DESIGNER AND SPECIALITY EGGS: A WAY TO IMPROVE HUMAN DIET

ABOUT AUTHORS:
Hitesh Jain*^1,  Parva Jani¹, Khushboo Patel¹, Priti Yadav¹, Kaenat Sindhi¹, T.Y Pasha^2
1Sigma Institute of Pharmacy, Baroda, Gujarat, India.
²Parul Institute of Pharmacy and Research, Baroda, Gujarat, India
*hitesh_hitachi@rediffmail.com

ABSTRACT:
One of the ways to market a new product is to change the old product. The rapid decline in consumption of the eggs over the last 50 year is one of the most challenging problems the industry is facing today. The high cholesterol content in eggs is a major contributing factor. This problem can be minimized by using designer eggs. This review article throws light on what a designer egg is all about and how it can be obtained, the advantages of designer egg over simple egg. Besides designer egg, this article also provides information about the specialty egg and fertile eggs. Designer eggs are those in which the content has been modified from standard egg. The content of the chicken egg can be changed in such a ways as to be more healthful. This designer egg is free from all negative factors and prepared by changing the diet of chicken or manipulating the immune system of laying chickens. Thus, Designer eggs are essentially an ideal food and vitamin supplemented product which offers the benefits like reduced cholesterol content, high unsaturated fatty acids, ideal omega-6 to omega-3 ratio, cardiac benefits, etc.

REFERENCE ID: PHARMATUTOR-ART-1998

INTRODUCTION:
Consumers are always in search of newer products and are driving the market for a new category of food with potential health benefits well beyond those traditionally recognized. In the context of functional foods eggs are considered by most consumers to be a healthy food.^[1] Due to its excellent nutrients profile, less cost and versatility in food preparation, egg is a popular food item for all societies of the world. During the assessment of its potential as a food product, the avian egg’s complexity is a major challenge for food scientists and nutritionists eager to elucidate its biochemical processes.^[2] Chickeneggs are the most commonly eaten eggs. They supply all essential amino acidsfor humans^[3] and provide several vitamins and minerals, including retinol(vitamin A), riboflavin(vitamin B₂), folic acid(vitamin B₉), vitamin B₆, vitamin B₁₂, choline, iron, calcium, phosphorusand potassium.^[4] They are also a single-food source of protein. Protein is necessary for the body tobuild and repair body tissues.

EGG COMPOSITION:
The main components of the hen’s egg are: water (74%), protein (13%), fat (11%), carbohydrates (1%) and other nutrients with minor percentage including minerals, vitamins and carotenoids. Egg’s macrostructure is approximately 9-12% of shell, 60% of albumen and 30-33% of yolk. Yolk lipid content is around 33% including 63.3% of triacylglycerols, 29.7% of phospholipids (phosphatidylcholine: 73%; phosphatidylethanolamine: 15%) and 5.2% of total cholesterol.^{[5, 6]}Knowledge of these properties is important, because can allow adoption of strategies to modify fatty acids characteristics.The structural composition of an egg is shown in figure 1.

FIG 1: COMPONENTS OF AN EGG

HEALTH ISSUES:
More than half the calories found in eggs come from the fat in the yolk; a large (50 gram) chicken egg contains approximately 5 grams of fat. Only 27% of the fat in egg is saturated fat(palmitic, stearicand myristic acids) that contains LDL cholesterol.^[7] Dietary cholesterolincreases the ratio of total to HDL cholesterol and, therefore, adversely affects the body's cholesterol profile.^[8]Consumer’s attitudes towards lipid in general have changed their attitude towards egg consumption because of fear that egg cholesterol will raise their blood cholesterol levels. Eggs therefore have been singled out by diet-heart advocates as a food to be avoided even though the egg contains the best and least expensive high quality protein and balanced distribution of minerals and vitamins.^{[9, 10]}

ESSENTIAL POLYUNSATURATED FATS:
Some polyunsaturated fatty acids (PUFAs) are an essential part of our everyday diet because our body cannot make them. Unfortunately, foods that are good sources of PUFA are often high intotal fat.The essential PUFA include twomain families and their derivatives. The omega-6 essential PUFA include linoleic acid and its derivative arachidonic acid. Small amounts ofomega-6 PUFA are found in wholegrains and meat from grain-fed animals.Some vegetable oils have lots of omega-6 PUFA. The omega-3 essential PUFA include linolenic acid and its derivatives EPA (Eicosapentanoeic acid) and DHA. Linolenic acid and its derivatives can be found in flaxseed and some fish.

NEED FOR DESIGNER EGGS AND ITS PREPARATION:
The hen egg is a potential source of unsaturated fatty acids because hens have a unique ability to deposit dietary lipid into the egg yolk.^[11]The many attempts to reduce egg cholesterol content have met little practical application.^[12]

Drugs have been successful in lowering egg cholesterol by as much as 50%. Drugs lower cholesterol in the egg by either inhibiting the synthesis of cholesterol in the hen or by inhibiting the transfer of cholesterol from the blood to the developing yolk on the ovary. Today, the drugs which have shown promise in lowering cholesterol are not yet approved by the FDA for commercial use.

 An alternative way to reduce the cholesterol effects of eggs is by altering the yolk fatty acid composition. Egg yolk total fat content cannot be altered; however, fatty acid composition can be altered by changing the type of oil used in hens’ diet. The scientific development in the field of nutrition excelled considerable interest in the long-chain polyunsaturated fatty acids (PUFAs) especially n-3 fatty acids in human health. The fatty acid composition of yolk fat can readily be modified by diet ^[13,14]. In recent years several researchers have investigated the ability of the hen to enrich the egg with omega-3 fatty acids. A large egg contains approximately 200 - 220 mg of cholesterol. Genetic selection of hens for lowered cholesterol has not been successful in lowering the egg cholesterol content.

The cholesterol lowering effects of (n-6) and (n-3) polyunsaturated fatty acids (PUFAs)  have been recognized for some years ^[15-17] and feeding layers diets rich in PUFA results in a large increase in the relative and absolute concentrations of PUFAs in yolk total lipid.^[18-23]The pioneering discovery that omega-3 fatty acids protect against coronary heart disease in Greenland Eskimos consuming fish has generated much research over the past decades on the various health benefits of dietary omega-3  fatty acid from fish oils.^[24]

Omega-3fatty acids, which are essential nutrients both for adults and children, have been reported to protect against cardiovascular and inflammatory diseases, as well as certain types of cancer. The benefits of dietary omega-3 PUFA include reduction in plasma triglycerides, blood pressure, platelet aggregation, thrombosis & atherosclerosis particularly in diabetics, tumor growth, skin diseases.

Longer chain PUFAs contain volatile compounds which produce characteristic “fishy” or “paint-like” aroma, and cause off-flavor in eggs enriched with these fatty acids.^[25]Flaxseed, marine algae, fish oil, perilla oils, sunflower oil, etc are incorporated to hen diets in order to increase the ω-3 fatty acid content in the egg yolk at the expense of saturated fatty acids, mainly palmitate and stearic acids.^[26]Flaxseed is among the most concentrated sources of PUFAs, especially linolenic acid, available in natural food and feedstuffs.Such enriched eggs or Nutritional Enhanced Eggs are called as Designer Eggs, Pre-Ovipositor Value Added Eggs, HealthPromoting Designer Eggs or Enriched ω-3 Eggs.^[27]"Designer eggs" are those in which the content has been modified from the standard egg.

Because of benefits associated with eating foods that contain omega-3 polyunsaturated fatty acids, most egg production companies now market the eggs of such kind.

Attempts to produce omega-3 eggs can be achieved in two ways:
1. Produce an egg enriched in linolenic acid, which is a precursor of DHA and is protective against fatal ischemic heart disease. For this purpose, hen’s diet is relatively rich in flaxseeds or linseeds as a result of which the egg yolk is enriched with linolenic acid and hence DHA levels are raised.^[28]
2. Directly, include pre-formed DHA in hen’s diet in form of fish oil.^[6]
One large designer egg supplies more than 600 mg of most need omega-3 fatty acids and 6 mg tocopherols; it would still have additional beneficial effects for egg consumers due to its balanced ratios of polyunsaturated /saturated fatty acids (1:1) and omega-6/omega-3(1:1). Thus designer eggs offer an alternative choice of food product to today’s nutrition-health conscious consumers around the world.

Yolk lipids and fatty acids are susceptible to oxidation. It is, therefore, essential to prevent the rancidity of designer egg yolk lipids by incorporating antioxidants in hen diet.

In a nutshell, the designer egg has raised levels of four important chemicals:

• Vitamin E - an important antioxidant found in vegetable oils that protects against cancer and other diseases.
• Docosahexanoeic fatty acid (DHA) - a fatty acid found in fish that is important for brain development and boosts the immune system.
• Lutein - one of the most important carotenoids found in vegetables that also protects against cancer.
• Selenium - a trace metal found in nuts that has similar benefits to the other nutrients.

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ADVANTAGES OF DESIGNER EGGS: ^{[27, 29, 30, 31]}
· Suppressing inflammation in humans and animals
· Reduces the stickiness of the blood thus making it less likely to form clots
· Protects the arteries from damage
· Reduces the risk of death from heart disease
· Sensory attributes like aroma, flavor, after taste and overall acceptability of designer eggs.
· Normal brain and retinal development
· Improved immune response.
· Prevention and management of diseases like embolism, allergy, Crohn’s disease, ulcerative colitis, hypertension, etc.

TABLE 1 depicts the benefits of designer eggs over generic eggs attributed to its constituents.

TABLE 1: COMPARISON OF TYPES OF FAT CONSTITUENTS FOUND IN GENERIC AND DESIGNER EGGS.^[31]

SPECIALITY EGGS^{[27, 32, 33, 34]}
In an effort to meet consumers’ demand for specialty eggs, egg producers have begun marketing free-range, cage-free, omega-3, vegetarian, organic, fertile, in shell pasteurized, and other branded eggs. These eggs offer alternative choices to consumers with special requirements. However, due to higher production costs specialty eggs are usually more expensive than generic shell eggs. Also, except for nutrient enhanced eggs, such as omega-3 enriched eggs, specialty eggs such as cage-free eggs and organic usually have similar levels of nutrients as generic eggs. Nutrient content can only be changed by altering the feed the hens eat, not by changing their environment.

1. VEGETARIAN/ORGANIC EGGS
Vegetarian eggs and organic eggs are available from hens fed either feed free of animal by products or feed grown without pesticides, fungicides, herbicides, or commercial fertilizers, respectively. Growth hormones are not used in the egg industry. Neither specialty eggs nor generic eggs have hormones in them while antibiotics are sometimes used to treat sick birds; this is not a routine industry practice.

2. FERTILE EGGS
Some cultures consider fertile eggs a delicacy. But aside from coming from a hen that has possibly mated with a rooster, there is no nutritional difference between fertile eggs and generic eggs.

3. FREE-RANGE EGGS
They come from hens that are either raised outdoors or have Access to the outdoors. Due to seasonal conditions however, few hens are actually raised outdoors and access to outdoors can vary greatly between producers.Cage-Free Eggs come from indoor floor operation. Hens do not necessarily have access to the outdoors. Mortality rates are higher in the Free-Range and Cage-Free birds since they tend to peck at each other and cause bodily harm in this environment.

4. PASTEURIZED SHELL EGGS
Pasteurized shell eggs are a good choice for people who want to use raw eggs in their recipes that don’t require further cooking, such as homemade ice-cream or Caesar salad Dressing. These eggs have been heat treated to kill potential salmonella bacteria found inside. (The risk of purchasing an egg contaminated with salmonella bacteria is one in 20,000 eggs.) However, due to the heat processing, these eggs may have slightly lower amounts of heat-sensitive vitamins. Thoroughly cooking generic shell eggs until whites are firm and yolks are beginning to thicken will also destroy any potential salmonella bacteria in the egg.

CONCLUSION:
For last few years, designer egg production has made substantial progress in many countries of world. By using designer egg, we can prevent several ill-health aspects that can arise by consumption of generic eggs.

REFERENCES:
[1] American Dietetic Association. Nutrition and you: Trends 2000: What do Americans think, need, expect? J. Am. Diet. Assoc.2000, 100:626-627.
[2] Noble RC.  Egg lipids. In: Egg Quality—Current Problems and Recent Advances (Wells, R. G. & Belyavin, C. G, eds) Butterworths & Company, London, UK1897: 159-177
[3] "Food and Agriculture Organization article on eggs" Fao.org. Retrieved 2010-01-10.
[4] Vitamin A, RAE Content of Selected Foods per Common Measure, sorted by nutrient content. United States Department of Agriculture (USDA), 2005:4
[5] Romanoff AL, Romanoff AJ. The avian egg. New York: J. Willey, 1947: 918.
[6] Leskanich CO, Noble RC. Manipulation of the n-3 polyunsaturated fatty acid composition of avian eggs and meat. World's Poult. Sci. J.1997, 53: 155- 183.
[7] U.S. Department of Agriculture, Agricultural Research Service. USFDA National Nutrient Database for Standard Reference, Release 20, 2007
[8] Weggemans RM, Zock PL, Katan MB . "Dietary cholesterol from eggs increases the ratio of total cholesterol to high-density lipoprotein cholesterol in humans: a meta-analysis". Am. J. Clin. Nutr.2001.73 (5): 885–91.
[9] Conor, SL, Connor WE.The importance of dietary cholesterol in coronary heart disease . Prev. med. 1983 12:115
[10] Shrimpton DH. The nutritive value of eggs and their dietary significance. In:  Wells RG, Beljavin CG, 1987. 11-25
[11] Jiang Z, Ahn DU, Ladner L, Sim JS. Influence of feeding full fat flax seeds and sunflower seeds on internal and sensory qualities of eggs. Poult. Sci. 1991, 71:378-382.
[12] Hargis PS.Modifying egg cholesterol in the domestic fowl. World Poult. Sci. J 1988, 44:17–29.
[13] Cruickshank E.M. Studies in fat metabolism in fowl. In: The composition of egg fat & depot fat of the fowl as the affected by the ingestion of large amounts of fats 1983, 28: 965-971.
[14] Sim JS, Hudgson GS, Bragg DB. Effect of dietary animals tallow and vegetable oil on fatty acid composition of egg yolk, adipose tissue and liver on hens 1973, 52:51-57.
[15] Demeyer D,Doreau M.Targets and procedures for altering ruminant meat and milk lipids. Proc. Nutr. Soc. 1999, 58: 593–607.
[16] Kinsella JE, Lokesh B, Stone RA. Dietary omega-3 polyunsaturated fatty acids and amelioration of cardiovascular disease: possible mechanisms. Am. J. Clin. Nutr.1990, 52:1–28.
[17] Hargis PS, Van Elswyk ME. Manipulating the fatty acid composition of poultry meat and eggs for the health conscious consumer. World Poult. Sci. J.1993, 49:251–264
[18] Caston L, LeesonS. Dietary flax and egg composition. Poult. Sci. 1990, 69:1617–1620.
[19] Farrell DJ, GibsonRA. The enrichment of eggs with omega-3 fatty acids and their effects in humans. In: Recent Advances in Animal Nutrition in Australia (Farrell, D. J., and Ed). University of New England, Armidale, N.S.W.1991: 256-270.
[20] HargisPS, Van Elswyk ME, Hargis BM.Dietary modification of yolk lipid with menhaden oil. Poult. Sci.1993, 70: 874–883.
[21] Huyghebaert G, De Munter G, De Groote G, Moermans RJ. Effect of dietary manipulations on egg fatty acid profile. In: Proceedings of the 4th Symposium on the Quality of Eggs and Egg Products, 1993:279–283.
[22] Huyghebaert G. Incorporation of polyunsaturated fatty acids in egg yolk fat at varying dietary fat levels and compositions. Arch. Geflu¨ gelkd. 1994, 59:145–152.
[23] Vahl HA, Stappers HP, Veen WG. Nutritional influences on the fatty acid composition and the cholesterol content of eggs. In: Proceedings of the 4th Symposium on the Quality of Eggs and Egg Products, 1991: 223–231.
[24] Yerberg J, Bang HO. Haemostatic function and platelet polyunsaturated fatty acid in Eskimos. Lancet 1973: 433-435.
[25] Karahadian C, Lindsay RC. Evaluation of compounds contributing characterizing fishy flavours in fish oils. J. Am. Oil Chem. Soc.1989, 66:953-960
[26] Yu MM, Sim JS.  Biological incorporation of polyunsaturated fatty acids into chicken eggs, 1987: 66-195
[27] Enhanced Egg Production in Practice: omega-3 eggs enriched with herbs COST 923 : Turku, Finland, June 2006: 28-30
[28] Ferrier LK, Caston LJ, Leeson S, Squires J, Weaver BJ, Holub BJ. Alpha-linolenic acid and DHA enriched eggs from hens fed from flaxseed: Influence in blood lipids and platelets phospholipid faty acid in human. American journal of clinical nutrition1995, 62:81-86.
[29] ams.uda.gov/poultry/pdfs/EggGrading%20manual.pdf(Accessed on September 17th, 2013)
[30] Mishra VK, Temelli F, Ooraikul B. Extraction and purification of omega-3 fatty acids with an emphasis on supercritical fluid extraction - A review. Food Res.  1993, 26:217-226.
[31] Fabien DM, Ronald RW. Wild type food in health promotion and disease prevention, the Columbus concept. Humana press: 2008,162.
[32] ufl.edu, Eggnutritioncenter.org (Accessed on September 25th, 2013)
[33]  natlfood.com (Accessed on October 4th, 2013)
[34] Cherian G, Holsonbake TB, Goeger MP. Fatty acid composition and egg components of specialty eggs. Poult. Sci. Jan 2002, 81: 303.

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