长白山榛仁分离蛋白及其主要组分的功能性质研究

Major Components and Functional Properties of Changbai Mountain Hazelnut Protein Isolate

摘要:

本文以长白山榛仁为原料，采用Osborne蛋白分级提取法得到纯度为72.32%，68.72%，40.60%的清蛋白（PAP），球蛋白（PGP）和谷蛋白（PLP），采用碱溶酸沉法得到纯度为90.31%的分离蛋白，对比分析四种蛋白的功能性质，结果显示：分离蛋白总巯基含量最高为6.71 μmol/g，清蛋白暴露巯基和二硫键含量最高分别为2.28 μmol/g和60.40 μmol/g。四种蛋白起泡性和泡沫稳定性随pH增大趋势相反，在pH5时，起泡性最低而泡沫稳定性最高，在偏酸或偏碱条件下，起泡性较好而泡沫稳定性皆较差。谷蛋白吸水性和吸油性均最高分别为3.40 mL/g和2.52 mL/g，清蛋白吸水性和吸油性最低分别为0.63 mL/g和1.79 mL/g 。四种蛋白质的溶解性，乳化性以及乳化稳定性随pH变化趋势相似，在等电点时最低。清蛋白、球蛋白、谷蛋白和分离蛋白中必需氨基酸含量占总氨基酸含量的29.83%、32.14%、35.23%和30.32%，除蛋氨酸外均能满足FAO/WHO规定成人需要摄入量。

Abstract:

Proteins were isolated from Changbai Mountain hazelnut and their functional properties were analyzed in this study. Osborne protein extraction was performed to obtain albumin, globulin and glutenin with purities of 72.32%, 68.72%, and 40.60%, respectively, while an alkali-solution and acid-isolation method was used to obtain a protein isolate with a purity of 90.31%. Functional properties of the four protein types were comparatively analyzed. The results showed that the protein isolate contained the highest total sulfhydryl content (6.71 μmol/g), while albumin extract contained the highest content of exposed sulfhydryl and disulfide groups (2.28 and 60.40 μmol/g, respectively). The emulsifying ability and emulsion stability of all four proteins showed opposite trends with increasing pH. For instance, at pH 5, the emulsifying ability was the lowest, while emulsion stability was the highest. Under acidic or alkaline conditions, emulsifying ability was good, while emulsion stability was poor. The water and oil absorption capacities of glutenin were the highest at 3.40 and 2.52 mL/g, respectively, while those of albumin were the lowest at 0.63 and 1.79 mL/g, respectively. Solubility, emulsifying ability, and emulsion stability trends with changes in pH were similar and the isoelectric point was at the minimum for all four protein types. The total amino acid content in albumin, globulin, glutenin, and the protein isolate was 29.83%, 32.14%, 35.23%, and 30.32%, respectively. Except for methionine, the amino acid content for the other three protein types met the FAO/WHO regulations for required intake in adults.