戊糖乳杆菌发酵对花生不同蛋白组分结构的影响

Effect of Lactiplantibacillus pentosus Fermentation on the Structure of Peanut Proteins

通过戊糖乳杆菌(Lactiplantibacillus pentosus)对花生不同蛋白组分进行发酵处理,研究对比发酵前后花生分离蛋白、花生球蛋白及伴花生球蛋白分子结构的变化,阐明戊糖乳杆菌发酵对花生蛋白组分结构的影响规律。结果表明,戊糖乳杆菌发酵可显著提升花生球蛋白的游离巯基含量、表面疏水性和变性温度,显著降低β-折叠含量和变性焓值(P<0.05);可以降低花生分离蛋白、伴花生球蛋白中游离巯基含量、表面疏水性及变性焓值,显著提高花生分离蛋白、伴花生球蛋白的变性温度和α-螺旋含量(P<0.05)。通过粒径、Zeta电位和光谱分析发现:戊糖乳杆菌发酵可显著提升各花生组织蛋白的粒径和Zeta电位,使蛋白荧光强度峰值发生红移;与花生分离蛋白、伴花生球蛋白相比,花生球蛋白荧光扫描最大发射波长红移幅度分别超过1.3、2.4 nm,热变性温度增幅分别高出19.54%、14.75%,结合热特性和扫描电镜分析发现花生球蛋白在发酵后结构展开程度最大、热稳定性更高,证明戊糖乳杆菌发酵更易促进花生球蛋白的分子改性,对花生蛋白的凝胶改性起到良好的促进作用。

In order to clarify the influence of Lactiplantibacillus pentosus fermentation on the structure of peanut proteins,changes in the structure of peanut protein isolate(PPI),arachin and conarachin before and after fermentation were studied.The results showed that L.pentosus fermentation significantly increased the free sulfhydryl content,surface hydrophobicity and denaturation temperature,and significantly reduced theβ-folding content and denaturation enthalpy of arachin(P<0.05).It reduced the free sulfhydryl content,surface hydrophobicity,and denaturation enthalpy,and significantly increased the degeneration temperature andα-helix content of PPI and conarachin(P<0.05).Through particle size,potential and spectral analysis,we found that L.pentosus fermentation significantly improved the particle size and zeta potential of each protein component,and resulted in a red shift in their fluorescence peaks.In contrast to PPI and conarachin,the maximum fluorescence emission wavelength of arachin showed a 1.3 and 2.4 nm red shift,and arachin exhibited a 19.54%and 14.75%higher increase in thermal denaturation temperature,respectively.Thermal properties and scanning electron microscopic(SEM)analysis showed that arachin had maximum structural unfolding and higher thermostability after fermentation,indicating that L.pentosus fermentation is more likely to promote the molecular modification of arachin,and contributes to the gel modification of peanut proteins.