明胶对凝胶油基植脂奶油搅打性能的影响机制

Mechanism of effect of gelatin on whipping properties of oleogel-based whipped cream

该文以明胶作为乳化体系中的主要蛋白质制备出一种新型搅打植脂奶油,研究了明胶添加量(0.5%~1.5%,质量分数)对其搅打性能的影响规律与机制。结果表明,明胶能吸附在油水界面与乳化剂一起共吸附以降低界面张力稳定搅打前乳液,且随着明胶添加量的升高(0.5%~1.5%),乳液粒径显著减小33.69%。0.5%~1%明胶添加量的样品打发性能优异,1.5%的打发倍数较低。微观观察结果表明,明胶添加量较低的奶油乳液黏度低,易于搅打充气,脂肪部分聚结的程度低,打发倍数更高;高浓度明胶植脂奶油黏度较高,难以搅打充入气体。搅打奶油的短期保形性和质构性能也随着明胶添加量的增加而显著提升,流变结果显示搅打奶油是弱凝胶体系,且随着明胶添加量的上升,屈服应力显著增大,搅打奶油内部网络更为坚固,从而奶油保持形状的能力更好,硬度、黏性也更高。因此,明胶改善搅打奶油品质的机制是明胶在奶油连续相中相互作用,形成了明胶网络结构,从而提升奶油的搅打性能。这为明胶在搅打植脂奶油中的应用提供了理论基础。

A new whipped cream was prepared by using gelatin as the main protein in the emulsification system,and the effect of gelatin concentrations(0.5%-1.5%)on the stability of whipped cream was investigated in this study.Results indicated that gelatin was adsorbed at the oil-water interface with the emulsifier to reduce the interfacial tension and stabilize the pre-whipped emulsion,and the particle size of the emulsion significantly decreased by 33.69%with the increase of gelatin concentration.The samples with 0.5%-1%gelatin concentration had excellent overrun,and the overrun of 1.5%was low.CLSM results demonstrated that the cream with low gelatin concentration had low viscosity and was easy to whip and aerate,and the partial coalescence of fat was low,so the overrun was higher,but the cream with high gelatin concentration had higher viscosity and was difficult to whip.The short-term shape-retention ability and textural properties of whipped cream also improved significantly with the increase in gelatin concentration.Rheological results showed that whipped cream had a weak gel system,yield stress increased significantly with the increase of gelatin concentration,and the internal network of whipped cream became stronger,so the cream had better shape retention ability,hardness and viscosity.Therefore,the mechanism of gelatin to improve the quality of whipped cream is the interaction of gelatin in the continuous phase of cream forming a gelatin network structure,thus improving the whipping properties of cream.This provides a theoretical basis for the application of gelatin in whipped cream.