Texture Analysis: Is chocolate demoulding an issue for you?

In today’s chocolate manufacturing, automated equipment has replaced the manual processes which traditionally relied largely on the experience and skill of the chocolatier.
 
For quality control purposes and hence customer satisfaction it is increasingly important to apply the right processing conditions and controlling parameters, such as the time, the temperature, the moisture content and the relative humidity of the surrounding air.
Researchers at Leeds University have investigated the influences of these factors during the cooling stage of the chocolate manufacturing process to assess the ease of demoulding. Experimental determination of chocolate adhesion to a mould was performed using a fixture specifically developed for this work.  

The surface adhesion force (or stickiness) was measured by pulling a flat polycarbonate probe off a solidified chocolate sample – as shown schematically below – imitating the forces involved in the demoulding process of commercial chocolate bars.

The results demonstrated that processing parameters, like temperature, contact time, and the relative humidity of the surrounding environment, have a significant impact on chocolate crystallisation and solidification processes and on the adhesion of chocolate to a mould surface.

 

The importance of temperature controlled testing

A Peltier Controlled Cabinet made it feasible to maintain a controlled experimental temperature range between 0° and 50°C.
The hardness of the solidified chocolate samples was also measured to determine the effect of different processing conditions on the chocolate using a 2mm stainless steel cylinder probe to penetrate to a depth of 5mm. The maximum force obtained during this penetration was taken as a measure of the hardness.
This is a summary of work carried out at the School of Food Science and Nutrition at the University of Leeds and Nestlé Product Technology Centre in York, UK and published by Esther L. Keijbets, Jianshe Chen & Joselio Vieira in the Journal of Food Engineering, 98 (2010), 133-140.

This study, focusing on the adhesive properties of chocolate in the demoulding process, is just one of the numerous user-generated projects which demonstrate the flexibility and capability of Stable Micro Systems’ Texture Analysers.

View our Confectionery article 'Extra Texture' featured on pages 36-38 of Kennedy's Confection (October 2012 edition) which gives a summary of texture analysis tests on solid confectionery products.