Fats & Oils: Applying the 'New' Oils
September 01, 2009
by Laurie Gorton
When it comes to oils, one “size” does not fit all, but some seem like they are being created specifically for bakery applications. Consider low-linolenic soy oil, mid-oleic sunflower and higholeic canola — all are stable without hydrogenation and figure prominently among the healthy, functional fats now replacing trans and saturated fats. Monounsaturated omega-9 oils sourced from canola and sunflower seeds are also gaining attention as heart-healthy fats. These “new” oils blend with other fats including palm oil, allowing shortenings to be tailored to exact processing and nutritional needs.
Now, it’s up to bakers and other food processors to put these new oils to use, and many applications are already on the market.
“The whole category of fats and oils has changed a lot in recent years,” said Lynne Morehart, technical service manager, Cargill Oils and Shortenings, Sidney, OH. Not only have oils with enhanced traits been introduced, but food processors working with such oils have grown to understand the flexibility possible with the many different options. “Decisions now involve nutrition as well as function,” she observed. Cargill just announced the launch of Clear Valley low-saturate canola oil, which contains 4 to 4.5% saturated fat — 25% less than in conventional canola oil and the lowest amount of saturated fat of any vegetable oil offered to food manufacturers to date.
Because of their oxidative stability, the new oils exert a positive effect on shelf life. “Also, these oils are better nutritionally and allow reductions in both trans and saturated fats,” Ms. Morehart added.
Changes in the fatty acid profile provide other benefits, and Terri Volpe, consulting food scientist for Asoyia, Iowa City, IA, observed, “This unique fatty acid profile delivers a very light clean flavor and mouthfeel.” The “ultra low linolenic” fat has a low melting point of 50°F, which ensures “that the oil clears quickly from the palate so the flavors that you want to characterize your product dominate, not the oil,” she explained.
By traveling down the fatty acid molecule’s backbone, researchers developed omega-9 oils, which Mary LaGuardia, market manager, Dow AgroSciences, Naperville, IL, described as “the next generation” of commercial cooking oils. She explained that omega-9 oils made from the company’s Nexera canola and sunflower seeds have zero trans fat, the lowest amount of saturated fat and uniquely high (>70%) levels of hearth-healthy monounsaturated fats. Shortenings based on these omega-9 oils “provide texture to bakery items without trading one ‘bad’ fat for another,” she stated.
In their pure forms, today’s trait-enhanced oils exist as liquids at room temperature. “They are excellent heavy duty frying oils due to their low polyunsaturated fatty acid (PUFA) content,” said Gerald McNeill, PhD, vicepresident, R&D and marketing, Loders Croklaan North America, IOI Group, Channahon, IL. “However, most baked foods require a solid fat to provide the taste and texture required by consumers.
“Apart from frying or salad oil applications, traitenhanced oils would not normally be used on their own in a bakery,” he continued. “Most baked foods require a solid fat for functionality.” Thus, the new oils are being blended with other fats, and in many cases, palm oil is the fat selected. “Palm oil is naturally semisolid and has excellent creaming properties that allow incorporation of air into doughs and batters; liquid oils alone cannot entrap air,” Dr. McNeill said.
STORE AND USE.
Stability is a key attribute. As explained by Ms. Volpe, linolenic acid with its three double bonds is as much as 100 times more prone to oxidation than oleic acid with only one double bond, so reduction of soy’s natural 6 to 8% linolenic acid content is at the heart of the first target in trait-enhancement soy. Low-linolenic soy, with a maximum of 3% linolenic acid, is now widely available. Some researchers were not content to stop at 3% and continued to work, pushing linolenic acid content as far down as 1.5% in the oil of the cultivar that Asoyia processes. This, Ms. Volpe continued, “is the foundation for extended shelf life of products.”
Because of the stability of the trait-enhanced oils, such oils do not demand special conditions for storage and handling in the bakery environment. If prepared as a solid or plastic shortening, they need what any standard shortening requires: a cool, dry environment away from materials with strong aromas, according to Ms. Morehart. In bulk, the liquid oils are stable at room temperatures.
As part of the blending process, the fat becomes solid at room temperature. “If you wanted to use the blend as a liquid, it would require some heat in storage,” Ms. Morehart observed. “But do not subject them to prolonged agitation, and use a nitrogen blanket for liquid oils if you can. Heat is the enemy of fat, so you don’t want to hold them any hotter than necessary.”
This is also true for omega-9 fats. They have natural stability, with no special requirements for storage as long as they are handled properly, according to Ms. LaGuardia.
Omega-9 oils find use as spray oils, frying fats and bakery shortenings, according to Ms. LaGuardia. “Shortenings made with omega-9 oils provide the required volume, height, firmness and textural properties in baked foods with up to 50% reduction in saturated fat compared with conventional shortenings,” she observed. Because these oils require no hydrogenation, interesterification or additives to assure their stability, they lend themselves to simple, clean product labels.
The liquid oils extracted from trait-enhanced soy, canola and other oilseeds have a variety of functional characteristics, permitting their use as single oils or as components of blended solid shortenings.
“There are different ways to look at these materials: first, as a liquid oil, and second, as a component of a solid fat blended to lower its saturated or trans fat content,” Ms. Morehart said. Bakery applications generally call for blends, and Cargill Oils and Shortenings has worked up formats, bulk or cube, that can be used “as is” by the bakery customer. “This considerably widens the group of possible products for our customers,” she noted.
“Our enhanced performance line of fats under the Clear Valley brand provides us a way to start discussions with bakers,” said Kristen Schmidt, technical service manager, Cargill Oils and Shortenings. “But many of the ‘solutions’ we offer customers are tailored to bakers’ specific uses.”
Blending the trait-enhanced oils with palm oil changes the physical properties, improves bakery functionality and allows longer shelf life than blends made with conventional soy or canola oils, according to Dr. McNeill. Loders Croklaan manufactures bakery shortenings that contain palm oils pre-blended with the right amount of liquid oils for certain applications.
“Asoyia Ultra low-lin performs very well in standard liquid oil cakes such as jelly rolls or traditional sponge cakes, which rely on egg foaming for aeration and volume,” Ms. Volpe said. High-ratio cakes, which get their volume through the creaming of solid fats with sugar, will require the liquid oil to be tailored by blending with emulsifiers such as monoglycerides and propylene glycol monstearates to stabilize aeration and cell structure development. “Preliminary evaluations of cake formulas with Asoyia Ultra and emulsifier blends displayed excellent volume and crumb quality,” she said.
Used as a cracker topping spray or in cookie and cracker doughs, the ultra-low-linolenic oil performs well and has yielded up to 24 months of shelf life, according to Ms. Volpe. She also reported that it functions as a 1:1 replacement for other oils or shortenings and does not require any special emulsifier. It adheres well to snack crackers, with absorption of 75 to 80% of the weight of the base cracker, or 43 to 44% of the finished product.
Experts agree that when substituting one fat for another, the new one must enhance the product as well as provide the correct processing functionality. The impact of substitutions on package label declarations of trans fat and saturated fat content must be considered.
Some changes in mixing, makeup and baking procedures may also occur when adopting these fats. Solid shortenings blended with such oils tend to be softer than previously used products, “so you may have to make machining adjustments,” Ms. Morehart said. “I would urge formulators to be open-minded.”