Change of course
August 14, 2013
by Laurie Gorton, Baking & Snack
The more things change, the more they stay the same. Trans-free shortenings have dramatically altered the world of bakery formulating, and their advent now spurs renewed interest in emulsifiers as mediators of dough strength, crumb texture and product keeping qualities.
“As bakers move away from shortenings with trans fat toward better-for-you and reduced-fat products, they are finding ways to use emulsifiers to help with the change,” said Joe Layton, R&D manager, patisserie
mixes, Puratos, Cherry Hill, NJ.
Most food uses for emulsifiers take advantage of how they stabilize otherwise immiscible liquids. In baked foods, however, it’s their additional ability to complex with starch and protein to aid structure. They also boost water-binding to keep finished products soft and appetizing.
They are actually more functional than traditional fats. “Adding a small amount of emulsifier to a formulation can have a more beneficial impact on shelf life than adding a large amount of shortening or oil,”
Mr. Layton said.
Going to zero-trans
For most purposes, trans fats are out. The 2010 Dietary Guidelines for Americans advised consumers to avoid foods containing trans fats as much as possible. This tenet rules out partially hydrogenated oils.
The problem this created for bakers is simple to describe but complex to solve. Solid fats give bakery shortenings their ability to cream and aerate batters, yet turning liquid vegetable oils into plastic shortenings requires addition of hard fats. Hydrogenation does the trick nicely, but it also creates unhealthy trans fats. Another approach uses liquid oils high in saturated fats. Although the nutritional attributes of saturated fats are still being debated, many consumers choose to shun these, too.
This change is not easy to navigate and exacts a toll. “As bakers move to zero trans-fat shortening solutions that have lower saturated fat content, the final product may lack volume due to the loss in structure from their fat system,” observed Steve Baker, scientist in the Emulsifier Innovation Center at Caravan Ingredients, Lenexa, KS. “The issue of lower solid fats or structure has opened the door to utilizing emulsifiers as structuring agents for their shortening systems.”
Simply put, new trans-fat-free shortenings are not quite as functional as the baker’s old standbys. “Trans fats were certainly not healthy for us, but they were very functional,” said Troy Boutte, PhD, group manager, bakery/fats and oils, DuPont Nutrition & Health, New Century, KS. “While bakers have not necessarily made a lot of changes to the emulsifiers they use, some shortening companies have switched to using distilled monoglycerides in emulsified bakery shortenings.”
The adjustments made by adding emulsifiers foster better results, Mr. Layton noted. “In general, many of the new-generation oils perform similarly to their traditional counterparts, but there may be some slight differences in flavor and texture in the finished product,” he said. Depending on the new oil selected, shifting emulsifier levels up or down will help duplicate the texture of the original product.
Because of their functionality, some partially hydrogenated shortenings continue to be used in bakery applications. But that use doesn’t rule out the benefits of adding emulsifiers, according to Mr. Baker. “In most applications, emulsifiers will function the same regardless of whether your shortening contains trans fat or not,” he said. “For example, mono- and diglycerides and Alphadim distilled monoglycerides continue to extend shelf life through crumb softening, and sodium stearoyl lactylate (SSL) and diacetyl tartaric acid esters of mono- and diglycerides (DATEM) continue to be excellent dough strengtheners.”
Taking new directions
Liquid oils present special difficulties in cake systems. “The emulsifier system needs to hold the liquid oil into the cake batter to avoid a change in mouthfeel and oiling-out in the cake,” explained Rosa Regalado, general manager, Palsgaard Inc., Morris Plains, NJ. “Emulsifiers that can tolerate high amounts of oil in both aerated and non-aerated systems are necessary.
“In our experience, by using the right emulsifiers, it is possible to substitute 90% of the saturated fat in a traditional pound cake with healthier unsaturated fats,” she added. In non-aerated cake batters, the fat’s creaming ability contributes volume of the finished cake. When the fat is taken out, the emulsifier compensates for the lost functionality and also binds the liquid oil into the batter.
Cake mixes that contain fats present another challenge. They are usually made by creaming emulsified shortening with the dry ingredients or spraying it in melted form onto them. As the mix cools over time, the fats and emulsifiers crystallize. “Not all may be in the whip-stable alpha form. They may morph from alpha to beta and beta prime crystals during the shelf life of the cake mix,” explained Manuel Ybarra, technical sales manager, bakery group, Palsgaard Industri de Mexico, Soledad de Graciano Sánchez, San Luis Potosi, Mexico.
Instead, he recommended adding a powdered activated cake emulsifier — in this case, polyglycerol esters (PGE) and mono- and diglycerides — instead of emulsified shortenings. Rather than the manufacturer putting the liquid oils into the dry mix, they are added by the end user during prep. “This ensures the cake mix is more stable, and the emulsifier stays in an alpha crystal form,” he said. And because the mix contains no fat, it is less prone to oxidation, and its shelf life is longer.
“For industrial baking, use of powdered emulsifiers can ensure that all the liquid oil is emulsified into the batter before the aeration stage,” Mr. Ybarra said. During
interaction of PGE, air, water and oil, the emulsifier helps disperse the oil around the air bubbles, he explained, stabilizing them without affecting the batter aeration.
In large-scale processing, Mr. Ybarra recommended putting the emulsifier in at the slurry stage. “Add the water before adding the liquid oil so that the emulsifier will have the chance to hydrate before the whipping stage,” he said. This promotes higher aeration. To avoid dryness in the finished product, its formula should be rebalanced to account for the starch that carries the powdered emulsifier.
Danish, biscuits and pastries made with low- and
zero-trans shortenings may become denser or experience other textural changes when made with non-trans shortenings, which are generally softer than previous bakery shortenings. “Increasing the level or type of emulsification in that system will help regain some of the attributes that were lost,” Dr. Boutte said. “Another approach would be to add a strengthening emulsifier such as Panodan DATEM to the dough component, which will help regain some volume and textural qualities.”
Paving improved roads
Emulsifier suppliers have adapted to new-generation oils with ingredients suited to the realities of
bakery use. With these new shortenings, the right emulsifier can make all the difference in creaming action, according to Mr. Baker. The standard mono- and diglyceride emulsifiers worked well with trans-containing or palm-based shortenings. “However, new-generation oils may not have the required structuring power for air incorporation,” he observed. “A combination of alpha-tending emulsifiers such as lactylated monoglycerides or propylene glycol monoesters (PGME) with higher levels of mono- and diglycerides may be needed. These types of systems allow the emulsifiers to provide structure to air cells in the product, yielding more acceptable volumes.”
The difference in mono- and diglyceride emulsifiers was described further by Dr. Boutte in the context of DuPont’s DIMODAN line. Distilled monoglycerides contain a minimum of 90% mono- and less than 10% diglycerides. The mono- and diglyceride emulsifiers previously used in shortenings were typically 50% mono-, 40% di- and 10% triglycerides. “The switch to distilled monoglycerides not only eliminates the trans fats, but distilled monoglycerides have higher melting points than the mono- and diglycerides and, therefore, help stiffen the trans-free shortenings and actually promote crystallization,” he said.
Powdered emulsifiers that address the concerns of mix blending also improve shelf life of finished products. This style helps retain the alpha crystalline form responsible for best air incorporation. Mr. Ybarra explained that the Palsgaard’s SA 6600 is based on specially selected PGE optimized for cake systems. “The emulsifier is finally activated on rice starch through extrusion, resulting in a free-flowing white powder,” he said. “The whipping active emulsifier is fixed to the outer surface of the starch particles during the extrusion process and has proved to be extremely stable in functionality during storage.”
In addition to this lean-label emulsifier, the company offers Emulpals 110 for sponge cakes, Swiss rolls, layer cakes, pound cakes and similar products where all ingredients are added at once. Both are all-vegetable, non-trans and non-GMO.
Adding to its portfolio, Caravan Ingredients introduced non-GMO emulsifiers recently. “The non-GMO area continues to gain popularity with consumers,” Mr. Baker said, “and it is important for us to be able to offer our customers the solutions to enable them to compete in this area.”
Charting paths ahead
By deconstructing shortening, Caravan Ingredients and DuPont Nutrition & Health separately developed emulsifier-based systems that provide the functionality of hard fats to allow preparation of bakery shortenings from zero-trans liquid oils.
“Transcendim is a customized mono- and diglyceride that brings firmness or structure to fat systems,” Caravan’s Mr. Baker explained. “It allows development of a network of small crystals to entrap the liquid portion of the shortening system. The result is a shortening comparable to the old trans-containing versions with improved nutritional value that still maintains desired eating qualities.
“By using Transcendim as a structuring agent, you can avoid having ‘hydrogenation’ on your ingredient statement,” he added.
DuPont’s Crystallizer 100 was specifically formulated for trans-free shortenings, according to Dr. Boutte. “It increases the solid fat index and promotes nucleation and crystal growth,” he said.
Supplementing the crystal structure of bakery shortenings is essential when using many of today’s liquid oils. “The trans-free shortenings undergo more ‘work softening,’ which simply means the crystal structure starts to break down and release the oil that was trapped in the crystal,” Dr. Boutte explained. “This in turn creates the denser texture [in the finished product].”
Going a step further, Puratos created Puraslim, a gel-style system using an emulsification process in combination with flavor and enzyme technology. It can reduce fat in baked products by 50% or more, according to Mr. Layton. “Puraslim is a gel that has a texture similar to traditional shortening but contains about 85% water,” he said.
In the long run, the road ahead with bakery shortenings will also take direction from the emulsifiers available to do the fine-tuning of performance. Such tools, now available for use by formulators, will help rev the engine of bakery product innovation.