A collaborative study between professors Kathryn and Michael McCarthy (UC Davis, U.S.A.), Alejandro Marangoni and Dr. Farnaz Maleky (University of Guelph, Canada) looked at ways to decrease oil migration through cocoa butter in order to prevent fat bloom in chocolate, an issue Marangoni called “the holy grail” of the chocolate industry.
Preventing fat bloom
The study ‘Effect of Cocoa Butter Structure on Oil Migration’ was recently published in the Journal of Food Science.
Speaking to ConfectioneryNews.com, Marangoni said: “We demonstrated that just seeding the cocoa butter with crystals in the desired polymorphic form is not sufficient to slow down oil migration from a cream filling to the cocoa butter phase.”
Oil migration into chocolate is a major cause of bloom formation.
Fat bloom can appear as a white film on the surface of chocolate when oil creates recrystallization of some cocoa butter triglycerides.
Chocolate with fat bloom is considered less appealing to consumers.
Shearing over seeding
Chocolate manufacturers have tended to use seeding to combat the problem, but Marangoni suggests there are better ways.
“Industry uses seeding extensively but here we show that it does not affect oil migration that much,” he said.
"This work demonstrated that shear (mixing) has a specific effect which is different from just creating a "seed crystal" in the proper polymorphic form."
“This points to the fact that the effects of shearing on cocoa butter structure and oil migration through cocoa butter must be better understood in order to exploit these findings. “
“I would say, abandon seeding in favour of developing specific shearing modes under specific temperature regimes,” he said.
Maleky, F., McCarthy, K. L., McCarthy, M. J. and Marangoni, A. G. (2012), Effect of Cocoa Butter Structure on Oil Migration. Journal of Food Science, 77: E74–E79. doi: 10.1111/j.1750-3841.2011.02575.x