Drugs Containing Lipid

Chapter 19

Drugs Containing Lipid

INTRODUCTION

The lipids are a large and diverse group of naturally occurring organic compounds that are related by their solubility in nonpolar organic solvents (e.g. ether, chloroform, acetone, and benzene) and are generally insoluble in water. There is great structural variety among the lipids and comprise of fixed oils, fats, and waxes. The lipids of physiological importance for humans have the following major functions:

They serve as structural components of biological membranes.

They provide energy reserves, predominantly in the form of triacylglycerols.

Both lipids and lipid derivatives serve as vitamins and hormones.

Lipophilic bile acids aid in lipid solubilization.

FIXED OILS AND FATS

Fixed oils and fats are obtained from plants or animal. They are rich in calories and in plant source, they are present mostly in the seeds, as reserve substances and in animals they are present in subcutaneous and retroperitoneal tissues. They differ only according to their melting point and chemically they belong to the same group. If a substance is liquid at 15.5–16.5°C it is called fixed oil and solid or semisolid at the above temperature, it is called fat. They are made from two kinds of molecules: glycerol (a type of alcohol with a hydroxyl group on each of its three carbons) and three fatty acids joined by dehydration synthesis. Since there are three fatty acids attached, these are known as triglycerides. These fatty acids may be saturated, monounsaturated or polyunsaturated. The terms saturated, mono-unsaturated, and poly-unsaturated refer to the number of hydrogens attached to the hydrocarbon tails of the fatty acids as compared to the number of double bonds between carbon atoms in the tail. Fats, which are mostly from animal sources, have all single bonds between the carbons in their fatty acid tails, thus all the carbons are also bonded to the maximum number of hydrogens possible. Since the fatty acids in these triglycerides contain the maximum possible amount of hydrogens, these would be called saturated fats. The hydrocarbon chains in these fatty acids are, thus, fairly straight and can pack closely together, making these fats solid at room temperature. Oils, mostly from plant sources, have some double bonds between some of the carbons in the hydrocarbon tail, causing bends or ‘kinks’ in the shape of the molecules. Because some of the carbons share double bonds, they are not bonded to as many hydrogens as they could if they weren’t double bonded to each other. Therefore these oils are called unsaturated fats. Because of the kinks in the hydrocarbon tails, unsaturated fats can’t pack as closely together, making them liquid at room temperature.

Analytical Parameters for Fats and Oils

Following are the parameters used to analyse the fats and oils.

Iodine value: The iodine value is the mass of iodine in grams that is consumed by 100 g of fats or oil. A iodine solution is violet in colour and any chemical group in the substance that reacts with iodine will make the colour disappear at a precise concentration. The amount of iodine solution thus required to keep the solution violet is a measure of the amount of iodine sensitive reactive groups. It is a measure of the extent of unsaturation and higher the iodine value, the more chance for rancidity.

Saponification value: The saponification value is the number of milligrams of potassium hydroxide required to saponify 1 g of fat under the conditions specified. It is a measure of the average molecular weight of all the fatty acids present.

Hydroxyl value: The hydroxyl value is the number of mg of potassium hydroxide (KOH) required to neutralize acetic acid combined to hydroxyl groups, when 1 g of a sample is acetylated.

Ester value: The ester value is the number of mg of potassium hydroxide (KOH) required to saponify the ester contained in 1 g of a sample.

Unsaponifiable matter: The principle is the saponification of the fat or oil by boiling under reflux with an ethanolic potassium hydroxide solution. Unsaponifiable matter is then extracted from the soap solution by diethyl ether. The solvent is evaporated and then the residue is dried and weighed.

Acid value: It is the amount of free acid present in fat as measured by the milligrams of potassium hydroxide needed to neutralize it. As the glycerides in fat slowly-decompose the acid value increases.

Peroxide value: One of the most widely used tests for oxidative rancidity; peroxide value is a measure of the concentration of peroxides and hydroperoxides formed in the initial stages of lipid oxidation. Milliequivalents of peroxide per kg of fat are measured by titration with iodide ion. Peroxide values are not static and care must be taken in handling and testing samples. It is difficult to provide a specific guideline relating peroxide value to rancidity. High peroxide values are a definite indication of a rancid fat, but moderate values may be the result of depletion of peroxides after reaching high concentrations.

WAXES

Waxes are esters of long-chain fatty acids and alcohols. The fatty acids are same in wax and fats, but the difference being saponification. Waxes are saponified only by alcoholic alkali but the fats may be saponified either by alcoholic alkali or by aqueous alkali. Along with fatty acids it also contains monohydroxy alcohols of high molecular weight especially cetyl alcohol, melissyl alcohol, and myricyl alcohol. Sometimes cholesterol or phytosterols are also present. As such they are not suitable as food because hydrolysing enzymes of wax are not present in system. Waxes are widely distributed in nature. The leaves and fruits of many plants have waxy coatings, which may protect them from dehydration and small predators. The feathers of birds and the fur of some animals have similar coatings which serve as a water repellent. Spermaceti, beeswax, carnuba wax, etc. are the examples of waxes.

ALMOND OIL

Biological Source

Almond oil is a fixed oil obtained by expression from the seeds of Prunus amygdalus (Rosaceae) var. dulcis (sweet almonds) or P. amygdalus var. amara (bitter almonds).

Geographical Source

The oil is mainly produced from almonds grown in the countries bordering the Mediterranean (Italy, France, Syria, Spain, and North Africa) and Iran.

Characteristics

Almond trees are about 5 m in height. The young fruits have a soft, felt-like pericarp, the inner part of which gradually becomes sclerenchymatous as the fruit ripens to form a pitted endocarp or shell. The shells, consisting mainly of sclerenchymatous cells, are sometimes ground and used to adulterate powdered drugs.

Almond trees are about 5 m in height. The young fruits have a soft, felt-like pericarp, the inner part of which gradually becomes sclerenchymatous as the fruit ripens to form a pitted endocarp or shell. The shells, consisting mainly of sclerenchymatous cells, are sometimes ground and used to adulterate powdered drugs.

Chemical Constituents

Both varieties of almond contain 40–55% of fixed oil, about 20% of proteins, mucilage and emulsin. The bitter almonds contain in addition 2.5–4.0% of the colourless, crystalline, cyanogenelic glycoside amygdalin. Almond oil is obtained by grinding the seeds and expressing, them in canvas bags between slightly heated iron plates. The oil is clarified by subsidence and filtration. It is a pale yellow liquid with a slight odour and bland nutty taste. It contains olein, with smaller quantities of the glycosides of linoleic and other acids. Bitter almonds, after maceration on hydrolysis of amygdalin yield a volatile oil that is used as a flavouring agent. Sweet almonds are extensively used as a food, but bitter almonds are not suitable for this purpose.

ARACHIS OIL

Synonyms

Groundnut oil; monkeynut oil; peanut oil; katchung oil; earth-nut oil.

Biological Source

Arachis oil is obtained by expression of shelled and skinned seeds of Arachia hypogaea Linn., belonging to family Papilionaceae.

Geographical Source

South America (Brazil) is the original home of ground nut and now found in South and Central America, Peru, Argentina, Nigeria, Australia, India, Gambia, and other reasonably warm regions of all countries.

Characteristics

Groundnut plant is a small, prostrate, diffuse, erect, branched, annual herb, 30–60 cm in height, leaves alternate with adnate stipules and yellow papilionaceous flowers. After fertilization, the pedicel elongates rapidly and enters the ground, where the ovary begins to develop into a pod maturing in about two months. Pods or nuts are cylindrical, hard, reticulated, indehiscent, and inflated, 2.5–5.0 cm long, one to three seeded, with pericarp constricted between the seeds. The seeds are covered by a light or deep reddish brown seeds coat, and consisting of two white fleshy cotyledons rich in oil and proteins. Fruits are dug out by raking the plants from the soil, seeds are separated by machine and expressed in a hydraulic press at ordinary temperature. The remaining oil of cakes is removed by solvent extraction. The two oil fractions are combined and purified.

Cultivation

Groundnut is predominantly a crop of the tropical and subtropical countries, up to an elevation of 1,160 m. It requires plenty of sunlight, timely and evenly distributed rainfall (50–125 cm) during its growth and a long season for its maturation and harvesting. It also requires a high temperature (21–26°) particularly during the nights to induce early flowering. The plant does not stand frost, long and severe drought and water stagnation. Groundnut seeds are sown from April–May to June–July. It requires light, well-drained, loose, friable soil. No regular manuring is done by the growers, and the plant is benefited from green manuring.

Chemical Constituents

The important constituents of the glycerides of groundnut oil are the fatty acids palmitic (8.3%), stearic (3.1%), oleic (56%), linoleic (26%), arachidic (24%), eicosenoic, behenic (3.1%), and lignoceric (1.1%) acids. Myristic, hexacosanoic, erucic, caprylic, lauric, and trace amounts of odd carbon fatty acids are also present. The principal glycerides of the oil are triolein (11%), dioleolinolein (21%), saturated oleolinoleins (22%), dilinoleoolein (12%), saturated diolein (15%), and saturated dilinoleoolein (6%).

The yellow colour of the oil is due to the presence of carotenoid pigments, chiefly β-carotene and lutein. The unsaponifiable matter consists of sterols, (campesterol, stigmasterol,β-sitosterol and cholesterol), sterol glycosides β-sitosterol-Dglycoside and others), and triterpenoid alcohols (β-amyrin, cycloartenol and 24-methylene cycloartenol). Tocopherols occur free in groundnut oil. Squalene, an unsaturated hydrocarbon, occurs in extremely small amounts in the unsaponifiable fraction. Two other unsaturated hydrocarbons, hypogene, and arachidene, have also been reported.

The kernels contain fixed oil (40–50%), proteins (26.2%), water (1.8%), carbohydrates (20.6%), ash, and high concentration of thiamine. The chief proteins are arachin and conarchin, both are globulins of different solubility. The vitamin content of groundnut is moderate, the largest being in the episperm.

Marketed Products

It is one of the ingredients of the hair oil known as J.P. Nikhar oil (Jamuna Pharma) and Sage baby oil (Sage Herbals).

CASTOR OIL

Geographical Source

It is mainly found in India, Brazil, America, China, Thailand; in India it is cultivated in Gujarat, Andhra Pradesh, and Karnataka.

Preparation

Castor oil is obtained from castor seeds. The oil is obtained by two ways; either after the removal of the seed coat or with the seed coat. Seed coats are removed by crushing the seeds under the grooved rollers and then they are subjected to a current of air to blow the testas. The kernels are fed in oil expellers and at room temperature they are expressed with 1 to 2 tons pressure per square inch till about 30%oil is obtained. The oil is filtered, steamed 80–100°C to facilitate the coagulation and precipitation of poisonous principle ricin, proteins and enzyme lipase present in it. Oil is then filtered and this oil with 1% acidity is used for medical purpose.

Characteristics

Medicinal or the first grade or Pale pressed castor oil is colourless or slightly yellow coloured. It is a viscid liquid which has slight odour with slightly acrid taste. Castor oil is soluble in absolute alcohol in all proportions; Specific gravity is 0.958 to 0.969, refractive index at 40°C is 1.4695 to 1.4730, acid value not more than 2, saponification value 177 to 187, and acetyl value is about 150.

Chemical Constituents

Castor oil consists of glyceride of ricinoleic acid, isoricinoleic, stearic, and dihydroxy stearic acids. Ricinoleic acid is responsible for laxative property. Castor oil also contains vitamin F. 90% of the fatty acid content is ricinoleic acid. The ricinoleic acid is an 18-carbon acid having a double bond in the 9–10 position and a hydroxyl group on the 12th carbon. This combination of hydroxyl group and unsaturation occurs only in castor oil.

Identification Tests

About 5 ml of light petroleum (50° to 60°) when mixed with 10 ml of castor oil at 15.5° shows a clear solution, but if the amount of light petroleum is increased to 15 ml, the mixture becomes turbid. This test is not shown by other oils.

Uses

Castor oil is mild purgative, fungistatic, used as an ointment base, as plasticizer, wetting agents, as a lubricating agent. Ricinoleic acid is used in contraceptive creams and jellies; it is also used as an emollient in the preparation of lipsticks, in tooth formulation, as an ingredient in hair oil. The dehydrated oil is used in the manufacture of linoleum and alkyl resin. The main use of castor oil is the industrial production of coatings, also employed to make pharmaceuticals and cosmetics in the textile and leather industries and for manufacturing plastics and fibres.

Marketed Products

It is one of the ingredients of the preparations known as Lip balm and Muscle and joint rub (Himalaya Drug Company).

CHAULMOOGRA OIL

Synonyms

Hydnocarpus oil; gynocardia oil.

Biological Source

Chaulmoogra oil is the fixed oil obtained by cold expression from ripe seeds of Taraktogenos kurzii King, (syn. Hydnocarpus kurzii (King) Warb.), Hydnocarpus wightiana Blume, H. anthelminticta Pierre, H. heterophylla, and other species of Hydnocarpus, belonging to family Flacourtiaceae.

Geographical Source

The plants are tall trees, up to 17 m high, with narrow crown of hanging branches; native to Burma, Thailand, eastern India, and Indo-China.

Characteristics

The oil is yellow or brownish yellow. Below 25°C it is a soft solid. It has peculiar odour and sharp taste. It is soluble in benzene, chloroform, ether, petrol; slightly soluble in cold alcohol; almost entirely soluble in hot alcohol and carbon disulphide.

Chemical Constituents

Chaulmoogra oil contains glycerides of cyclopentenyl fatty acids like hydnocarpic acid (48%), chaulmoogric acid (27%), gorlic acid with small amounts of glycerides of palmitic acid (6%), and oleic acid (12%). The cyclic acids are formed during last 3–4 months of maturation of the fruit and are strongly bactericidal towards the Micrococcus of leprosy. The seeds of H. wightiana contain a flavonolignan hydnocarpin; isohydnocarpin, methoxy hydnocarpin, apigenin, luteolin, chrysoeriol, hydnowightin, epivolkenin, and cyclopentenoid cyanohydrin glycosides.

Uses

The oil is useful in leprosy and many other skin diseases The cyclopentenyl fatty acids of the oil exhibit specific toxicity for Mycobaeterium leprae and M. tuberculosis. The oil has now been replaced by the ethyl esters and salts of hydnocarpic and chlumoogric acids. At present organic sulphones have replaced Chaulmoogra oil in therapeutic use.

COCONUT OIL

Characteristics

In temperate region below 23°C coconut oil is concrete oil. Coconut butter is a white or pearl white unctuous mass, odourless or with peculiar coconut odour and bland taste. Its melting point is 23°C to 26°C. It is soluble in two volumes of alcohol at 60°C but highly soluble in chloroform, ether and carbon disulphide. The oil readily becomes rancid on exposure to air. The coconut oil has the highest saponification value, 250–264 and the lowest iodine value, 7–10 among the vegetable oils in common use.

Chemical Composition

Coconut obtained from the hard, dried endocarp consists of a mixture of triglycerides of saturated fatty acids. The oil contains about 95% of saturated fatty acids with 8 and 10 carbon atoms. It shows the presence of caprylic acid, 2%; capric acid, 50–80%; lauric acid, 3%; and myristic acid about 1%.

Uses

Coconut oil is used as dietary products in many areas of the world. In European pharmacopoeia, fractionated coconut oil is known as ‘Thin vegetable oil’. It is useful as a nonaqueous medium for the oral administration of some medicaments. Fractionated coconut oil is used as a basis for the preparation of oral suspension of drugs unstable in aqueous media. Diets based on medium chain triglycerides including preparations made from coconut oil are used in conditions associated with mal absorption of fat such as cystic fibrosis, enteritis, and steatorrhoea. Abdominal pain and diarrhoea have been reported in patients taking diet based on medium chain triglycerides.

Marketed Products

It is one of the ingredients of the preparations known as Lip balm and Evecare (Himalaya Drug Company).

COD LIVER OIL

Preparation

The liver is cleaned and minced into small pieces and heated to 80°C in a vat by admitting steam for half an hour. The enzyme lipase is destroyed at temperature above 70°C. The oil is removed and put in tin drums which are encased with wooden barrels. The barrels are kept inside the snow and the oil is cooled to -2 to -5°C, the slow cooling process precipitates the palmitin, which is separated by filtration. The oil obtained is medicinal oil. The residual cake formed after the medicinal oil is subjected to heating at higher temperature to obtain oil with inferior quality and brown colour.

Characteristics

The oil is pale yellow in colour; it has fishy odour and taste. Cod liver oil is slightly soluble in alcohol and fully soluble in chloroform, ether, carbon disulphide and petroleum ether. Specific gravity: 0.922–0.929, Refractive index: 1.475–1.4745, Acid value is less than 2, Iodine value 155–173. The oil should be stored in well-filled airtight containers, protected from light, and kept in a cool place.

Chemical Constituents

The cod liver oil contains glycerides esters of saturated acids of linoleic, oleic, myristic, gadoleic, palmitic, and other acids. The oil has vitamin A and vitamin D. Cod liver oil also contains about 1% unsaponifiable matter; like cholesterol, fatty alcohol, squalene, α-glyceryl esters, etc.

CORN OIL

Geographical Source

Corn is cultivated throughout the world. The major producers of corn are United States, Canada, Russia, Argentina, Brazil, France, Mexico, Thailand, and India. Corn oil is generally obtained as a by-product during the production of Maize starch from the maize germs. The French pharmacopoeia specifies that the corn oil should be obtained from the germs or caryopsis which remains after the removal of major part of the cotyledon.

Characteristics

Refined corn oil is a clear to light golden yellow coloured liquid with a faint characteristic odour and taste. It is slightly soluble in alcohol, miscible with chloroform, ether and light petroleum. Weight per ml is 0.915 to 0.923 g. It can be sterilized by maintaining at 150°C for 1 hr and stored in a cool place in well-filled airtight containers protected from light. Acid value is 2–6; saponification value, 187–96 and iodine value 100 to 133.

Chemical Constituents

Dried corn embryo yields around 20% of fixed oil. The fatty acid composition of the corn oil indicates the presence of palmitic, 8–13%; stearic, 1–4.5%; oleic, 24–33%; linoleic 55–62%; linolenic 0.5–1.5% about 0.5% of arachidic, gadoleic, and behenic acids. It shows the presence of about 0.8–2% of unsapoifiable matter containing major proportion of β-sitosterol and compesterol.

Uses

Maize oil shows the properties similar to those of olive oil. As the oil consists of higher contents of unsaturated acids, it is regarded as of value in diets designed to limit blood cholesterol level in patients with hypercholesterolemia, particularly following cardiac infarction. The oil has also indicated good results in the patients with coronary heart disease and diabetes. It is used in place of other vegetable oils, in pharmaceuticals and cosmetic preparations.

Marketed Products

Esoban ointment containing maize oil is used for dermatitis and allergic skin conditions.

COTTONSEED OIL

Biological Source

Cottonseed oil is a refined fixed oil obtained by expression of seeds of Gossypium harbaceum Linn, belonging to family Malvaceae, in hydraulic or other presses.

Preparation

The cottonseed, after ginning off the fibres, is decorticated and cleaned of hulls. The kernels are steamed and pressed at about 1500 lb pressure to yield about 30% of oil which is turbid and reddish in colour. It is refined by filtering, decolourizing, and ‘winter chilling’, which removes the stearin.

Chemical Constituents

The important constituents of the glycerides of cottonseed oil are linoleic (45–50%), oleic (23–29%), palmitic (20–33%), myristic (1.5–3.5%), stearic (1.1–2.7%), and arachidic acids (1.0%). The glycerides present are palmitooleolinoleins (35–40%), palmitodioleins (20%), and trioleoor lineo-disaturated (12–13%). The unsaponifiable fraction contains β-sitosterol, ergosterol, vitamin E, and tocopherols. The phosphatides present are lecithin (29%) and cephalins (71%). The minor constituents present in the oil are free fatty acids (0.3–5.6%), gossypol (0.05%), raffinose, pentosans, resins, wax, proteoses, peptones, phospholipids, inosite phosphates, phytosteroline, xanthophyll, chlorophyll, and mucilage substances. Cottonseed cake contains about 0.6% of a toxic principle, gossypol, which occurs in secretory cavities in all parts of the plant. It is present in cold-pressed oil and can be removed by treatment with alkalies.

LINSEED OIL

Geographical Source

Linseed is cultivated in many sub-tropical countries such as South America, India, United States, Canada, England, Russia, Greece, Italy, Spain, and Algeria.

Collection

Linseed in an erect annual herb, 60–120 cm high with sky-blue flowers, and a globular capsule. The plant is cultivated for its seeds and fibre (flax). A moderate rainfall is best suited for its growth. It grows in almost all types of soils where sufficient moisture is available, but thrives best in heavy soils with high moisture retaining capacity. As a mixed crop it is sown either on the margins of fields or in rows alternating with the other crop. Nitrogenous fertilizers yield better crop. The crop is harvested in February and March before the capsules are dried. Plants are cut close to the ground, dried in the field, and threshed to separate seeds.

Morphology of Seeds

The seeds are oval, flattened, elongated, 4–6 mm long, and 2–3 mm wide. Testa is glossy, smooth, reddish-brown with minutely pitted surface. Seeds are rounded at one end. The other end is obliquely pointed where the hilum and micropyle are present in a slight depression. Raphe is present along one edge. Endosperm is narrow and encircles the embryo. It consists of two thick flattened, plano-convex cotyledons, and a radicle. The seeds art odourless but possess an oily and mucilaginous taste.

Microscopical Characters

Under microscope the testa shows a mucilage-containing outer epidermis; one or two layers of collenchyma or ‘round cells’; a single layer of sclerenchyma; the hyaline layers or ‘cross-cells’ composed in the ripe seed of obliterated parenchymatous cells; and an innermost layer of pigment ceils. The outer epidermis is composed of cells, rectangular or five-sided in surface view, which swell up in water and become mucilaginous. The outer cell walls, when swollen in water, show an outer solid stratified layer. The radial layers or ‘round cells’ are cylindrical in shape and show distinct triangular intercellular air spaces. The sclerenchymatous layer is composed of elongated cells, up to 250 μm in length, with lignified pitted walls. The hyaline layers are attached to portions of the sclerenchymatous layer in the powdered drug. The pigment layer is composed of cells with thickened pitted walls and containing amorphous reddish-brown contents. The cells of the endosperm and cotyledons are polygonal with thickened walls, and contain numerous aleurone grains and globules of fixed oil.

Preparation

The dried seeds are crushed in rollers, moistened and heated to 80–90°C in steam to soften the seed tissues. They are then pressed through hot hydraulic press at a high pressure. The oil so obtained is treated with alkali to separate free fatty acids and bleached with fuller’s earth or charcoal. On cooling the oil waxy substances are removed. Linseed oil is a yellowish liquid, with a peculiar odour and bland taste. On exposure to air it gradually thickens, becomes darker and acquires a more pronounced odour and taste. On drying it forms a hard varnish. It has a high iodine value (~170) which indicates the presence of excess amount of glycerides of unsaturated fatty acids. The oil is slightly soluble in alcohol, miscible with chloroform, ether, petroleum ether, carbon disulphide, and terpentine oil. It has density 0.925–0.935, viscosity 1.47, congealing point ~20°C, saponification number 187–195, refractive index 1.47–1.48, and unsaponifiable matters not over 1.5%. A water-soluble resinous matter with antioxidant properties has been isolated from the oil.

MUSTARD OIL

Biological Source

It is a fixed oil obtained from matured seeds of Brassica nigra (L) Koch or Brassica juncea L. Czern, belonging to family Cruciferae (Brassicaceae).

Geographical Source

It is cultivated in India, China, Canada, and England.

Description

It is yellow coloured liquid of strong acrid odour until refined, sp. gr. 0.914–0.923, saponification value 173–184, iodine value 96–194, and unsaponifiable matter 0.9–1.0%.

OLIVE OIL

Collection and Preparation

The olive is an evergreen tree, up to 12 m in height which produces drupaceous fruits about 2–3 cm in length, purplish in colour when ripe. The fruits are collected from November to April. After grinding, the pulp is introduced into coarse, grass baskets, and placed in a screw press. The oil coming out is collected into tubes containing water and the upper layer is skimmed off. The product is called as Virgin oil obtained by gently pressing the peeled pulp freed from the endocarp. The marc is then treated with water and again expressed to yield second grade of edible oil. Finally, the pulp is mixed with hot water and pressed again for technical oil. The pulp may be extracted with carbon disulphide to obtain ‘sulphur’ olive oil of inferior quality. The yield is from 15 to 40%. If the fruit is not fully mature, the yield of the oil is poor and its taste is bitter.

Characteristics

Olive oil is a pale yellow or light greenish-yellow due to presence of chlorophyll or carotenes, nondrying oily liquid with a pleasanting delicate flavour. Taste is bland becoming cloudy and at 0°C it usually forms a whitish granular mass. It becomes faintly acrid. It is miscible with ether, chloroform, and carbon disulphide and is slightly soluble in alcohol. Upon cooling at +5 to 10°, it becomes cloudy and at 0°C usually forms a whitish granular mass. It becomes rancid on exposure to air. It has specific gravity of 0.914–0.919, acid value 0.2–2.8, saponification value 187–196, and iodine value 79–90.

RICE BRAN OIL

Biological Source

Rice bran oil is the oil obtained from the rice bran of the seeds of Oryza sativa Linn., belonging to family Graminae.

Preparation

Rice bran is the cuticle present between the rice and the husk of the paddy; consists of embryo and endosperm of the seeds. Rice bran is the by product in rice mill during dehusking of paddy. Rice bran has 15% of fixed oil and the oil is obtained by solvent extraction method. The rice bran oil obtained from fresh brans are of good quality and has good taste and low free fatty acid content. The quality of rice bran oil depends upon the time duration taken between the milling of the rice and removal of oil from the bran. The enzyme lipase present in rice bran increases the free fatty acid content on storage and so the extraction of oil should be done as rapidly as possible. Rice bran occurs as extremely small pieces. Before solvent extraction the rice bran is subjected to various methods like drying, cooking, and flaking operations. The rice bran is impermeable to solvents, and so it is first pressed and then extracted with solvent in special continuous immersion extractors.

SAFFLOWER OIL

Geographical Source

This is one of the most ancient crops cultivated in Egypt as a dye-yielding herb. Now, it is cultivated as an oil seed plant and regarded as substitute for sunflower. It is cultivated in Russia, Mexico, India, United States, Ethiopia, and Australia.

Method of Preparation

For expression of oil, the seeds from promising varieties in India are selected, cleaned and further processed. About 1000 seeds of safflower weigh 20 to 50 g. The seeds normally contain 35 to 38% of fixed oil. The oil is prepared by expression in expellers or with the help of hydraulic presses. The oil is filtered and further purified. The seed meal or round seeds are subjected to cooking by means of open steam, which ensures maximum yield of oil. The filtered and decolourized oil is packed into suitable containers.

Characteristics

It is a clear, faint yellowish liquid with characteristic odour and taste. The oil thickens and becomes rancid on exposure to air. Safflower oil is slightly soluble in alcohol and freely soluble in ether, chloroform, benzene and petroleum ether. Specific gravity 0.9211 to 0.9215, acid value 01–9, refractive index 1.472 to 1.475, and saponifiction value 188–194.

SESAME OIL

Biological Source

Sesame oil is obtained by refining the expressed or extracted oil from the seeds of cultivated varieties of Sesamum indicum Linn., belonging to family Pedaliaceae.

Geographical Source

The plant is widely cultivated in India, China, Japan, East Indies, West Indies, and in the southern United States.

Cultivation

The plant is an annual herb, 1 m in height. Sesamum is cultivated in the plains and on elevations up to 1,200 m at temperature of 21°C and above. It requires a warm climate and cannot withstand frost, continued heavy rain or prolonged drought. It grows on a light well-drained soil which is capable of retaining adequate moisture. It thrives best on typical sandy loams. The seeds are sown broadcast. In northern India, the crop is sown in June–July and harvested in October–November. The crop is not generally manured.

Characteristics

The seeds are small, flat, oval, smooth, and shiny, whitish, yellow or reddish brown; sweet and oily taste; odour is slight. They are pointed at one end where hilum is located, raphe runs as a line from hilum, along the centre of one flat face to the broader end. The endosperm is present as a thin layer around the embryo. The seeds contain fixed oil (45–55%); proteins (aleurone, 22%); and mucilage (4%).

Preparation

The oil is expressed by hydraulic or low and mediumpowered screw presses. A good yield of the oil is obtained by three successive expression. Prior to processing in the screw press, the seed is subjected to a cooking process. If live steam is used for cooking, the cuticles separate partly from the kernels and the mixture of kernels, cuticles, and seed slips in the cage and lumpy material is obtained instead of a firm cake. If the seed is heated in cooker without the addition of steam or water, and water is added at the point of entry of dried seed into the screw press cage, the efficiency of oil extraction is greatly enhanced. Alkali refining, bleaching, hydrogenation, and decolourization of sesame oil can be affected with very little loss.

Chemical Constituents

Sesame oil consists of a mixture of glycerides of oleic (43%), linoleic (43%), palmitic (9%), stearic (4%), arachidic, hexadecenoic, lignoceric, and myristic acids. It also contains the lignan sesamin (1%), the related sesamolin and vitamins A and E. During industrial refining, sesemolin is readily converted into antioxidant phenols sesamol and sesamolinol. The seeds also contain a lignan sesamolinol, γ-tocopherol, sesaminol, pinoresmol, its glycosides, sesaminol glucosides VI, VII, and VIII, triglucoside KP3, carbohydrates (20%), proteins (20–25%), sterols (campesterol, stigmasterol, β-sitosterol, and ∆5 -avenasterol), γ- and δ-tocopherols.

SHARK LIVER OIL

Characteristics

Shark liver oil is pale yellow to brownish yellow, viscous liquid with fishy odour, and bland taste. It is insoluble in water, sparingly soluble in alcohol and freely miscible in nonpolar solvents such as petroleum ether, chloroform, and benzene. Its acid value is about 2, saponification value 150–200, and iodine value 160–350.

BEESWAX

Preparation

The worker bee secretes the wax due to the ability of maintaining a high temperature and the wax is secreted in the last four segments of abdomen on the ventral surface. Just below the sterna it has a smooth layer of cells form the chitinous area that secretes the wax. The chitinous area has small pores through, which the wax exudes out. The wax is passed to the front leg and later to the mouth; in the mouth it gets mixed with the saliva, which is then built on the comb. This wax forms a capping on the honey cells. Wax forms about 1/8th part of the honeycomb. After removal of honey, honeycomb or the capping is melted in boiling water. On cooling the melted wax gets solidified and floats on the surface of water while the impurities settle below and honey leftovers get dissolved in water. The pure wax is then poured into earthen vessels wiped with damp cloth and the wax so obtained is yellow beeswax.

Characterisitics

Yellow wax or Cera flava is yellowish to greyish brown coloured solid, with agreeable, honey-like odour and a faint, characteristic taste. When cold, it is somewhat brittle and when broken, shows presence of a dull, granular, noncrystalline fracture. Yellow wax is insoluble in water and sparingly soluble in cold alcohol. It is completely soluble in chloroform, ether, and in fixed or volatile oils, partly soluble in cold benzene or in carbon disulphide and completely soluble in these liquids at about 30°C.

Chemical Constituents

Beeswax contains myricin, which is melissyl palmitate; melting point 64°C, free cerotic acid (C26H52O2 ), myricyl alcohol (C30H61OH) is liberated when myricyl palmitate is saponified. Melissic acid, some unsaturated acids of the oleic series, ceryl alcohol, and 12 to 13% higher hydrocarbons are present.

Uses

Beeswax is used in the preparation of ointments, plaster, and polishes.

Adulterants

Beeswax is adulterated by solid paraffin, ceresin, carnauba wax, or other fats and waxes of animal or mineral origin. Spermaceti and lard render wax softer and less cohesive, of a smoother and less granular fracture and different odour when heated. The melting point and specific gravity are lowered by tallow, suet, lard, and especially by paraffin. Ceresin, a principle obtained from ozokerite is also employed as an adulterant. In yellow wax the iodine value is also of use as a test for detection of adulterants but in white wax the bleaching process has altered the bodies which absorb the iodine.

CARNAUBA WAX

Preparation

The leaves of Brazilian wax-palm are collected, dried, and then spread on cloth. By brushing and beating, the wax is separated. It is then melted, processed further to purify, and poured into the moulds.

Characteristics

It is hard greenish solid wax with crystalline fracture. It has sharp characteristic odour and bland taste. It is soluble in fat solvents.

COCOA BUTTER

Preparation

Cocoa seeds contain nearly 50% of cocoa butter. The seeds are separated from pods and are allowed to ferment. Fermentation process takes place at 30–40°C in tubes, boxes or in the cavities made in the earth for three to six days and during fermentation the colour of the seeds changes from white to dark reddish brown due to enzymatic reaction. If the seeds are not subjected for the process of Fermenta and dried in sun, then they are more astringent, bitter tasting and of less value. After fermentation, the seeds are roasted at 100–140°C to remove the acetic acid and water present in the seeds and facilitate removal of seed coat also. The seeds are cooled immediately and are fed into nibbling machine to remove the shells followed by winnowing. The kernels are then fed into hot rollers which yield a pasty mass containing cocoa butter. The pasty mass is further purified to give cocoa butter.

Characteristics

Cocoa butter is yellowish white solid and brittle below 25°C. It has pleasant chocolate odour and taste. It is insoluble in water but soluble in chloroform, petroleum ether, ether and benzene. Specific gravity ranges from 0.858 to 0.864, melting point between 30°C and 35°C, refractive index varies from 1.4637 to 1.4578, saponification value is 188–195, and iodine value 35–40.

KOKUM

Preparation

Fruits are collected, dried, and seeds are separated. The kernels from the seeds are churned, and it is then boiled with water. The melted fat is separated by skimming process and washed with hot water. Then the fat is decolourized.

Characteristics

Kokum is light grey to yellow in colour, very mild odour, with sweet sour taste. The marketed kokum have an egg shape. Butter is solid at room temperature, but melts readily on contact with the skin with melting point 39°C to 42°C. Refractive index varies from 1.4565 to 1.4575, Saponification value is 185–190 and Acid value not more than 3.

LANOLIN

Preparation

Wool is cut and washed with a soap or alkali. An emulsion of wool fat, called as wool grease, takes place in water. Raw lanolin is separated by cracking the emulsion with sulphuric acid. Wool grease floats on the upper layer and fatty acids are dissolved in the lower layer. Lanolin is purified by treating with sodium peroxide and bleaching with reagents.

Characteristics

Lanolin is a yellowish white, tenacious, unctuous mass; odour is slight and characteristic. Practically, it is insoluble in water, but soluble in chloroform or ether with the separation of the water. It melts in between 34 and 40°C. On heating it forms two layers in the beginning, continuous heating removes water. Lanolin is not saponified by an aqueous alkali. However, saponification takes place with alcoholic solution of alkali. Anhydrous lanolin is a yellowish tenacious, semisolid fat with slight odour. Practically it is insoluble in water but mixes with about twice its weight of water without separation. It is sparingly soluble in cold, more in hot alcohol, freely soluble in benzene, chloroform, ether, carbon disulphide, acetone, and petroleum ether.

Chemical Constituents

Lanolin is a complex mixture of esters and polyesters of 33 high molecular weight alcohols, and 36 fatty acids. The alcohols are of three types; aliphatic alcohols, steroid alcohols, and triterpenoid alcohols. The acids are also of three types: saturated nonhydroxylated acids,unsaturated nonhydroxylated acids, and hydroxylated acids. Liquid lanolin is rich in low molecular weight, branched aliphatic acids, and alcohols, whereas waxy lanolin is rich in high molecular weight, straight-chain acids, and alcohols.

Identification Tests

Dissolve 0.5 g of lanolin in chloroform, and to it add 1 ml of acetic anhydride and two drops of sulphuric acid. A deep green colour is produced, indicating the presence of cholesterol.

Uses

Lanolin is used as an emollient, as water absorbable ointment base in many skin creams and cosmetic and for hoof dressing. Wool fat is readily absorbed through skin and helps in increasing the absorption of active ingredients incorporated in the ointment. However, it may act as an allergenic contactant in hypersensitive persons.

LARD

Biological Source

It is the purified internal fat obtained from the abdomen of the hog Sus scrofa Linn., belonging to family Suidae.

Preparation

The abdominal fat consists of omentum and parts of peritoneum. They are obtained in the form of flat, leafy masses called the ‘flare’. The fats are washed to remove the salts or the preservatives used during storage and they are hung in a current of air for drying. The omentum and parts of peritoneum are minced to break the membranous vesicles and to liberate the lard inside then It is then heated to 50–55°C, not more than 57°C to melt the lard. The melted lard is then separated by passing through muslin cloth and cooled with proper stirring. If the lard is not stirred properly it can result in the crystallization. Entrapping of air should be avoided to prevent the lard from becoming rancid on storage.

Characteristics

It is a soft, creamy, white, solid, or semisolid homogeneous fat with butter-like consistency. Lard has slight fatty odour but not rancid, cool in nature and sweet taste. It is insoluble in alcohol and soluble in benzene, ether, carbon disulfide, and chloroform. Refractive index varies from 1.4520 to 1.4550, saponification value is 192–198, and acid value is not more than 2, melting point 34°C to 41°C, specific gravity between 0.934 and 0.938, and iodine value 52 to 56.

Chemical Constituents

Lard consists of about 60% olein and 40% of stearin and palmitin mixture. The oil separated at 0°C is called the lard oil. About 100 grams of lard contains 900 calories, 95 mg cholesterol, 39 g saturated fat, 45 g monounsaturated fatty acids, 11 g polyunsaturated fatty acids, 0.6 mg vitamin E, 0.l mg zinc, and 0.2 mg selenium.

Uses

It is used as an ointment base and in formulations where more effective absorption is preferred. It is used in difficult bowel movements, dryness in the internal organs like dry cough, skin, eyes, nose, and stool. Lard is also used in food manufacturing. Pure lard is especially useful for cooking since it produces very little smoke when heated and has a distinct and pleasant taste when combined with other foods.