According to new findings from the University of Nottingham and Nestlé Product Technology, the widely used industry technique of using defatted cocoa butter to prepare low-fat chocolate is the most effective in terms of particle size and morphology.
According to findings published in LWT - Food Science and Technology, there was also no added benefit of using highly defatted cocoa powder with less than one gram of fat per 100 grams, compared with regular defatted cocoa powder containing 11 grams of fat per 100 grams.
Tasty market potential
The issue of health is no longer a marginal topic for the food industry but wholly mainstream, and it finds confectioners, biscuit and cake makers seeking to juxtapose today's consumer desire for indulgence with their desire for foods with a healthy profile.
According to a recent study from the US, only 5 per cent of American children between 6 and 11 were overweight before 1980, but 25 years later this number had risen to 19 per cent. Similar increases have been reported in Europe, with the International Association for the Study of Obesity estimating in 2006 that the number of obese school age children in Europe increased by almost 50 per cents since the late 1990s.
Led by Dr Bettina Wolf, Associate Professor in Biomaterials Science at Nottingham’s Faculty of Science, the researchers examined the potential of manipulating the cocoa ingredient for trapped fat reduction in chocolates.
The researchers replaced the cocoa mass with defatted or highly defatted cocoa powder (11g/100g or less than 1g/100g fat, respectively). Results showed that chocolate prepared with standard cocoa mass had a higher viscosity than the reduced fat chocolates with the same fat content.
On the other hand, the highly defatted cocoa powder was also more viscous than chocolate prepared using the standard defatted cocoa powder. Scanning electron microscopy showed that particles in the highly defatted cocoa powder were smaller and more angular, which thereby increased the number of particles observed and total surface area to be coated by fat.
“This explains the higher viscosity of the chocolate based on highly defatted cocoa powder and there is no benefit in using this very low fat cocoa solid ingredient,” explained the researchers.
“Based on the evidence presented, it can be concluded that standard defatted cocoa powder, as widely used by the industry, is indeed the best compromise in terms of free fat, particle size and morphology attempting to formulate fat reduced chocolate of acceptable molten state viscosity,” wrote the researchers.
Another approach was reported last year by scientists from Birmingham University in England for the production of stable cocoa butter water-in-oil emulsions containing up to 60 per cent water by mass.
“Results [of our study] suggest low-fat chocolate formulations using this route may be feasible,” wrote the researchers, led by Dr Phil Cox in the Journal of Food Engineering (November 2009, Vol. 95, pp.172-178).
In an email to FoodNavigator in September 2009, Dr Cox stated: “We have just patented an extension to the preliminary work and are in discussion with companies.”
Source: LWT - Food Science and Technology
Published online ahead of print, doi: 10.1016/j.lwt.2010.10.006
“Structural characteristics of cocoa particles and their effect on the viscosity of reduced fat chocolate”
Authors: T.-A.L. Do, J. Vieira, J.M. Hargreaves, J.R. Mitchell, B. Wolf