Starch for Snack Development

Specialty starches have the potential for tremendous processing, textural, and mouthfeel advantages in snack development. With dozens of food starches available, it can be difficult to know which one will best meet a particular functional challenge. This article gives some guidance on how to select an ideal starch for a particular type of snack and specific attribute.

Baked Snacks

Key concerns for developers of baked snacks include texture, product shape, and surface color. Baking develops the product’s structure, makes it edible, and makes it aesthetically desirable. Baking concerns encompass internal product temperature, which increases slowly compared with extrusion or frying. Slow heating means pregelatinized starches, also known as instant or cold-water-swelling starches are needed for this application.

These starches are preferred because of the slow cooking process and because there is aminimum of water in the snack dough.

With their fine starch granule size, waxy-based starches are most suitable for baked snack products because tests show they permit easy sheeting and good binding, which results in minimal breakage. Carefully chosen specialty starches can improve texture and forming and reduce cracking and breakage. For texture improvement, a modified, pregelatinized starch derived from waxy maize will serve well. To minimize forming and shaping problems, a bland, modified food starch that mimics fat or a modified, cold-waterswelling starch will give good results. Resistant starches (see sidebar on resistant starches) and high-amylose corn starch and modified high-amylose starches (see sidebar on amylose and amylopectin) can be used to reduce cracking and breakage that result in excessive losses.

Fried Snacks

Frying cooks a product to make it edible and dehydrates the product, creating a unique texture and pleasing mouthfeel. Oil temperatures typically reach 204- 260°C (400- 500°F), and processing time is short due to fast heat transfer. Under- or over- frying may affect texture and color. The use of an appropriate specialty starch for fried snacks can result in better texture, mouthfeel, and reduced oil absorption. Cross-linked or modified starches prevent the disruption of starch granules that can lead to poor texture and toothpacking in the mouth. With proper modification, specialty starches made from waxy maize, corn, and tapioca may be used to prevent these problems. High-amylose starches sometimes are used as coatings and may reduce oil absorption during frying because of their strong film forming characteristics. Modified high-performance resistant starches can provide these functions.

Extruded Snacks

Moist, starchy ingredients heated and sheared at high temperatures and pressure produce a melted, putty-like dough that expands when the pressure is released. By manipulating the ratio of high-amylose to high-amylopectin starch, a target texture can be achieved.

Generally, native starches cannot resist the high temperatures and high shear associated with extrusion. In contrast, cross-linked starches can resist shear and very high temperatures. However, excessively cross-linked starches lower the starch granules swelling capacity, resulting in a snack with reduced expansion and nonuniform texture.

Thus, a snack developer must select from many potential cook-up starches, including those made from corn, tapioca, and waxy maize. To select the best starch for the application, developers need to correctly quantify their maximum shear and know the temperature range in the extruder. If a snack developer can tell a starch manufacturer the degree of shear, the temperature, and any preferences for the starch base, a quick recommendation can be made. If a snack developer increases the amylose content of an extruded snack formula, the snack will be firmer, more crunchy, and harder.

However, These gains will be made at the expense of expansion, which declines as the percentage of amylose increases. An increase in amylopectin, on the other hand, increases snack
expansion and softness. For puffed snacks, the optimum cross-linked waxy corn starch can help control expansion and increase product uniformity.

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