Aug. 1, 2014
by Laurie Gorton
No matter whom you consult, all observers describe the gluten-free category as big and getting bigger. Guestimates of current US sales range from Euromonitor’s $468 million to Mintel’s $10.5 billion. The experts quote double-digit expansion and agree that bakery makes up more than half the category. With a US target market of 44 million people — 1.8 million having celiac disease, 18 million being gluten sensitive and 24 million more eating gluten-free for its perceived health benefits — that’s a lot of consumers to satisfy.
So, how do you make attractive, appealing and gluten-free baked goods without gluten, the component that supports their structure, texture and mouthfeel?
Formulators employ gums and hydrocolloids to supply these needs. Added at very low levels, these ingredients help stabilize, emulsify, bind, suspend, whip, coat and inhibit crystallization. In a nutshell, they are the not-so-secret ingredients in many baked foods but especially in gluten-free items.
“Gums have a strategic role in formulating gluten-free foods,” said Andrea Caremoli, PhD, president and CEO, Caremoli USA, Miami. “Several natural gums do the job, but there are also modified gums, too.”
Moisture management figures prominently in such applications. “Gums’ ability to manage water and increase water-holding capacity dramatically improves gluten-free baked goods,” said Steven Baker, food scientist, TIC Gums, White Marsh, MD. “Optimal usage of gums contributes to increased volume in breads and improved texture in breads and sweet goods.”
Food gums derived from plants, including seaweed, have an added advantage. “None of these are GMO,” reported Rodger Jonas, technical director, food and beverage, and senior account manager, PLT Health Solutions, Morristown, NJ. “But you should follow up with your sources and be thorough about their supply chains.”
Because this ingredient category is so versatile, it has seen bakery use increase in recent years. Being products of nature, a number of conditions affect the size of the harvest and their availability, explained Dan Inman, director of R&D, J. Rettenmaier USA LP, Schoolcraft, MI. He also noted that competing large industrial applications — notably, the oil industry’s use of guar in fracking — could also affect the availability and price of hydrocolloids supplied to the food industry. “These dramatic changes in supply cause a shift from the use of one hydrocolloid to another,” he said.
Continuum of properties
The words gums and hydrocolloids are not exactly synonymous, but they are used that way by the food industry. These ingredients vary widely in sources and properties. Food gums come in six categories: cellulosic, microbial, plant extracts, plant exudates, seaweed extracts and seed sources.
The cellulosic hydrocolloids are carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxypropopyl methylcellulose (HPMC), methylcellulose (MC) and microcrystalline cellulose (MCC). Crudlan, gellan and xanthan gums are produced by microbial fermentation.
Plants provide the rest, which include extracts (konjac and pectin) and exudates (arabic, acacia, ghatti, karaya and tragacanth). Fenugreek, guar, locust bean (carob), psyllium, tara and flax seeds yield gums, and seaweed is the source for alginate, carrageenan and furcellaran.
For a long time, guar has been the baker’s “go to” gum. “It is a good ingredient for standard baked foods where it improves shelf life without compromising the texture of bread,” Dr. Caremoli said. “So, formulators start with guar because it is a known material. In gluten-free products, it contributes the structure to replace the gluten protein network.”
Shifting away from guar, formulators turned to gums derived from seeds of locust bean and tara. “Locust needs to be supported by other gums,” Dr. Caremoli observed. “In some applications, tara is similar to locust bean, but it has only limited ability to maintain volume.”
Psyllium, derived from the seeds of an herb, is new to the gums category. “This natural ingredient can have a huge impact on gluten-free foods,” Dr. Caremoli said. It also benefits foods by contributing soluble dietary fiber.
In addition to their insoluble dietary fiber content, the gums derived from plant cellulose exhibit interesting thermal properties. CMC helps improve crumb quality, according to Ana Maria Garavito Rojas, food scientist, Gum Technology, a business unit of Penford Food Ingredients, Tucson, AZ. She described what happens when HPMC is heated. “[Its] thermal gelation behavior is advantageous since the ability to gel upon heating mirrors gluten’s behavior during baking: It sets firm, therefore holding the baked mass and preventing it from collapsing,” she said.
When approaching a gluten-free project, bakery formulators need to identify the role that gluten would otherwise play. Different baked goods require different degrees of gluten development, which is controlled by the amount of protein present in the wheat flour and the degree of mixing.
Some items lend themselves to gluten replacement better than others. Cookies, for example, don’t need gluten development, but bread does. “Breads and other types of yeast-raised doughs need gluten development for strength and gas-retaining ability that produces a light and airy interior structure and a moist, flexible crumb,” Mr. Inman said. “In addition to replacing the wheat flour with gluten-free flour, other ingredients can hold gas. These products include egg whites, hydrocolloids and functional celluloses.”
Another issue is staling, and many gluten-free baked foods experience severe staling, especially when shipped frozen, according to Troy Boutte, PhD, group manager, bakery/fats and oils, DuPont Nutrition & Health, New Century, KS. These goods pass through 40°F, the optimum temperature for starch crystallization, a.k.a. staling, during freezing and thawing. Because most gluten-free items are also clean-label, they can’t use the standard anti-staling and preservative ingredients, he added.
“Hydrocolloids do significantly reduce the impact of freezing and are also very useful for products that aren’t frozen,” Dr. Boutte said. The company’s CMC, xanthan and guar increase viscosity in the dough, which reduces mobility of water and the gelled starch, thus slowing starch crystallization and staling. “During freezing, hydrocolloids will reduce moisture loss, increase yield and reduce freezer burn,” he added. “These ingredients are easy to use and are simply added as powders along with other dry materials during dough mixing.”
That’s the method also recommended by Jenna Derhammer, food scientist, Ashland Specialty Ingredients, Wilmington, DE, for adding modified cellulose to gluten-free breads. “Formulators are looking for longer shelf life, soft texture, good volume and even crumb structure,” she said. “We found that adding modified cellulose to gluten-free bread helps to increase bread height, contributes to softness, and it even slows the rate of retrogradation, a large contributor to staling.”
Structure, of course, is the primary assignment for ingredients that replace gluten. HPMC offers this and more. Describing HPMC as perhaps the most widely used hydrocolloid in gluten-free bread, Norman Schute; food manager, technical development and application lab, Brenntag North America, Bethlehem, PA, described its ability to capture and structure the height of the bread achieved during the chemical or mechanical leavening reactions.
“Additionally, the secondary emulsification properties of HPMC help stabilize any fat in the bread, helping to improve texture and crumb structure,” Mr. Schute explained. “Cellulose gum (CMC) is also used in bakery products to help prevent staling, an added benefit to those producers concerned with extended shelf life.”
Modified cellulose’s thermal gelation — and reversion — properties facilitate the needs for dough stability and moisture retention. “When the bread is baking, the modified cellulose helps to structure the bread before the starches have a chance to gel enabling increased volume,” Ms. Derhammer said. “Because the gel reverses back to a viscous liquid, this can help to give soft crumb and texture in the finished bread.”
To work best, these ingredients must be properly hydrated in doughs and batters. Then you must properly bake out this high-moisture system, Mr. Inman observed. Hydrocolloids derived from cellulose can improve a product’s moisture retention. Because they interrupt starch molecules, they decrease staling, he added. These ingredients also add insoluble dietary fiber and, thus, reduce calories and provide fiber in the diet.
Because gums are highly interactive with water, Mr. Baker recommended adjusting the water content of gluten-free formulations. “A good starting point is to add five to six parts of water for every part of gum added to your formulation,” he said.
In conventional baked foods, the typical usage levels for gums and hydrocolloids range from 0.1 to 0.3%, but this can increase 10-fold or more when making gluten-free baked goods. “When switching to a gluten-free system, levels are increased to 2 to 5%, based on flour weight, to achieve finished items with similar volumes and textural attributes,” Mr. Baker said. “For gluten-free sweet goods such as cakes and muffins, the increase is less but still significant, with usage levels two to three times the level in conventional items.”
Moisture concerns can be exacerbated by other ingredients present in the formula. Water-binding by gluten-free flours differs widely, and the very nature of the product — chemically leavened vs. yeast-raised — can also be an issue. For example, muffins act differently than bread, and because muffins permit more forgiveness, the formulator has more gum options.
That affinity for water promises yield benefits, too. “Everyone in the food industry, including bakers, is looking for ingredients to make their product better and more cost effective,” said Laurie Kronenberg, new product leader, food and beverage, Ashland Specialty Ingredients, Wilmington, DE. “Gums allow more water to be incorporated into the system resulting in higher yields and extended shelf life by improving the texture. At a usage level of under 1%, a formulator gets significant functionality for a low cost in use with gums.”
Blending for gluten-free
Gluten does a lot of things for baked foods, tasks not easily mimicked by a single gum. “Unlike gluten, there is not a unique hydrocolloid that when hydrated and mixed will perform all the functions that gluten does,” Ms. Gravito Rojas observed. “Different hydrocolloids or their blends are useful in restoring individual functionalities of gluten at the different stages of mixing, handling, leavening and baking.”
Mr. Jonas voiced this another way: “One size does not fit all. Applications become very segmented.”
Because each gum has unique properties, they are often blended to fit specific applications, an especially important approach for gluten-free formulations. “Konjak is highly synergistic with other hydrocolloids,” Ms. Gravito Rojas explained. “When combined with xanthan, it produces a strong and notably elastic network that gels once it is heated and cooled.” She described a blend of konjac and xanthan as an excellent gluten replacement in bread.
Ms. Gravito Rojas noted other synergistic combinations, including a blend of xanthan and guar that adds viscosity and provides structure. The company also blends xanthan, tara and citrus fiber to improve and refine the crumb of gluten-free muffins and brownies. “This blend synergistically combines with functional flours to mimic attributes such as chewiness and bite that gluten proteins typically impart to brownies,” she said.
Even within categories, formulating needs vary, as TIC Gums learned. The company created a number of blends, each addressing different outcomes. “For breads, the two most common requests are for more volume and increased consistency,” Mr. Baker reported. Xanthan alone wouldn’t do the job, but a blend could. Another blend addressed consistency of loaf shape and height.
“For sweet goods such as muffins and cakes, gums contribute to batter consistency and stability resulting in a moister crumb with reduced breakdown — crumbliness — of the mass during chewdown,” Mr. Baker continued. “However, high gum usage can also result in a product that is too moist and sticky in the mouth.”
Blending can also smooth out occasional bumps in the market. “By creating blends of gums or gums and starches, we can often offset any supply or pricing issues that crop up,” said Joshua Brooks, vice-president, Gum Technology.
The variety of blends reflects another aspect of gluten-free formulating: every gum is different. “You don’t want too much of any one hydrocolloid,” Mr. Jonas cautioned. “You have to get the right usage level for the right product, and it’s not simple.”