The

Mayonnaise & Margarine

Report

For

Dr. P. Alexandridis

CE 457 Colloid & Surface Phenomena

by

Kar-Chan Choong

Joseph Dorsheimer

Barry F. McLaughlin

Anthony Zientek

Introduction

Historically, “Mayonnaise is said to be the invention of the French chef of the Duke de Richelieu in 1756. While the Duke was defeating the British at Port Mahon, his chef was creating a victory feast that included a sauce made of cream and eggs. When the chef realized that there was no cream in the kitchen, he improvised, substituting olive oil for the cream. A new culinary masterpiece was born, and the chef named it "Mahonnaise" in honor of the Duke's victory” (http://www.bestfoods.com). On the other hand, “Margarine was created by a Frenchman from Provence, France -- Hippolyte Mège-Mouriez -- in response to an offer by the Emperor Louis Napoleon III for the production of a satisfactory substitute for butter. To formulate his entry, Mège-Mouriez used margaric acid, a fatty acid component isolated in 1813 by Michael Chevreul and named because of the lustrous pearly drops that reminded him of the Greek word for pearl -- margarites. From this word, Mège-Mouriez coined the name margarine for his invention that claimed the Emperor’s prize” (http://www.margarine.org.) The purpose of this research paper is to provide an extensive, scientific look into the world of mayonnaise and margarine.

Standards of Identification

Mayonnaise

When classifying a food product by name it must contain a standard set of ingredients put forward by the Food and Drug Administration. There can be substitutes for certain ingredients with others but these must be on the list that is provided by the FDA. Each of these ingredients is required to be written on the label, for all consumers to view. This is how the nomenclature for each food product is given (http://www.accessdata.fda.gov).

 Mayonnaise is an emulsified semisolid food that is made with vegetable oils. This is not limited to just vegetable oil however; sunflower oil, Soya oil, and rapeseed oil may also be used in making mayonnaise. No mineral oil may be used in the preparation of mayonnaise. 
 One or both of the following acidifying ingredients must also be used in the preparation of mayonnaise. These acidifying ingredients are any vinegar or any vinegar diluted with water to acidity, of no less than 2.5% by weight, calculated as acetic acid, or any type of vinegar or diluted vinegar that is combined with an extra acidifying ingredient that is listed in the following section. Salt and nutritive carbohydrate sweeteners are two of these ingredients. Any spice or natural flavoring may also be used as long as it does not change the color of the mayonnaise to a color, which is given by egg yolks. Saffron and turmeric may not be added to mayonnaise. Monosodium glutamate and Sequestrant(s) may also be used in the preparation of mayonnaise. These Sequestrants can be one of the following; calcium disodium EDTA (calcium disodium ethylenediamine- tetraacetate) and/or disodium EDTA (disodium ethylenediaminetetraacetate). Other Sequestrants may also be used. Sequestrants are used to preserve the color and the flavor of the mayonnaise. Other acidifying ingredients are citric and/or malic acid. These ingredients may be added in an amount that is no greater than 25% of the weight of the acids of the vinegar or diluted vinegar. This must be calculated as acetic acid. The last acidifying ingredient that may be added is the crystallization inhibitor. These can include lecithin, polyglycerol esters of fatty acids, and oxystearin. Other crystallization inhibitors may also be used. When talking about vinegars in this paragraph any mixture of two more vinegars can also be considered vinegar (http://www.accessdata.fda.gov). 
 The next ingredients that may be added are lemon juice and/or lime juice. These can be added in a type of mixture, which can be diluted with water to an acidity, of no less than 2.5% by weight. This acidity must be calculated as that of citric acid. The final ingredient that must be added before it can be officially called mayonnaise is the egg yolk-containing ingredient. The following type of egg yolks may be added to the mixture: frozen, dried, and liquid. The following types of whole eggs may also be added: liquid, frozen, and dried. Also any of the previous egg containing ingredients can also be mixed with liquid and or frozen egg whites. This final addition of eggs will give the name of this mixture as mayonnaise (http://www.accessdata.fda.gov). 

Suppliers

There are many suppliers of mayonnaise throughout the country. One such supplier is Kraft Foods. They market their product with the same name. Kraft mayonnaise can be found on the shelves of almost every supermarket. Unilever is another large food supplier, which markets their mayonnaise under two different names; one of which is Hellmann’s and the other which is Best Foods. They are essentially the same product only Hellmann’s is found east of the Rocky Mountains, and Best Foods is found strictly on the west coast. Another supplier of mayonnaise is Better Brands. They can be found primarily in New England and New York. Their brands include; Allen and Nugget. The Shurfine brand has a number of separate labels, which distribute different varieties of mayonnaise. Some of their product lines include; Shurfine, Ultimate Choice, Shurfresh, Saver’s Choice, and Price Saver. They all have different types of mayonnaise in their product lines. These are just some of the many varieties of mayonnaise, which can be found in stores today. There are many smaller brands and store brands which can be found in specific geographic areas.

Standards of Identification

Margarine

Margarine can be described as a liquid emulsion or a food in the plastic form. It must contain no less than 80% fat as determined by the “Official Method”, used the by the “Official Analytical Chemists”. Margarine must contain one or more of the ingredients in the following three paragraphs to be considered margarine.

 The first such section of ingredients is the edible fats and oils, or any such mixture of these. These fats and oils must have an origin or vegetable or rendered animal carcass fats. Also any type of oil that has been extracted from any marine species and has been listed as GRAS, or a food additive may be used. An accepted process of physico-chemical modification may alter these oils. The oils may have small traces of lipids, and free fatty acids that can be found naturally in the fat or oil (http://www.accessdata.fda.gov).
 The next such set of ingredients that must be used is the aqueous phase ingredients. One or more of these aqueous phase ingredients may be used in the preparation of margarine. The first set includes water, water and milk, or just milk products. The next set is the edible proteins; these can include the liquid, dry or condensed form of whey. The whey may be changed by the reduction of lactose and other minerals. The use of no lactose components as well as vegetable proteins, casein, albumin, and soy protein isolate may also be used to modify the whey. The amount used must be no greater than a reasonable amount to achieve the desired product. These ingredients are then subject to a pasteurizing process and then introduced to harmless bacterial starters (http://www.accessdata.fda.gov). 
 The previous set of aqueous phase ingredients may be combined with either one or more of the following ingredients. Vitamin D may be added to the mixture as long as there are 1500 international units of Vitamin D per pound of margarine. Sodium Chloride or Potassium Chloride may also be added to the ingredients. Emulsifiers and nutritive carbohydrate sweeteners are two more ingredients, which can be added to the aqueous phase ingredients. Preservatives may be added to margarine in varying amounts. Some of these preservatives and their amounts are listed here. Benzoic and Sorbic acid, and sodium, potassium, and calcium salts may be used. If used individually they can account for .1%, if combined .2%. EDTA can also be used in an amount of .0075%. The following gallates can be used: propyl, octyl, and dodecyl. These can be used separately or combined with BHA, BHT, ascorbyl stearate, and ascorbyl palmitate, at a .02% mixture. The last two preservatives that may be used are stearyl citrate, and isopropyl citrate. The respective amounts used are .15% and .02%. The color additive that can be used in margarine is beta-carotene. Acidulants and Alkalizers are also optional ingredients in margarine. Flavoring substances may be used. If they change the taste so that it does not taste like butter, the change has to be noted in the naming of the margarine. If all these rules are followed then the substance created can be officially named margarine (http://www.accessdata.fda.gov). 
 
Suppliers
 There are various brands of margarine, as well as numerous varieties of each brand. One such supplier of margarine is ConAgra Foods. They supply Fleischmann’s, Parkay, and Blue Bonnet. These brands are run by the Nabisco Tablespreads Company, which also has the products, Touch of Butter, Chiffon, and Move Over Butter brands of margarine. Another very popular brand of margarine is the I Can’t Believe It’s Not Butter line. They have various varieties including regular, light, sweet cream and calcium, spray, squeeze, fat free, and unsalted. ADM is another supplier of margarine, which uses the label Gold’N Flavor to sell its product. They also have varieties, which range from table grade, to bakers roll, to liquid grade margarine. Ventura Foods is another supplier of margarine, which promotes its products through the name Saffola. Their varieties include; real, soft, reduced fat, unsalted and safflower margarine. Shedd’s Spread Country Crock is another brand of margarine, which has various varieties such as regular, light, and churn style. Land O’ Lakes is another brand of margarine with various varieties. There are many varieties of margarine throughout the country. Nearly every supermarket carries their own specific variety as well as those from large food distributors such as ConAgra Foods.

Food Chemistry Behind Mayonnaise & Margarine

As previously stated, the organic/food chemical ingredients of mayonnaise and margarine have very solid general basics. However, each manufacturer of the respective food product has modified the “Standard of Identification” requirements to include ingredients to make their products unique compare to their competitions. The products selected to analyze food chemical ingredients were Hellmann’s® Real Mayonnaise, Hellmann’s® Just 2 Good Reduced Fat Mayonnaise, and Blue Bonnetâ Regular Margarine. The ingredients are listed in order of decreasing amounts.

Composition of Regular Mayonnaise

Hellmann’s® Real Mayonnaise consists of soybean oil, whole eggs, vinegar, water, egg yolks, salt, sugar, lemon juice, natural flavors, and calcium disodium EDTA. Soybean oil is typically composed of pure, edible, vegetable oil with no carbohydrates, cholesterol, fiber, protein, sodium or sulfites. It has the following unsaturated fatty acid (CH₃(CH₂)_xCOOH) composition: 0.1% Myristic (C14), 10.6% Palmitic (C16), 0.1% Margaric (C17), 4.0% Stearic (C18), 0.3% Arachidic (C20), and 0.3% Behenic (C22). The remaining composition is made from saturated fatty acids (carbon length: number of double bonds): 0.1% Palmitoleic (C16:1), 23.2% Oleic (C18:1), 53.7% Linoleic (C18:2), and 7.6% (C18:3). Soybean oil is an emulsifying agent that is produced by such companies as Karlshamns® Inc. (PDB 1).

Whole eggs, at best, are described in general terms. They consist of fats, proteins, mineral salts, and water, everything except oxygen necessary for the forming of a chic. As a result, “we are still adding to the list of chemical compounds which an egg contains” (Jacobs 995). Approximately per 100 g of whole egg includes: 24.68 g solids, 12.50 g protein (polyaminoacids), 10.02 g lipids (fatty acids) and 1.22 g carbohydrates (polysaccharides) (PDB 2). The diverse composition allows the whole eggs to play emulsifier and emulsifying roles in mayonnaise. They can be found at companies ranging from your local farmer to the Global Eggâ Corporation.

Vinegar is typically composed of 5% acetic acid, CH₃COOH, and water. It is produced by successive alcoholic and acetous fermentation of cider, grapes, sucrose, glucose or malt (Furia 248). It is classified as an acidulent, which is a multi-purpose title given to an ingredient that acts as a flavor agent, pH buffer, preservative, antioxidant synergist, and/or viscosity modifier in mayonnaise (248). It can be sourced from companies such as Indian Summerâ.

Water, H₂O, serves the hydrophilic side of the emulsion. It is the emulsifying agent that must be homogenized with it hydrophobic counterpart. The metal content of the water must be controlled through use of chelating agent to prevent off flavors in the mayonnaise.

Egg yolk’s chemical composition, like whole eggs, can only be explained in general terms. Egg yolks minimally consist of 56% fat (lipids) and 30% protein. It’s an emulsifier that also acts a coloring agent to the finished mayonnaise product (521). This product is found in a dry solid form and is available from Julius Goldman’s Eggâ City (PDB 3).

Salt, NaCl, is used as a preserving agent. The supplier IMC® Salt produces it by “industry standard solution mining and evaporation process, where the salt is washed, filtered, dried, screened, admixed and quality control tested” (PDB 5). The “sugar” used in mayonnaise is comprised mainly of the disaccharide sucrose C₁₂H₂₂O₁₁. A flavoring agent used in mayonnaise, it can be purchased from sugar refiners such as Colonialâ Sugars Inc.

Lemon juice is used in mayonnaise to complex harmful metal pro-oxidants in addition to adding desirable acidity. Sunkist Growers, Inc produces this juice “from selected lemons that are fine screened, centrifuged, stabilized, concentrated, and packaged without preservatives” (PDB 7). Natural flavors are the flavoring agents provided by the above ingredients.

Finally, calcium disodium EDTA, (C₁₀H₁₆O₈N₂)-Ca-Na₂, is a chelating agent which acts like a sequestrant in assisting anti-oxidant systems. For mayonnaise, it assists in stabilizing the soybean oil, extends shelf-life, retains flavor, and inhibits the oxidation of undesirable coagulation caused by the pre-freeze heat sterilization of whole eggs (Furia 305).

Composition of Low-Fat Mayonnaise

Hellmann’s® Just 2 Good Reduced Fat Mayonnaise consists of water, soybean oil, modified corn starch, sugar, egg whites, vinegar, salt, cellulose gel and gum, natural flavors (contain mustard), color added, xanthan gum, sodium benzoate, and calcium disodium EDTA. The ingredients used in both mayonnaises serve the similar roles and do not merit repeating.

Modified corn starch, 100% amylopectin (-O-C₆H₈O₂-O-C₆H₈O₂-O-)x, is “produced by modifying corn starch from waxy maize with proplyene oxide and crosslinking it with phosphorous oxychloride” (Maiolino Interview). It is classified as a thickening agent, which provides “back texture and viscosity” (Maiolino Interview). National Starch and Chemical Corporation produce this gumâ. Egg whites minimally consist of 12% solids, 10% protein, and 0.03% fat (PDB 9). They are collectively referred to as albumen and are classified as food binders by Maple Lynn Foodsâ.

Cellulose gel and gum are common synonyms for carboxymethylcellulose (CMC). It has a general chemical formula of (C₆H₁₀O₅)x. The CMC that forms a trivalent cation with such metals as aluminum is considered gel while CMC forms with a mono cation like sodium is considered a gum (Furia 339). Both are produced by cellulose treated with NaOH that later reacts with a metal-type monochloroacetic acid, and is washed with an alcohol-water mixture to remove salt (339). These gums are protective colloid uses as a thickener, suspender, stabilizer, and replacement for fat (PDB 11). They are soluble in hot or cold water and may be purchased from companies like Herculesâ and FMCâ (11).

Mustard “presumably operates as a finely-divided solid in the stabilization of mayonnaise”(Becher 346). It is a pungent, sharp, modifier that exhibits fair stability in mayonnaise (Furia 482). Xanthan gum is a cold soluble, hydrophilic, colloid that is produced by the bacteria, Xanthomonas campestrs (PDB 12). The chemical structure, (C₃₅H₄₉O₂₉)n, is “composed of a backbone of glucose units with trisaccharide side chains (two mannose and one glucuronid acid residues) which are regularly positioned at alternating glucose units (12). Xathan gum is used “at a level of 0.2%-1% in mayonnaise to provide stability, mouth feel and cling, and flavor release” (PDB 13).

Sodium benzoate, C₆H₅COONa, is a low-cost preservative that is active against yeast, bacteria, and to a lesser extent mold (Furia 142). It has a synergistic effect with salt and in sued at about 0.05%-0.1% in products (143). This ingredient is available from Kalamaâ Chemical, Inc.

Composition of Margarine

Blue Bonnet® Regular Margarine consists of soybean oil, partially hydrogenated soy oil, whey, salt, mono and diglycerides, soy lecithin, potassium sorbate, sodium benzoate, phosphoric acid, vitamin A palmitate, artificial flavor, beta carotene. Duplication of ingredients and there similar functions in both mayonnaise and margarine do not require repetition.

Partially hydrogenated soybean oil has a fatty acid composition of 23% saturates, 72% mono-saturates, and 5% poly-saturates (PDB 15). It is mainly used as non-dairy substitute and can be classified as an emulsifying agent. Central Soyaâ in Indiana produces this ingredient. Whey is primarily composed of water, solids, protein, lactose (disaccharide of galactose), and ash (Winton 195). It can “contribute significantly to flavour, appearance, texture, structure, and shelf stability” (PDB 16). Mono ((CH₂)₂CH(OH)₂(COOR)) and Diglycerides ((CH₂)₂CH(OH)₁(COOR)₂), are food grade emulsifiers derived from vegetable oils. They are composed of alpha-mono, beta-mono, di- and tri-esters of mixtures of fatty acids. Used in low levels, this ingredient improves stability of vegetable fat and water during storage of margarine (Furia 431). This produced can be purchased from such companies as Loders Croklaanâ.

Soy Lecithin, C₃H₅(COOR)₂POOOC₅H₁₄N, is also available from Central Soyaâ. It is a phospholipid emulsifier that is produced when triglycerol is esterified with a fatty acid and phosphoric acid. The phosphoric acid branch later combines with a nitrogen-containing compound (213). It also serves as a wetting agent in margarine.

Potassium Sorbate, CH₃(CH)₃COOK, is a white, fluffy powder that is water soluble. It is an effective preserve at low concentration for control of mold and yeast (151). Phosphoric acid, H₃PO₄, is used as acidulation agent in margarine. It is the only extensive inorganic acid used (268).

Vitamin A Palmitate, C₃₆H₆₀O₂, is as an anti-oxidant and used to fortify and help stabilize margarine (PDB 21). Beta-Carotene, C₄₀H₅₆, is a brick-red viscous oil used as a coloring agent/nutrient for margarine (21). Both of these products are available from Roche Vitamins Inc.

 
Analytical Methods to Determine Composition
 There are specified methods to determine chemical compositional properties of mayonnaise and margarine. For mayonnaise, these tests include total solids by vacuumed oven, total fats by Mojonnier, total nitrogen by Kjeldahl, total phosphorous by evaporation, egg content, total acidity by titration, emulsion stability over time, specific weight and gums by copper reduction (Fisher and Hart 355). For margarine, these tests include moisture by oven drying, fat by digestion and filtration, and salt by titration (128).
 

Basic Emulsion Theory

An emulsion is a homogenous mixture of oil and water that is stabilized by an emulsifier (Stokes, 205). Many compounds considered to be emulsions, such as sauces, are fat (oil) and water, but that is not a requirement. There are two classifications of emulsions, microemulsions and macroemulsions. Microemulsions are thermodynamically stable and are usually clear solutions. Macroemulsions are not thermodynamically stable and will eventually separate into an oil rich phase and a water rich phase (Stokes, 205). Significant amount of mechanical energy required in the emulsification process to disperse one of the liquids in the form of small droplets in the continuous phase. Janssen and Meijer describe the emulsion process in three stage based on the value of capillary number.

In the equation above, η_c is the viscosity of the continuous phase, γ is the shear rate and σ is the interfacial tension and R the radius of disperse phase droplets. The capillary (Ca) number and Reynolds number (Re) decrease in the emulsification process due to the increase in viscosity and reduction of the length scale. In the first stage of emulsification, the dispersed drops stretch; Ca is much higher than critical value, Ca_crit, local stress overrules the interfacial stress. “This mechanism is typically produced at the beginning of the process and leads to formation of large liquid threads. In the second stage, threads and drops consecutive breakup which take place when Ca > Ca_crit. In the last stage, coalescence of the disperse droplets occur when Ca is smaller or equal to Ca_crit.

The two critical steps in emulsification are the consecutive disruption of droplets and their coalescence, both of which are favored by an intense agitation. The evolution of this process as well as the microstructure of the final emulsion depends on many variables related to the processing conditions such as type and geometry of the emulsification equipment, residence time, agitation speed, temperature of emulsification or to the nature of the phases involved.

The most important property of a given emulsion is its stability. An emulsion is stable, from kinetic point of view, when the number, droplet undergo any discernible change over the storage time scale. If it is not stable, then the mixture could phase separate leading to product failure. Emulsion rheology and stability are closely related to several structural parameters. One important aspect of stability is interfacial tension. When an emulsion is formed, the interfacial tension increases. This, in turn, increases the likelihood of the mixture separating. An emulsifier is added to decrease the interfacial tension, and make the mixture less separated. The net interaction between the dispersed molecules can be found by the adding the van der Waals forces of attraction and the electrostatic force of repulsion. If the attractive force is greater than the repulsive force, the mixture is unstable. If the repulsive force is greater than the attractive force, the mixture is referred to as stable. If more stability is required, fine particles or macromolecules can be added to the mixture. These species will adsorb to the interfacial boundary and form a physical barrier around the droplets.

An emulsifier is typically required to improve of the emulsification process and emulsion stability. There are two important roles of emulsifier molecules during the emulsification process. First, “they adsorb at the o/w interface, which reduces the interfacial tension, yielding a decrease in the amount of mechanical energy required to deform and disrupt the droplet and thereby favoring emulsification” (Sanchez et al.). In the case of high surfactant concentration and low interfacial tension, by inducing strong interfacial tension gradient “spontaneous emulsification” will occur. Secondly, emulsifier prevents recoalescence. This effect is called Gibbs-Marangoni effect and caused by formation of interfacial tension gradients during emulsification. This effect is described as formations of a protective barrier around the oil droplets, which provide a repulsive force to prevent droplet from aggregating with each other. Typical emulsifiers often have the qualities of an amphiphilic molecule. The functionality of the emulsifier is a result of the chemical structure. A typical emulsifier consists of two parts, a hydrocarbon chain that is lipophilic and a hydrophilic polar group. Fine particles are often used to stabilize emulsions that contain oil-water interfaces. The efficiency of emulsifier molecules are strongly depends on the ability to enhance the interfacial rheological properties of emulsion droplets and the kinetics of adsorption to the interface. Under same homogenization condition, emulsifiers, which adsorb rapidly, produce smaller droplet sizes than those absorb slowly. Most of the food emulsifiers do not absorb rapidly enough to completely prevent droplet coalescence. There are three major classifications of emulsions. They are temporary, semi-permanent and permanent. An example of a temporary emulsion is oil mixed with vinegar. An example of a semi-permanent emulsion is pourable salad dressing. An example of a permanent emulsion is mayonnaise.

Regular Mayonnaise Formulation

Mayonnaise is primarily a mixture of oil, egg, a water based acid and spices for flavoring. Typically, in regular mayonnaise, the oil accounts for approximately 75% or more of the total volume (Depree, 157). Traditional mayonnaise is considered to be an oil-in-water emulsion even though it contains 70-80% fat and oils (Depree, 157). The two most common water based acids are vinegar and lemon juice. The important ingredient in the manufacturing of regular mayonnaise is the egg yolk that is added. The egg yolk consists of a soluble plasma fraction where low density lipoproteins (LDL) predominate and a particulate granule fraction consist of highly HDL with a highly charged phosphorylated phosvitin. “The presence of hydrophobic and hydrophilic proteins as well as phospholipids and cholesterol is believed to be responsible for the excellent emulsifying properties of egg yolk.” (Aluko et al.) The other ingredients are added for flavor and only minimally contribute to the interfacial chemistry of mayonnaise.

Some of the more active molecules include lecithin, lipovitellin, lipovitellinin and livetin (Depree, 158). All these components are thought to be active contributors to the quality of the emulsion; however, the most important emulsifying agent is lecithin. Lecithin is found in the egg yolk and also in the soybean oil that is added. It embeds itself into the water droplets in the mayonnaise and prevents them from clumping together. The functional component of lecithin is a mixture of phospholipids (http://www.foodproductdesign.com/archive/1995/1095DE.html). Phospholipids, similar to basic emulsifier structure, contain a hydrophilic polar head. Unlike the basic structure, the lipophilic portion contains two fatty acid tails. It has been shown that the adsorption of lipoproteins to the oil water interface occurs in three stages (Kiosseoglou, 502). The stages are diffusion of native protein molecules to the interface, penetration of the interface by these molecules and rearrangement of the adsorbed molecules to achieve the lowest free energy state.

The basic emulsion addition pathway is as follows. First the vinegar is mixed with the emulsifying agents. After that, the oil is added slowly to the mixture followed by the addition of stabilizers and preservatives. Finally, the spices and flavor agents can be added after the emulsion is complete. The result of properly mixing is an emulsion consisting of closely packed ‘foam’ of oil droplets (Depree, 157). If the oil and water based phases are mixed together at once, or if the oil is added to quickly, the result will be a water-in-oil emulsion with similar properties of the oil that was used (Depree, 157). There will be a point when the mixture will coalesce, or break up, into the water rich phase and the oil rich phase. If phase separation occurs, too much oil has been added to quickly to the mixture.

In an ideal emulsion, consisting of spherical shaped droplets in a bulk phase, the dispersed droplets can only account for a maximum of 74% of the volume (Depree, 157). As stated above, in mayonnaise the dispersed phase accounts for 75% or more. This leads to the oil droplets being distorted from their normal spherical shape. The close packing of the droplets allows them to interact more with each other than they would usually. This contributes to the viscosity of regular mayonnaise.

Salt can be added to the final mixture to improve the characteristics of mayonnaise for three reasons. First, the salt particles help to disperse the egg yolk granules to make more surface-active material available. Second, the added salt will neutralize any charges that are found on the proteins. This will allow the proteins to adsorb to and strengthen the existing layer on the oil droplet. Last, the neutralization of any charge allows the oil droplets adjacent to each other to interact more strongly (Depree, 158).

The other ingredients added to the mixture have different affects on the interaction of the droplets. The sucrose that is added tends to weaken the interactions. It does this by shielding the reactive groups contained in the mixture. Proteins found in egg whites and carboxymethyl cellulose will interact with the proteins found in the egg yolk and form cross-links between the droplets (Depree, 159). Modified starches are also added to increase the stability of the emulsion (Deis, 100). Modified starches contain a mixture of amylose and amylopectin. Besides, the interfacial film formed between the yolk protein and oil-in-water interface is strongly related to the medium condition such as pH, ionic strength and protein concentration. Mayonnaise is prepared less than pH 4.5. Studies of Anton et al. shows at pH 3, the oil droplet is around 11.8μm and proteins at interface are mainly phosvitin.

Low Fat Mayonnaise Formulation

Low fat mayonnaise is produced by the same basic mechanism that regular mayonnaise is produced. Some other ingredients are added to achieve the low fat requirement. The biggest difference in the two recipes is the use of eggs. In low fat recipes, the egg yolks are replaced with the egg whites. This decreases the amount of cholesterol added to the product and results in a “lighter” product. However, this poses a problem for the interfacial chemistry of the mixture. The emulsifiers found in the egg yolk are not as abundantly found in egg white. For this reason, other emulsifiers must be added to achieve the emulsion properties.

Additional lecithin is added through the addition of soybean oil. Another emulsifier that can be added to the mixture is finely ground particulate mustard. The mustard particles imbed themselves into the oil-water interface similarly to the lecithin. The mustard particles embed themselves into the water droplets and block the oil and water from coalescing. Another emulsifier added to the mixture is xathan gum. It acts as both an emulsifier and a thickener (www.xanthan-gum.net).

The general addition procedure stays the same with low-fat mayonnaise and regular mayonnaise. The steps can be seen above for reference. Once the egg whites and soybean oil is added to the water, the oil can be whisked in gradually. Once the proper amount oil has been added, the stabilizers, preservatives and seasonings can be added. Preservatives for low fat mayonnaise include calcium disodium EDTA, salt and sodium benzoate.

Low- fat Mayonnaise Cholesterol Extraction

In order to produce lower cholesterol mayonnaise, reducing cholesterol content of egg yolk is crucial. Organic solvents or supercritical CO₂ are the effectual methods to remove cholesterol from yolk. However, the substitution of yolk with other functional ingredients in food formulation impairs the flavor and mouth feel of a product.

“The stability and textural properties of highly concentrated emulsions such as mayonnaise depend to a great extent on the presence of whole egg or egg yolk constituents which stabilize the oil droplets against coalescence while at the same time are involved in complex interactions with the emulsion oil droplets resulting in the formation of a network that emulsion and especially its viscoelasticity” (Paraskevopoulou et al.). The yolk composition could be distorted and the protein could be denatured after cholesterol extraction. Selective method for this purpose is critical. Studies have found supercritical CO₂ is more selective in extracting cholesterol from yolk. Nevertheless, it result a higher phospholipids compare with the concentration prepared by ethanol/water extraction. On the other hand, the yolk extracted with an ethanol/water mixture exhibited higher viscoelastic moduli value. Results from the study also have shown mayonnaise prepared with spray dried yolk contains a lower amount of protein than the two emulsions prepared by the supercritical CO₂ extraction and ethanol/water extraction, as a result of the lower amount of protein, it gives a lower viscoelasticity but highest stability when aged for a certain period of time. The modulus studies of these samples conclude the protein concentration influences the viscoelasticity. Mayonnaise may be characterized as “weak” gel, which yields under strain sweep experiments. The yield point is the function of the type of yolk used during the preparation.

Margarine Formulation

An emulsion is fine dispersion of one liquid in a second largely immiscible liquid. In food emulsion like margarine, the liquids are always an aqueous solution and liquid oil. Margarine has complex colloids containing mixed dispersed phases and some crystallization may be occurred. As well known, emulsion formation requires a large energy input. This usually achieved with a high-speed mixer or valve homogenizer.

In an emulsion, there is always one phase that is continuous and another that is dispersed (the droplets). For margarine, the aqueous phase is continuous, so it is oil in water (o/w) emulsion. Emulsions behave most similarly to their continuous phase. That is the reason margarine feels greasy like oil and easily disperse in more oil.

In general, smaller emulsion droplets offer a more stable emulsion. However, higher energy is required to reduce the size (and higher surface areas) of droplets in emulsion. Typically in industrial production, the droplets size is around 300nm. Particles larger than 2 or 3mm are unfavorable and have limited stability.

Viscosity of margarine is a strong function of concentration of droplets. A high concentration of droplets causes an increase in viscosity and eventually the development of solid –like character.

In margarine process, the oil surfaces in aqueous continuum are energetically unstable because of the hydrophobic effects or formulated as the surface excess free energy. Margarine surface-active polymers accumulate at the surface to provide some stability to the emulsion by covering the surface and development of repulsive colloidal forces. An emulsion behaves like its continuous phase, so any material added to the continuous phase will affect perceived properties of the emulsion. In margarine, by the addition of viscosity- reducing hydrocolloids to the dispersed phased to thinker the product is a crucial step. Any additive can cause the protein aggregation and lead to emulsion destabilization due to flocculation if the protein is bound to the surface of an emulsion. As a result, changes in pH in addition of favor like salt and the action of proteolytic enzymes maybe destabilize emulsion.

Emulsion like margarine is always thermodynamically unstable structures given a limited lifetime by addition of surface-active material. Consequently, the properties will continuously change towards the equilibrium position of oil floating on top and of an aqueous solution. As the density of the continuous and dispersed phases is different, they will separate under gravity, e.g solid fat crystal in liquid oil sediment out to the bottom of the container. Another important properties of emulsion, in the case the margarine are the process of flocculation and coalescence. Flocculation is the process of two particles coming into semi-permanent contact without merging. Coalescence involves complete merging to the particles. Flocculation often occurs before coalescence and the merging of the particles happen subsequently. Flocculation causes an increase of viscosity and forms a continuous 3-D network throughout the container. Fast flocculation leads to the formation of large open flocs as the particles tend to rapidly adhere at the position of first contact. During the slow flocculation the droplets will form a more dense flocs. Most dispersed systems are prone to flocculation and coalescence to a greater or lesser extent because both processes lead to reduction in interfacial area.

Margarine is made from vegetable oils, which contain unsaturated carbon. Hydrogenation of these oils at 170°C using a nickel catalyst saturates the carbon chains; this raises the melting point of the oils so that they become solid (crystallize) at room temperatures.

During the process manufacturer has to make sure the fat blend have high liquid oil content, little or no hardened fat, substantially no trans-unsaturated fatty acid content and a relatively low level of saturated fatty acids. Margarine fat should be used having a well-balanced ratio of liquid and solid fats throughout the entire area and use temperatures, which usually is from 5°C to about 20°C.

In the past, natural fats are used to blend with the margarine mixture to maintain sufficient solids content. However, the result in products is unsatisfactory spreadability, consistency and mouth feel. The use if mixtures of fat hardened to different degree of saturated fat is an alternative way to achieve the desired “hardness”. Due to the nutritional reason, the level of saturated fatty acid (SAFA) of the component triacyl glycerides of the fats should be minimized.

Analytical methods to Determine Colloid Properties

Rheology of mayonnaise is of great importance and its correct evaluation can provide valuable information that can be used in quality control of commercial production, storage stability, sensory assessments of consistency, knowledge and design of texture, design of unit operations, and knowledge of the mechanical processing on the structure of emulsion (Davis). For example, the studies of rheology of mayonnaise concluded that a high oil content and presence of stabilizer increase the complexity of the structure of emulsion. While the presence of gum in mayonnaise as stabilizer, the emulsion is less sensitive. When the oil content in mayonnaise increased, the amount of irreversible structural breakdown is increased. Gallegos et al. experiment in mayonnaise suggested that structural recovery is associated with an elastic recovery of deformed flocs (instantaneous recovery) and the reflocculation of oil droplets (time dependent recovery). Numerous of semi-liquid foods materials such as mayonnaise or peanut butter reveal viscoelastic properties that result in stress overshoot in constant shear rate viscosity measurements. “The significance of this phenomenon is primarily in the sensory perception of such products’ consistency, which is based on transient flow regimes in the mouth and also in certain industrial operations such as mixing and pumping.” (Campanella et al.

Previously, transient viscoelastic flow occurs in polymers is used to describe mayonnaise flow by Bird-Leider equation:

Where t = shear stress

K and r = power law constants

g = Shear rate

l = Characteristic time constant

a and b = empirical constants

However, this four-parameter empirical model has one exponential decay term, which is derisory for viscoelastic fluid with a wide spectrum of relaxation times.

Campanella and Peleg proposed a model slight modification of a model developed by Larson for polymer melt with wide molecular weight distribution to describe the transient flow of mayonnaise. This model has three parameters and gives sensible description of the stress overshoot phenomenon. The model appears to give a better account of the real behavior of mayonnaise than the Bird-Leider equation.

The G(m) is gamma function. Details of the equation can be found in Campanella et al.

 Numerous rheometrical studies of mayonnaise have been studied and have highlighted complex flow phenomena exhibited by the material. “Indeed, mayonnaise has been shown to be shear thinning, viscoelastic, and thixotropic, it has yield stress, and in some studies apparent wall slip has been observed” (Goshawk et al.).

Production & Processing at the Plant Level

For plant production and processing of mayonnaise, two companies, Waukesha Cherry-Burrellâ and Bran-Luebbeâ supply the necessary equipment. According to the Waukesha technical literature:

Powdered egg and spices are dissolved in a mixer, cooled in a plate heat exchanger then stored in a jacketed tank prior to blending. Vegetable oil is also cooled in a plate heat exchanger prior to blending. Vinegar, the chilled oil and the chilled egg mixture are supplied to a continuous blending system, which consists of a multi-head metering pump and a pre-emulsion mixer. The metering pump insures that the various ingredients are fed in the correct proportions. The mixer blends the ingredients together and prepares them for finishing in the WCB colloid mill, which creates a uniform dispersion and stable emulsion. The product then flows to the filler. An optional tank acts as a filler feed buffer if the filler does not have an inlet tank or if garnish is added. (www.gowcb.com)

Bran-Luebbe describes the process as, “the mayonnaise ingredients are pump into suction vessels and the ingredient levels in the vessels are controlled by level probes and throttling valves.” Also a “metering pump proportions and pumps the ingredients through a back pressure valve into a pre-emulsifier.” The “resulting emulsion is pumped out of the emulsifier and into a colloid mill with the finished product sent to a filler buffer tank”(www.bran-luebbe.com). During this process, “the quality control tests performed on the product including Salt, T.A, Viscosity, pH, density, and Micro” (Fendinger Interview).

Mayonnaise packaging started in 1905 when Richard Hellmann “began selling it in "wooden boats" that were used for weighing butter” (http://www.bestfoods.com). Today, mayonnaise is typically packaged either in non-sterile glass or PET (-O-CO-C₆H₆COO-(CH₂)₂-)x) jars (www.seps.org). Operators “hand-dump” the jars onto the process line where “ they are flipped and air is forced into them to clean any packaging particulate” (Fendinger Interview). The containers are then “righted, filled and capped before being boxed as a finished product” (Fendinger Interview). Regular mayonnaise is available for sale once the microbiological tests have been completed. Besides micro results, low-fat or reduced mayonnaise must be allowed a day to “set” at ambient temperatures before it can be made available for sale (Fendinger Interview).

Product Processing For Margarine

The processing equipment needed to make margarine can be built by a number of different companies. The Waukesha Cherry-Burrell process will be the main focus of this part. The first pieces of equipment needed for this process are separate raw material tanks for the holding of the milk, concentrated emulsifier solution, brine, and margarine oils. This allows for the proper blending of ingredients, which ensure the correct emulsion. This is then fed to an emulsion feed tank where it is pasteurized using a WCB plate heat exchanger. Inside the pasteurizer there are separate heating and cooling sections. Inside there also contains a separate regeneration section to reclaim part of the energy put in. A high pressure pump then moves the emulsion to Votator® scraped surface heat exchangers that have controls which monitor temperature, and power sensors which help to prevent the freezing of this product due to overcooling. This emulsion is crystallized, plasticized, and conditioned. Votator® agitated holding units are used when filling tubs or bulk filling. Votator® quiescent holding tubes are then used when stick molding or sheet printing is done. WCB heat exchangers are also used in the end of the process to melt overfeed and return it to the pasteurization system (http://www.gowcb.com).

For mayonnaise and margarine production, the main concern is safety and contamination. It is expected that the operator(s) should be following good manufacturing practices (GMPs) when they make their respective product. This means that safety boots, goggles, lab coats, and other necessary apparatus need to be worn. Also, the equipment must be cleaned and sterilized both before and after shut down of the respective machine. Margarine can be packaged in a number of different ways. They can be packaged into large commercial tubs, smaller consumer tubs, small and large stick margarine, and now some are even packaged as sprays. Generally, tub margarines are mechanically worked this allows for crystal growth. It also prevents the formation of a firm crystal lattice. The longer the product is work the more the consistency softens. Stick margarine is produced by extrusion of chilled product into forming moulds and then they are wrapped and placed into boxes. It is important to allow the stick margarine to cool further so that it can withstand the pressure of wrapping, and remain in stick form. The whipped variety of margarine is processed by the injection of nitrogen into the emulsion where it is either packaged as a tub or stick (http://alfa.ist.utl.pt).

Operational Concerns in Mayonnaise & Margarine Manufacturing

For mayonnaise and margarine production, the main concern is safety and contamination. It is expected that the operator(s) should be following good manufacturing practices (GMPs) and standard operating procedures (SOPs) when they make their respective product. This means that personal protective equipment not limited to safety boots, goggles, and lab coats need to be worn (McLaughlin Interview). Also, the equipment must be cleaned and sterilized both before and after processing. It is expected that auditing be performed within specified time periods to assure that such regulations are being followed. This would include performing microbiological surface wipe on all equipment (Fendinger Interview).

Conclusion

Margarine and mayonnaise are mixtures of fats, oils along with carbohydrates and proteins and are useful energy sources of chemical energy in the diet. Oils provide energy, fat-soluble vitamins and essentially fatty acid that are required for proper growth and development. Cholesterol is required for homeostasis, because it is both an essential component of cell membrane and an intermediate in the biosynthesis of steroid hormones. The production of vegetable oil products is highly throughout the world and consumption is increasing especially throughout the lower socioeconomic groups.

As one of the most mature markets in the grocery world, fats often struggles to match other sectors in terms of innovation. The nature of margarine and mayonnaise is there is only so much they will be consumed. As increasing consumption is not an option, pricing strategies have played a big part in the shape of the market. Reducing production cost is the key strategy. Understanding the product chemistry and colloid properties are crucial to reduce production cost and meet the market demands.

For the last several years, the margarine category has been in decline, mainly due to negative publicity and research studies about trans fats. However, National Association of Margarine Manufacturers invested a large amount of funds on doing research. Results of the study have shown margarine significantly lowered totally cholesterol and LDL. Subsequent follow up advertising and media coverage was widespread, the sales increased by an astonishing 10% in a matter of weeks. The total margarine/spread category had sales of $1,292.8 million in year 2000.

Manufacturers have focus on the cost efficiency in mayonnaise production due to the tough competition. Other than cost efficiency, consumer demand such as a perfect texture, free-thaw stability and the ability to absorb water form. Last but not least, many of today consumers is looking for a cleaner label. Mayonnaise has a huge market in U.S. according to supermarket business, 2000 sales of mayonnaise was $747.45 million dollars.

Taking an average of the market price of mayonnaise, regular mayonnaise costs around $0.88 per lb but only $0.34 cents to make (Fendinger Interview). On the other hand, low-fat mayonnaise/ light mayonnaise is around $1.42 per lb. Regular margarine is sold in the grocery store for $1.30 per lb. and low fat-cholesterol margarine is around $2.00 per lb. Generally, low-fat product is more expensive than regular product due to the cost of production.

“The next stage of food treads has been set and once again, flavor plays the biggest role. Healthy eating has a significant though undefined parted. Audiences carve novelty, but the food industry is also aware of the parameters: different but not too different. It will always be in the mix.” (Restaurant and Institutions, January 1, 1999)

Sources

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Campanella O. H, Peleg M, Analysis of the transient flow of mayonnaise in a coaxial viscometer, J. of Rheology, 31(6), 1987, 439-452.

Davis S., Rheological properties of semi-solid foodstuffs J. Text. Studies, 4, 1973,15-40.

Deis, Ronald. “Salad Dressing and Sauces: Through Thick and Thin.” Food Product Design. May 2001.

Depree,J.A. and Savage,G.P. “Physical and Flavour Stability of Mayonnaise.” Trends in Food Science and Technology. 12(2001)

Fisher, Harry J., and F. Leslie Hart. Modern Food Analysis. New York: Springer-Verlag, 1971.

Furia, Thomas E. HandBook of Food Additives. Cleveland: CRC, 1968.

J.M.H. Janssen, H.E.H. Meijer, A 2-Zone Model, Polymer Engng. & Sc., 35(22), 1995, 1766-1780.

Gallegos C., Berjano M., Linear viscoelastic behavior of commercial and model mayonnaise, Soc. Rheology, 36(3), 1992, 465-477.

Goshawk J A, Binding D M, Rheological phenomena occurring during the shearing flow of mayonnaise, J. Rheol, 42(6), 1998, 1537-1553.

Jacobs, Morris B. The Chemistry and Technology of Food and Food Products. Vol. 2. New York: Interscience, 1951.

Kiosseoglou,VD and Sherman, P. “Influence of Egg Yolk Lipoproteins on the Rheology and Stability of O/W Emulsions and Mayonnaise.” Colloid and Polymer Science. Volume 261, June 1983

Paraskevopoulou A, Kiosseoglou V, Alevisopoulos S, Kasapis S, Influence of reduced-cholesterol yolk on the viscoelastic behavior of concentrated O/W emulsions, Colloids and Surfaces B: Biointerface 12, 1999, 107-111.

Solomons, T.W. Graham. Organic Chemistry. 5^th ed. New York: John Wiley & Sons, 1992.

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Websites

http://alfa.ist.utl.pt/~fidel/creac/sec373.html

http://www.bestfoods.com/profile_history_bestfoods.shtml

www.bran-luebbe.co.uk/mayo.htm

http://www.foodproductdesign.com/archive/1995/1095DE.html

www.foodservicedirect.com

www.foodstarch.com

www.gowcb.com/products/systems/mayonnaise.htm

http://www.gowcb.com/products/systems/PDF/9825MARGARINETUBSTICKLINE.PDF

http://www.margarine.org/historyofmargarine.html

www.seps.org/oracle/oracle.archive/Physical_Science.Chemistry/2001.01/000978561267.7817.html

United States. Food and Drug Administration. Center for Devices and Radiological Health. Code of Federal Regulations Title 21- Food and Drugs. Sec 169.140 Mayonnaise. 1 April 2001. http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPCD/ShowCFR.cfm?FR=169.140

United States. Food and Drug Administration. Center for Devices and Radiological Health. Code of Federal Regulations Title 21- Food and Drugs. Sec 166.110 Margarine. 1 April 2001.

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPCD/ShowCFR.cfm?FR=166.110

www.xanthan-gum.net

Personal Interviews

Fendinger, Andrew. Personal Interview. 13 Mar 2002.

Maiolino, Dana. Personal Interview. 1 Apr. 2002.

Mclaughlin, Barry Personal Interview. 13 Mar 2002.

Product Data Bulletins (PDB #)(Organized according to Product)

Mayonnaise

1. Karlshamns® USA Inc. (Columbus, Ohio): Soybean Oil

2. Global Egg® Corp. (Etobicoke, Ontario): Whole Eggs

3. Julius Goldman’s Egg City® (Moorpark California): Egg Yolks

4. Indian Summer® (Lyndonville, New York): Vinegar

5. IMC Salt® (Overland Park, Kansas): Sodium Chloride

6. Colonial® Sugars, Inc. (Gramercy, LA): Sugar

7. Sunkist® Growers, Inc. (Ontario, California): Lemon Juice

Reduced Fat Mayonnaise Additions

8. National Starch & Chemical Corporation® (Bridgewater, NJ): Modified Corn Starch

9.Maple Lynn Foods® (Upton, QC): Egg Whites

10. FMC® (Philadelphia, PA): Cellulose Gel

11. Hercules® (Wilmington, DE): Cellulose Gum

12. Nealanders® International Inc. (Etobicoke, Ontario): Xanthan Gum

13. Gumix® International (Hackensack, NJ): Xanthan Gum

14. Kalama® Chemical, Inc. (Need Location): Sodium Benzoate

Margarine

15. Central Soya® (Fort Wayne, Indiana): Partially Hydrogenated Soy Oil, Soy Lecithin

16. Ault Performance® Ingredients (St. Laurance, QC): Whey

17. Loders Croklaan® (Glen Effyn, Illinois): Mono-and Diglycerides

18. Archer Daniels Midland® Co. (Decatur, Il): Lecithin

19. American Hoechst® Corp. (Somerville, NJ): Potassium Sorbate

20. Rhone-Poulene® Basic Chemicals Co. (Shelton, CT): Phosphoric Acid

21. Roche® Vitamins Inc. (Parsippany, NJ): Beta Carotene, Vitamin A Palmitate