08 : Carbohydrate Protein Lipid 1. Definition of carbohydrates Carbohydrates ('hydrates of carbon', carbon hydrates) or saccharides derived from Greek meaning "sugar" are complex organic compounds that are most commonly found in various food ingredients, both animals and plants. Carbohydrates are natural carbonyl compounds with several hydroxyl groups. Adenosine triphosphate (ATP), as a universal means of exchanging free energy, is a phosphorylated sugar derivative. The structure of carbohydrates is also in the form of ribose and deoxyribose sugars which form part of the structural framework of RNA and DNA. The flexibility of these two sugar rings is important in the storage and expression of genetic information. Glycophyrin sugar, a single integral membrane protein, provides red blood cells with a layer of highly polar anions. Several studies have revealed that carbohydrate units on the cell surface play a key role in the intercellular recognition process. 2. Definition of Protein Protein comes from the Greek proteios which means first or main sequence by Jons J. Berzelius 1938. Proteins are among the most abundant macromolecules that can be found in living cells. Protein is the main structural component of all body cells and functions as enzymes, hormones and other important molecules. Protein is known as a unique nutrient because it provides essential amino acids to build body cells and is a source of energy. Protein quality varies greatly and depends on the protein's amino acid composition and digestibility. Animal protein obtained from eggs, fish, meat, poultry and milk, is generally high quality protein. As for vegetable protein obtained from grains and nuts, it is generally lower quality protein, except for soybeans and their processed products (tempeh, tofu). Foods with high protein digestibility (>95%) are eggs, beef (98%), cow's milk and soybeans (95%). However, if nuts and grains are consumed in combination, vegetable protein can form a more complete protein. Protein molecules have a very high level of diversity, for this reason proteins can be classified based on their properties, one of which is based on biological function, namely: 1. Enzymatic catalyst; Almost all chemical reactions in living cells are catalyzed by specific macromolecules called enzymes. 2. Transport and storage; various small molecules and ions are transported by specific proteins, for example oxygen transport in erythrocytes by hemoglobin, iron in blood plasma is bound to transferrin and stored in the liver in the form of a ferritin complex 3. Movement coordination; Muscle contractions occur due to the shifting of two types of protein filaments and the movement of chromosomes in mitosis and the movement of sperm by flagella. 4. Mechanical support; Skin and bone tension is caused by the presence of collagen, a type of fibrous protein. 5. Immune protection; Antibodies are proteins that can recognize foreign objects such as viruses, bacteria, etc. 6. Generate and transmit nerve impulses; Nerve cell responses to specific stimuli are mediated by receptor proteins. 7. Regulation of growth and differentiation; regulation of the sequence of expression of genetic information is important for cell growth and differentiation. Proteins can be isolated from whole cells and cell parts. The average composition of chemical elements contained in protein is as follows: 50% carbon, 7% hydrogen, 23% oxygen, 16% nitrogen, 0-3% sulfur, and 0-3% phosphorus. By relying on a nitrogen content of 16%, the protein content in a food can be determined. Amino acids are the monomeric units that make up proteins, and amino acids are the primary products of protein breakdown. If proteins are heated in a strong acidic or basic environment, the covalent bonds that connect one amino acid to another will be broken, as a result we will get relatively simpler molecules, namely amino acids. The first amino acid isolated was aspargine, which was discovered in 1806. 3. Definition of Lipids Lipids (Greek: lipos, fat) are one of the 4 macromolecules found in all living cells. Unlike carbohydrates, proteins and nucleic acids, lipid compounds are not polymers. Lipids are found in all parts of the human body, especially in the brain and lipids have an important role in metabolism and most tissue cell lipids are found as the main component of cell membranes. Lipids are a group of biological compounds that are generally soluble in organic solvents such as chloroform and methanol, and insoluble in water solvents which have an important role as the main source of energy reserves for living things, such as triacylglycerol. Besides that, it also acts as an insulator which functions as a heat retainer so that body temperature can be maintained in normal conditions. Phospholipids and cholesterol, important compounds that form cell membranes and precursors of sexual hormones. Lipids also act as vitamins, namely lipid-soluble vitamins such as A, D, E, K. Based on the level of carbon group bonding ability, we can distinguish several types of lipids, namely: a. Fatty acids are compounds consisting of a long hydrocarbon and a carboxylic group attached to the end. Fatty acids have two important physiological roles, namely: (1) forming phospholipids and glycolipids which are amphipotic molecules as components of biological membranes; (2) as an energy source molecule. b. Glycerides, lipids which have the main function as energy reserves. Glycerides consist of neutral glycerides and phosphoglycerides. c. Complex lipids, lipid groups that bind to other compounds, complex lipids consist of lipoproteins; if lipids bind to proteins (cholesterol) and glycolipids; Lipids bind to glycogen compounds. d. Non-glycerides, lipid compounds that are not bound to glycerol consist of sphingolipids and steroids. Based on the level of saturation or the presence of double chain bonds of carbon atoms, lipids are divided into two parts :1) saturated lipids; does not have double chain bonds in the carbon group. In everyday life we can recognize saturated fats including: animal fats and plant fats (oils) that have been heated to temperatures above 60oC.2) unsaturated lipids; has double chain bonds at its carbon atoms. In everyday life we can recognize unsaturated fats, including: vegetable fats and sea fish fats.