isolate was approximately 5.0. At the appropriate pH, the solubility, emulsifying capacity, emulsion stability and foam stability of macadamia nut meal protein isolate were good and the foamability was relatively poor. Its oil-binding capacity reached the maximum value of 50.10% at 70 ℃.