Abstract

Proteins were extracted from a prickly pear seed cake using the Osborne extraction method. Physico-chemical, antioxidant and functional properties of the major protein fractions (albumin and glutelin) were studied. Glutelin fraction presented good amount of proteins (60.42% dry weight) with appreciable essential amino acids content (24.45% of total amino acids). The Fourier transform-infrared spectroscopy spectra showed between ~ 1200 and 1700 cm⁻¹, characteristically peaks of proteins, namely, amide I, II and III for both fractions. Antioxidant activities of protein fractions were assessed in vitro through different antioxidant tests. The protein fractions exhibited good DPPH and metal scavenging activities. However, they demonstrated moderate reductive ability. Protein fractions had a minimum equilibrium surface tension at the isoelectric pH. They were characterized by interesting techno-functional properties such as emulsifying and foaming capacities which were affected by pH values. They also displayed significant water holding (480% for albumin fraction at pH 7) and oil holding (420% for glutelin at pH 7) capacities. The found results suggested that albumin and glutelin extracted from prickly pear seed cake could have important applications in food formulations.

Graphic Abstract

中文翻译：

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刺梨种子饼中主要蛋白质组分的理化，功能和抗氧化特性

摘要

使用奥斯本提取法从刺梨种子饼中提取蛋白质。研究了主要蛋白组分（白蛋白和谷蛋白）的理化，抗氧化剂和功能特性。谷蛋白部分表现出大量的蛋白质（干重的60.42％），必需氨基酸含量明显（占总氨基酸的24.45％）。傅里叶变换红外光谱显示在1200至1700 cm ^-1之间，两个部分的蛋白质的特征峰，即酰胺I，II和III。通过不同的抗氧化剂测试在体外评估蛋白质级分的抗氧化活性。蛋白质级分表现出良好的DPPH和金属清除活性。但是，他们表现出中等的还原能力。蛋白质级分在等电点pH下具有最小的平衡表面张力。它们的特征在于有趣的技术功能特性，例如受pH值影响的乳化和发泡能力。他们还显示出显着的保水能力（在pH 7时，白蛋白含量为480％）和保油能力（在pH 7的情况下，谷蛋白为420％）。研究结果表明，从花梨籽饼中提取的白蛋白和谷蛋白在食品配方中可能具有重要的应用。

图形摘要