Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338
December 19, 2002
Chocolate has 'inner beauty,' U of G food scientist says
Enough of this superficial adoration of chocolate this holiday season – a University of Guelph food scientist says it’s time to appreciate chocolate’s inner beauty.
Prof. Alejandro Marangoni says a microscopic look at chocolate reveals an intricate crystalline network involving oils and fats -- chocolate contains about 30 per cent fat, 50 per cent sugar, and 20 per cent cocoa powder. Interaction among that network’s components influences appearance, feel and taste.
For example, cheap chocolates will often leave a waxy taste in the mouth. But good chocolates can melt on the tongue. Marangoni says that has much to do with the crystalline structure. He’s developing new ways to characterize a crystal’s structure as it appears under a microscope.
Crystal shapes are diverse – some resemble small, sharp needles, while others take the shape of sunflowers or snowflakes. Marangoni says that the size and shape of the microscopic crystals is determined by three factors: temperature, cooling rate, and shear (the speed at which the chocolate is mixed).
Information revealed through crystals is helping him to solve some practical problems in the chocolate industry, such as oil migration (when chocolate turns white). “Oil migration occurs when chocolate is stored in a place where it’s been frequently exposed to heat and cool, like a gas station, where the door’s always opening,” Marangoni said. “The fat frequently starts to melt and then harden.”
Oil migration is also typical in expensive European chocolates with special liqueurs or creams inside, which are seen everywhere in the holiday season Marangoni thinks he could help to solve oil migration with a variety of techniques such as controlling crystal orientation and engineering crystal structures, or by using additives in the oils.
Marangoni’s worked with major food companies such as Masterfoods USA, Nestle Switzerland, Unilever Holland and the Malaysian Palm Oil Board to find answers to similar product problems. His research is sponsored by the Ontario Ministry of Agriculture and Food and the Natural Sciences and Engineering Research Council.