Organic Acids: Carboxylic Acid PDF

Organic Acids: Carboxylic Acids Sir Rm Organic Acids ► are weak acids with pKa values ranging from 3 (carboxylic) to 9 (phenolic) meaning that they do not dissociate totally in a neutral aqueous solution to produce H+ cations. Organic Acids ► The representative low...

Organic Acids: Carboxylic Acids Sir Rm Organic Acids ► are weak acids with pKa values ranging from 3 (carboxylic) to 9 (phenolic) meaning that they do not dissociate totally in a neutral aqueous solution to produce H+ cations. Organic Acids ► The representative low molecular weight organic acids have a relatively low pKa. ► play significant and varied roles in our contemporary society as evidenced by multiple applications in the field of medicine, agriculture, pharmaceuticals, food, and other industries. Organic Acids ► have important roles in the food industry, since they affect the organoleptic properties and the stability of food items. Organic Acids ► They can be present as natural food components, for example, the acids present in fruits and vegetables, or added artificially, as acidulants, preservatives, emulsifiers, antioxidants, or flavors in a wide variety of products for human consumption. ► The level and nature of organic acids present in foods and drinks provide relevant information for monitoring the fermentation processes, control the production, storage, and distribution stages or identify possible adulteration actions. Organic Acids ► Precisely for this purpose, analytical methods need to be continuously developed and applied in order to identify and quantify the amounts of different acids present in food and beverages. ► The beverage industry is one of the most controlled and regulated industries in terms of composition and authenticity of products. ► Are well-known as effective preservatives, and their antimicrobial action is due to the ability to change from undissociated to dissociated form, depending on the environmental pH, making them effective antimicrobial agents. Organic Acids ► An example, some organic salts prevent spoilage by inhibiting the growth of bacteria and fungi and are used as preservatives in dairy and bakery food products. ► Several studies on the inhibitory effect of various organic acids on PPO ► The successful results of these studies have had a positive economic impact in the food industry, where maintaining the quality and extending the products shelf-life represents a necessity Organic Acids ► are intermediate metabolites of all major groups of organic cellular components, it has been repeatedly proven that their presence in excess in various fluids of the human body is linked to the manifestation of certain diseases. ► are indicators of organic acidurias associated with various inborn errors of protein metabolism. ► More than 65 disorders well-known these days are due to enzyme deficiency in the amino acids degradation pathways resulting in an increase of the organic acid concentration in circulation or excreted urine Organic Acids ► This toxic accumulation of metabolites, which are not present under physiological conditions in the organism, causes an intoxication-like clinical condition. ► The urinary organic acid pattern yielded from these metabolic abnormalities is essential for diagnosis. For example, the levels of HVA and VMAs in body fluids are used in the diagnosis of neurological diseases and disorders. ► Studies of the metabolic fingerprints associate the alternative less efficient degradation pathways of fatty acids that leads to increased levels of adipic and suberic acids in urinary excretion with disorders like autism. Carboxylic Acids ► Knows as an Organic Acids ► Are the compounds containing in the molecule the carboxyl functional group attached to the hydrocarbon radical. ► They are largely distributed in nature and are intermediates in the degradation pathways of amino acids, fats, and carbohydrates. Carboxylic Acids ► In the IUPAC nomenclature, carboxylic acids have an “-oic acid” suffix added to hydrocarbons having the same number of carbon atoms. ► Still, some organic acids are called by their common name, for example, formic acid and acetic acid. ► The molecular weight of organic acids varies widely from relatively small compounds such as formic and acetic acids too much larger compounds with higher numbers of carboxylic and phenolic functional groups. Carboxylic Acids ► As the carbon chain length increases the acids are waxlike solids, and their smell diminishes with increasing molar mass and decreasing volatility. ► Due to the presence of both hydroxyl and the carbonyl groups in the molecule, the carboxylic acids can exhibit hydrogen bonding with themselves leading to increased stabilization of the compounds and show elevated boiling points. ► They are polar molecules soluble in polar solvents, but as the alkyl chain increases their solubility decreases due to the hydrophobic nature of the carbon chain  Carboxylic Acids ► In non-polar media, carboxylic acids exist as dimeric pairs due to their capacity to form hydrogen bonds ► are compounds occurring naturally in different stages of life cycles or can be produced in the laboratories or at large scale (synthesis) from oxidation reactions of aldehydes, primary alcohols, and hydrocarbons, oxidative cleavage of olefins, base catalyzed dehydrogenation of alcohols or through the hydrolysis of nitriles, esters, or amides. ► Carboxylic acids and their derivatives are used in the production of polymers, biopolymers, coatings, adhesives, and pharmaceutical drugs. Carboxylic Acids ► They also can be used as solvents, food additives, antimicrobials, and flavorings. ► have a beneficial effect on micro-organisms, helping their growth by acting as vitamins for microbial nutrition. ► also play significant roles in the medicinal fields. Monocarboxylic Acids ► with 5–10 carbon atoms in the chain ► are colorless liquids with unpleasant smells. Carboxyl Group ► consisting of a carbonyl (C=O) with a hydroxyl group (O–H) attached to the same carbon atom and is usually written as –COOH or CO2H. ► The compounds presenting two or more carboxylic groups are called dicarboxylic, tricarboxylic acids, while their salts and esters are called carboxylates. ► By the nature of the radical, they can be classified into saturated, unsaturated, or aromatic acids. Miscellaneous Polyphenol Oxidase (PPO) ► the enzyme responsible for the browning of damaged fruits and vegetables, have been conducted over the years. End