Organic Acids and Their Applications

Organic Acids: Carboxylic Acids

• Organic acids, also known as carboxylic acids, are weak acids.
• Their pKa values range from 3 (carboxylic) to 9 (phenolic).
• They do not completely dissociate in neutral aqueous solutions, meaning they do not produce all their H⁺ cations.

pH Scale

• The pH scale measures acidity or alkalinity of a substance.
• A pH of 7 is neutral.
• A pH less than 7 is acidic.
• A pH greater than 7 is alkaline (basic).

Low Molecular Weight Organic Acids

• Low molecular weight organic acids play significant roles in contemporary society.
• They are found in various applications, including medicine, agriculture, and the food industry.

Organic Acids in Food Industry

• Organic acids are involved in food properties and stability.
• They affect organoleptic properties (taste, smell, touch, sight, and hearing).
• The level and type of organic acid present in food help monitor fermentation processes.
• Monitoring helps control production, storage, and distribution, and identify possible adulteration.

Analytical Methods

• Analytical methods are continuously developed and used to identify and measure the amounts of different acids in food and drinks.
• The beverage industry is one of the most highly controlled and regulated industries dealing with composition and authenticity of their products.
• Organic acids are used as antimicrobial preservatives.

Organic Acids and Food Products

• Organic salts prevent spoilage by inhibiting the growth of bacteria and fungi.
• They are used as preservatives in dairy and bakery products.
• Studies on the inhibitory effects of organic acids have positive economic impacts in the food industry.
• Maintaining quality and extending shelf life of products is a necessity for the food industry.

Indicators of Organic Acidurias

• Organic acids are intermediate metabolites found in all major organic components of cells.
• Excess presence of these acids in body fluids is linked to certain diseases.
• Organic acidurias, associated with various inborn errors of metabolism, also have more than 65 different disorders known today.
• These disorders result from enzyme deficiency in amino acid degradation pathways.
• Organic acid concentrations increase in circulation or excreted urine.

Toxic Accumulation of Metabolites

• Toxic accumulation of metabolites occurs in cases where they are not present in physiological conditions.
• Urinary organic acid patterns can help determine the cause of metabolic abnormalities that result.
• Levels of certain metabolites, like HVA and VMAs, help diagnose neurological diseases.
• Studies show increased levels of specific organic acids like adipic and suberic in the urine which can be linked with disorders like autism.

Carboxylic Acids (Chemical Composition)

• Carboxylic acids are compounds containing a carboxyl group (-COOH) attached to a hydrocarbon radical.
• This group is often written as -COOH or -CO₂H.
• Carboxylic acids can exist as dimers (two molecules joined together) due to hydrogen bonding.

Carboxylic Acids-IUPAC Nomenclature

• IUPAC nomenclature for carboxylic acids uses the prefix of the corresponding alkane with the suffix "-oic acid."
• Common names are used for some carboxylic acids such as formic (methanoic) and acetic acid (ethanoic).

Carboxylic Acids-Chemical Properties

• Solubility in polar solvents is affected by the "alkyl" chain.
• Chain length influences the state (solid, liquid, gas) and volatility of the acid.
• Longer chains lead to wax-like solids.
• The presence of hydroxyl and carbonyl groups often leads to hydrogen bonding, higher boiling points, and increased stability.

Carboxylic Acids in Nature and Production

• Carboxylic acids occur naturally through the different stages in life cycles.
• They are also produced in large-scale laboratories through different reactions and processes.
• This includes oxidation of aldehydes, primary alcohols, cleaving of olefins, and dehydrogenation of alcohols and hydrolysis of esters, amides, and nitriles.
• Carboxylic acids and their derivatives are often used in polymer products, coatings, adhesives, and pharmaceuticals).

Additional Uses of Carboxylic Acids

• Carboxylic acids are used as solvents, food additives, antimicrobials, and flavorings.
• They can have a beneficial effect on microorganisms by supporting growth.
• They play a role in medicinal fields.

Monocarboxylic Acids

• Monocarboxylic acids with 5-10 carbon atoms are colorless and have unpleasant smells.

Carboxyl Group

• The carboxyl group consists of a carbonyl group (C=O) connected to a hydroxyl group (–OH).

Phenol

• Phenol is a type of organic acid with a hydroxyl (–OH) group on a benzene ring.

Miscellaneous

• The chemical that causes fruits and vegetables to brown when injured is called Polyphenol Oxidase (PPO).

This quiz covers the properties, pH scale, and roles of low molecular weight organic acids, especially carboxylic acids. Explore their importance in various industries, including food, medicine, and agriculture, while understanding their effects on taste and stability.