Storage lipids

Storage Lipids

1. STORAGE LIPIDS 1.Butter 2.Olive Oil 3. Bees Wax

2. LIPIDS : INTRODUCTION Biological lipids are diverse group of chemicals having common defining property of insolubility in water. Two major categories of lipids are 1) Storage lipids 2)Membrane lipids Other lipids are present in relatively small amounts yet play crucial roles as a) Enzyme cofactors, b) electron carriers, c)light-absorbing pigments, d) hydrophobic anchors for proteins "chaperons” to help membrane proteins fold, e) emulsifying agent in the digestive tract, f) intracellular messenger, g) harmones.

3. STORAGE LIPIDS:INTRODUCTION Storage lipids or neutral lipids:- The simplest lipids constructed from unbranched fatty acids usually of even number of carbon atoms are triglycerides , also known as triacylglycerol , animal fat and vegetable oil etc. These are composed of three fatty acids each in ester linkage with a single glycerol . The general formula of fats and oils is given below-

4. STORAGE LIPIDS-NOMENCLATURE Lipids containing the same kind of fatty acids in all three positions are called simple triacylglycerols and are named after the fatty acids they contain. Simple triacylglycerols of 16:0,18:0, and 18:1, for example , are tripalmitin, tristearin and triolein, respectively. Tripalmitin Tristearin Triolein

5. STORAGE LIPIDS-NOMENCLATURE Normally naturally occurring lipids contain mixture of fatty acids in a molecule ,ie. they contain two or three fatty acids. For the naming of such a molecule the name and position of each fatty acid is specified for eg. a mixed triacylglycerol named 1-Stearoyl, 2-linoleoyl, 3-palmitoyl glycerol, contains one glycerol and three different fatty acids at C-1 , C-2 and C-3 positions. Structures of two such lipids are drawn below- Oleodipalmitin Oleopalmitostearin (α-Oleo-β,α-dipalmitin) (α-oleo-β-palmito -α / -stearin)

6. STEREOISOMERISM IN LIPIDS Leaf abscission When the groups attached to C-1 and C-3 differ a centre of asymmetry is created at C-2 .The two optical isomers may, thus, be represented as follows. The naturally occurring fats are L-type. D-isomer L-isomer

7. PHYSICOCHEMICAL PROPERTIES OF FATS AND OILS The physicochemical and chemical properties: of a fat or oil are determined by the ratio of its component saturated and unsaturated acids. Triglycerides have lower densities than water(they float on water). At normal room temperature they may be solid or liquid. When solid , they are called “fats” or “ butters” and when liquid they are called “oils” . Fats and oils are insoluble in water and readily soluble in organic solvents; they are usually slightly soluble in alcohol. When treated with superheated steam, inorganic acid or alkali fats undergo hydrolysis( saponification ) with the formation of glycerol and fatty acids or their salts. Emulsions are formed by vigorous agitation with water. An example of a stable aqueous fat emulsion is milk. The emulsification of fats in the intestines (a necessary condition for their absorption) is effected by salts of bile acids. Fats are main energy source of the body . The energy value of fats is more than twice as great as that of carbohydrates Fat deposits in skin provide the pronounced elasticity

8. The fats have extremely low heat conductivity and thus the fat deposited in the subcutaneous fatty cellular tissue acts as heat insulator, protecting the body from heat loss which is particularly useful for warm –blooded marine animals such as whales and seals. The fat content of human body and of animals varies greatly. In cases of great corpulence and of hibernating animals before hibernation, the fats content of the body reaches 50%. Similarly when farm animals are fattened, their fat content is particularly high. In the body a distinction is made between reserve fats, which are deposited in the subcutaneous fatty cellular tissue and in the omentum, and protoplasmic fat, which is a component of protoplasm in the form of complexes with proteins, called lipoproteins. In case of starvation or inadequate feeding, the reserve fat disappears, but the percent of protoplasmic fat in the tissues stays almost the same, even when the body is extremely emaciated. Organic solvents readily extract reserve fat from fatty tissue. Protoplasmic fats can be extracted from fatty tissue with organic solvents only if the tissues have been previously treated to denature the proteins and split up their complexes with fats. In cooking the “smoke” point of an oil or fat is the temperature at which , under defined conditions, enough volatile compounds emerge from the oil that a bluish smoke becomes clearly visible. At this temperature, volatile compounds, such as water, free fatty acids, and short-chain degradation products of oxidation come up from the oil. The smoke point is the temperature at which the oil is decomposed and where possibly toxicologically relevant compounds are formed. Considerably above the temperature of the smoke point is the “Flash point”, the point at which the vapors from the oil can first ignite when mixed with air. PHYSICOCHEMICAL PROPERTIES OF FATS AND OILS

9. CHARACTERISATION OF FATS Fats are characterized and their purity or otherwise assessed by determining certain chemical constants for individual fats- SAPONIFICATION– Number of mgs of KOH required to neutralize the free and combined fatty acids in a gm of a given fat is its saponification number. A high saponification number indicates that the fat is made up of low molecular weight fatty acids and vice versa. IODINE NUMBER - is the number of gms of Iodine required to saturate 100 gms of fat .Since Iodine is taken up by the double bonds , a high Iodine number indicates a high degree of unsaturation of the fatty acids of the fat. ACID NUMBER – Number of mgs of KOH required to neutralize the free fatty acids in a gm of fat is known as acid number .The acid number indicates the degree of rancidity of the given fat . REICHERT – MEISSL( R.M. )NUMBER – The number of ml of 0.1 N alkali required to neutralize the volatile fatty acids ( separated by saponification , acidification and steam distillation of the fat ) contained in 5 gms of the fat is the R.M. number

10. Categories of Storage Fats and Oils Natural fats are subdivided into animal and vegetable fats. Plants contain relatively small quantities of fats. Exceptions are oil producing plants, whose seeds differ in that they have high oil content. Animal fats and oils : These are lipid materials derived from animals. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides. In consumer products in U.S. animal remains are found to be classified as animal fats once the particle size of bone solids is more than 3 percent, protein content is less than14 percent and or the product contains over 30 percent pure fat content. Although many animal parts and secretions may yield oil, in commercial practice, oil is extracted primarily from rendered tissue fats obtained from live-stock animals like pigs, chicken and cows. Dairy products also yield popular animal fat and oil products such as cheese, butter, and milk. Animal fats are largely used in the production of margarine, shortening and compound fat. They also enter into many processed food products. Industrial and non-food uses of animal fats include the production of soaps, fatty acids, lubricants and feedstuff. Animal fats are thus distinguished between edible fats and inedible fats. Edible fats used in food frying processes are called “Used Cooking Oils”. Inedible fats are used only in pet food, oleochemistry, biodiesel or to generate energy.

11. Animal Fats and Oils A list of animal fats and oils is given below with the description of their nature and uses:- Animal Fats and oils Description Lard Pig fat; both in its rendered and unrendered forms, it was commonly used as cooking fat or shortening or as spread similar to butter. Now a days it is not used much. Milk, butter Dairy products are animal secretions which contain varying levels of water, oil, ’fats and animal cells from circulatory and lymphatic systems such as blood and mammary glands. Goose fat Produce a higher smoke point than other animal fats, but are still lower than many vegetable oils . Greases Inedible lard. Tallow Obtained from suet (t he hard white fat on the kidneys and loins of cattle, sheep, and other animals) and used in making soap, candles, and lubricants. Beef fat is edible and is used for other purposes too.

12. Animal Fats and Oils Lanolin, wool- fat A yellow viscous animal oil extracted from wool; a mixture of fatty acids and esters; used in some ointments and cosmetics Dippel’s oil Dark colored ill-smelling oil obtained by carbonizing bone. . Bone oil Used in lubricant and in leather manufacture Cod liver oil An oil obtained from the livers of cod and similar fishes; taken orally as a sources of vitamins D &A. Halibut-liver oil A fatty oil from halibut livers that is used as a source of vitamin A. Lard oil Oil consisting chiefly of olein that is expressed from lard and used especially as lubricant, cutting oil or illuminant Menhaden oil A fatty oil obtained from the menhaden fish and used in paint and ink and in treating leather.

13. Animal Fats and Oils Neat’s –foot oil A pale yellow oil made from feet and legs of cattle; used as dressing for leather. Oleo oil Obtained from beef fat; used in making margarine and soap and in lubrication. Porpoise oil A yellow fatty oil obtained from porpoises and used as a fine lubricant. Dolphin oil An unsaturated fatty oil obtained from dolphins and used as a fine lubricant. Sardine oil Oil obtained from sardines and chiefly as a lubricant and in soap. Salmon oil A fatty oil obtained from the wastes in canning salmon; used in making soaps and dressing leather. Seal oil A pale yellow to red-brown fatty oil obtained from seal blubber; used in making soap and dressing leather and as lubricant. Shark oil, shark- liver oil A fatty to yellow to brown oil obtained from livers of sharks; used for dressing leather and as a source of vitamin A. Sperm oil An animal oil found in the blubber of the sperm whale.

14. Vegetable oils and fats Both tropical and temperate plant families contain fatty oils. They are stored, frequently in large amounts, in seeds and somewhat in fruits , tubers, stems and other plant organs. They may also contain proteins. This kind of reserve food material is available as a source of energy for the processes involved in seed germination. Fatty oils are bland and lack the strong taste , odor and antiseptic qualities of essential oils. Thus they are suitable for human food. These edible oils contain both solid and liquid fats and form an important part of the human diet. With some exceptions, and in contrast to animal fats, vegetable oils contain predominantly unsaturated (light, liquid) fatty acids of two kinds: monounsaturated (oleic acid- mainly in extra virgin olive oil) and polyunsaturated (linoleic acid and linolenic acid-in oils extracted from oilseeds).

15. Vegetable oils and fats Industrial and non food uses of vegetable oils include the production of soaps, detergents, fatty acids, paints, varnish resin , plastic and lubricants. Vegetable oils have a wide variety of food uses, including salad and cooking oils as well as in production of margarine, shortening and compound fat. They also enter into many processed products, such as mayonnaise, mustard, potato chips, French fries, salad dressing, sandwich spread and canned fish. Extraction of fatty oil varies. Usually the seed coats have to be removed and then the remainder is reduced to a fine meal. The oils are removed by solvents or by subjecting the meal to hydraulic pressure. The residue is rich in proteins and is valuable as an animal food and fertilizer. Pressure causes the cell wall to break and the fats are released. The extracted oils are filtered and may be further purified . Higher grades are edible and lower grades may be used in various industries. Fatty oils may also have medicinal value.

16. Classes of plant fatty oils Four classes of plant fatty oils are- Drying oils:-. these can absorb oxygen and on exposure dry into thin elastic films. Such oils are important in the paint and Varnish industries. Semidrying oils:-these oils absorb oxygen slowly and only in small amounts. They form a soft film only after long exposure to air. Some are edible; others are used as illuminants or in making soaps and candles. Nondrying oils:- These remain liquid at room temperature and do not form a film. Such oils are edible and may be used for soap and lubricants. Fats or Tallows:-these remain solid or semisolid at room temperature. They are edible and also useful in the manufacture of soap and candles. Drying and semidrying oils are more common in plants of temperate climates, while nondrying oils and fats predominate in plants of tropical areas. Classes of plant fatty oils

17. Given below is a list of examples of Drying oils :-                                        Name of oil Description Drying oils these can absorb oxygen and on exposure dry into thin elastic films. Such oils are important in the paint and Varnish industries Examples:- Linseed oil Flax seed, Linum usitatissimum , has been the source of one of the most important drying oils. The oil content in seed is 32-43 percent. It is yellow to brown in color, has an acrid taste and smell, forms a tough elastic film when oxidized and is used mainly in making paints, varnishes, linoleum, soft soap and printer’s ink. Following oil extraction from seed, the oil cake can be used as an animal feed. A List of examples of Drying oils

18. A List of examples of Drying oils Tung oil/Chinawood oil This is obtained from the seeds of the two Chinese species of Alurites . Oil is used in varnish industry and as a substitute of linseed oil. It is used for waterproofing wood, paper, and fabrics. It is a good preservative and is resistant to weathering, so it is especially valuable for painting outdoors. Boatmen have sought after tung oil because it is little affected by water. Large quantities were also used in producing linoleum, oilcloth, brake lining, soap, leather dressings, inks, insulating compounds and fiberboard. The oilcake is a good fertilizer but is unsuitable as an animal feed . Soybean oil Glycine max is native to China and has been most important food plant in Eastern Asia. The oil is midway between linseed and cottonseed in its character. Refined oil is used in salads or as cooking oil. Margarine, tofu , ice cream substitute, vegetable meat substitute etc are made from soybean. Oil is also used in making soap, candles, varnishes, lacquers, paints, linoleum, greases, rubber substitutes, cleaning compounds, disinfectants and insecticides. The oil cake has 40-48 percent protein content and is valuable as a meat substitute and feed for livestock. It is also used for adhesives, plastics, foaming solutions, spreaders, fertilizers, sizing, synthetic textiles etc.

19. A List of examples of Semidrying oils Name Description Semidrying oils These oils absorb oxygen slowly and only in small amounts. They form a soft film only after long exposure to air. Some are edible; others are used as illuminants or in making soaps and candles. Examples:- Cottonseed oil Most important of the semidrying oils, and it is used as the standard of comparison. The pure refined oil is used for salads and cooking oil and for making margarines and lard substitutes. For industries it is the source for soap, oilcloth, washing powders, artificial leather, roofing tar, insulating materials, putty, glycerin and nitroglycerin. Cottonseed meal is important as a food for animals and as a fertilizer. List of examples of Semidrying oils is given below:-

20. A List of examples of Semidrying oils Corn oil There is about 50 percent oil located in the embryo of the maize kernels. Refined oil is used for human consumption either directly or in margarines, while the crude oil has industrial uses such as the rubber substitutes, paints, soaps. Corn oil has little lubricating value. Sesame oil Also known as gingerly oil, sesame oil is the product of an annual herb, Sesamum indicum. Seeds contain about 50 percent oil that is easily extracted by cold pressure. The finer grades of oil are used as a substitute for olive oil in cooking and in medicine. It is also used in the manufacture of margarine and other foods. Poorer grades of oil are used for soap, perfumery and rubber substitute and sometimes as a lubricant. Oil cake is a good cattle -feed, and sesame seeds are also used in confectionery and baking industry. Sunflower Helianthus annuus seeds contain 32-45 percent of light golden-yellow oil equal to olive oil in its medicinal and food value. It is an excellent salad oil and is used in margarines and lard substitutes. The seeds are a nutritious bird and poultry food, while the oil cake is excellent for livestock and the whole plant is often grown for silage. The oil has semidrying properties rendering it useful in the varnish, paint and soap industries.

21. A List of examples of Non drying oils A list of examples of nondrying oils  is given below:-   Name Description Nondrying oils These remains liquid at room temperature and do not form a film. Such oils are edible and may be used for soap and lubricants. Examples Olive oil The fruits of the olive, olea europaea , provide olive oil, and it is the most important of the nondrying oil. The oil is golden yellow, clear and limpid. Used chiefly as salad and cooking oils , in canning sardines and in medicine. Inferior grades have greenish tinge and are used for soap making and as lubricants. It is one of the most important food oils as it can be stored for long periods and becomes rancid only when exposed to air. The oil cake is used for stock feed and as a substitute for humus in soil conditioning.

22. A List of examples of Non drying oils Peanut oil Seeds of the common peanut, Arachis hypogaea , provide peanut oil. Refined oil is edible and used as a salad oil, for cooking , for packing sardines, in making margarines and shortenings, and as an adulterant for olive oil. Inferior grades are for soap making, lubricants, and illuminants. The oil cake is an excellent live stock feed as it has higher protein content than any other similar product. Castor oil Seeds of Ricinus communis furnish versatile oil. It is a colourless or greenish oil that is used in medicine as purgative. Being water resistant it may be used for coating fabrics and for protective covering for airplanes, insulation, food containers, firearms etc. It is an excellent lubricant especially for airplane engines. When hydrated it is converted into a quick-drying oil used in paints and varnishes. It may also be used in making soap, inks and plastics, for preserving leather and as an illuminant. The oilcake is poisonous but makes an excellent fertilizer.

23. A List of examples of Vegetable fats and Tallows List of examples of vegetable fats is given below:- Names Description Vegetable fats and Tallows These remain solid or semisolid at room temperature. They are edible and also useful in the manufacture of soap and candles. Coconut oil A widely used fatty oil, obtained from dried white interior of the seeds of Cocos nucifera. This is pale yellow or colourless and is solid below 74 deg. Fahrenheit. Refined oil is edible. It is especially adapted for the purpose of margarine as it is solid at room temperatures. It is used for candy industry and for making highest quality soaps, cosmetics, shaving creams, shampoos and suntan lotions. It is used for marine soaps and as an illuminant. The cake is an excellent livestock feed.

24. A List of examples of Vegetable fats and Tallows Palm oil It is a white vegetable fat that is solid at room temperature and which is obtained from Elaeis guineensi Palm kernel oil This is a white vegetable fat that is solid at room temperature. It is brownish red in colour, it is used making soap and in manufacture of tin plate, tern plate and cold reduced sheet steel. The refined oil is used in margarine and vegetable shortenings. It has also been used as a fuel for diesel motors in Africa. This fat like coconut fat has saturated fatty acids and so now a days used less as food. Babassu oil It is the most important of the New World palm oils and is obtained from the babassu palm. Oil is expressed from kernels and when refined it is used as a substitute for coconut oil. It is used in making bulletproof glass, lubricants, and explosives and as a fuel for diesel engines.

25. Differences between animal and plant fats- Animal fat Plant fat 1-These are relatively rich in saturated fatty acids esp.,C16 and C18 acids. 2-These are solid at ordinary room temperature. 3-. These have usually low Iodine number. 4-These have usually high Reichert-Meissl number. 5-These are stored mainly in adipose tissues and liver(in vertebrates). 6- Oxidative rancidity is observed more frequently. These are relatively rich in unsaturated fatty acids, esp., polyunsaturated acids. These remain liquid at ordinary room temperature. These have usually high Iodine number. These have usually low Reichert-Meissl number. These are stored mainly in seeds and fruits. Oxidative rancidity is observed less frequently.

26. Waxes are far less spread but equally important storage lipids. Old English word weax is the originator of the term wax which means’ the material of the honey comb’. Chemically these are esters of long chain saturated and unsaturated fatty acids with long –chain monohydroxy alcohols. The fatty acids range in between C 14 and C 36 and the alcohol range from C 16 to C 36. Some waxes are impervious and harder than fats with higher melting point. They do not become rancid and get less easily hydrolyzed. 7.1_Functions of waxes:- Main functions of waxes are as follows:- In vertebrates, waxes are secreted by cutaneous glands as a protective coating   to keep the skin pliable, lubricated and water- proof. Wool, hair and fur are also coated with wax. Birds secrete waxes to make their feather water- repellent. The leaves of Rhododendron , calotropis , ect., are shiny because of the deposition of protective waxy coating . On leaf epidermis wax coating prevent water loss through transpiration. Waxes are the chief storage fuel in plankton. Since marine organisms (Whale, Herring, and Salmon) consume plankton in large quantities, waxes act as major food and storage lipids in them. Waxes And Functions of Waxes

27. A List of different examples of Waxes Name of the wax Description Sperm whale wax (spermaceti) It is composed mainly of palmitic acid esterified with either hexacosanol CH 3 (CH 2 ) 24 .CH 2 OH, or triacontanol, CH 3 (CH 2 ) 28 .CH 2 OH. This wax is also rich in cetyl palmitate. Bees wax It is composed mainly of palmitic acid esterified with either hexacosanol CH 3 (CH 2 ) 24 .CH 2 OH, or triacontanol, CH 3 (CH 2 ) 28 .CH 2 OH. This wax is also rich in myricyl palmitate. Most of the waxes are mixtures of esters, examples are given below Hexacosanyl palmitate Myricyl palmitate List of different examples of Waxes:-

28. A List of different examples of Waxes Carnauba wax It is the hardest known wax consists mainly of fatty acids esterified with tetracosanol CH 3 (CH 2 ) 22 .CH 2 OH and tetratriacontanol, CH 3 (CH 2 ) 34 .CH 2 OH. It is the most important vegetable wax and is used in the manufacture of candles, soap, high-luster varnishes, paints, carbon paper, batteries, sound films, insulation, salves, ointments and previously phonograph records. Ambretolide It is extracted from seeds of lady’s finger. These have characteristic odour which is due to the presence of hydroxy acids in the form of lactones in them. Candelilla wax It is another vegetable wax which is softer, contains more resin and has lower melting point than carnauba. It is less valuable too.

29. Lipid accumulation as a survival strategy in unicellular organisms--- despite the differences in lipid composition various organisms store lipids intracellularly. Prokaryotes do this as a response to nutrient deprivation or certain imbalance and lipid is stored as intracytoplasmic inclusion bodies . Following table shows the comparison of lipid accumulation from simple prokaryotes to mammals— Lipid storage-from prokaryotes to mammals PHAs- polyhydroxyalkanoates, PHVs- polyhydroxyvalerates , TAG- triacylglycerol, SE-sterol ester, CE-Cholesterol esters, CIDE-cell death inducing DNA fragmentation factor-like effector, Lsd -lipid storage droplet Texa Lipid types Bacteria Polymeric lipids(PHA ,PHV), TAG (in Mycobacteria, Rhodococcus, Dietzia) Yeast 50% triacylglycerol ;50% SE Worms High TAG and low SE Flies High TAG; low SE Fish TAG and CE(in adipocytes) Amphibia TAG and CE(in adipocytes) Reptiles TAG and CE(in adipocytes) Mammals TAG and CE(in adipocytes); mostly SE (in macrophages)

30. Lipid storage :-At cellular level At cellular level lipid droplets (LDs) are ubiquitous dynamic organelles that store and supply lipids in all eukaryotes and some prokaryotes cells for energy metabolism, membrane synthesis, and production of essential lipid derived molecules. Lipid droplets are the dispersed phase of oil in water emulsion in the aqueous cytosol of the cells. Their unique architecture with an interface between the dispersed oil phase and the aqueous cytosol, specific mechanisms underlie their formation, growth and shrinkage which enable cells to use emulsified oil when the demands for metabolic energy or membrane synthesis changes. The cytosol represents the continuous aqueous phase, and the dispersed oil phase, the lipid droplets, includes neutral lipids, such as triacylglycerols, sterol esters, retinyl esters, waxes or ether lipids, depending on the cell type and the neutral lipids they store. The regulation of the composition of the phospholipid surfactants at the surface of lipid droplets is crucial for lipid droplet homeostasis and protein targeting to their surfaces. Cells deal with excess lipids such as fatty acids (which can act as detergents)by esterifying the potentially toxic lipids to form more inert neutral-lipid oils, such as triacylglycerols or sterol esters. The formation of these oils occurs within the membrane bilayers; however, because bilayers are unsuited for storing large amounts of oil an emulsion of oil droplet forms in the cytoplasm. Specific proteins act on cytoplasmic lipid droplets to regulate their growth and utilization in an regulated manner.

31. Lipid storage :-At Tissue level Initially evolved as a facultative response to nutrient deprivation in unicellular organisms, lipid storage in the form of triacylglycerol is primarily handled by a group of specialized cells, namely adipocytes in vertebrates. Adipocytes constitute the majority of cells in the adipose tissue, an active endocrine and immune organ that secretes a plethora of factors (adipokines) that regulate several metabolic processes (like regulation of energy homeostasis) in distant body tissues. Excessive fat accumulation and adipocyte dysfunction (resultant obesity)have been linked to various health complications such as insulin resistant, type 2 diabetes, cardiovascular diseases and cancer. There are two types of fat tissue found in humans: white adipose tissue (WAT) that accumulates lipids, and brown adipose tissue (BAT) that can burn lipids to produce heat. BAT is mainly found in babies, although recent studies show that adults may retain a small amount of BAT.BAT is considered important in obesity research as it represents a potential pathway by which the body can control metabolism by burning excess lipid to produce heat. Using gene expression analysis, immunophenotyping and differentiation tools, they found the two cell types had different properties, in particular in their potential to differentiate into BAT cells, thus indicating a different developmental pathway for the two types of fat cells..