Because consumers value freshness so highly, wholesale bakers must use all their formulating savvy to make sure this quality carries through from processing plant to customer and end consumer. To effectively compete, commercial bakers must find ways to simulate homemade freshness. Yet commercial products often travel across the country. They need extended shelf life and, by the end of that shelf life, must still be of the highest quality. To accomplish this, many commercial bakers are turning to hydrocolloids to provide a variety of functional properties to batters, doughs, fillings and overall finished baked food quality.
ROLES AND TYPES
The term hydrocolloid refers to a range of polysaccharides and proteins that emulsify, foam, gel, stabilize, thicken, inhibit ice crystal formation and even control the release of flavors. Typically used at levels less than 1%, that little bit can have a significant influence on the textural and organoleptic properties of baked foods.
There are basically four types of hydrocolloids: algal (agar, alginate, carrageenan, etc.), animal (caseinate, gelatin, whey protein, etc.), botanical (cellulose, guar gum, konjac, pectin, starch, etc.) and microbial (gellan gum, xanthan gum, etc.).
Some hydrocolloids form thermo-reversible gels where gelation occurs on cooling or heating. Others form nonthermo-reversible gels, also called thermally irreversible gels. With these hydrocolloids, gelation may be induced by cross-linking polymer chains with divalent cations.
"Hydrocolloids are all about binding water and controlling moisture migration to ensure shelf life," said Susan Gurkin, global applications manager for bakery, Degussa Foods Ingredients, business line texturant systems, Atlanta, GA. "Hydrocolloids do not lower water activity, so they do not have an effect on microbial activity, but they have a huge impact on the texture and stability of baked foods."
Certain hydrocolloids can replace highercalorie ingredients in baked food formulations, as well as contribute to the product’s fiber content.
"Hydrocolloids are being formulated into recipes in response to the current need for healthier baked foods and snacks, in addition to providing extended shelf life in cookies, cakes and frozen dough," said Donna Pechillo, senior research scientist, FMC BioPolymer, Philadelphia, PA.
Protein-based hydrocolloids provide nutritional benefits and appeal to the "lowering carbohydrate" phenomenon recently embraced by so many Americans.
"Certainly whey proteins have moderate water-binding properties, but what is really new news is the basic research being conducted at North Carolina State," said Bill Haines, vice-president, product innovation, Dairy Management Inc., Rosemont, IL. "Scientists have patented a technology to create whey protein polymers able to assume more traditional polysaccharidebased hydrocolloid properties. These whey proteins have unique functional properties but also have all the same great nutrition associated with whey."
PUTTING THEM TO WORK
What bakers must remember is that hydrocolloid use is formulation specific.
In certain batters, microbial-derived xanthan gum contributes smoothness, air incorporation and retention, and recipe tolerance. The baked product will have increased volume and moisture, higher crumb strength, less crumbling and greater resistance to shipping damage compared with baked products made without xanthan. In refrigerated doughs, as well as reduced-calorie baked foods, xanthan improves volume, texture and moisture retention.
Indeed, moisture control is very important in baked foods, particularly cakes, which are among the highest-moisture baked food categories. Improper moisture control can result in lumpy cake batters and uneven mixing, giving poor structure. This leads to cakes collapsing during or after baking.
Poor hydration of dry ingredients during batter mixing can also harm the quality of the baked cake, particularly after storage because volume may be reduced. Also, when moisture is not evenly distributed, a cake’s texture may be nonuniform or fragile. This is where xanthan gum can help.
When xanthan is added to cake batter at 0.05% of total batter weight, without any other formulation changes, it hydrates rapidly and evenly, helping prevent lumping during the critical initial mixing stage. This even hydration aids in the uniform distribution of moisture in cake batter, which helps stabilize the fine air cells formed during the mixing process.
Obtained from plants, carboxymethyl cellulose (CMC) helps improve the volume yield of certain cake batters and doughs because of its viscosity drop during baking. And CMC can improve suspension and distribution of ingredients such as fruits and nuts in batters.
Fine grinds of CMC are typically used in bakery mixes, allowing better water absorption. In fact, when CMC is used, additional water is required compared with recipes not containing CMC. This results in increased yields and improved moistness, particularly after storage.
"Recently, there has been a lot of activity with konjac gum," said Joshua Brooks, vice-president of sales, Gum Technology, Tucson, AZ. Konjac is a linear polysaccharide composed of mannose and glucose and is derived from tubers of elephant yam (Amorphopallus konjac).
"Konjac has been used for years in Japan and is a rather new hydrocolloid in the United States," he continued. "It both thickens and gels, and can be used as a dough conditioner and extender in bakery applications, much like xanthan. Usage level in dry mixes ranges from 0.05% to 1.0%."
Derived from algae, the hydrocolloid alginate suits a wide range of bakery products, mainly bakery fillings. "In fruit fillings, alginate imparts outstanding bake stability, which prevents boil-out," Ms. Pechillo said. "It provides fruit fillings with a very pulpy, rich-in-fruit appearance and high gloss.
"In custard and Boston cream-style fillings, alginate is a typical ingredient used to formulate dry mix preparations," she continued. "Alginate allows instant bakery cream to hydrate easily, build up viscosity, create a shiny appearance and provide very good heat-bake stability."
Carrageenan, another algal hydrocolloid, is a high-molecular-weight polysaccharide. There are three types of carrageenan — iota, kappa and lambda — each having different chemical and functional properties. Kappa makes a strong, rigid gel, while iota forms an elastic gel. Lambda, on the other hand, yields a viscous solution that does not gel at all.
"Iota carrageenan offers a unique capability to protect yeast cells and retain gluten functionality during dough freezing," Ms. Pechillo explained. "Therefore, after thawing, the volume of the baked dough is improved, allowing for better consumer appeal."
Iota carrageenan can also be used in icings and glazes to prevent drying out and cracking. It improves stability and coating properties.
ADJUST AND IMPROVE
Indeed, mixtures of hydrocolloids are commonly used to impart enhanced and unique rheological characteristics to bakery applications. These hydrocolloids often work together synergistically and thus assist in reducing ingredient costs.
"The Emulzym range from Degussa combines select hydrocolloids with emulsifiers, enabling bakers to reduce the fat content of products in a natural way," said Ms. Gurkin. "By using the Emulzym product designed for a specific application, fat can be reduced 50% or more. It provides excellent emulsification and increases the functionality of the small amount of fat present. It also heightens moisture retention and improves mixability and dough handling."
Indeed, sometimes ingredients are added to bakery formulas to make the product healthier; however, other times, usage levels of ingredients such as fat are reduced. In this instance, "Avicel colloidal microcrystalline cellulose (MCC) can be useful," Ms. Pechillo said.
"Fully dispersed Avicel colloidal MCC will greatly improve the mouthfeel and impart or enhance fat-like properties in certain bakery applications," she continued.
MCC is a unique, insoluble hydrocolloid that produces a thixotropic structure. It can impart heat, foam and emulsion stability; enhance opacity; create a uniform suspension; control ice crystal growth; and modify the texture of finished food systems.
"When properly dispersed in water under shear conditions, MCC forms a 3-D matrix particularly suited to stabilize frozen bakery products and baked bakery fillings," said Ms. Pechillo. "It functions at any temperature, is shear thinning and remains insoluble."
Unlike soluble hydrocolloids, MCC provides a minimal increase in viscosity. Therefore, it is possible to obtain very good bake-stable properties in ready-to-use bakery creams and bakery fruit fillings while keeping a very low in-process viscosity.
"The Coyote TC stabilizer line was developed specifically for use in tortillas and other flat, soft breads," said Mr. Brooks. (TC stands for tortilla conditioner.) "By maintaining moisture levels, TC stabilizers help reduce cracking and flaking, and at the same time, they also strengthen the dough. They help make tortillas stronger and last longer. TC stabilizers are blends of gums. Which TC stabilizer you use depends on the application."
"The line also includes TC-20, which has been shown to allow 11% greater rework of the material. It keeps the edges of the tortilla soft and pliable after freezing," he added. "It practically eliminates side burst in frozen burritos and is one of the best choices for tortillas used in frozen entrees."
Tara gum is another increasingly popular hydrocolloid in the US. It is less costly than locust bean gum, which tara resembles from a functional perspective. Both tara and locust bean work synergistically with kappa-carrageenan and xanthan gum to increase gel strength and make such gels less prone to syneresis.
Gum karaya, a tree exudate, is primarily used in the pharmaceutical industry but does have some bakery applications. It is effective in retarding staling when 0.1% to 0.9% karaya is combined with 0.01% to 0.02% alginate or carrageenan.
Another tree exudate, gum tragacanth, stabilizes bakery fillings and toppings made with fruit, fruit purees and flavors. Tragacanth provides a shiny and transparent appearance and a creamy mouthfeel. In frozen pie fillings, tragancanth provides clarity and brilliance when used with starch as a thickener.
"Very often, frozen dough products deteriorate in quality over prolonged frozen storage, and consequently, finished bakery products fail to meet quality standards for volume, color and other sensory parameters," said Ms. Pechillo. "Our Viscarin carrageenan helps maintain the quality of the frozen dough over extended freezer storage, resulting in finished products that are similar to bakery items produced from freshly prepared dough. The carrageenan protects yeast cells’ viability and helps maintain the gluten network’s strength during freezing and storage."
Doug Rector, group leader, texture systems, Kerry Bio-Science, Hoffman Estates, IL, explained, "In frozen doughs, it is important to control ice crystal growth, because ice crystals have a deleterious affect on product quality," he said. "Myvatex Fro-Do stabilizer is a blend of hydrocolloids designed to give optimum performance in frozen doughs. It effectively stabilizes and inhibits ice crystal growth at usage levels between 0.5% and 1.5%, on a flour weight basis.
There are many hydrocolloids available to help commercial bakers more effectively compete in today’s diverse marketplace. Hydrocolloids enable production of highquality, affordable, convenient, nutritional and fresh-tasting bakery products.