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Förslaget inkom 2010-06-02

The influence of emulsifiers on fat bloom development on chocolate


YKI – Your Research and Innovation Partner in Applied Surface Chemistry

YKI is a world-leading industrial research institute with a focus on innovation transfer in applied surface chemistry. YKI develops and transfers competence, solutions and new technologies to industrial sectors where surface chemistry is of importance. YKI works with a variety of industries including personal care, pharmaceutical, food, packaging and cleantech. YKI is part of Sweden’s leading research institute SP Technical Research Institute of Sweden.

Introduction: This Master’s thesis project is a part of the EU project ProPraline – Structure and processing for high quality pralines, where the development and prevention of fat bloom and cracking in chocolate pralines is researched. The research consortium consists of four academic partners, five companies, and three industrial associations for chocolate and confectionery industry. Within this framework, fat crystallization and the mechanisms of fat bloom are studied in a PhD thesis at YKI.
Chocolate is unique in that it is solid at room temperature and at the same time melts easily in the mouth. This property in chocolate is mostly due to the lipid matrix, i.e. the crystallized cocoa butter, which has six polymorphic forms, also described as form I-VI. Form V is the desired form in chocolate, achieved when it is well tempered (controlled crystallization) during production, while form VI is a thermodynamically stable transformation from form V, normally associated with fat bloom. Chocolate that has developed fat bloom is characterized by the loss of its initial gloss and the greyish/whitish haze formed on the surface. Thus, the development of fat bloom is a major issue that leads to reduced shelf-life in chocolate. Therefore, it is important to develop ways to control the fat crystallisation in chocolate, as well as other foods. One way to achieve this is by adding emulsifiers that alter the properties of the fat surface and the crystallisation process.

The project: In this project you will study how the addition of emulsifiers to cocoa butter and chocolate can influence the microstructure, fat migration and bloom development. You will use techniques such as differential scanning calorimetry (DSC), scanning electron microscopy (SEM), profilometry, X-ray diffraction to characterize the material. Your will summarize your research in written report and present it orally at YKI.

Your background: University level education in chemistry or/and chemical engineering. It is a benefit if you have any previous experience of physical chemistry of lipids, surface chemistry, interpretation of phase diagrams or any of the characterization techniques mentioned above.

Supervision: The daily supervision will be performed by Hanna Dahlenborg, PhD student at the Life Science and Chemical Industries Section, YKI. Head supervisors will be Dr. Anna Fureby and Dr. Daniel Kalnin, Life Science and Chemical Industries Section, YKI.

Starting date: Preferably August/September 2010.
Duration: 20 weeks (30 hp).
Contact: Hanna Dahlenborg, [email protected], www.yki.se


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