Oral processing of two milk chocolate samples
Oral processing of two milk chocolate samples
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DOI：
10.1039/c2fo30173c
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发表时间：
2013-03-01
期刊：
影响因子：
6.1
通讯作者：
Wolf, Bettina
中科院分区：
文献类型：
--
作者：
Carvalho-da-Silva, Ana Margarida;Van Damme, Isabella;Wolf, Bettina
对两种成分和粘度相同的牛奶巧克力进行了口腔加工，以了解其质地行为。先前的研究表明，口腔涂层和相关属性（如从口腔中清除的时间）的差异是样本之间最具区别的。小组成员在吃两颗巧克力前后唾液的蛋白质浓度和特征也被纳入分析，但没有显示出与口感感知的任何关联。口腔处理后的巧克力样品的微观结构明显不同，由于巧克力在口中的相反转，其微观结构类似于乳剂，咀嚼20次后，口腔涂层较多的样品出现较少的絮凝现象。絮凝行为的差异反映在用激光衍射粒度分析仪获得的基于体积的粒度分布中。咀嚼10次和咀嚼20次后，口腔包膜较少和絮凝较多的样品显示出明显的双峰大小分布，峰在40和500 μ m左右，而咀嚼10次和咀嚼20次后，另一个样品的第二个峰较小，然后逐渐减弱。咀嚼20次后的平均粒径分别为184 +/- 23 μ m和141 +/- 10 μ m。此外，咀嚼10次和20次后，更多的口腔涂层样品熔化（80 +/- 8%，而咀嚼20次时为72 +/- 10%）。最后，使用旋转流变仪上的商用摩擦学附件，研究了软、硬表面（弹性聚合物/钢）和口内温度下的摩擦行为。揭示了复杂的材料行为。观察结果包括在非常低的滑动速度下摩擦系数的不同寻常的增加，最初两个样品重叠，到更多口腔涂层样品的三倍高的值。随后通常观察到摩擦系数随着滑动速度的增加而下降（混合和弹性流体动力状态），在更多的口腔涂层样品的情况下更陡峭，直到两个样品之间的差异在滑动速度接近0.2 mm s（-1）时可以忽略不计。在这些机制中摩擦学行为的明显差异开始允许基于对潜在材料行为的洞察力的感官和物理测量数据的相关性。这幅复杂的图片还包括两种样品在弹流动力状态晚期和水动力状态早期的可比较行为，直到观察到斜率的变化，然后，在更高的滑动速度下，较少的口涂层样品显示出更高的摩擦系数。总之，这项研究揭示了一种复杂的食物组合物在感官行为和与熔化和摩擦行为有关的物理材料特性之间的新相关性。
Oral processing of two milk chocolates, identical in composition and viscosity, was investigated to understand the textural behaviour. Previous studies had shown differences in mouthcoating and related attributes such as time of clearance from the oral cavity to be most discriminating between the samples. Properties of panellists' saliva, with regard to protein concentration and profile before and after eating the two chocolates, were included in the analysis but did not reveal any correlation with texture perception. The microstructure of the chocolate samples following oral processing, which resembled an emulsion as the chocolate phase inverts in-mouth, was clearly different and the sample that was found to be more mouthcoating appeared less flocculated after 20 chews. The differences in flocculation behaviour were mirrored in the volume based particle size distributions acquired with a laser diffraction particle size analyser. The less mouthcoating and more flocculated sample showed a clear bimodal size distribution with peaks at around 40 and 500 mu m, for 10 and 20 chews, compared to a smaller and then diminishing second peak for the other sample following 10 and 20 chews, respectively. The corresponding mean particle diameters after 20 chews were 184 +/- 23 and 141 +/- 10 mu m for the less and more mouthcoating samples, respectively. Also, more of the mouthcoating sample had melted after both 10 and 20 chews (80 +/- 8% compared to 72 +/- 10% for 20 chews). Finally, the friction behaviour between a soft and hard surface (elastopolymer/steel) and at in-mouth temperature was investigated using a commercial tribology attachment on a rotational rheometer. Complex material behaviour was revealed. Observations included an unusual increase in friction coefficient at very low sliding speeds, initially overlapping for both samples, to a threefold higher value for the more mouthcoating sample. This was followed by a commonly observed decrease in friction coefficient with increasing sliding speed (mixed and elasto-hydrodynamic regime), steeper in the case of the more mouthcoating sample until the differences between the two samples became negligible at a sliding speed of approximate to 0.2 mm s(-1). The stark differences in the tribological behaviour in these regimes begin to allow correlation of data from sensory and physical measurements based on insight into the underlying material behaviour. The complex picture also included comparable behaviour of both samples in the late stages of the elastohydrodynamic regime and the early stages of the hydrodynamic regime, until a change of slope was observed and then, at higher sliding speeds, the less mouthcoating sample showed higher friction coefficients. In conclusion, this research uncovered novel correlations of a complex food composite between the sensory behaviour and the physical material properties relating to melting and friction behaviour.