In one of my former positions, I spent my first week listening to consumer comments. A mother called to complain that the strawberry-filled fruit bars she purchased for her child were hard. I could hear her hitting them against a tabletop to drive home her point. These were long, stick–like fruit bars similar to a Fig Newton, and they were much too hard for the mom to eat, let alone her toddler.
As illustrated by this frustrated consumer, cold-extruded bars and baked cookies will become hard over their shelf life if they’re not formulated properly, especially when the shelf life is over six months. But how do you control the softness of bars and cookies? Check out my suggestions below.
Typically, high water activity can be blamed for the hardening of granola and protein bars, as well as shortening the shelf life of baked cookies. High water activity means that the water present in the ingredient matrix has a chance to become mobile, migrating from the binding ingredients to the proteins and other dry materials in the bar.
For cold extruded bars, make sure your binder has the proper solids level in the correct proportion to your dry material. Some soy protein isolates (EU) and whey protein hydrolysates (EU) have been processed in a manner to be more hydrophilic, thus less encouraging of water migration.
Baked goods stabilize after cooling to a moisture level where the sucrose present in the formula is still in an amorphous, unstable state, and will try to recrystallize over time. This is what causes a soft cookie to harden. If you swap a portion of crystalline sugar for a high fructose corn syrup (EU), invert syrup (EU), brown rice syrup (EU), or liquid inulin (EU), the sugar recrystallization will be inhibited and products will be softer for a longer time. This is true for both baked and cold extruded bars. In addition, look at decreasing the sugar/syrup ratio in baked products by increasing the syrup while decreasing the solid sugars.
Emulsifiers (EU) are commonly used for starch complexing in baked goods and aid in reducing the likelihood of starch retrogradation. Cookies can benefit from the use of emulsifiers for maintaining softness over time, as well as improved machinability, mold release and moisture retention. Common emulsifiers used for cookies include lecithin (EU), distilled monoglycerides (EU) and DATEM (EU).
Adding glycerin (EU) to cold-extruded bar doughs, especially those with high protein, aids in reducing water activity, keeping the dough pliable during machining, and reducing stickiness. In cookies, it is often used to soften and reduce crystallization in icings, and it aids in keeping a moist texture in products where it’s needed.
Modified Starches & Fiber
Starches can absorb water without producing changes in the cookie structure. Pregelatinized starches (EU) help cookies maintain a soft, chewy texture, retain moisture over their shelf life and control the spread of the cookies as they bake. Adding fiber aids in maintaining softness due to its high water-holding ability, but some trial and error may be needed as it might require adjusting your water absorption. In my experience, oat fiber (EU) works well for soft cookies, without producing off flavors or causing issues with processing.
And those bars I mentioned at the beginning? Figuring out how to fix the issue became my first project with the company. Adding glycerin and distilled monoglycerides to the bar formula made a much softer, more stable product. Better yet, we didn’t have to hear any more fruit stick drum solos from dissatisfied customers.
Grist.org – Food Studies: the Science of Cookie Texture
American Institute of Baking – FAQ – Cookies
Food Ingredients Online – Prolonging Bakery Product Life
DigitalCommons@USU: Mechanisms of Nutrition Bar Hardening – Effect of Hydrolyzed Whey Protein and Carbohydrate Sour – Shaun P. Adams
Food Product Design – Texture Solutions For Snack Bars
Prepared Foods: Ask the Expert – Whey Proteins and Nutrition Bars
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