Why texture is so important
Feb. 1, 2013
by Donna Berry
Bakers know consumers shop with their eyes and taste buds. They also know that consumers tend to not think about texture unless it is bad, as in a stale slice of bread, a soggy cracker or a muffin that crumbles apart. Texture can be the most important unvoiced expectation in the new product equation.
“A product with an undesirable or poor texture can easily deter a consumer from repurchase, even if it has great flavor and color,” said Daniel Bailey, R&D scientist, Gum Technology Corp., Tucson, AZ.
Pleasing texture is not always a given. Patrick O’Brien, marketing manager, bakery, Ingredion, Inc., Westchester, IL, explained, “Today’s consumers want better-for-you options such as reduced fat, reduced sugar, fiber fortified and whole grain. In making these nutritional adjustments, maintaining texture is a challenge.”
To help ensure unobjectionable texture, bakers often include ingredients that are categorized as texturants. These include emulsifiers, enzymes and hydrocolloids, plus some specialty carbohydrates.
“Generally speaking, bakers use texturants to extend shelf life,” said Teresa Yazbek, US vice-president and technical sales director, Nexira, Somerville, NJ. “Texturants do this by decreasing staling, improving smoothness and fullness, regulating water activity and moisture migration, and improving freeze-thaw resistance in both prebaked and raw frozen dough. Texturants can also improve microwaveability, decrease glycemic index by reducing carbohydrate content, add fiber, replace eggs or fat, and improve texture of gluten-free products.”
Examples of what texturants do were offered by Bill Gilbert, principal food technologist, texturizing solutions, Cargill, Minneapolis. “With bread, the right texturant can assist with developing volume and a crispy crust, and this varies by the type of bread such as white versus whole grain, as well as bread form and shape,” he said. “With cookies and biscuits, the challenge is to find the right combination of texturants to optimize dough rheology while also delivering desirable and lasting softness or crispiness.”
Texturants also assist with uniform distribution and suspension of fruit or other inclusions such as nuts and chocolate chips. This function improves texture and mouthfeel.
“We recently developed a hydrocolloid system to bind particulates commonly found in granola, cereal and energy bars while significantly reducing the amount of sugar, honey or high-fructose corn syrup in the formula,” said Maureen Akins, technology manager, TIC Gums, Inc., White Marsh, MD. “In many of these products, texture and appeal of a fully sugared product can be very closely mimicked or even improved upon with hydrocolloids.”
Typical usage levels range from 5 to 20% of the binding syrup, depending on the level of sugar reduction. “With higher sugar reductions, sweetness can be replaced with high-intensity sweeteners,” Ms. Akins explained. “What is not easy to replace are the texture and bonding qualities that sugar provides to shape and hold such crunchy products together. But this hydrocolloid system has been designed to do just that.”
Variety of gums
The texturant category of hydrocolloids is quite broad. Common hydrocolloids for baking applications include select gums and starches, as well as pectin. The name says it all — “hydro” meaning water and “colloid” describing a gelatinous substance — in explaining their primary function to bind moisture.
Free moisture can pose problems and not just with water activity. “Pectin does a great job of reducing ice crystal growth in frozen dough when used at 0.5 to 1.0%,” said Troy Boutte, group manager-bakery/fats and oils, DuPont Nutrition & Health, New Century, KS. “This ultimately results in better volume of the baked food and a finer, smoother texture with overall improved eating quality.”
Gums can increase the viscosity of the water phase in batters and doughs. “Higher viscosity results in less coalescence of gas bubbles, reduced coalescence of oil droplets in emulsions and reduced water mobility,” Mr. Boutte added. “The result is finer texture, softer eating properties and improved shelf life due to immobilization of the water.”
Some gums such as acacia gum (also known as gum Arabic) not only assist with emulsifying, stabilizing and texturizing properties but also provide a source of soluble fiber that adds to the product’s nutritional profile.
“For example, when 3% acacia gum is added to a chocolate chip cookie formula, a 100-g serving jumps from containing 1 g of fiber to 4 g,” Ms. Yazbek said. “Further, gum acacia’s superior water-retention properties allow more water to be bound and readily available within the cookie matrix. This contributes to a chewier, less crumbly cookie over an extended shelf life compared with the cookie without acacia.
“In puffed baked snacks, not only does acacia gum add soluble fiber, it improves the homogeneity and definition of shape as well as crispiness even during short storage in humid conditions,” she explained. “It even allows a reduction of the specific mechanical energy during extrusion.”
Acacia provides other benefits, according to Mr. Bailey. “Acacia gum can improve batter emulsification and provide aeration in all types of baked foods, resulting in even cell structure,” he said. “Good cell structure equates to reduced tunneling.”
Like hydrocolloids, emulsifiers vary in their function. Many are all about reducing surface tension between oil and water, two ingredients present in most baked foods but ones that don’t like to combine. Emulsifiers assist by producing small stable micelles that contribute to a pleasant texture and mouthfeel.
“When it comes to creating either water-in-oil or oil-in-water emulsions, monoglycerides are often used because of desirable functionality, pricing and labeling, although many choices are available,”
Mr. Boutte said. “Some emulsifiers such as distilled monoglycerides are often used for their excellent starch complexing.” He explained this function as a physical reaction between the amylose and the monoglyceride that prevents amylose from recrystallizing and participating in the staling process. The result is improved texture of the baked food through its entire shelf life.
“Protein complexing involves the joining together of gluten proteins by emulsifiers,” he continued. “This function is most important in yeast-raised baked foods, where we want the protein to hold gas and expand during baking to produce fine crumb cells and good volume.” Diacetyl tartaric acid esters of mono- and diglycerides (DATEM) and sodium stearoyl lactylate (SSL) are the most commonly used protein-complexing emulsifiers in the US, according to Mr. Boutte. He noted, too, that powdered lecithin is increasing in popularity for clean-label applications.
“Emulsifiers also provide aeration in bakery products,” Mr. Boutte added, citing the example of cakes, where the baker must create both an oil-in-water emulsion and a fine dispersion of leavening gas cells. “Propylene glycol monostearate (PGMS) is most commonly used for this application,” he said. This alpha-tending emulsifier promotes crystallization in the alpha state. Such crystals are very small and flexible, promoting formation of a saclike film around oil droplets. “This keeps the oil separate from the water phase, allowing egg proteins to be aerated,” he observed.
The enzyme solution
Enzymes also influence the texture of baked foods. “Anti-staling enzymes reduce crystallization, also known as retrogradation, of starch over time,” Mr. Boutte said. Slower retrogradation results in a moister bakery product with soft eating properties. Ranging widely in functionality, enzymes can be selected to produce highly specific results, including improvement of texture.
“We developed a line of texture solutions for soft breads and rolls,” said Richard Leboucher, R&D director West Coast, Puratos, Cherry Hill, NJ. Based on enzymes selected for synergistic activity, these texture solutions — termed by the company “melting,” “moist” and “intense” — optimize individual characteristics of dough and final bread products. “The systems enable bakers to differentiate the texture of products in terms of resilience, short bite, softness, moistness and melting properties,” he said.
Bakers use these systems by adding them on top of existing formulas, Mr. Leboucher explained. “This enables bakers to influence one specific characteristic in the dough or bread without reformulating the entire recipe.” He said the “melting” system improves the eating characteristics by making the bread easier to swallow, while the “moist” system improves freshness by increasing softness and moisture. There’s even one designed to improve texture after reheating or defrosting in the microwave. Formulators also can combine systems to create a custom texture.
“When bakers lower the fat in many baked foods, texture is compromised,” Mr. Leboucher said. “We offer a fat alternative that delivers the same taste and texture sensation in breads and cakes as traditional fats while improving the nutritional value and being cost competitive.” He described this ingredient as a unique combination of emulsifier, enzyme and flavor technologies. “It mimics all the properties of traditional fat such as softness, short bite, shelf life and taste while lowering the levels of fat. In some recipes, it actually improves texture,” he said.
Such customized texturant systems offer control during processing and in the finished baked product that a single ingredient typically cannot provide. “It is important to work closely with your supplier to deliver a baked food with the texture your customers expect,” Mr. Gilbert said.