射流空化对大豆11S球蛋白结构和功能特性的影响

Effect of Jet Cavitation on the Structure and Functional Properties of Soybean 11S Globulin

以大豆11S球蛋白为研究对象,探究射流空化处理时间对不同质量浓度大豆11S球蛋白结构(荧光光谱、傅里叶变换红外光谱、表面疏水性以及羰基、巯基和二硫键含量)与功能特性(溶解度、乳化特性、起泡特性)的影响。结果显示:在射流空化处理下,2 g/100 mL与5 g/100 mL大豆11S球蛋白的荧光最大吸收波长(λmax)随处理时间的延长呈先红移后蓝移的趋势,荧光强度呈先升高后降低的趋势,且5 g/100 mL大豆11S球蛋白λmax均大于2 g/100 mL;2 g/100 mL大豆11S球蛋白中α-螺旋与β-折叠转变为β-转角,在处理末期,β-转角向α-螺旋转变,无规卷曲结构相对含量在处理过程中变化不明显;5 g/100 mL大豆11S球蛋白中α-螺旋、β-折叠与β-转角转变为无规卷曲结构,在处理末期,无规卷曲和β-转角向α-螺旋和β-折叠转变;两种质量浓度的大豆11S球蛋白表面疏水性、羰基与游离巯基含量均随处理时间的延长呈先升高后下降的趋势,二硫键含量呈现先下降后升高的趋势;11S球蛋白的溶解度、乳化特性与起泡特性均得到明显改善,且5 g/100 mL大豆11S球蛋白与2 g/100 mL大豆11S球蛋白相比,结构和功能特性的变化更明显。结果表明:射流空化技术可改变大豆11S球蛋白的结构,进而改善其溶解、起泡和乳化特性,且5 g/100 mL大豆11S球蛋白的展开与聚集程度更明显,功能特性更佳。

The effect of different durations of jet cavitation treatment on the structural(fluorescence spectrum,Fourier transform infrared spectrum,surface hydrophobicity,and the contents of carbonyl groups,sulfhydryl groups and disulfide bonds)and functional properties(solubility,emulsifying properties,and foaming properties)of soybean 11 S globulin at different concentrations was investigated.The results indicated that with the prolongation of jet cavitation treatment time,the maximum absorption wavelength(λmax)of 11 S globulin at concentrations of 2 and 5 g/100 mL showed a red shift first and then a blue shift(the higher the concentration,the higher theλmax),and the fluorescence intensity increased first and then decreased.Theα-helix andβ-sheet structure of 11 S globulin at 2 g/100 mL were converted intoβ-turn.Toward the end of the treatment,β-turn was converted intoα-helix,and the content of random coils did not change significantly during the entire treatment period;at 5 g/100 mL,theα-helix,β-sheet andβ-turn were transformed into a random coil structure,and toward the end,the secondary structure was transformed from random coil andβ-turn toα-helix andβ-sheet.At both concentrations,the surface hydrophobicity and the contents of carbonyl groups and free sulfhydryl groups increased first and then decreased with increasing treatment time,while the opposite trend was found for the content of disulfide bonds.The solubility,emulsifying properties and foaming properties were significantly improved by jet cavitation,and this effect was more obvious at 5 g/100 mL than at 2 g/100 mL.These results showed that jet cavitation can change the structure of soybean 11 S globulin,and consequently improve its solubility,foaming properties and emulsifying properties,resulting in more obvious unfolding and aggregation of soybean 11 S globulin at 5 g/100 mL as well as more improved functional properties.