Today’s food industry faces the growing challenge of delivering premium taste and texture to customers facing economic challenges. Thankfully, colloidal science is also growing, providing an array of products that help create rich mouthfeel on a tight budget.
When you wish upon a starch
Specialty starches can enhance crucial elements of mouthfeel, such as meltaway and mouth-coating, both of which affect the perception of “creaminess.”
Starch’s varied functionality stems from variations in structure. Chemically speaking, they are polysaccharides—repeating glucose units with different ratios of amylose and amylopectin, associated by hydrogen bonding, and arranged radially into granules of varied size. Larger granules have lower molecular bonding and will, therefore, hydrate more rapidly. Viscosity typically increases with granule size. Larger granules are, however, more delicate and more sensitive to shear.
Linearly structured amylose can come together easily and form gels. Branched amylopectin chains cannot come together, and will be more-effective thickeners. Starches high in amylose provide greater gelling, while higher-amylopectin (also called “waxy”) starches promote viscosity. Carefully balancing these effects allow developers to simulate the nuances of texture and mouthfeel of a familiar product, despite the removal of otherwise crucial textural contributors.
“Many starches are modified to improve their process tolerance, or refrigerated or frozen storage stability,” says Doris Dougherty, senior food scientist, Tate & Lyle, Decatur, IL. Acid, oxidative or enzymatic conversion of starch can affect solubility, viscosity, gel strength and stability. Crosslinking, forming bridges between some of the starch’s hydroxyl groups, bolsters the starch’s hydrogen bonds and inhibits granule swelling, resulting in a shorter texture and increased temperature, acid and shear resistance. Stabilized starches are resistant to retrogradation (the reassociation of linear fractions), which improves freeze/thaw stability and shelf life. “Highly substituted starches are available to provide moistness and tenderness when fat is reduced,” she adds. “Starches may be physically modified so that they do not require heating during processing.”
Within these categories lie countless variations and combinations of functionality that present opportunities for developers to improve the perception—and cost—of a given application. “Starch-based solutions enable manufacturers to replace ingredients that have a higher cost-in-use,” says Robert Allin, director of marketing, National Starch Food Innovation, Bridgewater, NJ.
In dairy applications, starches can reduce casein levels in processed cheese and imitation cheese products, milk solids in yogurt, and milkfat in ice cream. “This is possible because our starches are designed to provide the texture, viscosity, stability and enhanced mouthfeel qualities that mimic the texture and mouthfeel inherent in milk-based or high-milkfat-based ingredients,” says Allin. “While raw-material costs for dairy ingredients have decreased since last year, many manufacturers see specialty starches as a reliable, less economically volatile ingredient in an uncertain and unpredictable dairy-ingredients market.”