Starches act as an adhesion aid for glazes and help manage moisture to increase shelf life.

Primary considerations

According to Nieman, “The key consideration for formulators selecting the appropriate starch is to consider the effect other ingredients might have on the starch. For example, acids break starch bonds. This accelerates gelatinization and viscosity breakdown. Sugars, gums and protein compete for the available water, but also complement structure support.”

Sugars impede the swelling of the starch granule and different sugars have different influences. The retardation of swelling and extension in the gelatinization range may result in both decreased viscosity and gel strength.

Fats and oils and emulsifiers coat the starch granules, which can delay gelatinization and hamper viscosity development. Modified starches can be prepared to withstand certain processing conditions and adapted to a degree to interact in a synergistic manner with other ingredients.

Grain Processing Corp. (GPC), Muscatine, Iowa, offers cook up starches and an instantly hydrating starch that enhances texture in a range of bakery products. By adding 5 percent instantly hydrating starch to their dry formulations, bakers can improve crispness in pizza crusts and increase chewiness in cookies without hampering spread. This instant hydrating starch also can be used as a tack coating or egg wash replacement.

GPC also offers intact granule starches that help provide stability in chemically leavened products, such as cookies, muffins, cakes and brownies. The intact granule holds onto moisture over time even through freeze/thaw cycles. “We have more than 18 months of shelf life studies on frozen cakes. These cakes show no signs of the cracking or shrinking seen in many frozen baked products today,” says Casey Lopez, associate scientist for GPC. These starches are resilient as well, and are able to withstand mixing, pumping, baking and freeze/thaw cycles.

Managing moisture to increase shelf life is always a concern, and the shrinking and cracking of products is often a result of over-stabilizing, Lopez notes. Determining the few key ingredients needed is the challenge. “Examine the formulation and add one thing at a time using moisture management tools. It helps keep the costs down and keeps the label simpler,” she adds.

Size matters

Particle size can have a big impact on the dispersion and hydration rate of both pregelatinized (roll dried) and granular cold water swelling starches. This may impact mixing times, incorporation of particulates and depositing.

Granule size also affects starch blend properties, according to a new study published in Food Researcher International. The relative size of starch granules used in a blend could determine overall gelation behavior, in addition to determining whether or not the starch components add to each others' properties or interact to promote new ones. These granules are generally either small and spherical or large and ellipsoidal. Rice starch is relatively small in granule size (2 µm in dia.) compared to the average granule size of potato starch (48 µm in dia.).

Temperature also affects the starch granules. If the starch is cooled too fast in a freezer, for example, there will be a loose alignment of the amylose and amylopectin, resulting in a weak gel. If the mixture is cooled too slowly, there will be considerable alignment, and again a poor gel with a lot of syneresis.