Effects of different vegetable fats on chocolate properties

Viscosity, solid fat content (SFC), texture and melting profile have been studied by adding different vegetable fats, namely, hazelnut oil, palm kernel stearin and shea butter stearin to the dark chocolate formulation at a level of 5% (w/w) on product bases. Four different samples were tempered in a way to get a temper index 5 after conching with same steps. Then the samples were cooled at 12 oC for 2 hours after moulding in dimensions of 44 mm diameter and 4 mm height. The samples were stored at 18±3 oC up to the end of measurements. Viscosity and SFC measurements were done at the day of sample preparation. Melting profile and texture measurements were done after 0, 3, 15, 30, 45, 60 days storage.Viscosity, SFC, melting profile and textural changes of the dark chocolate samples that were prepared with different vegetable fats were evaluated. Viscosity of standard sample (only with cocoa butter) and samples that were prepared with hazelnut oil, palm kernel stearin and shea butter stearin were found to be 13 000 cP, 19 875 cP, 28 625 cP ve 16 875 cP, respectively at 40 oC and 2 RPM.When shea butter stearin mixed with cocoa butter, an increase in SFC of the mixture was observed, especially at 30 and 35 oC. But although palm kernel stearin has high SFC than cocoa butter, the mixture exhibited a significant decrease, especially at 20 oC, because of eutectic effect. SFC value of the hazelnut oil and cocoa butter mixture was decreased when compared with SFC of the cocoa butter.It was founded that the melting profile of the sample that was prepared with shea butter stearin had higher melting point and harder structure from first day to the end of 60th day compared to standard sample. In addition, because of incompatible structure with cocoa butter, palm kernel stearin spoiled the melting profile of the chocolate, decreased melting point and hardness of chocolate despite the high SFC of palm kernel stearin. Due to low SFC, hazelnut oil decreased the melting point of the sample and gave a softening effect on chocolate.Key Words: dark chocolate, cocoa butter, shea butter stearin, palm kernel stearin, hazelnut oil, melting profile, texture, solid fat content, viscosity