The influence of formulation and packaging material on the rheological properties of milk chocolate

Abstract

Fiber is a substitute for sugar in chocolates but changes its hygroscopicity and rheological characteristics if their packaging doesn’t avoid its moisture gain. The objective of this study was to evaluate the water vapor permeability of different packaging materials (BOPP/metBOPP (biaxial oriented polypropylene /metallized) BOPP/BOPP white and Cellophane) and the effect of the permeability on the rheological properties (by Casson model) of three types of milk chocolate: standard, with the addition of Inulin and Fructooligosaccharides during storage at 20 °C /75% RH. Due to the high hygroscopicity of the fibers, the initial moisture content of the chocolates with fibers was higher than that of standard chocolate. No increase in viscosity were observed at standard and with Inulin chocolates during 270 days at 20 °C/75% RH, regardless of the packaging material used. However, chocolate with FOS packed in cellophane showed changes in their viscosity, with values ranging from 4.63 Pa.s to 7.5 Pa.s after 210 days of storage. In addition, the Inulin chocolate in Cellophane package showed an increase at flow limit from 3 Pa to 6 Pa after 270 days. Therefore, the results indicated that chocolates with fibers should be packed in materials with medium or high barrier to water vapor, such as BOPP/metBOPP and BOPP/BOPP, to avoid rheological changes during storage.