Exploring some of the most common enzymes used in the baking industry.
Enzymes help bakers increase shelf life, enhance production tolerance, improve dough strength and reduce costs. The cost of stale returns, for example, can be greatly reduced by using fresh-keeping enzymes to achieve a longer shelf life. Fresh-keeping enzymes also allow manufacturers more flexibility in production scheduling and distribution.
To perform effectively, enzymes rely on many factors, including temperature and pH. Enzyme activity increases with temperature, finally becoming inactive when heated above a certain temperature. Because enzymes are deactivated during baking and no longer present in the final product, they do not have to be labeled, a benefit for those seeking all-natural labels.
Different types of enzymes
Some of the most common enzymes used in baking are amylases, lipases, proteases and xylanases.
Amylases break starch down into sugar and help achieve a softer crumb. Three main amylase varieties exist: fungal, bacterial and maltogenic. Fungal amylase manages fermentation in yeast raised bakery items and is usually added to the flour by the miller. “Fungal amylases are used usually in flour supplementation,” says Brian Fatula, national account manager, DSM Food Specialties USA Inc., Parsippany, N.J. “If you're producing a sponge-and-dough type bread, for example, the fungal amylase in the flour regulates the fermentation to obtain the desired results as you produce the sponge.”
Bacterial amylase and maltogenic amylase are primarily used to increase shelf life. Bacterial amylases are more thermally stable and might still be active upon leaving the oven, notes Bernie Bruinsma. Ph.D., vice president, technology, Innovative Cereal Systems, Wilsonville, Ore. “There is some use of bacterials, but percentage wise there is more use of amylases produced from fungi.”
Lipases are used as emulsifier replacements and to improve dough rheology to produce a finer crumb and a softer texture in bread. Some lipases are used in cakes to replace emulsifiers or strengthen the batter to produce an airy cake with a silky texture, notes Fatula. DSM offers a microbial phospholipase product for cakes that reduces overall manufacturing costs. It also allows for egg reduction, adds volume, improves crumb structure, increases softness and improves shelf life in cakes.
Lipases also work to free up some of the lipids in flour bound by proteins. “By loosening those lipids and breaking them up from where they are bound, they are free to function in the bread as well, so you can use the lipids in the flour in a positive way, if you chose the correct lipase,” Bruinsma says.
Proteases are used as a processing aid to achieve a more extensible dough rheology, by breaking down proteins to make the dough softer, so it can be stretched further or rise higher. If the dough is too strong to move through equipment properly or the mixing time is too long, bakers can add a protease to shorten the mix time and make the dough more flowable, Bruinsma says.
Still, it is important not to add too much of the enzyme. “You don't find a whole bunch of proteases in use because, if you add too much and it continues to break down the protein, the dough could turn into a liquid dough. You find them more heavily used in tortillas and crackers — bakery items that require a very extensible dough,” Fatula notes.
Xylanases improve dough rheology. “It's working on the small 2 percent to 3 percent of the flour made up of xylans and hemicellulose and pentosans (five carbon sugars in flour), causing the release of water or causing the dough to absorb more water,” Fatula says. Managing the water in a dough with xylanases allows bakers more control over the dough rheology and can allow bread to have improved internal characteristics and greater volume potential.
Issues to consider
Bakers should remember enzymes continue to work over time, making time and temperature crucial elements. “If you cannot control time and temperature in a bakery, my recommendation is don't use enzymes because achieving consistency while using enzymes on a routine basis depends on being able to control time and temperature. Then you get the same amount of activity every day, every dough,” Bruinsma says.
It also is important to remember all amylases are not the same. This is because the various amylases come with side activity, meaning when the enzyme is isolated, another enzyme or two may accompany it. “Enzymes are proteins and when you isolate proteins you get more than just one pure enzyme. You might get 98 percent purity on an amylase, but you might have a two percent protease with it. That two percent protease might affect your dough somehow, so you have to be careful,” Bruinsma says.
With this current economic environment most of the focus has been on cost reduction. “Some of the newer enzymes are being used to replace or reduce emulsifiers to provide ingredient cost savings. Also, because enzymes are more concentrated and their usage rate is much lower than some emulsifiers, there are opportunities to reduce freight costs, save on inventory costs and have a postive impact on the environment,” Fatula says.
The price of ascorbic acid along with industry concerns about azodicarbonamide (ADA) as an oxidation compound are compelling some bakers to use glucose oxidase-type enzymes for more natural oxidation, replacing ascorbic acid.
At the 2008 AACC International technical meeting, FDA's Gregory Noonan, Ph.D., Center for Food Safety and Applied Nutrition, presented data that showed semicarbazide, a known carcinogen in animals, is formed by baking bread with ADA as a dough strengthener or flour-maturing agent. While the FDA is not planning changes in legislation, it suggests bakers use significantly less than the 45 ppm legal limit, notes Todd Forman, CS application scientist, Novozymes North America Inc., Franklinton N.C.
“If bakers decide to heed the FDA's suggestions, the resulting dough may not be strong enough to withstand the stress of high speed production. This is where enzymes can help,” Forman says. “In the presence of oxygen and water, the enzyme glucose oxidase oxidizes glucose to form gluconic acid and hydrogen peroxide. The hydrogen peroxide is a strong oxidizing agent and helps the formation of a strong dough via the formation of disulfide bonds from free sulfhydryl groups. When used in combination with ascorbic acid and perhaps other dough conditioning enzymes, such as xylanases, the baker can reduce the level of ADA in the formula or eliminate it, allowing for a more label-friendly ingredient line…With the addition of a few parts per million of glucose oxidase, bakers also may reduce ascorbic acid levels by half,” Forman adds.
Using enzymes to reduce acrylamide
Acrylamide is a chemical compound that forms naturally in a variety of foods that are cooked or baked at high temperatures, including cookies, breads and biscuits. Acrylamide is classified as “probably carcinogenic to humans” by the International Agency for Research on Cancer (IARC).
While IARC and the Joint FAO/WHO Expert Committee on Food Additives both have expressed concerns regarding human exposure to acrylamide, research into a carcinogenic link for humans has been inconclusive, says Gary Johnson, regional marketing manager, Novozymes. The FDA has acrylamide mitigation as a priority, but because of the complexity of acrylamide studies in humans, it will likely be some time before a decision is reached. Other countries, however, are taking action. Health Canada has recommended that acrylamide be included on the nation's list of toxic substances and, in Germany, “signal values” have been determined for each product group. If acrylamide levels above the signal value are found, food control authorities contact the food producer to discuss minimization, notes Johnson.
The enzyme asparaginase has been shown to reduce acrylamide levels. While acrylamide cannot be easily removed once it is formed, it can be prevented from forming. “[Asparaginase] prevents the formation of acrylamide by modifying its precursor, the naturally present amino acid asparagine to form another common amino acid, aspartic acid,” Johnson says. Novozymes' asparaginase product is produced by submerged fermentation of a genetically modified microorganism, Aspergillus oryzae. “The enzyme protein, which in itself is not genetically modified, is separated and purified from the production organism. It comes in liquid and granulated versions that can be easily measured into the dough system during its normal mixing stage. Recommended dosages range from 70 ppm to 570 ppm, so the amount actually added is quite small,” he adds. Although it depends on several factors, such as temperature, pH and water activity, Novozymes' asparaginase has achieved a 40 percent to 95 percent reduction in acrylamide levels in baked products from cookies to crisp bread without negatively impacting appearance or sensory characteristics.
While some bakers are enjoying the results of asparaginase, many are waiting for FDA's ruling for how the baking industry should proceed before incorporating the enzyme.