Lipids - Lumaghan-Morales-Taupan PDF

LIPIDS 1. Lipids - A biomolecule that contains fatty acids or a steroid nucleus - Soluble in organic solvents but not in water - Derived from the Greek word lipos which means fat - Extracted from cells using organic solvents Types...

LIPIDS 1. Lipids - A biomolecule that contains fatty acids or a steroid nucleus - Soluble in organic solvents but not in water - Derived from the Greek word lipos which means fat - Extracted from cells using organic solvents Types of Lipids: - Waxes - Fats and oils (triacylglycerols) - Glycerophopholipids - Prostaglandins - STEROIDS DO NOT CONTAIN FATTY ACIDS Structures of Lipids 2. Fatty acids - Long-chain of carboxylic acid - Typically contains 12-18 carbon atoms - Insoluble in water - It can be saturated or unsaturated  - There are two ways to write the formula of a fatty acid (e.g.: caprylic acid with 8 carbon atoms): - Condensed formula: - Line-bond Formula: 2.1 Fatty Acids (Saturated) - Single C-C bonds - Molecules that fit closely together in a regular pattern - Strong attractions between fatty acid chains - High melting points that resulted in their solid composition at room temperature - Some examples of foods high in saturated fats are beef, cheese, butter, and ice cream  2.2 Some Saturated Fatty Acids 3. Fatty acids (Unsaturated) - Have one or more double C=C bonds - Typically contain cis double bonds - Have two types of double bonds: - cis-Oleic acid, Cis double bond: both hydrogen atoms are located on the same side  - trans-Oleic acid, Trans double bond: two hydrogen atoms are on opposite sides - Have ‘kinks’ in the fatty acid chains: - Do not pack closely - Have few attractions between chains - They have low melting points, resulting in their liquid form at room temperature - Some examples of unsaturated fat foods are olive oil, avocado,  3.1 Comparing Melting Points of Some Fatty Acids 4. Waxes, Fats, and Oils 4.1 Waxes - Lipid molecules composed of glycerol and three fatty acids - Formed through esterification (condensation) reaction - Key energy storage compounds in biological systems 4.2 Triacylglycerols ( Fats and oils ) - made up of -OH group and this molecule referred to as glycerol and 3 fatty acids - Formation of Triglycerides:  - Esters derived from glycerol. - Formed through esterification. - Created when the hydroxyl groups of glycerol react with the carboxyl groups of fatty acids. 4.3 Melting Points Fats - State at Room Temperature: Solid. - Sources: Commonly found in animal-based products like: - Meats - Whole milk - Butter - Cheese Oils - State at Room Temperature: Liquid. - Sources: Typically derived from plant-based sources such as: - Olive - Safflower 5. Chemical Properties of Triacylglycerols (Hydrogeneration, Hydrolysis, Olestra) - Triglycerides can be chemically transformed to modify their structural and functional properties through processes like hydrolysis, hydrogenation, and olestra synthesis. 5.1 Triacylglycerols reactions Hydrogenation - Adds hydrogen (H₂) to carbon atoms with double bonds - Converts unsaturated to saturated fatty acid structures - Increases the melting point of lipids - Transforms liquid oils into solid products - Produces commercial food products like margarine and shortening  Hydrolysis - Chemical breakdown of triglycerides using water - Splits triglyceride molecules into component parts - 1. One glycerol molecule - 2. Three fatty acid molecule - Typically catalyzed by lipase enzymes or chemical reagents Olestra - Synthetic fat molecule designed to be indigestible - Zero-calorie fat substitute - Regulated and restricted in some food products - Trigger gastrointestinal discomfort 6. Cis and Trans Fatty Acids Hydrogeneration - Hydrogenation transforms unsaturated fatty acids by restructuring molecular geometry, creating distinct isomers with significant implications for food chemistry and health. 6.1. Cis Fatty Acids - Natural configuration in unsaturated fats - Double bond creates a slight bend in molecular structure - Found in most natural oils - Typically considered healthier 6. 2 Trans Fatty Acids - Formed during hydrogenation by converting cis double bonds to trans configurations - Metabolically behave like saturated fats, negatively impacting cholesterol levels - Contribute 2-4% of total dietary calories, significantly increasing cardiovascular disease risk - Increases shelf stability of foods 7. Glycerophospholipids (Structure and Polarity) - The most abundant lipids in cell membranes. Composed of glycerol, two fatty acids, phosphate and an amino alcohol. 7.1 Glycerophospholipids are polar - Two nonpolar fatty acid chains. - A phosphate group and a polar amino alcohol. 7.2 Structure and Polarity of a Glycerophospholipids  7.3 Lecithin and Cephalin - Abundant in brain and nerve tissues - Found in egg yolk, wheat germ, and yeast 8. Sphingolipids and Lipid Diseases - Are similar to phospholipids. - Contain sphingosine (a long-chain amino alcohol), a fatty acid, phosphate, and a small amino alcohol. Have polar and nonpolar regions. - A long-chain unsaturated amino alcohol.  Sphingomyelin, a sphingolipid found in nerve cells - There is an amide bond between a fatty acid and sphingosine, an 18-carbon alcohol. 8.1 Glycosphingolipids - contain monosaccharides bonded to the -OH of sphingosine by a glycosidic bond. Glycosphingolipids and Cerebrosides - Are sphingolipids that contain monosaccharides. - Can be a cerebroside with galactose.  8.3 Gangliosides - Similar to cerebrosides, but contain two or more monosaccharides. - Are important in neurons. Act as a receptor for hormones and viruses. - Can accumulate and cause genetic diseases. GM₂ is a ganglioside