The Effect of Micro-aeration on the Chocolate Oral Process

N. Charalambides ¹ , D. Bikos ¹ , G. Samaras ¹ , A. Sergis ¹ , P. Cann ¹ , M. Masen ¹ , Y. Hardalupas ¹ , C. Hartmann², J. Vieira ^3
1 Department of Mechanical Engineering, Imperial College London, ² Nestlé Research, Lausanne, ³ Nestlé Product Technology Centre, York.

A​bstract

Aeration in food products has been widely utilised in the food industry to develop healthier foods by reducing the energy content and improving the consumer’s experience. Aeration in chocolates has a significant impact on the mechanical, thermal and tribological oral processes which may lead to improved sensory attributes. This study aims to characterise the oral processes such as the first bite conditions and the thin film formation for two chocolate materials, a non-aerated and aerated one. Mechanical, heat transfer and tribological experiments were employed to measure the material properties, which could be correlated with consumer attributes such as hardness, chewiness and smoothness. Mechanical tests included uniaxial compression tests to measure material properties such as Young’s modulus and yield stress together with in vivo mastication tests to define the fragmentation performance of the two materials. Steady and unsteady heat transfer numerical tests performed to measure thermal properties such as thermal conductivity and specific heat capacity, predicting the effect of micro-aeration on the melting time. A novel tribological rig that mimics the tongue-palate interaction, including the effect of artificial saliva, was developed to measure the friction coefficient for both types of chocolates. The results showed significant effect of micro-aeration on all material properties resulting in lower fracture stresses and strains, a rapid melting time and a lower friction coefficient. The work provides a new insight of how micro-aeration affects the oral process, leading to potential tools for designing products with improved consumer perception and/or higher nutritional profile.