香菇蛋白的提取工艺优化、功能特性及氨基酸评价

Optimization of Extraction, Functional Characteristic, and Amino Acid Evaluation of Lentinula edodes Protein

摘要:

该研究采用响应面优化超声波辅助提取香菇蛋白工艺，确定蛋白质的最佳提取条件为料液比1:50（m/V）、pH值12，在功率90 W、50 ℃条件下超声提取16 min，蛋白提取率为28.56%，蛋白质纯度为61.70%。通过扫描电镜、傅里叶变位红外光谱对香菇蛋白结构特性进行分析，后对香菇蛋白的功能特性进行测定，并对香菇蛋白氨基酸组成进行分析和评价。结果表明，香菇蛋白呈颗粒状且表面较为粗糙，具有明显的蛋白特征官能团吸收峰；持水性在70 ℃时最好，为436.73%，在40 ℃持油性最佳，为179.47%，起泡性、乳化性与蛋白质量浓度呈正相关。氨基酸分析发现香菇蛋白中含有17种氨基酸，必需氨基酸占氨基酸总量的比值（E/T值）和必需氨基酸与非必需氨基酸的比值（E/N值）均高于FAO/WHO理想蛋白质标准，是一种优质的蛋白质，且具有较高的营养价值。该研究为香菇蛋白的利用奠定了基础。

Abstract:

Response surface methodology was used to optimize the ultrasonic-assisted extraction of Lentinula edodes protein (LEP). The optimal extraction conditions determined were solid-liquid ratio 1:50 (m/V), pH 12, and ultrasonic extraction at 90 W and 50 ℃ for 16 min. The extraction rate and purity of protein extracted were 28.56% and 61.7%, respectively. The structural characteristics of LEP were analyzed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR); additionally, the functional characteristics were determined and the amino acid composition was analyzed. The SEM results showed that the surface of LEP is granular and rough, and FT-IR spectra demonstrated obvious absorption peaks indicative of characteristic functional groups of protein. The functional property analysis suggested that the water holding capacity is highest (436.73%) at 70 ℃ while the oil holding capacity peaks (179.47%) at 40 ℃. Meanwhile, the foaming and emulsifying properties were positively correlated with protein concentration. Amino acid analysis identified 17 kinds of amino acids in LEP. Both the ratio of essential amino acids to total amino acids (E/T) and the ratio of essential amino acids to nonessential amino acids (E/N) were higher than the FAO/WHO ideal protein standards, indicating the high-quality of LEP. Moreover, LEP exhibited a high nutritional value on amino acid evaluation. This study thus lays a foundation for the improved utilization of LEP.