1. FUNCTIONS
1.1. Preservatives
1.1.1. stop the growth of microbes
1.1.2. enhance the work of heat sterilization
1.1.3. anti-browning agent
1.2. Buffering capacity
1.2.1. maintain pH to protect from color and flavour alters
1.2.2. maintain acidic fermentation process
1.2.3. i.e : citric acid, tartaric acid
1.3. Leavening action of CO2
1.3.1. i.e : citric acid
1.4. Chelate formation
1.4.1. ring struct forming to prevent metal ions react with other material
1.4.2. i.e : citric acid, lactic acid
1.5. Antioxidant
1.5.1. fat and oil preservation
1.6. Flavour enhancer
1.6.1. i.e : acetic acid, citric acid
1.7. Gelation control
2. ORGANIC
2.1. Carboxylic acid
2.1.1. Monocarboxylic acid
2.1.1.1. acetic acid
2.1.1.2. propionic acid
2.1.1.3. lactic acid
2.1.2. Dicarboxylic acid
2.1.2.1. malic acid
2.1.2.2. tartaric acid
2.1.2.3. adipic acid
2.1.2.4. fumaric aci
2.1.3. Tricarboxylic acid
2.2. Phenolic acid
2.2.1. benzoic acid
2.3. Fatty acid
2.3.1. sorbic acid
2.3.2. caprylic acid
2.3.3. butyric acid
2.4. Lactones
2.4.1. ascorbic acid
2.4.2. gluconolactane