A Method to Assess Changes in Mechanical Properties of Chocolate Confectionery Systems Subjected to Moisture and Fat Migration During Storage

Abstract

An Instron universal testing machine was used to assess fundamental parameters, such as Young's modulus, tensile strength and tensile strain, in order to determine the effect of fat and moisture migration on the mechanical properties of chocolate during storage. Two thin steel anchorages were inserted into each end of the chocolate samples during molding. These anchorages were used to mount the samples in the instrument without inducing stresses prior to the start of the experiment. Longitudinal forces applied to the chocolate provided a measure of the strength of the bond between different chocolate components (nonfat solids and cocoa butter). The new method proved to be a valid technique that can be used to measure fundamental mechanical parameters and quantify the impact of fat or moisture migration. PRACTICAL APPLICATIONS The described method enables traction test of chocolate without inducing stresses from the instruments' clamps, thus enabling more precise measurements of fundamental mechanical parameters. The material properties of the chocolate during storage could be quantified and compared with samples subjected to fat or moisture migration, which is a crucial quality defect in confectionery products. The new methodology using an Instron universal testing machine allows for better understanding of the effect of migration from the filling, different chocolate recipes (milk, dark and white) and processing on the material properties in chocolate during storage, which are strongly related to quality or sensorial perception. The assessed fundamental parameters can also be used in mathematical modeling of quality defects such as the cracking behavior of chocolate pralines.

Tensile Strength of Dark Chocolate

“…The obtained values of tensile strength are in agreement with results presented by Svanberg et al (2012). The explanation of observed results should be based on a detailed analysis of chocolate microstructure.…”

Effect of micro-aeration on the mechanical behaviour of chocolates and implications for oral processing

“…[28][29][30] However, compared to the number of reported rheological studies of melted (liquid) chocolate, there are limited studies available in the literature investigating in depth the mechanics of chocolates at solid-state. [31][32][33][34] From these, only Svanberg et al 34 measured the mechanical properties such as elastic modulus using a newly proposed experimental method. No studies according to the authors' knowledge used systematic mechanical protocols to determine the mechanical properties of either aerated or non-aerated chocolates, such as the Young's modulus, Poisson's ratio, yield stress and fracture toughness.…”

Chocolate Swelling during Storage Caused by Fat or Moisture Migration

“…Thus, the material properties in the chocolate shell are highly influenced by migration of filling components (Svanberg and others 2011). Fat migration dissolves parts of the crystalline cocoa butter, and consequently decreases the solid fat content (SFC) of the chocolate.…”