Lipids

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Lipids

  1. 1. A PROJECT REPORT ON- Submitted to: Mrs. MADHU KAGAT (Subject teacher : Food and nutrition, Bio chemistry) Submitted by: HARSHITA BHARGAVA (B.sc. Home sci. II yr)
  2. 2. Lipids are ester of Fatty acids and Glycerol. • They are also naturally occurrence product /substance . • They form a group of organic compound which are widely distributed in living system. • They are formed by carbon, hydrogen and oxygen. • They are also known as fats. • Chemical name of fats is TRIGLYCERIDE • Which have 1 part of glycerol and 3 part of fatty acid. CHEMICAL FORMULA OF LIPIDS. CH3 –CH2-CHn-COOH
  3. 3. Name of food Amount of lipids Calories /100g Ghee 100 900 Oil 100 900 Butter 81.0 729 Coconut 42.0 370 Almonds 59.3 532 Cashew nut 47.0 530 Groundnut 40.1 360 Soybeans 20.0 180 Egg 13.3 120 Fish 3.2 28 Meat 13.3 119 Wheat 7.4 69 Bajara 5.0 45
  4. 4. The major sources come from soybean,  palm, rapeseed/canola, sunflower seed,  coconut and others.  Soybean Oil  The major fatty acids in soybean oil are linoleic (53  %), oleic (23 %), palmitic (11 %), linolenic (8 %) and  stearic (4 %) (Wang, 2002).  A healthy oil, low in saturated acids and rich in  polyunsaturated fatty acids (PUFA), especially  linoleic acid.  Soybean oil in its native but refined form or in some  partially hydrogenated form is widely used for food  purposes such as frying and salad oils, margarine  and shortening, and mayonnaise and salad  dressing. 
  5. 5.                     Palm Oil The oil palm produces two different oils – palm kernel oil and palm oil. Malaysia and Indonesia are the major producing and exporting countries of palm oil. Palm oil is considered as a saturated fat in comparison to the more highly unsaturated vegetable oils. The oil is rich in nutritionally important minor components. Because of its fatty acid composition and its minor components which act as antioxidants, palm oil has high oxidative stability. Palm oil is used for a wide range of food purposes including frying, in spreads and in shortenings. Palm olein is a major frying oil, and palm stearin finds increasing use as hard stock in fat blends which are interesterified to produce spreads with no hydrogenated oil and therefore containing little or no trans acids.
  6. 6. Rapeseed/Canola Oil Rapeseed and canola are terms describing the seed  and extracted oil from Brassica species including B.  napus (formerly B. campestris), B. rapa and  B.juncea.  The seed oil from these species was typically rich in  erucic acid (22:1), and the seed meal had an  undesirably high level of glucosinolates.  Typically it contains palmitic (4 %), stearic (2 %),  oleic (62 %), linoleic (22 %) and linolenic (10 %)  acids and has less saturated acids than any other  commodity oil.  With its low level of saturated acids, its high level of  oleic acid and the presence of linoleic and linolenic  acids at a favourable ratio (~ 2:1) rapeseed oil rates  highly in the classification of healthy oils.  The oil is used as a salad oil and salad dressing and  mayonnaise, in margarine and other spreads, as a  frying oil, and in many minor food applications. 
  7. 7. Sunflower Seed Oil  Oil obtained from sunflower seeds (Helianthus  annuus)  Sunflower oil is available in three ranges of fatty acid  composition. The traditional and still major sunflower  oil is linoleic-rich, but two other forms have been  produced by conventional seed breeding; these are  a high oleic oil and a mid-oleic oil.  Crude sunflower oil contains phospholipids (0.7–0.9  %), tocopherols (630–700 ppm), sterols (~ 0.3 %)  and carotenoids (1.1–1.6 ppm).  The seeds are also a rich source of selenium  compared to most other seeds and nuts.  Sunflower seed oil contains some wax (esters of  longchain alcohols and long-chain acids) coming  from an outer protective seed coat, which makes the  oil appear cloudy.  The oil is to be used as a salad oil. 
  8. 8.  Lauric oils (coconut, palmkernel)  Coconut oil and palmkernel oil are similar to one  another in their fatty acid composition.  Both have high levels of medium-chain saturated  acids, especially lauric acid (12:0), hence the term  lauric oils.  They have only low levels of unsaturated C18 acids  and low iodine values.  They are used extensively both as food and as nonfood  oils and serve as the major source of C8  (caprylic or octanoic) acid and C10 (capric or  decanoic) acid.
  9. 9. There are two major sources of land animal derived  lipids used for human nutrition: the lipids in animal  body tissues, commonly referred to as animal fats or  meat fats, and the milk lipids.  The technical term ‘animal fats’ or ‘meat fats’  actually refers to fat obtained from adipose tissues  of land animals by a process called rendering.  Fat is typically deposited in the abdominal  cavity, particularly around the kidneys and  the stomach (internal fat), peripheral under  the skin (subcutaneous adipose tissue),  between muscles and between muscles and  bones (intermuscular fat) and within skeletal  muscles (intramuscular fat). 
  10. 10. Classification of lipids according to nutritional value in foods: Lipids Simple Compound Types of classification: Simple Compound Derived/Sterols •Fats and oil •Wax •Sulpholipids •Glycolipids •phospholipis •liprotein Derived/Sterols
  11. 11. Derived lipids: These are the substance liberated after the hydrolysis of simple and compound lipids.
  12. 12. Structure of fatty acid
  13. 13. CHEMICAL FORMULA OF:- Saturated fatty acid :CH3-CH2-CH2-COOH Butyric acid: CH3-CH2-CH2-COOH Caprylic acid: CH3(CH2)8 COOH Palmitic acid:CH3(CH2)14 COOH Stearic acid: CH3(CH2)16 COOH Unsaturated fatty acid Mono unsaturated fatty acid: a.) oleic acid: C18 H34 O2 b.) palmitolic acid: C16 H30 O2 polyunsaturated fatty acid: a.) linolic acid: C18 H32 O2 b.) eleostearic acid: C18 H30 O2 c.) arachidonic acid: C20 H32 O2
  14. 14. Unsaturate d fatty acid Saturated fatty acid
  15. 15.  Physical Properties of Oils & Fats  Thermal properties:  crystallization & melting  the formation of solid and liquid  the behavior of plastic fats that are mixtures of solid and  liquid components  Mandatory, example:  salad oils do not contain lipids that will crystallize during  storage in a refrigerator.  Most frying oils and oils used as food coatings (and  lubricants) should also be free of solid components
  16. 16.  Physical Properties of Oils & Fats  Spreads:  depends on having appropriate levels of solid fat at  refrigerator temperature, at ambient temperature and  at mouth temperature.  The solid fat content at 4 °C should not exceed 30– 40  % (to be spreadable from the refrigerator); at 10 °C it  should be 10–20 % (the fat will ‘stand up’ --- not  collapse to a puddle of oil).
  17. 17.  Chemical Properties of Oils & Fats  Food lipids are not usually considered to require  defined chemical properties, but without  oxidative stability of their lipid components foods  would quickly become rancid and have a short  shelf life.  For this reason they should be oxidatively stable.  This can be determined by the peroxide value of  fats/oils. This indicates the degree of oxidation  that has been taken place in a fat/ oil.  Saponification value indicates the average molecular weight of fatty acid in a fat.
  18. 18.  Chemical Properties of Oils & Fats  Iodine value – express the degree of  unsaturation of the FAs in the fat (the amount of  iodine absorbed by a fat/100 g basis). The  higher iodine value indicates the greater the  degree of unsaturation.  Hydrolytic rancidity refers to the rancidity that  occurs under conditions of moisture, high  temperature, and natural lipolytic enzymes. The  acid value represents free fatty acids in fat that  were released during hydrolysis.
  19. 19. HYDROLYSIS Hydrolysis is the process where in a covalent bond within a molecule is broken down. A water molecule is used up in the process (hydro=water ; lysis=cut/sever) Usually the process results in one of the reaction products having a Hydrogen atom where the bond used to be, and the other having a hydroxyl group (-OH, also known as an alcohol) In the case of lipids, the molecule itself consists of a glycerol backbone bonded to three long chain fatty acids. Hydrolysis of the lipid results in breaking the fatty acids off, leaving free fatty acids and a glycerol molecule, and using up three water molecules. This process can be catalyzed under acidic or basic conditions, and is actually how soap is made. Reacting the free fatty acids with some ionic salts actually gives you soap. The left over glycerol is more commonly known as glycerin, which is itself found in a great many products.
  20. 20.  Types  Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both substance and water molecule to split into two parts. In such reactions, one fragment of the target molecule (or parent molecule) gains a hydrogen ion.  Esters and amides  Perhaps the oldest commercially practiced example of ester hydrolysis is saponification (formation of soap). It is the hydrolysis of a triglyceride (fat) with an aqueous base such as sodium hydroxide (NaOH). During the process, glycerolis formed, and the fatty acids react with the base, converting them to salts. These salts are called soaps, commonly used in households
  21. 21. SAPONIFICATION Saponification is a process that produces soap, usually from fats and lye. In technical terms, saponification involves base (usually caustic soda NaOH) hydrolysis of triglycerides, which are esters of fatty acids, to form the sodium salt of a carboxylate . In addition to soap, such traditional saponification processes produce glycerol. "Saponifiable substances" are those that can be converted into soap. . Saponification is the alkaline hydrolysis of the fatty acid esters.
  22. 22. . In the industrial manufacture of soap, tallow (fat from animals such as cattle and sheep) or vegetable fat is heated with sodium hydroxide. Once the saponification reaction is complete, sodium chloride is added to precipitate the soap. The water layer is drawn off the top of the mixture and the glycerol is recovered using vacuum distillation
  23. 23.    One of the organic chemical reactions known to ancient man was the preparation of soaps through a reaction called saponification. Natural soaps are sodium or potassium salts of fatty acids, originally made by boiling lard or other animal fat together with lye or potash (potassium hydroxide). Hydrolysis of the fats and oils occurs, yielding glycerol and crude soap. Vegetable oils and animal fats are the main materials that are saponified. These greasy materials, triesters called triglycerides, are mixtures derived from diverse fatty acids. Triglycerides can be converted to soap in either a one- or a two-step process. In the traditional one-step process, the triglyceride is treated with a strong base (e.g., lye), which accelerates cleavage of the ester bond and releases the fatty acid salt and glycerol. This process is the main industrial method for producing glycerol. If necessary, soaps may be precipitated by salting it out with saturated sodium chloride. The saponification value is the amount of base required to saponify a fat sample. For soap making, the triglycerides are highly purified, but saponification includes other base hydrolysis of unpurified triglycerides, for example, the conversion of the fat of a corpse into adipocere , often called "grave wax." This process is more common where the amount of fatty tissue is high, the agents of decomposition are absent or only minutely present. Cheese
  24. 24.  Fats and oils are esters made from glycerol propanetriol) and long chain fatty acids such as stearic acid ( ). Different acids combined with glycerol produce different fats and oils  Glycerol is an alkanol with 3 hydroxy groups and the formula CH2OHCHOHCH2OH. Its systematic name is 1,2,3-propanetriol.  During saponification glycerol present in fats and oil act as acid which react with base and separetes after the reaction as a bi-product.
  25. 25. SAPONIFICATION ON REACTION OF GLYCEROL..
  26. 26. EXAMPLES
  27. 27. Saponification Explained  In simple terms, saponification is the name for a chemical reaction between an acid and a base to form a salt. While making soap using the cold process, mix an oil or fat (which is acid) with Lye (which is base) to form soap (which is a salt).   The base must always be composed of one hydroxide ion. For the most part, people use lye (one sodium ion and one hydroxide ion) as their base. Notice that the sodium ion does not take part in the reaction at all. For this reason, other bases like potassium hydroxide can be used as well because it too is made up of one hydroxide ion. Potassium hydroxide is more prominently used for liquid soap making.   There are many different types of acids that will react with base and saponify.Acid could be olive oil, coconut oil or tallow among others. Each acid has a unique combination of triglycerides (compounds made of three fatty acids, attached to a single molecule of glycerol) which combines with the base (lye) differently. The amount of base needed to react with the acid will vary depending on the chemical makeup of the acid..   Combine , and stir the carefully measured acid and base together, they start to react. The triglycerides within the acid release the single glycerol molecule (which turns into skin nourishing glycerin) allowing the fatty acids to combine with the hydroxide ions within the base, forming soap.   Two reactions occur. The first reaction is glycerol turning into beneficial glycerin, and the second reaction is the acid and the base combining to form a salt which is soap.
  28. 28. Unsaturated fatty acids may be converted to saturated fatty acids by the relatively simple hydrogenation reaction. The addition of hydrogen to an alkene (unsaturated) results in an alkane (saturated). A simple hydrogenation reaction is:
  29. 29. Hydrogenation – to treat with hydrogen – is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, generally an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogenation reduces double and triple bonds in hydrocarbons. Because of the importance of hydrogen, many related reactions have been developed for its use. Most hydrogenations use gaseous hydrogen (H2), but some involve the alternative sources of hydrogen, not H2: these processes are called transfer hydrogenations. The reverse reaction, removal of hydrogen from a molecule, is called dehydrogenation. A reaction where bonds are broken while hydrogen is added is called hydrogenolysis, a reaction that may occur to carbon-carbon and carbon-heteroatom (oxygen, nitrogen or halogen) bonds. Hydrogenation differs from protonation or hydride addition: in hydrogenation, the products have the same charge as the reactants. Hydrogenation of unsaturated fats produces saturated fats. In the case of partial hydrogenation, trans fats may be generated as well.
  30. 30. EXAMPLE OF REACTION OF HYDROGENATION
  31. 31. Halogenation is a chemical reaction that involves the reaction of a compound, usually an organic compound, with a halogen. Halogenated fatty acids which are one of the most interesting groups among the naturally occurring halogen compounds are not well known but several reviews on these compounds may be found. Halogenated fatty acids are found in different groups of organisms from microorganisms to the highest plants and animals. As halogen, they contain one or several atoms of fluor, chlorine, or bromine. • Fluorinated fatty acids • Chlorinated fatty acids • Brominated fatty acids
  32. 32. FLUORINATED FATTY ACIDS CHLORINATED FATTY ACIDS BROMINATED FATTY ACIDS
  33. 33. IODINE NUMBER The iodine value (or "iodine adsorption value" or "iodine number" or "iodine index") in chemistry is the mass of iodine in grams that is consumed by 100 grams of a chemical substance. Iodine numbers are often used to determine the amount of unsaturation in fatty acids. Full Definition of IODINE NUMBER : a measure of the unsaturation of a substance (as an oil or fat) expressed as the number of grams of iodine or equivalent halogen absorbed by 100 grams of the substance <the iodine numbers of linseed oil, olive oil, and coconut oil are approximately 175–201, 77–91, and 8–9.5 respectively>
  34. 34. What is rancidity?  Rancidity is the development of unpleasant smells in fats and oils, which are often accompanied by changes in their texture and appearance.  Two types of rancidity: Hydrolytic rancidity Oxidative rancidity (auto-oxidation)
  35. 35. Hydrolytic rancidity Oxidative rancidity (auto-oxidation) Caused by the breaking down of a lipid Occurs due to the oxidation of fatty into its component fatty acids and acid chains, typically by the addition of glycerol. oxygen across the C=C bond in unsaturated fatty acids. C-O-CO-R + H2O → C-O-H + HO-CO-R Occurs more rapidly in the presence of The process proceeds by a free radical enzymes such as lipase, and with heat mechanism catalysed by light in the and moisture. presence of enzymes or metal ion. The water present in the food and the The complex free radical reactions will high temperature will increase the rate produce a wide variety of products, of hydrolysis to fatty acids. many of which have unpleasant odours or tastes. The free fatty acids have an unpleasant In highly unsaturated lipids, such as fish smell giving a rancid smell and taste to oils, oxidative rancidity can be a major milk and butter that have been stored problem. for too long. Longer chain acids are less volatile, so the smell is less noticeable.
  36. 36.  Packaging - Opaque packaging and coloured glass bottles will reduce light induced oxidative rancidity. - Gas impermeable wrapping film will reduce the exposure of the product to oxygen and water vapour in the air. - Free space in the container should be kept to minimum to reduce the amount of oxygen and water vapour present. The best way is to use vacuum packaging or fill the package with inert gases. -Example: Potato crisps which are usually packed in thick foil packets filled with nitrogen.
  37. 37. Acid value (or "neutralization number" or "acid number" or "acidity") is the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of chemical substance. The acid number is a measure of the amount of carboxylic acid groups in a chemical compound, such as a fatty acid, or in a mixture of compounds.
  38. 38. The acid number is used to quantify the amount of acid present, for example in a sample of biodiesel. It is the quantity of base, expressed in milligrams of potassium hydroxide, that is required to neutralize the acidic constituents in 1 g of sample. Veq is the volume of titrant (ml) consumed by the crude oil sample and 1 ml of spiking solution at the equivalent point, beq is the volume of titrant (ml) consumed by 1 ml of spiking solution at the equivalent point, and 56.1 is the molecular weight of KOH. WOil is the mass of the sample in grams. The molar concentration of titrant (N) is calculated as such:
  39. 39. Phospholipids. A Phospholipid molecule is like a triglyceride in which one of the fatty acids have been replaced by a phosphate group. The phosphate group gives the phospholipid a hydrophilic head and a hydrophobic tail. Phospholipids have two ends. A head that contains a phosphate group. This has an uneven charge that makes the head able to mix with water (hydrophilic). A tail that contains 2 fatty acid chains. They have an even charge and this makes them unable to mix with water (hydrophobic).
  40. 40. Cholesterol is a fat-like substance with a waxy consistency that is produced in the livers of humans and other animals. Every human cell needs a minute amount of cholesterol in order to function properly. While some cholesterol is essential, too much can be harmful. Cholesterol is a lipid with a unique structure consisting of four linked hydrocarbon rings forming the bulky steroid structure. There is a hydrocarbon tail linked to one end of the steroid and a hydroxyl group linked to the other end. The hydroxyl group is able to form hydrogen bonds with nearby carbonyl oxygen of phospholipid and sphingolipid head groups. Cholesterol is known as a "sterol" because it is made out of a alcohol and steroid. Cholesterol is present in most animal membranes with varying amounts but is absent in prokaryotes and intracellular membranes.
  41. 41. Function Cholesterol is required to build and maintain membranes; it modulates membrane fluidity over the range of physiological temperatures The structure of the tetracyclic ring of cholesterol contributes to the decreased fluidity of the cell membrane as the molecule is in a trans conformation making all but the side chain of cholesterol rigid and planar cholesterol also functions in intracellular transport, cell signaling and nerve conduction cholesterol has also been implicated in cell signaling processes, assisting in the formation of lipid rafts in the plasma membrane.
  42. 42. Dietary sources Major dietary sources of cholesterol include cheese, egg yolks, beef, pork, poultry, fish, and shrimp. Hum an breast milk also contains significant quantities of cholesterol.

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