挤压温度对火麻蛋白理化、加工功能特性的影响

Effects of extrusion temperature on physical, chemical and processing functional properties of hemp protein

中文关键词:  火麻仁饼粕  蛋白  挤压膨化  理化性质  功能性质

英文关键词:hemp protein  extrusion and expansion  physical and chemical properties  processing functional properties

中文摘要:

      目的 探究不同挤压温度(60、80、100、120、140℃)对火麻蛋白的理化、加工功能特性的影响。方法 以火麻蛋白饼粕为原料, 经过挤压前处理后, 使用碱溶酸沉法从火麻蛋白饼粕中提取火麻蛋白, 测定其提取率、等电点、氮溶解指数、体外消化率、巯基和二硫键含量、持水性和持油性, 并利用傅里叶红外光谱、内源性荧光光谱、差式扫描量热仪、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、扫描电镜对火麻蛋白进行表征。结果 挤压处理会导致火麻蛋白的提取率、体外消化率和游离巯基含量提高, 但在140℃时游离巯基含量降低, 等电点、持水性、总巯基和二硫键含量均有所下降, 随着挤压温度的升高, 火麻蛋白的氮溶解指数先下降再升高后下降, 持油性先降低后升高; 傅立叶红外光谱和内源性荧光光谱结果表明挤压不会引起火麻蛋白生成新的吸收峰, 挤压温度的升高会使其荧光强度先增加后减少; 差式扫描量热仪结果表明在挤压温度为120℃时, 火麻蛋白氢键断裂, 热焓值升高; 十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示挤压处理使火麻蛋白形成了大的聚集体, 条带较未挤压的火麻蛋白颜色变浅; 观察扫描电镜发现挤压处理导致火麻蛋白表面孔隙减小, 并且随着挤压温度的升高逐渐形成了致密的熔融结构。结论 挤压膨化会对火麻蛋白的理化、加工功能特性产生一定的影响, 本研究可为火麻蛋白的深加工提供理论依据。

英文摘要:

      Objective To investigate the effects of different extrusion temperatures (60, 80, 100, 120, 140℃) on the physical, chemical and processing functional properties of hemp protein. Methods The hemp protein was extracted from the hemp protein meal by alkaline solution and acid precipitation after pre-extrusion treatment. The extraction rate, isoelectric point, nitrogen dissolution index, in vitro digestibility, content of sulfhydryl and disulfide bonds, water and oil retention were determined. The hemp protein was characterized by Fourier transform infrared, endogenous fluorescence spectroscopy, differential scanning calorimeter, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and scanning electron microscope. Results Extrusion treatment could increase the extraction rate, in vitro digestibility and free sulfhydryl group content, but decrease the free sulfhydryl group content at 140℃, and the isoelectric point, water holding capacity, total sulfhydryl group and disulfide bond content decreased. With the increase of extrusion temperature, the nitrogen dissolution index of hemp protein first decreased, then increased, and then decreased, and the oil retention index first decreased and then increased. The results of Fourier transform infrared and endogenous fluorescence spectra showed that the extrusion did not cause new absorption peaks, and the fluorescence intensity increased first and then decreased with the increase of extrusion temperature. The results of differential scanning calorimeter showed that the hydrogen bond of hemp protein was broken and the enthalpy value increased when the extrusion temperature was 120℃. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that large aggregates of hemp protein were formed by extrusion treatment, and the bands were lighter than those of unextruded hemp protein. Scanning electron microscopy showed that the surface pores of hemp protein were reduced by extrusion treatment, and a dense melting structure was formed gradually with the increase of extrusion temperature. Conclusion Extrusion and expansion can affect the physical, chemical and processing functional properties of hemp protein to some extent, this study can provide a theoretical basis for further processing of hemp protein.