Serbian researchers found that chocolate manufacturers can substitute dairy milk with soy milk without impacting the quality of the final product by prolonging refining times.
The study by Biljana Pajin et al was funded by the Serbian government and published in the Journal of Food Engineering.
Improved structure with longer refining
A refining time of 90 minutes at the pre-crystallization temperature of 30°C is optimal, said the researchers.
“Increasing the refining time leads to organized chocolate systems with soya mlik,” said the study.
The researchers tested chocolate containing 20% soya milk at different times and temperatures in a ball mill.
Milling and conching of chocolate mass are performed in a ball mill to obtain optimum particle size. The process is known to affect the finished product’s texture and sensory properties.
The researchers tested three refining times (30, 60, 90 mins) and three pre-crystallization temperatures (26, 28, 30°C).
Refining for 90 minutes at 30°C gave the best viscosity, yield stress, and area of the thixotropic loop, they found.
“It is assumed that an increase in the refining time results in a better packing of the chocolate mass particles,” said the study.
The researchers suggested that a longer refining time for soya milk chocolate would not influence crystallization rates, but an increase in pre-crystallization temperature would slow the crystallization process.
Journal of Food Engineering, Vol 114, Issue 1, January 2013, pp 70–74
‘Crystallization and rheological properties of soya milk chocolate produced in a ball mill’
Authors: Biljana Pajina, Ljubica Dokića, Danica Zarićb, Dragana Šoronja-Simovića, Ivana Lončarevića and Ivana Nikolića