Development of a new bakery product made with ostrich egg

SUMMARY.

Since the eighties, a general preference for low calorie, fat and cholesterol foods arises, this food culture has grown significantly in recent years and that is where the ostrich appears as an interesting alternative due to its features.

In Mexico, the ostrich industry started in 1991 in the state of Coahuila, where the first company dedicated to its breeding was established. Currently it is estimated that there are around 800 farms in various states of the republic, it is considered that this situation will not take long to achieve a significant number of breeders in the country that allows entering the next stage of the industry which is that of slaughter animals for the marketing of their products. Ostrich currently uses its meat, skin, feathers, eggs and eggshells.

In general, most of the studies have been carried out on the chicken egg, and some others on the paw or goose egg; but there are no studies on the technological use of ostrich eggs. In Mexico, shell is only used economically as a craft, while the yolk and the white are not used technologically, since they are consumed directly in the form of homemade dishes, wasting their functional properties for the manufacture of other types of food products such as dressings, mayonnaise, desserts, flan, bakery products, among others, that use the egg as an ingredient in its preparation.

For this reason, the objective of this study was the exploitation of the yolk and the white of the ostrich egg in order to obtain an additional technological and economic benefit, through the elaboration of a bakery product. From the proximal analysis and the functional properties of the ostrich egg white; determining the proximal analysis of the bread product (corn bread), and determining its degree of acceptance by means of affective sensory evaluation tests. The following results were obtained:

When comparing the composition of the ostrich egg (by means of the Proximal Chemical Analysis) with that of the chicken egg, it is observed that the values are very similar, which suggests that there should be no notable differences in the food products that use it. as an ingredient. But when experimentally determining the values of the functional properties of the ostrich egg white, and when comparing it with the values reported in the literature for the chicken egg white, it was observed that the ostrich egg white has higher values. higher than emulsifying capacity, foaming capacity, water absorption and oil absorption than the white of the chicken egg, without either of the 2 types of white showing the ability to form gels, favoring only coagulation.Due to these differences in the functional properties of the white of the 2 types of eggs, changes may occur in the physicochemical and sensory characteristics of food products that use the egg as an ingredient, so they cannot be used interchangeably for its elaboration..

Based on the previous results, a comparative study was then carried out between a bakery product (Corn bread) made with chicken egg, with another made under the same conditions, but replacing the chicken egg with the ostrich. The following differences were observed from the study carried out: the Proximal Analysis of both types of bread was very similar, with the exception of the% of proteins, which was (9%) for corn bread made with ostrich egg (PEAV), compared to (6%) for corn bread made with chicken egg (PEG). Regarding the Sensory Evaluation tests, (PEAV) presented a slightly fluffier and slightly more greasy consistency than (PEG), both types of bread presenting a very pleasant flavor,according to the opinions of the 100 judges who tasted the product. However, it should be noted that although both breads had very good acceptance by the judges; if there were noticeable differences in flavor and consistency.

Finally, through the manufacture of a bakery product (which in this case was corn bread), the objective of giving added value to the use of the yolk and the white of the ostrich egg was achieved, achieving a technological contribution and an additional economic benefit to the one that is had at present, solely for the sale like crafts of its shell.

1. INTRODUCTION.

The ostrich (Struthio camelus) has its origin on the African continent, for approximately 60 million years, during the Eocene period. After millions of years of evolution and natural selection, the ostrich has become a bird resistant to extreme weather conditions and tolerant to diseases and some parasites. (www rachoavestruz.com, 2002)

1.1. OVERVIEW OVERVIEW.

The ostrich is a bird native to Africa, it belongs to the group of running birds that cannot fly or ratites, they belong to the Order Struthioniformes, of the Subgenus Struthiores, to the Family Struthocridae, to the Genus Struthio, to the Species camelus, and their common Name is the ostrich one. (www rachoavestruz.com, 2002)

The ostrich is the largest bird in the world, which can reach a weight of 200 kilograms and a height of 2.75 m. in adult state. Likewise, it can reach a sustained speed of 60 kilometers per hour for 20 minutes. Its longevity is of the order of the 70 years and due to its wild nature, it presents very good adaptability to a great diversity of climates, mainly arid, semi-arid and temperate climates, in addition to withstanding extreme weather conditions from 4 months of age. Males generally mate with two females. (www rachoavestruz.com, 2002; www oronegro.com, 2002)

Each year a female can produce 40 to 70 chicks that in a few months become adults over two meters tall and 150 kilograms in weight. In Mexico, according to data from the Mexican Ostrich Producers Association (AMPA), there are more than 150,000 copies in full reproduction. (www oronegro.com, 2002)

These birds are docile in temperament and have few natural enemies. Chicks are very vulnerable to attack by predators and must be very well protected during the first six months of age. At the moment of hatching the chicks weigh approximately 1 kilogram, in addition to having an appearance on the feathers that serves as natural camouflage, which they lose as they develop over the months and years. (www oronegro.com, 2002).

They spread their little wings as they run and use their long, strong legs to defend themselves. They only have two toes on each leg. Ostrich males are black, with white wings and tails. The male's large, soft white feathers have commercial value. The female is dull grayish brown. (www oronegro.com, 2002).

There are three subspecies or breeds of ostriches: the red-necked, the blue-necked and the African black, being the red-necked little used in commercial farms due to its aggressive temperament and a lower volume of meat and skin compared to two other subspecies. (www ranchoavestruz.com, 2001; www oronegro.com, 2002)

1.2. THE PRODUCTS OF THE OSTRICH.

The main productive characteristics and other data of interest to the ostrich are shown in Table 1, where it can be seen that practically everything can be used from these birds, although the main products obtained from this bird are meat, skin, feather and egg, which will be discussed in more detail later; There are other products that are obtained from the ostrich. For example, eyelashes are used to make fine brushes, beak and nails are used in jewelry. There is research that plans to make use of the ostrich's eyes to take advantage of them in human corneal transplants. The possibility of applying ostrich tendons to human tendons is also being studied, as they have similar characteristics in terms of strength, consistency and length. Likewise,It has been observed that the brain of these birds produces an enzyme that is currently used to treat Alzheimer's disease. (www oronegro.com, 2002).

TABLE 1. PRODUCTIVE CHARACTERISTICS OF THE OSTRICH.

PARAMETERS	AVERAGES
Productive life	40 years
Carcass meat production	47% of live weight
Boneless meat production	37% of live weight
Skin production	1.2 - 2 square meters
Feather production	1 - 4 Kg per year
Annual stance	40 eggs average
Daily feed intake	1 - 1.5 Kg
Male sexual maturity	2.5- 3 years
Sexual maturity of the female	2 - 2.5 years

(www michoacan.com, 2002; www texcale.com, 2001)

The two most important products of the ostrich are skin and meat. Ostrich skin has always been highly valued, there are large companies dedicated to tanning this type of skin, however, the short supply has not been enough to satisfy world demand, making it a hitherto virgin market. and with great possibilities of exploitation. The potential market for ostrich meat is huge, with over 30 million tons of beef, pork, chicken and turkey consumed annually in the United States. (www rachoavestruz.com, 2002).

Since the eighties, a general preference for low calorie, fat and cholesterol foods begins to emerge in the world, this culture of healthy eating has grown significantly in recent years and that is where ostrich meat It appears as an interesting alternative due to its characteristics. (www texcale.com, 2001)

The ostrich egg weighs a total of about 1.5 kilograms, serves to feed ten people, and has a volume of about 1.4 liters. The male incubates it at night and the female during the day. (www texcale.com, 2001)

1.3. THE ACTUAL SITUATION.

In Mexico, the ostrich industry is relatively new, since it started in 1991 in the state of Coahuila, where the first company dedicated to the breeding of ostriches was established. At present it is estimated that there are around 800 ostrich farms located in various states of the republic, these farms are in the midst of reproduction to form breeding stock and commercialize breeding birds, it is estimated that this situation will take some years to achieve a significant number of breeders in the country that allows entering the next stage of the industry, which is to slaughter animals for the commercialization of their products. (www oronegro.com, 2002)

Their diet consists of a balanced diet of protein, alfalfa, grass, sorghum, bran and soy. Each female of childbearing age (from two years of age) can have 40 to 70 chicks a year, which after twelve months generate 2,400 kilograms of meat from a single womb (as if a cow had 5 calves a year). (www oronegro.com, 2002; www texcale.com, 2001)

280 days are required for the gestation of a calf, while the incubation period for an ostrich egg is only 42 days. According to AMPA estimates, for this year it is expected to reach a production of more than 500 thousand copies in the 31 states of the Republic. Currently Tamaulipas occupies the first national place, with the production of 30 thousand standing ostrich heads. (www texcale.com, 2001; www oronegro.com, 2002)

1.4. THE OSTRICH EGG.

The egg is a food that since ancient times has been consumed by humans from different cultures. Initially it was only used to flavor or to obtain the desired consistency in a food, but it was not used because it was a food that provided a great variety of nutrients that helped improve the consumer's diet. (Fennema RO, 1985; Charley, H., 1996). Its high consumption may be due to its pleasant taste that it has for some, but nevertheless, this taste is not shared by all people, since the egg also has the characteristic of having a sulfur flavor that can be not very pleasant on the palate for some others. Another factor for which the egg is not always consumed by some people, is because in some of them it causes allergies. (Fennema RO, 1985)

In addition to eggs being cooked and served in different ways, they also perform a number of functions in products where they are used as ingredients. They create an emulsifier in mayonnaise, cream puffs, and cheese souffle; it can give shine to some foods, as is the case of bakery products; it acts as a gelling agent in flan and as a covering material in kibble; as a thickening agent in soft cake fillings and as a structural material in cakes whose main ingredient is butter. When beaten into a foam, the eggs serve as a means of incorporating air into the meringues, into the puffed cake of the yolks, into the white cake also into the butter-based cakes. (Charley, H., 1996)

Eggs, such as chicken and quail eggs, are the most consumed in industrialized countries, both in cities and in the countryside. They are taken "soft-boiled" (only the white is cooked), hard (they cook both the white and the yolk), soft-boiled so that the white is soft, to the plate, poached (cooked without shell in a boiling liquid), scrambled (fried in a pan by stirring them with other products), steamed (fried in oil), tortilla (mixing white and yolk) and raw (they are drilled by drilling a small hole in the shell). In addition, they make numerous dishes, sauces and pastry products. (Potter, N., 1978)

The ostrich egg, as far as Mexico is concerned, is only used as an ornament (to paint on its surface) and is a very expensive product, where the shell is used and the rest is wasted. (www oronegro.com, 2002)

Due to the similar characteristics of all bird eggs, it could be consumed in the same way as chicken or quail eggs.

1.4.1. CONSTITUTION OF THE EGG

SHELL

The egg is made up of a shell that is formed for the most part by calcium carbonate crystals deposited in an organic matrix that surrounds, supports and protects the consumable part of the egg. The shell of the chicken egg is fragile, very thin and rigid, it contains thousands of pores that most of them are not visible to the naked eye. In the ostrich egg the shell is also made of calcium carbonate crystals, it is around seven millimeters thick, it is rigid, it is not brittle, so much so that in order to open it, it is necessary to use a blade; the pores of this type of egg are large enough to be seen with the naked eye through which an exchange of gases takes place. (Charley, H., 1996; Potter, N., 1978)

EGG WHITE

The white is a solution of albumin, a protein of high energy value, rich in amino acids: lysine, methionine and tryptophan. The main components of egg white apart from water are proteins, among which are ovalbumin, ovomucoid, and avidin, among others. (Charley, H., 1996)

BUD

The yolk contains protein, neutral fat, lecithin, cholesterol, iron, and vitamin A (carotenoids). Altogether, one chicken egg contains for every 100 useful grams (equivalent to two pieces without shell): 160 calories, 0.6 g of carbohydrates, 11.5 g of lipids, 12.8 g of proteins, 74 g of water and the rest corresponds to others components (vitamins and minerals). It weighs between 40 and 70 g, and from the point of view of the relationship between energy content and volume, eggs clearly outperform meat. (Potter, N., 1978)

The main components of egg white apart from water are proteins, among which are ovalbumin, ovomucoid, and avidin, among others. (Charley, H., 1996)

1.5. THE FRESHNESS OF THE EGG.

After laying, the egg has gas exchange through the shell. One of these gases is water vapor, which is lost due to different factors such as evaporation and storage temperature. Another of the gases formed is carbon dioxide, which is generated as a result of the metabolism of the egg, since as the egg gets older, these gases are eliminated, the air chamber increases its volume (Charley, H., nineteen ninety six).

One of the main reasons for evaluating the freshness of the egg is to check the quality of the eggs used for food purposes. In the ovoscope tests, it can be seen if the eggs that are used in the elaboration of the various products have small air chambers and little movement of the yolk, these being some of the main parameters of freshness of the eggs. (Charley, H., 1996)

When storing the egg, it undergoes different modifications in its composition; In addition to a gas exchange, another important change is the deterioration of proteins, due to their enzymatic degradation. The proteins of the thick white undergo this degradation, solubilizing the different components of the same, which causes a decrease in the height of the thick white and an increase in the proportion of the thin white. (Charley, H., 1996; Fennema RO, 1985)

In the paving tests, the white should not be overextended, since an enzymatic degradation causes the loss of firmness of the white, and therefore becomes more fluid, also ensuring that the yolk remains firm and does not break. (Charley, H., 1996; Fennema RO, 1985)

1.6. BAKING PRODUCTS.

Wheat flours have their main applications in the preparation of baked products. Most of these differ from other wheat products, such as pasta and breakfast cereals, in that they contain lower density agents due to the formation of carbon dioxide. (Potter, N., 1978)

Although many baked items are alike in terms of formula, processing methods, and characteristics, it is possible to divide them based on the applied method of fluffing. This division is not perfect, but it can be done as follows (Potter, N., 1978):

Yeast-puffed products - Include breads and confectionery breads fluffed with carbon dioxide produced by yeast fermentation Chemically fluffed products - Such as cakes, donuts and biscuits fluffed with carbon dioxide produced by baking powders and other chemical agents. The product to be produced during the project corresponds to this classification. Air-blown products - Include angel cake and sponge cakes made without baking powder. Partially fluffed products. - Include bread dough, some cookies and other items in that no fluffing agents are used, but that some fluffing occurs due to the expansion of steam and other gases during the cooking operation in the oven.

The gas can only produce the overrun, if it is trapped within a system capable of retaining it and expanding with it. Therefore, a large part of cereal science related to baking technology, actually consists in the production of food structures through the correct formation of masses capable of retaining the gases that produce puffing, and then coagulation or fixation of these structures by means of the application of heat. Hence the need to better understand certain properties of flour and some other ingredients in baked goods. (Potter, N., 1978)

1.6.1. FLOUR.

It is the ingredient for making bread, all kinds of cakes and Italian pasta and is obtained by grinding the cereals into a very fine powder. The preferred and most nutritional flour is wheat, but there are also other cereals. The flour used in this case is generally called “All-purpose flour”, and bread is made from it and used in cooking in general. The most important of the functional proteins in wheat flour is gluten, and an important property it has is that, when it is wetted and kneaded by mechanical action, it forms an elastic mass. The gluten in the flour combines with the starch, which when moistened and heated, forms a paste that stiffens, or gelatinizes. Consequently, gluten and starch in combination form doughs according to the amount of water added;that contribute to the semi-rigid structures that result from the heating of these masses. (Potter, N., 1978)

1.6.2. YEAST.

They are microscopic fungi (Saccharomyces cerevisiae) that produce fermentation of simple sugars, in other organic substances such as carbon dioxide and alcohol, such as wine, beer and flour. Today, pure strains of these microorganisms are sold on the market that facilitate home-made breads and cakes due to the uniformity of their properties. It can be in different presentations: dry (granulated), or compressed into rectangles of 200 - 400 grams, or fresh (must be kept in the refrigerator). Fermentation is gradual, which is increased over time. (Reader's Digest, 1989)

1.6.3. MILK.

It plays an important role due to its great nutritional value. Fresh milk should be heated to the boiling point before use, because otherwise the dough softens and doesn't taste good. Using pasteurized milk, heating and cooling is not necessary; however, it is advisable to heat it moderately to melt the butter, or dissolve the honey or sugar, if they are to be used, but this depends on the type of yeast to be used. (Reader's Digest, 1989)

1.6.4. POWDERS FOR BAKING.

They contain sodium bicarbonate particles as a source of carbon dioxide, in addition to particles of an edible acid for gas generation as soon as water and heat are supplied. It also generally contains monocalcium phosphate as an acid. The differences between the different baking powders lie in the speeds and times of the reactions they cause, and their formulas are prepared in order to regulate the release of gases for various applications in specific products. (Reader's Digest, 1989)

1.6.5. EGG.

In addition to contributing nutrients, flavor and color, eggs can help create the structure of cakes. The white is a mixture of proteins. It forms films and catches air when it is beaten, and when heated it coagulates, producing rigidity. Egg yolk proteins have similar properties. In the oven. Gluten, starch, and egg stiffen and subdivided air bubbles inflate further due to heat. The generated water vapor enters the bubbles and also helps to inflate them. This explains why the ability of eggs to beat and the stability of their foam are so important to the pastry chef and baker. (Reader's Digest, 1989)

1.6.6. OTHER INGREDIENTS.

The fats make the dough richer and more tender, but it takes longer to rise, it contributes to the sponging action, due to the release of air bubbles that the fat contains when melting in the oven. They delay the hardening of the bread. Salt enhances the flavor of the other ingredients, although too much can delay the action of the yeast. Sugar gives flavor and color to bread. (Reader's Digest, 1989)

1.7. THE BAKING STAGE.

Baking is a heating process in which many reactions occur and at different speeds, among them we have (Potter, N., 1978):

Coagulation of gluten and eggs, and gelatinization of starch, Production and expansion of gases, Partial dehydration due to evaporation of water; Development of flavors, Color changes due to Maillard-type reactions, between milk, gluten and egg proteins with reducing sugars, and other changes of chemical origin, Crust formation in bread due to superficial dehydration, and Darkening of the crust due to Maillard-type reactions and caramelization of sugars.

The rates of these various reactions and the order in which they occur depend largely on the rate of heat transmission through the mass. Regardless of the temperature distribution in the furnace, the speed of heat transmission is also affected by the nature of the mold used (both color and shape). (Potter, N., 1978)

A factor of utmost importance is the height above sea level at which the baking stage is carried out, generally the recipes are made considering a height close to the sea. But at an elevation of more than 1000 meters, the expansion of fermentation gases under reduced atmospheric pressure causes stretching and weakening of the forming cell structure. This can be corrected by decreasing the amount of baking powder, and increasing that of hardeners such as flour, or by using a stronger flour, or by decreasing the amount of softeners such as vegetable fat or sugar. But because the doughs of breads are stronger than that of cakes, they are less sensitive to height than cakes. (Potter, N., 1978)

1.8. FUNCTIONAL PROPERTIES.

Proteins of animal and vegetable origin have various nutritional, physicochemical and mechanical properties, which together are called Functional Properties. In addition to its nutritional function, such as meeting the energy and constitution needs, proteins play an essential role in the appetite of food, that is, its organoleptic properties. (Bourgeois, CM, 1986; Fennema, O., 1985)

It is defined as a functional property of a food substance, as any nutritional property or not, that intervenes in its food use, and covers the multiple aspects of research currently carried out in this field. To appreciate these properties, methods with other physicochemical characteristics are used that simulate as best as possible the effect of interest that is intended to correlate with its intensity. (Bourgeois, CM, 1986)

In the living organism, the main function of proteins is dynamic, when the protein is transformed into food, its role is often perceived from a nutritional point of view. However, these proteins are less and less consumed in their original form, since they are incorporated into complex mixtures, where appetite is of more importance to the consumer than nutritional value. (Bourgeois, CM, 1986)

For this reason, it is thought that a protein that comes from food does not have a good nutritional value if its organoleptic qualities are not satisfied. This is the step that will prevail when adopting any new protein as food or food additive. (Bourgeois, CM, 1986)

One of the main objectives of technological treatments is to create a three-dimensional structure that provides the food with a texture and an acceptable appearance for the consumer. To achieve this end, some products use proteins of animal or vegetable origin, since in addition to contributing nutritional value, they have other functional properties such as: solubility, wettability, water retention, emulsification capacity, foaming, gelling; all of them intervene in a very important way to obtain mechanical characteristics of the food, these nutritional properties will be influenced by the interaction with other components of the food, such as salts, fats and carbohydrates. (Bourgeois, CM, 1986)

For example, when you beat the egg white, the air bubbles are trapped inside the liquid albumin and this is how the foam is formed; a change occurs in the molecular configuration of proteins, resulting in greater solubility or coagulation of some albumins, becoming a liquid-air interface. The adsorption of this film is essential in the stability of the foam. (Bourgeois, CM, 1986)

Factors such as temperature, surface tension, viscosity, and vapor pressure; influence the stability of the foam. Globulins influence the increase in viscosity and lower surface tension, which helps to stabilize the foam, which will present smaller air globules and therefore a better texture in the products. Foaming is a functional property and the characteristics of the foam formed influence the properties of meringues and cakes made in the bakery industry. (Bourgeois, CM, 1986)

1.8.1. MAIN FOOD FUNCTIONS OF ANIMAL PROTEINS.

The primary role of protein as food is to administer essential amino acids to the body, after having undergone more or less intense hydrolysis under the action of enzymes in the digestive system. Amino acid composition is an important parameter, but insufficient to ensure this function. Protein digestibility is obviously a limiting factor in the availability of these amino acids. (Bourgeois, CM, 1986)

TABLE 2. SENSORY FUNCTIONS OF PROTEINS.

PARAMETER	CHARACTERISTIC
Appearance	Turbidity, opacity (insoluble proteins: gelatin).
Color: pigments like hemoglobin; melanins and melanoidins (Maillard reactions).
Texture: proteins that retain water; gelling agents (gelatin, ovalbumin, lactoproteins); sparkling wines (ovomucine) and emulsifiers.
Taste	Astringency of tannin-protein complexes.
Bitterness of certain peptides obtained from proteolysis.
Smell	Retention of aromas.
Proteolysis products during ripening.

(Bourgeois, CM, 1986)

Proteins, peptides and amino acids can act to stabilize these qualities: antibiotic peptides, flavor enhancers, aromas or nutritional value. (Bourgeois, CM, 1986)

1.8.2. PHYSICAL PROPERTIES OF INTEREST TO FOOD TECHNOLOGY IN RELATION TO THE STRUCTURE.

One of the main objectives of technological treatments is to create a three-dimensional structure that gives the food its texture and appearance. Properties such as gelling, texturing, are more than the structural and physicochemical mechanisms that cause them.

The functional properties are classified according to the nature of the interactions, but often several types of reactions that are carried out simultaneously are responsible for a single type of structure. (Bourgeois, CM, 1986)

1.8.3. FUNCTIONAL PROPERTIES IN RELATION TO HYDRATION.

1.8.3.1. SOLUBILITY.

Proteins in aqueous media can form a true solution, a colloidal solution or a stable suspension of stable particles. It depends directly on the ratio of hydrophobic and hydrophilic groups of amino acids. In addition to an irregular distribution in the peptide chain, it facilitates hydrophobic intermolecular interactions with other hydrophobic proteins or with little polar substances. (Bourgeois, CM, 1986)

The appearance of a protein solution can vary greatly, so the results of solubility tests may depend on the method used. (Bourgeois, CM, 1986)

In general, the soluble nitrogen contained in the centrifugation supernatant of the protein solution is determined. The solubility depends on the pH, and increases with increasing ionic strength, until reaching an optimal value. (Bourgeois, CM, 1986)

1.8.3.2. WATER ABSORPTION CAPACITY.

Water retention is an essential property especially in sausage products. Fixation of water, or swelling, is facilitated by hydrogen bonds that form between non-ionized polar groups and water, depending mainly on pH. (Bourgeois, CM, 1986)

In addition, any dissociating factor of ionic or covalent bridges will facilitate the entry of water; This is the case with the polyphosphates that complicate Calcium ions, responsible for interchain ionic bridges. (Bourgeois, CM, 1986)

In practice this can be seen by determining the dispersion index of swelling or fixing of water, after having suspended 1 gram of protein in 20 milliliters of water, decanting for one hour. (Bourgeois, CM, 1986)

1.8.3.3. GELIFICATION CAPACITY.

It results from the balance between interactions of electrostatic repulsion and those of attraction of Van der Waals. (Bourgeois, CM, 1986)

Coagulation can be thought of as disordered aggregation, as occurs in denaturation. On the contrary, gelation allows the formation of more or less ordered continuous structures. In general, gels show a behavior of solids with a certain degree of elasticity. (Bourgeois, CM, 1986; Hetyarachy, 1991)

The stability of the gels will depend on the type of bond involved. If the bonds are like Van der Waals or London forces, the gel is unstable and varies with mechanical agitation. With hydrogen bonds, the gel can be reversibly transformed into solution, by heating. Covalent bonds give high stability to the gel. (Bourgeois, CM, 1986)

The appearance of the gel can be observed by turbidimetry, which allows the kinetic study of the phenomenon to be carried out continuously. The texture of the gels can be observed with a wide variety of rheogonometers, of which none provide information on a single physical property. If knowledge of gel texture is essential in food technology, two other qualities of gel are systematically determined: formation time and stability. (Bourgeois, CM, 1986)

1.8.4. FUNCTIONAL PROPERTIES RELATED TO SURFACE PROPERTIES.

In oil-in-water type food emulsions, proteins are important due to their tendency to localize at the interface, lowering surface tension. Certain insoluble proteins do not settle because they are fixed at the interface of the fat globules of stable emulsions. These properties depend on the nature of the interacting amino acid residues, the environment and the spatial coagulation on the surface, of the original or denatured proteins. Two tests show the ability of a protein to facilitate the formation of an emulsion or to stabilize it. (Bourgeois, CM, 1986)

The capacity of the emulsifier determines the maximum amount of oil that can be emulsified in one volume of water containing the protein to be tested. (Bourgeois, CM, 1986)

Stability indicates the duration of the emulsion, without phase separation. In general, the emulsifying capacity varies considerably with the origin of the protein; it acquires a maximum value for a certain optimal concentration of protein. (Bourgeois, CM, 1986)

Another surface property is manifested by foaming. If the surface tension is very low, mechanical agitation causes the incorporation of air in the form of bubbles; the quality of the foam depends on the magnitude of its specific volume and stability. (Bourgeois, CM, 1986)

The foaming power varies with the origin of the protein, with its composition; the conditions of the environment or the eventual treatment suffered by the protein; A surface mechanical denaturation of the protein helps stabilize the foam. Finally, proteins have adsorbent properties that are sometimes used to delay the volatilization of natural or food-added aromas. (Bourgeois, CM, 1986)

2. BACKGROUND.

Currently, ostrich meat can already be found in various markets, reaching a channel price of $ 80 per kilogram (Rancho Texcale, 2000), unlike ostrich egg, which is not being exploited, since its economic utility It is through the sale of the shell, with which crafts are made.

When performing the bibliographic search, only studies related to its physical characteristics and lipid composition were found, but no research was found regarding the study of the functional properties of white and yolk, nor of their technological use.

3. JUSTIFICATION.

P It can be perceived that the raising of ostriches is not a passing fad, but rather indicates a strong tendency of producers towards raising more efficient and productive animals, and on the part of consumers towards healthier meat products with less fat content, because they have become more selective about the quality of their food. The ostrich industry has had a very important growth in recent years, there are farms in a large number of countries around the world, so we are sure that in a few years, the raising of ostriches will no longer be seen as an activity. strange and uncommon, and will undoubtedly become some of the 21st century livestock. (www oronegro.com, 2002; www rachoavestruz.com, 2002)

P Ostrich farms are established monthly in Mexico, the investment is moderate and the profits are considerable, since these animals take advantage of absolutely everything. (www oronegro.com, 2002)

P In Mexico, the shell is only used economically in the form of handicrafts, while the yolk and the white are not used technologically, since they are consumed directly in the form of homemade dishes, wasting their functional properties for the manufacture of other types of food products. such as dressings, mayonnaise, desserts, meringues, flan, bakery products, among others, which use the egg as an ingredient in its preparation.

So the use of the yolk and the white of the ostrich egg, would bring us 2 benefits:

1) An additional economic benefit to that currently obtained from the sale of the shell.

2) The technological use of its functional properties to give added value to the current economic exploitation of this product. In this case by means of the elaboration of a bakery product that is the Corn Bread.

4. OBJECTIVES.

4.1. OVERALL OBJECTIVE.

Take advantage of the yolk and white of the ostrich egg in order to obtain an additional technological and economic benefit, through the preparation of a bakery product.

4.2. SPECIFIC OBJECTIVES.

Determine the composition (Proximal Chemical Analysis) of the ostrich egg and compare it with that of the chicken egg. Determine the Functional Properties (Emulsifying Capacity, Emulsion Stability, Gelling Capacity, Foaming Capacity, Water Absorption and Oil Absorption) a the white of the ostrich egg. Preparation of 2 cornbreads using ostrich egg and chicken egg as an ingredient, looking for the most suitable proportion of the yolk and the white of the ostrich egg, to obtain the best possible formulation. the composition (Proximal Chemical Analysis) of the 2 types of breads. Apply sensory evaluation tests to the 2 types of breads made, in order to compare their degree of acceptance

5. MATERIALS AND METHODS.

5.1. MATERIALS.

The project will be carried out with ostrich eggs from a ranch located in the state of Morelos, at the latest before one month after being expelled from the bird. Own laboratory material. Analytical grade reagents.

5.2. EQUIPMENT.

The equipment used in the different determinations of the study are those shown in Table 3. All of which belong to the Laboratory of the Food Academy.

TABLE 3. EQUIPMENT USED IN THE DETERMINATIONS.

Equipment	Brand	Model
Analytical balance	Mettler	H 31
Granataria Balance	Ohaus
Kjeldahl Nitrogen Determination Equipment	Lab Conco	3122
Soxhlet Fat Determination Kit	Lab Line Inst	5000
Centrifuge	Beckman	JL –HS
Muffle	Heavy duty	052 - PTI
Stove	Carlo Euba	1000 / A

5.3. METHODS.

5.3.1. DETERMINATION OF THE FRESHNESS AND QUALITY OF THE EGG.

5.3.1.1. WHOLE EGG QUALITY.

a) Determine the weight of the egg on a granataria scale, and in the case of chicken egg, this is compared with the corresponding Standard. However, its quality cannot be established based on its size - weight as it is done in chicken eggs.

5.3.1.2. DETERMINATION OF EXTERNAL QUALITY

SHELL.

Observe the surface characteristics of the shell such as: size, shape, color, dirt and roughness; This is done by checking the egg with the naked eye.

OVOSCOPE TESTS.

Place the egg in front of the focus of a dark chamber, observe the air chamber and mark it with a pencil, identify the location of the yolk and if it has mobility. Analyze the possible presence of contamination that can be detected by dark areas.

To observe the egg through a light source, an ovoscope appropriate to the size of the ostrich egg was constructed, using a cardboard box and a 100 Watt flat-surface spotlight, using pieces of cardboard and other accessories, in order to obtain darkness inside the box and be able to better observe the internal parts of the egg. (Desrosier, R., 1998)

EGG DENSITY.

Put the egg in a 10% sodium chloride solution and observe If it goes to the bottom (it is a fresh egg), it does stay in the middle position or protrude from the surface (it is an old egg).

5.3.1.3. DETERMINATION OF INTERNAL QUALITY.

SPREADING TEST.

Paving tests are carried out on 6 mm thick glass, and its dimensions are: 1.20 m long and 1 meter wide, one of the parameters considered in the freshness of the egg is its paving surface. in the glass, since generally a fresh egg does not extend much (both yolk and white) and an old one extends too much.

RELATIVE SPREADING SURFACE OF THE THIN CLARA AND THICK CLARA.

Below the glass where the paving test was carried out, the periphery of the thin and thick white was traced with a marker, as well as the outline of the yolk. Trace the diagram on bond paper, cut the periphery of each of the parts and weigh each one separately on an analytical balance.

Cut a 1cm2 sample of bond paper in duplicate, weigh them on an analytical balance and obtain the average to calculate the percentage of each one.

5.3.1.4. YEMA QUALITY.

VISUAL CHARACTERIZATION OF THE YEMA.

Observe the following characteristics of the yolk:

Form Elevation Visual presence of defects.

When the yolk is umboned and has a relatively high elevation, it is a fresh egg; but if the yolk has a flattened shape and a relatively low elevation, it is an old egg.

It should also be noted that the yolk does not show blood or other stains, microorganisms, strange colors, fragments of foreign material (tissue, membranes or chicks).

5.3.2. PROXIMAL CHEMICAL ANALYSIS OF THE RAW MATERIAL.

From the sample used in the previous tests, where the egg is determined to be fit for human consumption, the white and the yolk of the ostrich egg are separated, to continue with the following determinations.

The determinations were made according to the techniques established by the AOAC (1995).

5.3.2.1. DETERMINATION OF ASHES.

Weigh from 1 to 2 g. of white or yolk sample separately in a constant weight crucible. Carbonize the sample inside the crucible with the lighter, slowly to avoid sample losses due to smoke dragging or projections thereof. When the smoke evolution has ceased, bring the crucible to the flask at 500 - 600 ° C. until a gray-white color is obtained in the ashes of the sample.Transfer the crucible to the stove (approximately 100 ° C) and let it cool gradually, then transfer it to the desiccator.Keep in the desiccator for approximately 15 minutes, so that it reaches the temperature Weighing on the analytical balance and transferring to the flask, repeating the cycle until the crucible with the ashes reaches constant weight.apply the following formula and determine the ash percentage for the white and the yolk separately:

Where a is the weight of the ash pot (grams), b is the weight of the ashless pot (grams), and m is the weight of the original sample in grams.

5.3.2.2. DETERMINATION OF MOISTURE.

It is determined by the heating method. The determination is carried out with the yolk already clear separately, since the humidity values are different in both.

Bring the tray with the piece of filter paper to constant weight, placing it in the oven at 70 ° C, for two hours, and weigh the desiccator for 15 minutes, so that it reaches room temperature and repeat the procedure with the tray until the desired constant weight. Weigh 5 to 10 grams of sample on the tray at constant weight and take to the stove, taking care that the temperature does not exceed 90 ° C. Transfer the capsule to the desiccator, and cool for half an hour and quickly weigh the sample, the weight loss corresponds to the moisture loss of the bread sample.Expression of results:

Where P is the loss of the sample in grams and m is the mass of the original sample in grams.

5.3.2.3. DETERMINATION OF ETHEREAL EXTRACT.

It is carried out by the Soxhlet method, separately determining the fat content of the white and the yolk.

Place a cotton bed in the cellulose cartridge, plus another piece that will serve to cover the sample, bring the flask from the Soxhlet unit to constant weight in a stove at 100-110 ° C. Add the dehydrated sample obtained in the humidity determination, cover with the cotton and adapt the cartridge of the Soxhlet apparatus to a reflux kit. Add approximately 40 ml. of anhydrous petroleum ether in the receiving flask and connect the heat source. Maintain the reflux until the extraction of the fat is complete, approximately 4 hours, depending on the fat content of the sample. Remove the cartridge and keep it in the air in order all solvent is lost. Gently heat the Soxhlet flask containing the sample fat together with the solvent in order to separate the solvent by distillation,leaving only the sample fat in the flask. When the flask no longer has ether, transfer it to the stove (approximately 50 ° C) and keep it there for 1 hour. Transfer to the desiccator and keep it for 15 minutes to reach room temperature and weigh.Repeat the cycle from the stove, until it reaches constant weight.The calculation is made with the following formula:

Where a is the weight of the cartridge with the degreased sample (grams), b is the weight of the empty cartridge (grams), and m is the weight of the original sample in grams, BS indicates that the result is expressed in Dry Base.

The result can also be expressed in Wet Base with the following formula:

5.3.2.4. DETERMINATION OF PROTEINS.

Determination carried out by the Kjeldahl method, where, due to the different content and the different type of protein present in the yolk and in the white, it is determined separately, in addition to the fact that these values will help us in the subsequent determination of the functional properties of ostrich egg proteins. (Horwitz, W., 1980; Jacobs, MB, 1973)

Weigh from 0.5 to 1.0 g. of sample, according to its nitrogen content, on nitrogen-free paper. Place the sample in the bottom of the Kjeldahl flask and add 2.0 grams of catalyst mixture and 10 to 15 ml of sulfuric acid. Place the flask in the digester, gently warm at first, and then vigorously, heat to complete oxidation, at which point the mixture forms a clear, clear green solution, sometimes a gray precipitate corresponding to the catalysts occurs. After digestion, cool the flask in a fume hood, and add 300 to 350 ml. of water to dissolve the sample, add some zinc granules, shake, cool, and add an antifoam. Prepare the distillation apparatus. At the outlet of the refrigerant, adapt a glass tube,It will be immersed in 75 ml of 4% boric acid, with Wesselow indicator. Add to the Kjeldahl flask 5 ml of 40% NaOH for each milliliter of sulfuric acid added during digestion, plus 10 ml of excess due to the possible carbonation of the sodium hydroxide. Immediately connect to the distillation system of the Kjeldahl apparatus. Turn on the grill, open the tap and slowly mix the contents of the flask already connected to the still. After recovering a little distillate, you should turn the color of the indicator, from violet to green, distill 300 ml to ensure that all the ammonia has passed, checking with red litmus indicator paper.Remove the collecting flask and then turn off the heat source, to avoid siphoning. Wash the coolant, putting a glass with distilled water, at the outlet of it,and wait for the Kjeldahl flask to reflux, Titrate the distillate with 0.1 N HCl solution, until it turns from green to gray; an excess will give us a violet color. Carry out the calculation, using the following formula:

Where V is the volume of HCl expended in the titration, N is the normal value of the HCl solution, m is the weight of the sample in grams and meq are the milliequivalents of Nitrogen (0.014 g.).

The nitrogen-protein ratio differs considerably depending on the sample, so it is necessary to use the appropriate factors for each type of food, a different factor is used that must be consulted in the bibliography, in our case, the factor used is 6.25 for ostrich egg protein.

5.3.3. DETERMINATION OF FUNCTIONAL PROPERTIES OF THE ALBUM OF EGGS OF OSTRICH.

The determinations of the following functional properties were made in ostrich egg white:

Foaming capacity, Foam stability, Gelling capacity, Emulsifying capacity. Emulsion stability.

5.3.3.1. EMULSIFYING CAPACITY.

The determination of emulsifying capacity and stability of the emulsion were carried out by means of the method of Balmaceda et al. (1976).

Prepare a suspension of 0.01% egg white albumin in a 1 Molar solution of sodium chloride according to the following: Place 250 ml of the 1 Molar NaCl solution in the blender, adding the amount of sample necessary to reach the concentration of 0.01% of total protein (albumin), mix for 15 seconds. Add the oil to the suspension without stopping mixing, from 2 separating funnels of 250 ml each, placed in series so that the level of Funnel that remains at the bottom is kept constant. At the same time, record the resistance to the passage of current, using a multimeter. When the resistance becomes infinite, suspend the addition of the oil. Measure the amount of oil added, by difference in the cylinder. Run a witness,containing only 250 ml of 1 Molar NaCl solution in the blender and proceed from part c. The difference between the oil expenditure of the test sample and the control sample is the amount of oil emulsified by the protein contained in the sample. Results: The emulsifying amount of protein is reported as, milliliters of oil / milligrams of protein.

5.3.3.2. STABILITY OF THE EMULSION.

Transfer the emulsion prepared in the previous determination of Emulsifying Capacity, to a 500 milliliter glass graduated cylinder. Measure the total volume of the cylinder and the drained liquid at 12, 24, 36 and 48 hours. Expression of results:

Where EE is the stability of the emulsion, A is the total volume (emulsion plus drained liquid, B is the total volume of the emulsion formed, and C is the volume of the drained liquid in each time interval. (Cherry, JP, 1981; Webb NB, 1970)

5.3.3.3. FOAMING CAPACITY AND STABILITY OF THE CLEAR FOAM.

Foaming capacity and foam stability were determined by the methods reported by Canella (1978) and modified Kabirullah - Wills (1982).

Prepare a suspension of albumin protein containing 1 gram of protein in 50 milliliters of distilled water, with pH 7.Submit the suspension to agitation with a hand mixer for 5 minutes at high speed. Transfer the mixture including all the foam to a 250 milliliter glass cylinder. Immediately measure the volume of the drained liquid. Expression of results:

Where CFE is the foaming capacity, A is the total volume after stirring and B is the total volume before stirring.

Leave the prepared mixture, foam and drained liquid at rest for 30 minutes, 2, 4 and 16 hours and measure in each time interval the total volume of the cylinder and the drained liquid. Expression of results:

Where EE is the stability of the foam, A is the total volume, of foam plus liquid drained at each rest interval, B is the total volume of foam formed at time zero and C is the volume of liquid drained at each time interval.

5.3.3.4. GELIFICATION CAPACITY.

This determination is carried out by the modified Coffmann and García Method (1977)

Prepare in test tubes, suspensions at 2, 6, 10, 14 and 18% protein weight / volume in 5 milliliters of distilled water. Place the tubes in a water bath at boiling (92 - 94 ° C) for 1 hour. Cool the tubes quickly in an ice bath and refrigerate for two hours at 4 ° C. Interpretation of results: report as positive when gel formation is observed. Note at what protein concentrations said gel is formed. It is considered negative when the gel formation is not observed at the concentration used.

5.3.3.5. WATER ABSORPTION CAPACITY.

Determination of water capacity was carried out using the method of Wang and Kinsella (1976), Karibulah and Wills (1982).

P Place 0.5 g in the conical tube. Sample and add 5 ml of distilled water, shake the Vortex tube for 1 minute until the sample dissolves in the water.

Let stand for 30 minutes. Centrifuge at 1600 rpm for 25 minutes and finally measure the volume of free water remaining after centrifugation. Express the results using the following formula:

ml. absorbed water / g. sample = (A - B) / C

ml. absorbed water / g. protein = (A - B) 100 / (C x D)

Where A is the initial volume of water, B is the free volume of water, C is the weight of the sample and D is the percentage of protein.

5.3.3.6. OIL ABSORPTION CAPACITY.

The determination was carried out with the method of Lin et al. (1974).

Place 0.5 g in the conical tube. Sample and add 5 ml of vegetable oil, shake the Vortex tube for 1 minute until the sample dissolves in water. Let stand for 30 minutes. Centrifuge at 1600 rpm for 25 minutes and finally measure the volume of free water that remains after centrifugation Express the results using the following formula:

ml. absorbed oil / g. sample = (A - B) / C

ml. absorbed oil / g. protein = (A - B) 100 / (C x D)

Where A is the initial volume of oil, B is the oil-free volume, C is the weight of the sample, and D is the percentage of protein.

5.3.4. ELOTE BREAD MAKING.

Using the recipe shown in Table 4, two breads were made with the same formulation, and the same methodology, under the same conditions of temperature and baking time, the only difference between the two breads will be that one of them will be made with commercial chicken egg, the other will be made with ostrich eggs.

5.3.4.1. RECIPE OF THE BREAD.

The recipe only considers the production based on commercial chicken eggs, later the equivalence will be made with ostrich eggs for the preparation of the other bread. Table 4 shows the initial formulation of sweet corn bread.

TABLE 4. INITIAL FORMULATION TO PREPARE ELOTE SWEET BREAD.

Ingredients	Quantity
Shelled corn	450 g.
Whole (chicken) eggs	150 g.
Wheat flour	30 g.
Baking Powder	24 g.
Butter	90 g.
Condensed milk	400 g.

5.3.4.2. ELOTE BREAD PREPARATION METHOD.

Blend all the ingredients for 3 minutes, then empty into a floured mold.

The corn breads have been made in a homemade oven at 180 ° C, and cooked for 30 minutes, and as mentioned above, all the ingredients are blended for 3 minutes.

The fact of liquefying is because, the corn kernels contained in the formulation are crushed more easily, while when whisking, the kernels would remain almost whole and that is not the proper presentation of the final product.

5.3.5. SENSORY EVALUATION.

Once the two types of corn bread were made, the affective-type sensory evaluation of the finished product was carried out, taking a sample of 100 judges. In both types of bread, the attributes that were evaluated are flavor and consistency. (Pedrero, FD, 2000)

The evaluations were carried out in the sensory evaluation laboratory of the Food Graduate and Research section, equipped for these activities.

The format used is the one shown in figure 1, in which the judge is asked for a rating ranging from 0, which indicates his total dislike for the finished product, up to 10, which indicates that the product was your complete satisfaction. (Pedrero, FD, 2000)

FIGURE 1. SENSORIAL EVALUATION FORM OF ELOT BREAD.

5.3.6. PROXIMAL CHEMICAL ANALYSIS OF ELOTE BREAD.

The protein, ash, humidity and ethereal extract determinations carried out for the corn bread made, either with chicken egg or with ostrich egg, are the same as those made for the white and the ostrich egg yolk.

6. RESULTS AND DISCUSSION.

6.1. DETERMINATION OF THE FRESHNESS AND QUALITY OF THE EGG.

6.1.1. WHOLE EGG QUALITY.

The average ostrich egg weight was 1210 grams, it can be considered that 3 relatively small eggs were used for this study. However, it is not possible to establish a quality parameter, since there are no Standards for them.

The weight of the ostrich eggs that were used is shown in Table 5.

TABLE 5. WEIGHTS OF THE USED OSTRICH EGGS.

Egg No.	one	two	3	Average
Weight (Kg)	1,240	1,145	1,245	1,210

It can be seen in table 6, 25% of the ostrich egg corresponds to the shell, which currently is practically the entire commercial part of the ostrich egg, while the remaining 76% is discarded, same as when used in the preparation of bakery products, and other foods, means the use to make secondary and alternative products.

TABLE 6. WEIGHTS OF THE DIFFERENT PARTS COMPOSING THE EGG OF THE OSTRICH.

Egg No.	one	two	3	Average	% in weigh
Clara (Kg)	0.630	0.618	0.680	0.636	52.73
Yolk (Kg)	0.315	0.275	0.311	0.303	25.12
Shell (Kg)	0.295	0.252	0.254	0.267	22.13

6.1.2. DETERMINATION OF EXTERNAL QUALITY

SHELL.

In general, the ostrich egg shell has a shiny porcelain appearance, and has a slightly yellowish coloration, contrary to the chicken egg, on its surface you can see pores, so the ostrich egg shell has a rough surface and its shape is generally ovoid.

The surface characteristics of the ostrich eggshells that were observed are length, width, shape, color, dirt and roughness. And they are shown in Table 7.

TABLE 7. CHARACTERISTICS OF THE OSTRICH EGGS.

FEATURES	EGG 1	EGG 2	EGG 3
Length	14 cm	16 cm	15 cm
Width	12 cm	13 cm	14 cm
Shape	Characteristic of an egg	Characteristic of an egg	Different, a little more squashed egg
Shell color	Light and bright yellow	Light and bright yellow	Very faint and opaque yellow
Others	There were no alterations in its shell.	There were no alterations in the shell.	It had some cracks on its surface.
Shell dirt	No dirt	No dirt	No dirt

OVOSCOPE TESTS.

The ostrich eggs used were fresh, because they had a small air chamber. Likewise, there was apparently no presence of microorganisms, since these normally manifest as spots when viewed through the ovoscope.

On the other hand, it could be seen that the yolk did not show mobility and was centered inside the egg, which is another parameter, it gives us an idea of the freshness of the egg.

EGG DENSITY.

When determining the density of the three ostrich eggs, it was observed that they sank in most of their volume, which is why they are considered fresh.

Fresh eggs when immersed in NaCl solution must sink, since having a small air chamber (approximately 10% or less of the total content of the egg), they have a smaller amount of air and therefore their average density it is higher, so that as the density is higher, the egg is more easily immersed in the salt solution; if the egg had a larger air chamber, the average density is lower, and therefore the egg would not submerge and on the contrary, having a higher air content, would float.

6.1.3. DETERMINATION OF INTERNAL QUALITY.

SPREADING TEST.

The spread surface of the ostrich eggs presented a higher proportion of thick white with respect to thin white, while the yolk was umboned, this test is important to demonstrate the freshness of the egg. The average results of the paving test are shown in Figure 2, where the percentages of the white and the yolk are presented as a function of the surface.

6.1.4. YEMA QUALITY.

VISUAL CHARACTERIZATION OF THE YEMA.

The following characteristics of the yolk were observed:

Form Elevation Visual presence of defects.

Due to the fact that in the three eggs, the yolk was umboned and had a relatively high elevation, it was three fresh eggs. Likewise, no blood stains or other foreign materials were observed.

The color of the yolk was determined by means of the Roche Fan, obtaining the yellow color 8.

6.2. PROXIMAL CHEMICAL ANALYSIS OF THE OSTRICH EGG.

When comparing its composition with that of a chicken egg, it is observed that the results in percentage are very similar, both in the white and in the yolk, so there is no great difference, and therefore they should not exist. noticeable differences in the elaboration of food products that use it as an ingredient. However, this is not true, as will be discussed later in the sensory evaluation tests applied to corn bread made with both chicken and ostrich eggs.

The results obtained in the Proximal Chemical Analysis for the white and the yolk of the ostrich egg, are shown in Table 8.

TABLE 8. COMPOSITION OF ONE EGG OF HEN AND ONE OF OSTRICH.

Parameter	Ostrich	Hen
clear	Bud	clear	Bud
HUMIDITY (%)	87.5	50.28	88.00	48.00
PROTEIN (%)	11.20	16.50	10.50	16.10
E. ETÉREO (%)	0.02	31.50	0.03	33.0
ASHES (%)	0.51	1.08	0.55	1.10

6.3. PROXIMAL CHEMICAL ANALYSIS OF ELOTE BREAD (FINISHED PRODUCT).

In the Proximal Chemical Analysis determined for corn bread, the results shown in Table 9 were obtained.

TABLE 9. COMPARATIVE TABLE OF PROXIMAL ANALYSIS IN BOTH BREADS.

PARAMETER	BREADS
CHICKEN EGG	OSTRICH'S EGG
% Protein	6.38	9.62
% Humidity	54.93	56.91
% E. Ethereal
% Ash	1.31	1.38

And as it can be observed, there is a small difference in the values of the protein and ether extract (fat) determinations, which was not expected since all the other raw materials were exactly the same in both breads.

But it had some impact on the consistency and flavor of corn bread, and despite these differences in their composition, the degree of acceptance of both breads was not significantly affected, only the opinion of the judges was divided regarding your preference or taste.

Therefore, it would be convenient to carry out a subsequent study to characterize the white and yolk proteins in the ostrich egg.

6.4. DETERMINATION OF FUNCTIONAL PROPERTIES OF THE ALBUM OF EGGS OF OSTRICH.

6.4.1. EMULSIFYING CAPACITY.

The difference between the oil expenditure of the test sample and the control sample is the amount of oil emulsified by the protein contained in the sample, the sample was made in triplicate. Table 10 shows the results obtained in the determination of emulsifying capacity.

TABLE 10. DETERMINATION OF EMULSIFYING CAPACITY IN SAMPLES OF OSTRICH EGG WHITE.

	Witness	Sample 1	Sample 2	Sample 3
Sample weight (mg.)	-	285	287	287
Protein weight (mg.)	-	31.92	32.14	32.14
Oil volume (ml)	112	220	222	223
Difference between control and sample (ml)	-	108	110	111
ml. of oil / mg. protein	-	3.32	3.42	3.48
ml. of oil / 100 mg. protein	-	10.80	10.89	10.99
ml. of oil / 100 mg. protein (average)	-	10.89

Although the original technique uses soybean oil, it had to be replaced by corn oil, because it reported strange values, which is because it apparently was not pure oil or was mixed or contaminated with other oils.

The bibliography () reports that for chicken egg white, the emulsifying capacity is 7 ml of oil for every 100 ml of protein from egg white, while the value determined for ostrich egg white was 10.89 ml of oil for every 100 ml of protein. This indicates that the protein in the white of the ostrich egg fixes a greater amount of lipids, which will affect the consistency or texture of the corn bread that was produced, which tends to be slightly more greasy. This situation made it more pleasant for approximately 40% of the judges who participated in the sensory evaluation.

6.4.2. STABILITY OF THE EMULSION.

As time passes, the ostrich egg white emulsion loses stability, reaching the minimum value (4%) at 120 minutes, so it can be considered that the emulsion that is formed is not very stable, which has importance when making products such as mayonnaise and dressings, in our case it does not affect much the texture of corn bread.

In figure 3, the variation of the emulsion stability values obtained experimentally in intervals of 30 minutes is represented.

6.4.3. GELIFICATION CAPACITY.

The gelling capacity is determined based on the amount of protein that the fresh egg has, when a minimum concentration of 10% of ostrich protein is reached, and it was found that the proteins of the white of the ostrich egg have the capacity to coagulate but do not gel, while at lower protein concentrations a too weak and heterogeneous clot is obtained. just like the white of the chicken egg does, so the behavior in both is very similar

The experimental results obtained are presented in Table 11.

TABLE 11. GELIFICATION CAPACITY RESULTS.

	CONCENTRATION
two	4	6	10	14
Results and characteristics	Weak and heterogeneous clots form.	Very heterogeneous clots can be formed in the sample.	The clot is not very homogeneous but it is firmer than the previous one.	A firm and homogeneous clot forms and dissolves when the tube is turned over.	It is a clot with even greater firmness than the previous one.

6.4.4. OIL ABSORPTION CAPACITY Oil absorption is a property that helps food retain aromas and flavors, in addition to the ability to provide pleasant taste sensations in some foods.

Table 12 shows the amount of oil absorbed for chicken eggs () and for ostrich eggs (experimentally determined), and it can be seen that the proteins of the white of the ostrich egg are capable of retaining greater amount of oil, than the proteins in chicken eggs, this is reflected in obtaining products of slightly more greasy consistency than the consistency of products originally made with chicken eggs.

TABLE 12. RESULTS OF OIL ABSORPTION CAPACITY.

PARAMETER	OSTRICH'S EGG	CHICKEN EGG
Milliliters of oil per gram of sample	0.27	-
Milliliters of oil per gram of protein	3.56	2.92

6.4.5. WATER ABSORPTION CAPACITY.

The water absorption capacity of the proteins of the ostrich egg white determined experimentally, is greater than that of the proteins of the chicken egg white (), and taking into account that this characteristic, like the Capacity of Water absorption, influences the texture, color and sensory properties of food. It could be co-responsible for the slightly fluffier texture of corn bread made with ostrich eggs, compared to bread made with chicken eggs.

One of the causes to which the variation can be attributed is the carbohydrate content, since it has been found that the higher the content of this compound, the greater the amount of water absorbed (Tjahjadi, 1988). However, this determination was not carried out, so it cannot be discussed.

In Table 13, the values of water absorption capacity of the proteins of chicken egg white () and ostrich determined experimentally are observed.

TABLE 13. RESULTS OF WATER ABSORPTION CAPACITY.

PARAMETER	OSTRICH'S EGG	CHICKEN EGG
Milliliters of water per gram of sample	0.85	-
Milliliters of water per gram of protein	11.05	8.58

6.4.6. FOAMING CAPACITY.

Table 14 shows the experimental results obtained for ostrich eggs, as well as those reported in the literature for chicken eggs.

TABLE 14. RESULTS OF THE FOAMING CAPACITY OF THE AVESTRUZ EGG WHITE.

	OSTRICH'S EGG	CHICKEN EGG
Sample weight (g.)	1.0630	1.0600
Volume before mixing (ml)	fifty	fifty
Volume after whisking (ml)	62	60
% CFE	19.35	16.66

As can be seen, there is a small difference between the foaming capacity values of both types of eggs, so it could be thought that the food products that can be produced based on this functional property will have a spongier texture or consistency for those that Ostrich eggs are made compared to those made with chicken eggs. This was true for corn bread that was made with ostrich egg.

6.5. SENSORY EVALUATION.

For the first evaluation of both corn breads, although it had a good acceptance in terms of flavor and consistency, some judges found that the flavor of the baking powder was a little strong, so the concentration of this ingredient was decreased from 24 at 8 grams, this, in order to correct the taste problem of the leavening agent used, also improving the consistency of the final product in passing.

Having made this modification, the second sensory evaluation of the two corn breads was carried out and it was observed that their acceptance improved both in flavor and consistency, which was reflected in the ratings that the judges awarded.

Another important detail was that the flavor and consistency of both breads was different, with the bread made with ostrich egg slightly more fluffy and slightly more greasy than the bread made with chicken egg; which was slightly more compact and sweet, and although chicken egg bread had a preference of approximately 55% of the judges, by 45% preference for bread made with ostrich egg. This difference was mainly due to the pleasant sensation produced by the slightly greasy and fluffy consistency, as well as the sweetness of the bread.

These ratings show that, regardless of the egg used (chicken or ostrich), this type of bread had good acceptance among the judges, however, they cannot be used interchangeably in the different products that use it as an ingredient, since it can be significantly affected the characteristics of said products (texture, color, flavor, among others).

Therefore, it is convenient to carry out this type of study in other products that use chicken egg as an ingredient and, on the other hand, it would be convenient to characterize and quantify the types of proteins present in ostrich egg in future work.

The results obtained during the 2 Sensory Evaluation tests are shown in Figure 4.

7. CONCLUSIONS.

In the Proximal Chemical Analysis of the ostrich egg, when comparing with the existing bibliographic data for chicken egg, it was found that there are no significant differences in the composition in both the white and the yolk. As can be seen, there are small differences in the proximal analysis of corn bread made with ostrich egg, compared to corn bread made with chicken egg. Where it stands out that the bread made with ostrich egg has a little more protein (9%) than the bread made with chicken egg (6%). In the rest of the determinations that make up the Proximal Chemical Analysis, there are no significant variations between one and the other bread.The results of the sensory evaluation for the 2 types of corn bread,indicate that both had very good acceptance in terms of flavor and consistency, with the observation that a part of the judges showed a preference for some of the breads, based on their texture or flavor, which were different. You can use chicken egg and ostrich egg interchangeably, in the formulation of different products, which currently use chicken egg as an ingredient (gelatin, flan, mayonnaise, dressings, meringue, etc.) since they can be affected The characteristics of these products (texture, color, flavor, among others) are significant. Within the functional properties of proteins, the determination of the emulsifying capacity of ostrich egg albumin shows that this value is greater than that reported in the bibliography for chicken egg.This seems to be related to the fact that the bread made with ostrich egg is slightly more greasy and fluffier than the bread made with chicken egg.The composition of chicken egg and ostrich egg is very similar, this led to to think that the products that use the egg as an ingredient, can be invariably made with one or the other, but it was also shown that there are variations in the functional properties, so that in the end, in the case of bakery products, They obtain products with different characteristics, which has an impact on sensory evaluations. The elaboration of corn bread proves that additional use can be made of the white and yolk of the ostrich egg, which are currently consumed in the form of homemade dishes,without being given a technological advantage, which gives us an additional economic benefit as a secondary product.

8. BIBLIOGRAPHY.

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In the information on the functional properties and technological application of ostrich egg, no information was found on the subject. Only 2 references were obtained that deal with its composition, so it is interesting to carry out this study to obtain a processed product, using ostrich egg as an ingredient.

Hence the importance of its study, but in general numerous works have been carried out around chicken eggs and others have been carried out on paw eggs, but not on eggs of another species such as, for example; the ostrich egg.

so it is feasible to carry out this investigation. In order to fully exploit the ostrich egg and provide foundations that serve to develop various technologies.

While the yolk and the white are not used technologically, since they are consumed directly in the form of homemade dishes, and although it is consumed providing nutrients, its functional properties are being wasted for the manufacture of other types of food products such as dressings, mayonnaise, desserts, puddings, bakery products, among others, that use the egg as an ingredient in its preparation.

Hence the interest to carry out a study on the sensory analysis and functional properties of one of the products that can be derived from ostrich eggs in order to give added value to the exploitation of this product. In this case, the preparation of sweet breads.

Ostrich egg currently only takes advantage of its shell and, although the egg is consumed directly by providing nutrients, its possible uses are being wasted in products that are normally made with chicken eggs, such as bakery products, mayonnaises, desserts, among others.

Baking proves that additional technological use can be made with respect to what is currently given to the white and yolk of the ostrich egg

According to the above, the following conclusions were obtained:

1) The composition of chicken egg and ostrich egg is very similar, but they presented differences in the functional properties of their white, so they cannot be used interchangeably for the production of food products that use the egg as an ingredient.

2) Due to the differences in the functional properties of both types of eggs, the 2 corn breads made also showed differences between each other in terms of flavor and consistency.

3) The use of the yolk and the white of the ostrich egg, gives us an additional economic benefit, which is currently obtained by selling the shell even as a secondary product.

4) The elaboration of bakery products proves that additional technological use can be made with respect to what is currently given to the white and yolk of the ostrich egg

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