乳脂肪球口腔聚合特性对奶油感感知的影响机制

Creaminess is the most appreciated sensory attribute by consumers. Creaminess perception is closely related to the properties of milk fat, which mainly depends on the friction coefficient of fat during oral processing. Fat coalescence can significantly improve oral friction and enhance the effective perception of creaminess. However, the effect of in-mouth coalescence characteristics of milk fat globules on creaminess perception remains to be elucidated. In this study, firstly, milk fat globules with different instability towards coalescence will be prepared by varying the interfacial components of milk fat globule membrane, the proportion of solid fat and the particle size. Then the in-mouth coalescence characteristics of milk fat globules in emulsion and gel system will be evaluated separately by simulating the oral processing conditions along with different inducing ways towards coalescence. At the same time, the tribological properties will be determined by the tribometer, and the mechanism of in-mouth coalescence characteristics of milk fat globules on tribological properties will be analyzed. Finally, the Temporal Check-All-That-Apply and other sensory analysis will be used to evaluate the creaminess perception. By combining rheological properties, fat oral coating and aroma release content, along with the principal component analysis, effect of in-mouth coalescence characteristics of milk fat globules and the corresponding oral friction properties on creaminess perception will be revealed. The finding of this study will provide a scientific basis for precise regulation of milk fat globule microstructure and improvement of milk fat efficacy, and also provide a reference for the development of low-fat food with high creaminess perception.

奶油感是最受消费者喜爱的食品感官属性。奶油感与乳脂肪属性密切相关，主要取决于脂肪在口腔中的摩擦学特性。调控脂肪聚合可显著改善口腔脂肪摩擦性，增强奶油感有效感知，然而乳脂肪球的口腔聚合特性对奶油感感知的影响机制尚不明确。本项目首先通过调控乳脂肪球膜界面组分、结晶态脂肪比例及粒径，构建具有不同聚合稳定性的乳脂肪球模型；然后模拟口腔加工条件，设定不同的诱导脂肪球聚合方式，评价脂肪球在乳液与凝胶两种体系下的聚合特性，阐释乳脂肪球特性与口腔聚合的关系；利用压力控制流变仪测定乳脂肪的口腔摩擦性，分析脂肪球聚合特性对口腔摩擦性的影响；最后采用动态时间多选型感官测试评价乳脂肪的奶油感，并结合流变性、口腔表面脂肪沉积能力和风味物质含量，采用主成分分析等手段，多角度揭示乳脂肪球口腔聚合特性对奶油感感知的作用机制。本研究为精准调控乳脂肪微结构、充分发挥乳脂肪效能提供科学支撑，为开发高奶油感的低脂食品提供理论依据。

天鹅绒般的奶油感是大部分乳制品与非乳类高脂食品（如甜点、巧克力）等食品共同具有的特性，是最受消费者喜爱的食品感官属性之一。奶油感与脂肪属性密切相关，但过量摄入脂肪存在健康风险。因此，如何在不增加甚至降低脂肪含量的基础上天然地增强奶油感的感知，成为国际食品科学领域研究的难点。.针对以上问题，项目建立了奶油感定量表征的方法，明确了乳脂肪球特性与其口腔聚合特性的构效关系，阐释了乳脂肪球聚合特性对口腔摩擦学特性的影响机制，揭示了乳脂肪球口腔聚合特性在奶油感感知中的作用机制。通过项目采用顶空固相微萃取-气相色谱-四极杆飞行时间质谱法结合偏最小二乘回归分析，发现口腔加工后2,3-丁二酮的释放率可用于定量表征发酵乳乳脂香气的感知；通过模拟口腔加工，利用原位仿生摩擦仪耦合共聚焦显微镜实时观测等技术，揭示了Stribeck摩擦曲线中第三区域的斜率v3与乳液凝胶的乳脂感具有最大相关性，可用于定量表征乳液凝胶的乳脂感的光滑感感知。建立了乳液凝胶的双峰摩擦曲线分区，首次提出针对乳凝胶体系的脂肪含量与摩擦系数的关系可精准分为零脂、低脂（1.5 ~ 4.5%）和高脂（6.0 ~ 10.5%）三种。通过调控脂肪酸组成调控甘油三酯结晶态脂肪含量，首次揭示乳脂肪内结晶态脂肪含量达到40%时最利于乳脂肪的口腔聚合及奶油感的感知；通过重力结合离心分离技术筛选脂肪球粒径大小不同的牛乳，利用凝胶时脂肪球自然上浮的原理，经过简单叠加调控凝胶网络的脂肪球分空间分布，在不增加整体脂肪含量的基础上使奶油感的有效感知提升了32.5%。项目研究结果对调控乳脂肪特性以提升产品奶油感感知提供了重要依据。.项目共发表SCI论文7篇，卓越期刊论文1篇（均为第一标注）；申请专利3项，授权1项，培养硕士研究生2名，获2021年度中国商业联合会科学技术奖一等奖1项。