April 01, 2009
by Donna Berry
The food industry is polarized these days regarding what consumers want. On one side, there’s a strong consumer base demanding all-natural products using the most sustainable options. On the other, the growing group of recession-hit consumers are struggling to afford a well-balanced meal for their family.
In a perfect world, bread would be baked daily, but there’s a reason food manufacturers rely on a number of commercially produced ingredients — it’s called economics. Product improvers, shelf life extenders and manufacturing aids enable formulators to efficiently develop affordable nutritious foods to serve the masses.
One such category of ingredients is emulsifiers, often also referred to as surfactants. Bakery emulsifiers are best known for reducing staling; however, many contribute other benefits specific to the emulsifier and application.
When it comes to staling, generally, the higher the moisture content of fresh baked foods, the greater the effects of staling. Yeast-raised products and cakes are more susceptible to staling than cookies and crackers.
Emulsifiers are inherently present in some foods, as well as commercially produced as ingredients. They have a chemical affinity to both lipid and aqueous phases of a food product. In other words, they are polarized compounds that allow two immiscible materials to co-mingle. In general, the polar region of emulsifiers is attracted to other polar molecules such as water, while the non-polar region is attracted to other non-polar molecules such as oil. This attraction reduces the surface tension of the immiscible compounds, enabling them to combine or, in scientific terms, create an emulsion.
The baking industry is the largest user of food emulsifiers, which vary in functionality based on type of emulsifier and application. Emulsifiers used in baking come in a variety of physical forms ranging from plastic, shortening-like materials to powdered or beaded forms to even liquids. The original bakery emulsifier comes in a shell.
Eggs are a natural source of lecithin, a phospholipid that functions as an emulsifier in baked foods. Chemically, lecithin resembles a triglyceride where one of the three fatty acids on the glycerol backbone is instead a molecule of phosphoric acid attached to a nitrogen-containing group. The two fatty acids are non-polar and exert a strong affinity for fats, while the polarized phosphoric region has an affinity to water.
"Eggs, specifically egg yolks or the yellow of the egg, have long been recognized as playing an important role in bakery products. Not only do they provide color and richness, the yolk is also a natural source of lecithin," said Elisa Maloberti, director of egg product marketing, American Egg Board, Park Ridge, IL. "Using eggs for their emulsification properties, as compared with adding an emulsifying ingredient, is the most ‘natural’ way to bake."
The lecithin in the yolk reduces the rate of moisture loss as well as exerts a tenderizing effect on baked foods. Further, the carotenoids that make the yolk yellow also provide a rich color.
"Cracking single eggs is not a realistic scenario for commercial baking operations, thus many bakers turn to egg products, which are convenient forms of whole eggs, as well as just the white or just the yolk," added Ms. Maloberti. "Egg products for bakers come in refrigerated liquid, frozen and dried forms. They are pasteurized, all-natural and contribute to a clean ingredient legend."
According to the American Grocery Shopper Study released in January by BrandSpark International, New York, NY, more than half (58%) of the 51,295 US shoppers surveyed consider it important for a new product they purchase to be "natural." Further, shoppers revealed health as a greater priority, with 68% reporting increasing concerns about their health. Specifically, 68% of respondents expressed increased concern about chemicals in food products.
Mintel Global New Products Database (GNPD), Chicago, IL, reported that natural claims appeared on nearly one in four (23%) food and drink launches in 2008, a 9% increase from 2007.
OTHER NATURAL OPTIONS.
In addition to egg products, a number of commercially produced emulsifying ingredients are also considered natural, including lecithin obtained from corn or soybeans.
Commercially produced lecithin can extend the shelf life of yeast-raised baked products by slowing starch retrogradation. Lecithin also strengthens gluten to improve both the elasticity and extensibility of yeast-raised doughs, which make them more machineable. The improved gluten strength results in higher gas retention, yielding better volume and crumb structure.
The use of lecithin in bread dough is said to increase fermentation tolerance, produce better dough machineability, yield a more uniform crust color, give a more tender crust and a smoother texture with a more uniform grain, and produce a softer and less rapidly staling loaf.
In soft cookies and cakes, lecithin slows moisture loss. It can increase cookie spread and cake volume and can improve the creaming stage of products like cookies and cakes for better fat distribution. This results in more tender baked foods, even with lower fat levels.
A growing use for lecithin is in low-fat and fat-free baked products. These products are often made from dough that is sticky and difficult to machine without added fat. Lecithin adds lubricity and contributes to increased throughput and decreased clean-out time for extruded products.
Minneapolis, MN-based Cargill is introducing a clean-label, non-genetically modified sunflower lecithin. The product matches soy lecithin in functionality, taste and color. The primary difference is that it does not require soy allergen labeling.
"This lecithin offers an attractive alternative to soy lecithin because it helps reduce soy-based allergy issues in manufacturing," said Dana Craig, marketing manager and fruit, beverage and confection category manager, Cargill Texturizing Solutions, North America. "What’s more, the product offers smoothness, fine texture and quality emulsifying properties." The ingredient can replace synthetically produced emulsifiers such as ammonium phosphatide and citric acid esters of mono- and diglycerides, without compromising performance, taste or appearance, according to the company.
However, sometimes synthetics are necessary for economics and even desired functionalities.
Mono- and diglycerides are considered borderline natural emulsifiers. Natural status varies by how it is sourced and processed. Regardless, they are by far the most widely used in the baking industry.
Like lecithin, mono- and diglycerides consist of a glycerol backbone where either one (mono) or two (di) of the three hydroxyl groups of the glycerol is attached to a fatty acid. The fatty acids provide a non-polar region that exerts an affinity to fat. The other hydroxyl groups are unattached and slightly polarized, thus they show an affinity to water. However, the lack of attached hydrophilic group(s), like that attached in the third position on lecithin, suggests that mono- and diglycerides are not as effective emulsifiers as lecithin.
Both mono- and diglycerides occur naturally as minor constituents in fats and oils; however, the naturalness of most commercially produced ingredients is typically questioned by die-hard naturalists. This is because the chemical process employed to attach specific fatty acids to certain hydroxyl groups to obtain a desired functionality are considered synthetic.
Many bakers, however, appreciate this technology because it allows varied physical states of softness or hardness, which are dictated by the type and nature of fatty acids involved in the composition of the mono-and di-glycerides. For example, the more unsaturated the fatty acid on a monoglyceride, the more soft and plastic is the ingredient. These monoglycerides are typically used in high-fat sweet items. Monoglycerides containing a saturated fatty acid are harder and more brittle. They are considered to be choice for use in lower-fat baked foods.
While mono- and diglycerides are available in a variety of forms, they are most often used as components of complete bread shortenings. Usage levels are determined by the desired function in a given application.
DEVELOPED IN THE LAB.
A number of emulsifiers are derived by chemically manipulating mono- and diglycerides. For example, to overcome the lack of hydrophilic groups in monoglycerides, they can be esterified with a water-soluble acid of appropriate molecular weight such as diacetyl tartaric acid anhydride. This results in a more polarized compound — diacetyl tartaric acid esters of mono- and diglycerides (DATEM) — and thus a more efficient emulsifier.
When monoglycerides are reacted with ethylene oxide, the result is an ethoxylated monoglyceride (EMG). This treatment produces a region that is hydrophilic and imparts pronounced dough strengthening properties. However, it does not function very well as a crumb softener.
Interestingly, emulsifiers with the best dough strengthening properties (DATEM and EMG) are usually the poorest crumb softeners, while the emulsifiers with the best crumb softening effect are usually inferior dough stabilizers. Thus, some emulsifiers work best in combination.
To improve crumb softness of doughs strengthened with DATEM, monoglycerides might be added. DATEM can be added to applications lacking dough stability. Commonly used blends are part of most ingredient suppliers’ product list.
Some chemically produced emulsifiers exert both dough stabilizing and crumb softening action. This includes calcium stearoyl lactylate (CSL), the calcium salt of the reaction product of lactic and stearic acids (stearoyl lactylic acid). When used at the recommended maximum level of 0.5% based on flour weight, CSL increases dough absorption; measurably improves dough mixing tolerance and machineability; increases loaf volume; and enhances grain and texture, crust tenderness and keeping properties of bread.
Another is sodium stearoyl lactylate (SSL), the sodium salt of stearoyl lactylic acid. The ingredient is a free-flowing powder that is insoluble in water but readily soluble in hot fats and oils. When used at the recommended levels for a specific bread application, with a maximum of 0.5% based on flour weight, SSL measurably increases dough absorption, strengthens the gluten structure and improves mixing tolerance, machineability and the overall quality.
Innovations continue in this category. Danisco, New Century, KS, introduced a line of sustainable emulsifiers to meet increasing demand for ethically correct consumer goods. They are based on sustainable palm oil or palm kernel oil from Malaysia and Indonesia.
"At Danisco, we focus on sustainability at all levels. For that reason, we are especially pleased to offer sustainable emulsifiers. It is a major product area for us and hence contributes to giving us a strong profile in the food industry," said Martin Klavs Nielsen, executive vice-president, emulsifiers. "In step with the general focus on environmental and ethical issues, this opens up new opportunities for our customers to meet consumer demand for sustainable foods."
Opportunities are endless when it comes to selecting emulsifiers for specific applications. By design emulsifiers are polarized … just like today’s consumers’ requirements.
This article can also be found in the digital edition of
Baking & Snack
, April 1, 2009, starting on Page 59. Click
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