Application of a β-sitosterol + γ-oryzanol-structured Organogel as Migration Barrier in Filled Chocolate Products
Alexandra Wendt, Eckhard Flöter, Technische Universität Berlin 
D-14195, Germany

Organogelation has in the past decade drawn increasing attention because of its potential to play a major role in structuring lipid phases as an alternative to trans-unsaturated and saturated fatty acids. Even though numerous oil gelation systems have been studied thoroughly (e.g., Co et al) little work has been reported on the food product application of organogels. The work reported by Zetzl et al. on Frankfurters is an exception to this. The work reported here is concerned with the application of organogels structured with a mixture of  β-sitosterol and γ-oryzanol as an oil migration barrier in filled chocolate products. As known for the studies on the pure organogel (Sawalha et al.) this gelation system is very sensitive to humidity and hence limited in the range of its applications in food products. The chosen application is consequently related to a low water activity. Different model systems composed of chocolate, organogel, and nougat filling have been studied for elongated periods of time to assess the capability of the organogel to limit the extend of oil migration. As it is generally acknowledged oil migration into a chocolate layer has a profound effect on the promotion of the occurrence of chocolate bloom.  Even though it is counter intuitive to use a fat-continuous phase as a barrier between two fat phases this has been reported earlier to be successful (Nöbel et al.). In detail we have studied the effect of a separate gel film between the nougat filling and the chocolate layer, a chocolate layer in contact with gelled nougat filling, and a nougat filling gelled chocolate layer system. Oil migration was primarily monitored via the crystallizable amount of oil that migrated in the chocolate layer. This was achieved through DSC determination. Based on the experimental results presented a general evaluation of this organogel considered for purposes of migration reduction will be given.