Comparison of isothermal and cycling temperature storage of filled dark chocolate products for accelerated shelf life prediction

Beside a loss in texture, the main quality aspect of filled chocolate products during storage is the development of fat bloom. For these products isothermal or cycling temperature storage tests are used for accelerated shelf life prediction. However, the applicability of these tests compared to real storage conditions is complicated and shelf life estimation is vague. Com;1;paring storage tests of different authors is difficult because products and analysis methods vary. Additionally most of the storage tests are performed to identify the reasons for fat bloom and therefore the storage conditions are not separately investigated. However, all studies agree that temperature has a major impact due to its influence on migration and crystallization. While migration is accelerated at higher temperatures, crystallization shows an optimum at lower temperatures. Therefore, migration and crystal state have to be evaluated during storage, as well as fat bloom formation. In this study, cold stamped dark chocolate shells with nougat filling were chosen to compare isothermal and cycling temperature storage conditions. Cycling temperature storage at adequate levels includes optimum for fat bloom formation, but takes crystallization and migration influence in unequal account. In contrast, isothermal storage at optimum temperature leads to faster fat bloom formation.