A Supplement to Food Product Design

By Elaine KnehrContributing Editor

Food labels greatly influencewhether a product collectsdust on the store shelf ordraws shoppers to add it to

their cart. Many consumers scruti-nize the Nutrition Facts panel, look-ing for high levels of “good,” nutri-ents, such as protein, and lowamounts of “bad” ones, such as satu-rated and trans fatty acids. Somelook for banners that highlight healthbenefits. Still others warily eyeingredient statements, avoiding prod-ucts with chemical-sounding sub-stances. Designing these label-friendly products is simplified withingredients that are nutrient-dense,natural and diversely functional—allcharacteristics of the humble egg.

Grade A nutritionWhile the “Grade A” stamped on

egg cartons refers to eggs’ physicalquality, the rating could also apply totheir nutrient content. “Eggs arenutrient-dense, providing more nutri-tion per calorie than many foods,”

explains Donald J. McNamara, Ph.D.,executive director, Egg NutritionCenter, Washington, D.C. “A largeegg (50 grams) supplies 75 calories,which is 3.75% of the calories of a2,000-calorie diet. Many of the nutri-ents in an egg are present at higherlevels, including 10% to 13% of theDRV (Daily Reference Value) forprotein, 15% RDI (RecommendedDaily Intake) for riboflavin and 4% to9% RDI for numerous vitamins andminerals.”

Nutritionists regard the egg as acomplete-protein food, since it sup-plies all nine essential amino acids, aswell as nine nonessential aminoacids. The essential amino-acid com-position of egg protein is similar tothe human body’s requirement, allow-ing the body to use the protein moreefficiently for growth. Using protein’sbiological value (BV) scale, with 100representing top efficiency, whole-egg protein has a BV of 93.7, as com-pared to milk (84.5), fish (76.0), beef(74.3) and soybeans (72.8).

Whole egg is composed of about75% water, 12% to 14% protein, 10%to 12% lipids and almost every essen-tial vitamin and mineral. (Eggs lackvitamin C, as chickens produce theirown vitamin C and do not need toobtain it from the diet.) The wholeegg has two parts: the albumen, orwhite, and the yolk, or yellow—eachwith a unique nutrient profile.

Egg white contains 56% of thewhole egg’s total protein, as well asmost of the egg’s riboflavin, niacin,chlorine, magnesium, potassium,sodium and sulfur. Plus, it containsvirtually no fat or cholesterol. Theyolks supply all of the egg’s fat, a lit-tle less than half of the protein and alarge proportion of vitamins and min-erals. The yolk lipids, consistingmainly of triglycerides, lecithin andcholesterol, are trans-free with lowlevels of saturated fat. Micronutrientcontent includes choline; iron; phos-phorus; calcium; zinc; vitamins A, D,E and B12; biotin; folic acid; pan-tothenic acid and thiamine. Egg yolk

is one of the few foods that naturallycontain vitamin D, a key nutrient thata growing number of Americansaren’t getting enough of. One largeegg furnishes 6% RDI of vitamin D.Also present are lutein and zeaxan-thin, xanthophylls that contribute toyolk’s golden color.

Eggs can help consumers meetstandard daily nutritional needs as well as specialized requirements.The 2005 Dietary Guidelines forAmericans recommends consuming“a variety of nutrient-dense foods andbeverages within and among the basicfood groups while choosing foodsthat limit the intake of saturated andtrans fats, cholesterol, added sugars,salt and alcohol.” As noted, eggs arenutrient-dense and trans-free, plusthe 5.0 grams of lipid present in the yolk of a large egg consist of just1.5 grams saturated fat. USDA’sMyPyramid lists eggs as a choiceunder the meat and beans group, withone large egg providing 6.25 gramsprotein, the equivalent of 1 oz. of leanmeat, fish or poultry. Egg’s high-quality protein can help satisfydiverse population protein needs. For

example, adult’s protein DRV is 50grams (for a 2,000-calorie referencediet), while studies indicate that preg-nant women need at least 60 gramsprotein per day, and lactating womenneed a minimum of 65 grams. Forthose on weight-management diets,products can be designed with nutri-tious, low-calorie egg whites, whichdeliver 47 calories per 100 grams.These are just the basics—eggs canenhance a finished product’s labelappeal in many ways.

The heart of the matterCoronary heart disease (CHD) is

the leading cause of death in theUnited States for both men andwomen, and many look for productsthat won’t increase the risk of thisdisease. Major risk factors areincreased levels of low-densitylipoprotein (LDL, “bad”) cholesteroland a rise in the ratio of total choles-terol to high-density lipoprotein(HDL, “good”) cholesterol.

For years, consumers avoidedeggs, fearing that consuming the cho-lesterol naturally present in eggs sig-nificantly impacted blood cholesterol

levels. However, “evidence is accu-mulating that serum cholesterol levelis determined almost entirely by theamount of saturated and trans fat inthe diet,” says McNamara. “Dietarycholesterol has minimal effect at nor-mal intakes.” In a comprehensivestudy (Hu et al., Journal of theAmerican Medical Association, 1999;281:1,387-1,394) involving data fromthe Nurses’ Health Study (80,082women) and the Health ProfessionalsFollow-Up Study (37,851 men), nocorrelation was found between eggconsumption and CHD risk. While 50grams of whole egg contains 213 mgcholesterol and 5.1 grams of fat, all ofwhich is found in the yolk, there areonly 1.57 grams of saturated fat.

Most saturated fats raise LDL cho-lesterol (some studies indicate stearicacid might be neutral), while trans fatsincrease LDL cholesterol and, at thesame time, lower HDL cholesterol.Eggs’ favorable fatty-acid profile—along with the emulsifying effect oftheir lecithin—can help reduce saturat-ed and trans fats in a product whensubstituted for other high saturated fatand trans fat ingredients, therebyimproving the label’s fat declaration.This has become a highly visible issue,because as of Jan. 1, 2006, food manu-facturers must list trans-fat content onthe Nutrition Facts panel on a separateline, immediately under the saturatedfats. FDA regulations allow labels tolist trans fat as zero as long as the foodcontains less that 0.5 grams trans fat.Egg products are virtually trans-free,with liquid egg whites containing zero grams trans per 100 grams,liquid whole egg, 0.11 grams per 100grams, and liquid yolk 0.28 grams per100 grams.

Eggs provide a natural protein binder fornoodles and can add lutein and choline.

Eyeing eggs’ benefitsThe xanthophyll pigments in egg

yolk not only add attractive coloring,they are also associated with eyehealth. Studies have shown thatlutein and zeaxanthin protect the eyeagainst age-related macular degener-ation (AMD) and cataracts. Thesesubstances are present in the eye’smacula lutea, where they absorbultraviolet-blue light and function as antioxidants to protect cells from free-radical damage. In the“Lutein Antioxidant Supplementa-tion Trial” (Richter et al., Optometry,2004; 75(4):216-230), researchersfound that too low an intake of lutein and zeaxanthin increases therisk of AMD.

Research also suggests that theseantioxidant xanthophylls impact skinhealth and may reduce the risk ofsome cancers. Humans cannot syn-thesize lutein and zeaxanthin andmust obtain them from the diet.

Egg yolks, along with spinach,broccoli, squash, peas and corn, arecommon dietary sources of lutein,with 50 grams liquid whole egg con-taining 0.15 to 0.25 mg of lutein. A recent study (Chung et al.,The Journal of Nutrition, 2004;134:1,887-1,893) indicates that eggyolk’s lutein is significantly morebioavailable than the lutein in cookedspinach or supplements. “In the hen,lutein is removed from the plantmaterial and then stored in a highlyabsorbable lipid matrix in the yolk,”explains McNamara. “To improve the lutein content in eggs, some egg processors are altering the hens’feed to produce specialty eggs with1.0 to 1.5 mg lutein per 50 gramswhole egg.”

The choline connectionEgg yolk is also a good source of

choline, a component of phos-phatidylcholine (lecithin). Lecithin isfound in human cell membranes and the covering of nerve fibers.Choline, an essential nutrient impor-tant for brain function, plays a critical role in fetal brain develop-ment, both in utero and duringbreast-feeding. It also acts a precur-sor to acetylcholine, a neurotransmit-ter involved in memory storage and muscle control.

In 1998, the Institutes of Medicineestablished an adequate cholineintake of 550 mg per day for men and425 mg per day for women, as wellas 450 mg per day during pregnancyand 550 mg per day during lactation.Dietary sources of choline includebeef and chicken liver, egg yolks,wheat germ, and soy lecithin. Eggscontain about 125 mg choline per 50grams liquid whole egg, which quali-fies for labeling as an “excellentsource of choline.” As defined by theFDA, “excellent source” means that“one serving of a food contains 20%or more of the Daily Value for a par-ticular nutrient.”

Enriching eggsTo further improve eggs’ beneficial

nutrition, feeding hens enriched dietsproduces specialty eggs with not onlyhigher lutein content, but alsoincreased levels of vitamin E andomega-3 fatty acids.

Standard whole egg containsabout 0.7 mg vitamin E (4.5% RDI),17 mg alpha-linolenic acid (ALA)and 18 mg docosahexanoic acid(DHA) omega-3 fatty acids per 50 grams. By fortifying feed withingredients like flaxseed and algae, egg producers can increasevitamin E to 3.5 to 7.0 mg, ALA upto 300 mg and DHA up to 150 mg per50 grams.

Enriched shell eggs have beenavailable for years and interest inthem as ingredients is growing.“Some baby-food manufacturers areusing the yolks from these eggs toimprove the nutrient content of vari-ous products,” notes McNamara.

Weighing in on satietyConsumers struggling to maintain

or reduce their weight might want tolook closely at their egg intake.Recent studies indicate that higher-

Egg ingredients on ice cream labels lend a natural perception—and a

smooth, light mouthfeel.

protein diets and egg consumptionpromote satiety and weight loss.

In a clinical trial (Weigle et al., American Journal of ClinicalNutrition, 2005; 82:41-48), proteinintake was increased while the pro-portion of calories from carbohydratewas held constant. The objective wasto evaluate moderate- and high-pro-tein diets, not very high protein con-sumption. In fact, the study’s high-protein diet provided 30% of totalcalories from protein, a value wellwithin the acceptable range of proteinintake of a healthy diet—15% to 35%of energy from protein—set by theInstitutes of Medicine. The datafound that increasing protein intakeresulted in higher satiety scores,greater weight loss and improvedbody composition.

Another study (Jillon et al., Journalof the American College of Nutrition,2005; 24(6):510-515) compared an egg

breakfast to an equal-weight, bagel-based breakfast with the same caloriecontent. Participants eating the eggmeal reported greater satiety and sig-nificantly lowered their caloric intakeduring the subsequent 24 hours.

Going without glutenEggs can be a tool for those look-

ing to eliminate gluten. A functionalprotein found in wheat, rye, oats, bar-ley and related grain hybrids like trit-icale and kamut, gluten has beenidentified as the trigger for celiac dis-ease (CD), a lifelong autoimmuneintestinal disorder. For individualswith CD, ingesting gluten causes animmunologically toxic reaction thatdamages the mucosal wall of thesmall intestine, which interferes withnutrient absorption and, in somecases, water and bile salts. Accordingto the Celiac Disease Foundation,Studio City, CA, 1 out of every 133people in the United States is afflict-ed with the disorder.

The only treatment for CD is toavoid gluten, which often has sur-

prising sources, such as puddingmade with a wheat-starch-based sta-bilizer or soy sauce fermented withwheat. A logical replacement forgluten would be another functionalprotein, like egg albumen. These eggproteins can thicken sauces, gravies,smoothies and other products thattypically rely on wheat flour andstarch ingredients, thus helping toachieve a gluten-free label.

A functional feastAt the same time they improve the

nutritional appeal of food labels, eggscan simplify and enhance ingredientstatements. Consumers are comfort-able with eggs, and their inclusion infoods assures them that products con-tain natural, wholesome ingredients.For product designers, eggs are easyto use and offer a wide array of func-tionalities, including coagulation,emulsification, foaming and crystal-lization control.

Coagulation converts a liquid mix-ture to a solid or semisolid state. Eggproteins, which are good binders,provide thickening and structurewhen whipped, heated or formed intogels. For instance, egg whites areused in surimi as a binder and gelagent and can add a firmer bite topasta; egg yolks produce rich, thickcustards; and whole eggs give cakes alight, moist structure. “Eggs can beused in functional foods as a high-quality protein source, as well as forgood sensory attributes,” says GlennFroning, Ph.D., food technologyadvisor, the American Egg Board,Park Ridge, IL. “For example, eggsfunction as a binder in health bars andgive a thick texture to high-proteinbeverages.”

Many foods, such as mayonnaise,salad dressings, ice cream andsauces, require the formation of an

A classic French éclair gains sensoryindulgence—but no trans fats—with eggs.

emulsion. Egg yolk contains severaleffective emulsifying agents, includ-ing lecithin, lipoproteins and pro-teins. “Egg yolk, as well as wholeegg, can be used as a natural emulsi-fier in place of other emulsifiers,”says Froning. “In addition to supply-ing a stable, smooth mouthfeel in many products, eggs can possiblybe used to reduce or replace starchesor gums.”

When eggs are whipped and airbubbles become trapped in thematrix, it creates a foam. This aera-tion process provides leavening,yielding products with a light, airytexture. Heating expands the air cellsand coagulates the egg protein, set-ting the foam structure. Volume variesdepending on the type of egg productused, with whites yielding foams withthe highest volume and whole eggsthe least. Common applicationsinclude cakes—especially angelfood—meringues and soufflés.Crystallization can adversely affectthe smooth texture and mouthfeel ofproducts like ice cream and confec-tionery. Egg yolks help control icecream’s density, hardness and textureby encouraging the formation ofsmall ice crystals, while egg whitescan retard crystallization in chocolateand other candies.

Furthermore, eggs lend color andflavor to products. Due to its naturalyellow pigments, the yolk can pro-vide a rich, golden appearance toproducts like baked goods and cus-tards. “The lipids in the yolk helpcarry different flavor compounds,”says Shelley McKee, Ph.D., associateprofessor, poultry and egg productsafety and quality, Auburn University,Auburn, AL. “Depending on the use level, eggs can contribute charac-teristic egg notes or enhance otherflavor systems.”

Eggs also act an effective humec-tant, a function of the proteins’ water-binding property and lecithin’s abilityto reduce moisture loss. In bakedgoods, for instance, eggs helpimprove texture and mouthfeel bymaintaining product moisture. Eggsalso work as a dough conditioner,such as in frozen doughs where theyolk lipids, in particular, contribute toa softer structure and improved stor-age stability.

Market demands are constantlychanging, and eggs can be a valuabletool in meeting diverse productrequirements. “When designinggluten-free baked goods, such asmuffins, eggs can help bind togetherthe different ingredients and providetexture and structure,” says McKee.“For foods targeting health-con-scious consumers, replacing some ofthe formulation fat with eggs can

improve both the fatty-acid profileand overall nutrient content.” Eggsalso have application in ovo-lactovegetarian products.

A recent study, Shopping forHealth 2004, conducted by the FoodMarketing Institute, Washington,D.C., found that consumers areincreasingly influenced by theNutrition Facts label on food prod-ucts, and many are using the informa-tion to make purchase decisions.Keeping that in mind, what otherproduct can beat eggs when it comesto contributing so much to quality andnutrition, while providing cleanlabels that consumers crave? ■

Freelance technical writer Elaine Knehrholds a B.S. in Food Technology and an M.S.in Business Administration. Her 10 years ofexperience in product development covers awide range of food products.

Eggs contribute wholesome, natural color to a range of baked goods,

including classic biscotti.