By Cindy Hazen, Contributing Editor
No matter the flavor, snack and nutrition bars once came in one form: hard. However, advances in protein technology and a rich palette of fruits, syrups, grains and hydrocolloids can now fine-tune the bar’s eating quality, from chewy to crunchy. Yet, the most-important ingredient to consider comes right from the tap.
Water, water everywhere
Nutrition bars, if not formulated correctly, will harden upon storage. “Water activity (aw) is directly related to rate of bar hardening, as well as bar shelf life,” explains Luping Ning, associate science fellow, The Solae Company, St. Louis. “Water serves as a plasticizer in nutrition bars and helps to maintain the structural flexibility of the bar matrix. Therefore, bars with higher aw value will have a higher amount of available water to act as a plasticizer to keep the bars softer. Bars are considered shelf stable and are typically produced without a final thermal-processing step, or kill step,” so bars will need to maintain an aw less than 0.65 “for food-safety reasons.”
Managing the movement of water in the bar matrix is especially important when the bar contains a high amount of protein. “Water tends to migrate from binders, such as syrups, into proteins or other dry ingredients after bars are produced” which means that, over time, syrups lose their ability to act as a plasticizer, Ning says. Proper selection of proteins is key to minimizing water migration and maintaining softness throughout shelf life.
“With bars, it all comes down to using the right ingredients from the beginning to hit the final product specifications. Not all proteins work the same in all bars, because not all bars are alike. Developers need to work closely with their suppliers early in the process to get the right ingredients for their specific bar system,” says Courtney Kingery, marketing manager, specialty products—oilseeds, ADM, Decatur, IL.
For the joy of soy
As the bar market has matured, the quality of ingredients has improved. “Soy proteins have long been a cost-effective alternative to other protein sources in a bar, but can sometimes have detrimental effects on bar hardness and shelf life,” says Kingery. Special processing of soy protein minimizes the hydrophilic tendencies sometimes associated with them. “The result is lower water migration to the proteins, more consistent bar texture over the shelf life and reduced bar hardness,” she says. Today’s soy protein isolates provide high protein (90%) and a wide variety of functionality and texture options, “from a short, cookie-like texture to a chewy or fudgy bite,” she says.
