Food chemist Paul Dimick inspects the leaf of a cocoa plant. Dimick's chocolate research and education programs are helping manufacturers improve the quality and consistency of their products.

Food chemist Paul Dimick is studying another process that could benefit the dairy industry. His work on fractionated milkfat may yield useful ingredients for many food products. "Milkfat can improve the flavor of chocolate and other foods, but it hasn't been widely used as a food ingredient," Dimick says. "Through a process called fractionation, we can capture the desirable characteristics of milkfat and tailor them to the needs of the manufacturer or processor." To create these fractions, milkfat is melted, then slowly cooled. During cooling, the fat molecules that have a higher melting point crystallize first and can be filtered from the remaining liquid fat without using solvents or chemicals.

Milkfat fractions offer several advantages to food processors. These fractions could soften refrigerated butter and make it more spreadable, improve the taste of cakes and butter cookies, and cause pastries and other bakery products to rise more evenly and consistently. "Chocolate manufacturers could save money by replacing some cocoa butter with milkfat fractions, which cost about half as much," Dimick adds. "We've also found that some milkfat fractions can lengthen shelf-life by inhibiting fat bloom, which is a greyish cast that develops on the surface of chocolate. In addition, these fractions can standardize the consistency and melting characteristics of chocolate when manufacturers must use cocoa butter of varying quality from different countries.

"Finding more uses for milkfat could be a big help to the dairy industry," Dimick says. "Some dairy plants produce surplus milkfat. When dairy processors make skim or low-fat milk, they don't have enough uses for the removed fat, which is then sold at below-market support prices. A 1 percent increase in the use of milkfat in manufacturing milk chocolate alone would require about 20 million additional pounds of milkfat, worth about $18 million per year. Fractionation turns milkfat from a commodity with limited uses into a versatile food ingredient."

Much of Dimick's research focuses on different aspects of chocolate, from manufacturing processes and ingredients to flavor. "Chocolate has at least 400 flavor compounds, and we don't know all the magic combinations that produce the taste of milk chocolate," he says. "This is especially important because manufacturers are somewhat at the mercy of suppliers in other countries for their cocoa beans. If there's political or economic instability, a cocoa disease outbreak, or adverse growing conditions in the major producing countries in western Africa or South America, manufacturers here may have to use lower-quality beans and supplement the flavor. But to do that and maintain consistency, they have to understand how that flavor is produced and how it could be modified through reactions during roasting."

Maintaining chocolate consistency also is at the center of Dimick's work on cocoa butter crystallization, or the mechanism by which it solidifies. "Variations in cocoa butter hardness result from differences in the geographic origin of the cocoa beans," Dimick explains. "The farther from the equator the trees are grown, the softer the cocoa butter the beans produce. But chocolate manufacturers want the same ingredient characteristics, day in and day out. If we understand how cocoa butter crystallizes, we may be able to produce a more uniform product, even when beans from different regions are used."

Dimick and his graduate students have isolated and characterized the material in cocoa butter that acts as the seed for crystallization. "This material has a very high melting point and is the catalyst for turning liquid fat into a solid," says Dimick. "Some countries have developed seed materials that perform the same function, but because they are synthetic, they can't be used in the United States. Isolating this natural component and understanding how it works should help us to develop modifiers that can be added to chocolate to hasten crystallization and reduce variations in cocoa butter hardness, which will help maintain quality and consistency of the finished product."