The soybean (Glycine max) is a species of legume nature to east Asia, widely grown for its edible bean which has numerous uses. The plant is classed as an oil seed rather than a pulse by the Food and Agricultural Organization (FAO, 2005) Oil and protein contents account for about 60% of dry soybeans by weight, protein at 40°A and oil at 20%. The remainder consists of 35% carbohydrate and about 5% ash. Soybean cultivars comprise approximately 8% seed coat or hull, 90% cotyledons and 2%hypocotyls axis germ (USDA NUTRIENT DATA BASE, 2003)

Soybeans are an important global crop, that provide oil. In the United State, the bulk of the harvest is solvent extracted with hexane.
2.2       SOYBEAN OIL
Soybean seed contain about 19% oil. To extract soybean oil from seed, the soybeans are cracked adjusted for moisture content, rolled into flakes and solvent extracted with commercial hexane. The oil is then refined, blended for different applications and sometimes hydrogenated, are exported abroad, sold as vegetable oil or end up in a wide variety of processed foods. The remaining soybean meal is used mainly as animal feed.
Soybeans contain all three of the micro nutrients required for good nutrition complete protein, carbohydrate and fat as well as vitamin and minerals; include calcium, folic acid and iron. Soybeans are the only common plant foods that contain complete protein. Soybean protein provide all the essential amino acid in the amount needed for human health. The amino acid profile of soybean protein is nearly equivalent in quality to meat, milk and egg protein.
Soybean oil is 61% polyunsaturated fat and 24% monounsaturated fat which is comparable to the total unsaturated fat content of other vegetable oil (85%) like other vegetable oils, soybean oil contain no cholesterol.
Polyunsaturated vs saturated fats
Excessive intake of any fat is undesirable. Nutrition experts recommends limiting total fat consumption to 30% or less of the total daily calories and limiting saturate fats to 10% or less saturate fatty acid raise blood cholesterol which can thicken arterial walls and increase the risk of heart disease. (Soybean National Research February, 2010).
Essential Fatty Acid
Soybean oil is rich in polyunsaturated fatty acid including the two essential fatty acids, linoleic and linolenic that are not produced in the body. Linoleic and linolenic acid aid the body absorption of vital nutrients and are required for human health. These two essential acids are also precursors to hormones that regulate smooth muscle contraction blood pressure and the growth of health cells.
Pure soybean oil is about. 50% linoleic acid and & Iinoienic acid.
Hydrogenation is used to solidify soybean oil for the manufacture of margarine. This process increase stability of oils and to raise the melting point of soybean oil shortening hydrogenation changes the chemical composition and physical properties of oils and effects of the nutritional value. The degree of changes in nutritional value depends upon the amount of hydrogenation necessary to produce the final product and the reduction of polyunsaturation that occurs. The hydrogenation process also creates trans fatty acids from acids unsaturates rearranging hydrogens around the double bond in a monounsaturated or polyunsaturated fatty acid. The table below shows the fatty acid composition of soybeans oil per 100g.
Table 1: Fatty acid composition of soybean oil
Fatty acid
Saturate fat
Monounsaturated fat
Polyunsaturated fat
Source: Soybean Natural research February, 2012.

Table 2:  The major unsaturated fatty acids in soybean oil triglyceride are
Fatty acid
Chain length
Alpha linolenic acid
Linoleic acid
Oleic acid
SOURCE: Soybean natural research February,2012.

It also contains the saturated fatty acids 4% stearic acid and 10% palmitics acid. (USDA Nutrient Data Base 2003).

            Soybeans are cleaned and dried, then dehulled by cracking and separating the soybeans from the hulls. Magnets are used to separate any iron from the soybeans. The soybeans are adjusted for moisture content and heated to coagulate the soy proteins and make the oil extraction easier.
The prepared soybeans are cut into flakes and placed into percolation extractors and combined with a solvent. The hexane/soybean oil mix is separated from the flakes and transferred to evaporators where the oil and hexane are separated. The evaporated hexane is recovered and reused in future extraction processes, while the hexane free crude soybean oil is taken for further refining.
Refining Soybean Oil
The crude soybean oil contains many impurities that need to be removed oil insoluble materials are removed through filtration, while oil soluble materials are removed through degumming, neutralizing or bleaching. A stripping and/or deordorizing step completes the refining process. However, these processing techniques allow us to refine oils, make them melt more slowly or rapidly change their crystal habit, rearrange their molecular structure, and literally take them apart and put them back together again to suit our requirements of the moment. Processing involves a series of stages which are outlined below.
Crude oil
Winterization Interesterification Hydrogenation
RBD oil

Refining /Neutralization
The process of refining (sometimes referred to as alkali refining) is aimed at reducing the free fatty acid content. The acids are removed by neutralizing the soil with a solution of caustic soda, which converts the fatty acid into an insoluble soap. The soap is then removed by allowing it to settle to the bottom of the neutralizing tanks. If the acid impurity is palmitic acid for example, then insoluble sodium palmitate is formed according to the reaction.
C15H31COOH+NaoH    C12H13COONa + H2O

Washing and Drying
In other to remove the last traces of soap from the oil, it is washed with warm water. Two layers form and lower water layer is run off leaving the oil layer which is then dried under vacuum.

The process aim at removing colour producing substances from fats and oils. Normally, bleaching is accomplished after the oil has been refined. The usual method of bleaching is by absorption of the colour producing substances on an adsorbent. Acid activated bleaching earth or clay sometimes called betonite, is the adsorbent that has been used extensively. This substance consists primarily of hydrated aluminum silicate. Anhydrous silica gel and activated carbon are also used as bleaching adsorbents.
Deodorization is a vacuum steam distillation process for the purpose of removing trace constituents that gives rise to undesirable odors and flavors in oils. This process is normally accomplished after refining and bleaching. Deodorization is simply the removal of relatively volatile compound from fats and oils, using steam. It is carried out under vacuum to facilitate the removal of the volatile substances and to avoid hydrolysis.
Winterization/De Waxing/Fractionation
Winterization is the process whereby component triglycerides of fats and oils are crystallized from a melt. The two component fractional crystallization is a accomplished by partial solidification of higher melting triglyceride components, followed by separation (by filtration) of the two components.
The term winterization evolved from the observation that refined cotton seed oil, stored in outside tanks during the winter months physically separated into a hard and clear fraction. Decanting the clear oil from the top of the tanks provided oil that remained liquid without clouding for long periods at cool temperatures. The need for liquid oil with these characteristics was created by the use of refrigerators in the home and the requirements of the mayonnaise and salad dressing industry. A similar process called dewaxing is used to clarify oils containing trace amounts of clouding constituents.
Edible fats and oils are complex multicomponent mixtures of various triglycerides with different melting points. The melting behaviours of fats are important properties for functionality in various prepared food products.

Process separates fats and oils into fractions with different melting points. The aim of fractionation is to provide new materials that are more useful than the natural product.
The term refers to the reaction in which fatty acid esters react with other esters or fatty acids to produce new esters by an interchange of fatty acid groups. More simply state, interesterification can be visualized as a break up of a specific triglyceride removal of a fatty acid at random, shuffling it among the rest of the fatty acid pool, and replacing at random by another fatty acid. Because of the random re-arrangement of the fatty acids of the natural oil, the interesterification process is also commonly referred to as randomization, rearrangement or modification.
Interesterifcation process can alter the original order of distribution of the fatty acids in the triglyceride molecule with melting and crystallization
characteristics different from the original oil or fat. Unlike hydrogenation, interesterification neither affects the degree of saturation nor cause isornerization of the fatty acid double bond. It does not change the fatty acid composition of the starting oil, but rearranges the fatty and on the glycerol molecule.
Hydrogenation is the conversion of oil to a fat by a chemical method. It involves the addition of hydrogen to the double bonds of unsaturated fatty acids of triglyceride, using nickel as catalyst. During hydrogenation, one molecule of hydrogen is absorbed by a double bond, according to the reaction.
- CH = Ch- + H2    CH2 - CH2
Hydrogenation only proceeds at a reasonably fast rate in the presence of a catalyst, nickel being used industrially. The catalyst is added in small quantities large closed steel vessel known as converters. The oil is stirred and hydrogen gas is pumped in. the oil is heated to star reaction, and after reaction the oil is cooled and filtered to remove the nickel which can be reused. Hydrogenation is a selective process, some triglycerides becoming saturated more rapidly than others. The most unsaturated triglycerides are partially hydrogenated before the less unsaturated ones react. Thus, more linolenic acid is converted into linoleic acid in a given time than linoleic into oleic. The reactive rates of reaction of oleic, linoleic and linolenic are in the ratio 1:20:40.
In the process of hydrogenation, hydrogen gas chemically reacts with the double bonds in the carbon chain of an unsaturated fatty acid converting it to a more saturated fatty acid, shifting it to a new position, or twisting it to the trans configuration, all of which increase it melting point.
Oil is hydrogenated for two(2) reasons.
1.         Change naturally occurring fats and oils into physical forms with the consistency and melting characteristics required for functionality.
2.         To increase oxidative stability.
Crude oil having relatively high level of phosphatides (e.g soybean is degummed prior to refining to remove the majority of those phospholipids compounds. The process generally involves treating the crude oil with a limited amount of water to hydrate the phosphatide and make them separable by centrifugation. The phospholipids content of some crude vegetable oils are shown in the table below.
Vegetable oil           
Phosphotide content (%)
Cotton seed
Rape seed
A relatively new process in the United State is enzymatic degumming An enzyme, phospholipids present in crude oil, into lysophospholipids that can be removed by centrifugation. Crude oil is pre-treated with a combination of sodium hydroxide and citric acid, mixed with water and enzyme (phospholipase) by a high share mixer which results in a stable emulsion. The emulsion allows the transforming them into water solution lysophospholipids. This emulsion is broken by centrifuge, separating the gums and phospholipids from the oil. This process generates a better oil yield than traditional degumming; however, it had not been widely commercialized.
2.5       TALLOW
Tallow consists mainly of triglyceride (fat) whose major constituents are derived from stearic and oleic acids. Rendered animal fat is fat derived from rendering meat, including bones and intended for human consumption. Tallow is rendered animal fat from bovines origin. For the purpose of the present opinion, tallow is defined as fats obtained by pressing or any extraction system down from ruminant tissues which are derived directly from discrete adipose tissue masses from mechanically recovered meat and from rendered animal waste including bones.
General Description of Fat
Commercial fats produced by organic processes in plants are
palm kernel oil is an edible plant oil derived from the kernel of oil palm Elaeis guineenis) coconut oil, extracted from the kernel of the coconut, and palm oil, extraction from the pulp of the oil palm fruit.
Palm kernel oil, coconut oil, and palm oil are three of the few
highly saturated vegetable fats. Palm kernel oil, which is semi-solid at room temperature, is more saturated than palm oil and comparable to coconut oil. like all egetab1e oils, these three palm derived oils, do not contain cholesterol (found in unrefined animal fats) although saturated fat intake increases both LDL and HDL cholesterol.
The approximate concentration of fatty acids (FAS) palm kernel oil is as follows.

Fatty Acid Content of Palm Kernel Oil
Lauric saturated C12
Myristic saturated C14
Palmitic saturated C16
Capric saturated C10
Caprylic saturated C8
Stearic saturated C18
Oleric monounsaturated C18
Linoleic polyunsaturated C18
Source – (USDA Nutrient data base 2003).
And other fatty acids. Tallow is a refined hard fat extracted from fatty deposits of animals, especially from suet (fatty tissue around the kidneys of cattle and sheep). The molecules of most natural fatty acid have an even number of carbon chains due to the linkage together by ester units. Analogue compounds of odd numbers carbon chain fatty acid can be made synthetically. All fats are insoluble in water and have lighter weight than water. Industrial fat can be sub classified as fat or oil depending on melting point. Fat that are liquid at room temperature are referred to as oil.
Most naturally occurring fats and oils are the fatty acid esters of glycerol. Coconut or palm oils are better source to get saturated fatty acids than sunflower, soybean or rapeseed oils which have more unsaturated fatty acid composition of triglyceride. Oil fatty acid is a low cost unsaturated fatty acid (oleic acid) and is a source of low boiling point fatty acids.
Tallow does not appear in its usable from when separated from cattle. It first needs to be cooked and separated from cattle residue. This separation can occur either through filtering or centrifugal processing, using gravity. The pure tallow is then produced after the processing and directed to its next purpose.

3774KJ (902k cal)
Source – (USDA Nutrient data base 2003).
The composition of the fatty acid typically as follows:
Palmatic acid
Myristic acid
Stearic acid

Oleic acid
Palmitoliec acid

Linoleic acid
Linolenic acid

2.5.2               MELTING POINT
This is an important property; it is about the same for the fatty acid and for the homogenous saturate triglyceride (with the three fatty acid). Important consideration is as follows (Brain and Cameron, 1982).
For a given type, the melting of the fatty acid increases according to the length of the hydrocarbon chain, for example in the saturated acid series, the increase varies from between 6.5 and 9.5 degree for every 2 additional carbon atoms.
Fatty acid
Chain length
Melting point (oC)
Lauric acid
Myristic acid
Palmitic acid
Steraric acid
Arachidic acid
Lignoceric acid
For a given chain length, the melting point is lowered with increase in the number of double bonds, the reduction is greater for the CIS form than for the trans form (rare) (Brian and Cameron 1982).
Fatty acid
Chain length
Melting point (oC)
Vaccenic (trans)
C 18: 1
Oleic (Cis)
C 18:1
Linoleic (Cis)
C 18:2
Linolenic (Cis)
The plasticity of fat results of from its being a mixture of a number of different triglycerides, each triglyceride having its own melting point. When a large proportion of the triglycerides are below their melting point the
mixture is solid and consists of a network of minutes crystals surrounded by a smaller quantity of liquid triglyceride. The solid network is not rigid, however, and the crystals can slide over one another so given rise to the plastic character of the fat. (Brain and Cameroon. 1882).
If the temperature of the fat is raised an increasing proportion of trigylcerides melt, the solid network gradually breakdown and the plasticity of the mixture increase until it become liquid when all the triglycerides have melted. The melting point of fat is also affected by the fact that many triglycerides exist in several crystalling forms that is they are polymorphic. Each crystalline form has its own melting point and when oils are cooled, mixture of different crystalline form, and therefore, different melting point, ma be obtained depending upon how the cooling was carried out. The way
in which oil is cooled therefore affects the texture and consistency of the product formed. Such considerations are important in commercial methods of fat manufacture.
Chemical Properties
Tallow includes 70% of carbon, the remaining third is made up of 11% hydrogen and 19% oxygen. A kilogram of tallow can produce 40,000 calories of energy. However, the temperature needs to be high enough to actually convert the material to a usable form. Tallow burns at a heat range of 288 — 316 degree Celsius (288-3160°C). So an average cow, when slaughtered produces between 15kg to 115kg of tallow, depending on how the meat on the cow is cut. In consistency terms, tallow keeps a solid form a room temperature but it does need to remain sealed. If not, the tallow eventually rots due to oxidation, similar to other biological material.
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