Definitions [3]
Define:
a. Analgesics
b. Antimicrobials
a. Analgesics: The drugs which relieve pain by acting on the central nervous system without loss of consciousness or disturbance of the nervous system are called analgesics.
b. Antimicrobials:
The drugs used to kill or stop the growth of micro-organisms like fungi, bacteria, and virus are called antimicrobial drugs.
A chemical which interacts with biomolecules such as carbohydrates, lipids, proteins and nucleic acids and produces a biological response is called a drug.
When the biological response is therapeutic and useful, then the chemicals are called medicines.
Key Points
What Food Does:
- Food provides nutrients used by the body as the source of energy; nutrients also regulate growth, maintain and repair body tissues
- Nutrients include: carbohydrates, lipids, proteins, vitamins, minerals, and water
- Quality of food changes on shelving due to enzyme action, chemical reactions with the environment, and action of microorganisms
- Food preservation and processing are essential techniques to enhance shelf life, safety, and nutritional value
Main Categories of Food Additives:
| No. | Category | Purpose |
|---|---|---|
| i | Food colours | Appearance |
| ii | Flavours and sweeteners | Taste |
| iii | Fat emulsifiers and stabilising agents | Texture |
| iv | Flour improvers — antistaling agents and bleaches | Quality |
| v | Antioxidants | Prevent oxidation |
| vi | Preservatives | Shelf life |
| vii | Nutritional supplements (minerals, vitamins, amino acids) | Nutrition |
Natural Fats and Their Physical States:
| Property | Saturated Fats | Mono-unsaturated Fats | Poly-unsaturated Fats |
|---|---|---|---|
| van der Waals force | Strong | Weak | Weak |
| Physical state | Solid | Liquid | Liquid |
| Examples | Coconut oil, butter, margarine, vanaspati ghee | Olive oil, peanut oil, canola oil | Safflower oil, sunflower oil, soyabean oil, corn oil, fish oil |
Cleansing agents are substances used to remove stain, dirt, or clutter from a surface.
Soaps:
- Soaps are sodium or potassium salts of long chain fatty acids
- Obtained by alkaline hydrolysis (saponification) of natural oils and fats with NaOH or KOH
- Reaction: Natural oil/fat + NaOH/KOH → Soap + Glycerol
- Example: Sodium stearate (C₁₇H₃₅COONa)
- Chemically, soaps are triesters of long chain fatty acids and propan-1,2,3-triol (commonly called glycerol or glycerin)
Synthetic Detergents:
Synthetic detergents work in hard water (unlike soaps). Three types:
| Type | Example | Use |
|---|---|---|
| Anionic detergents | (Sodium lauryl sulphate) \[CH_3(CH_2)_{10}CH_2OSO_3^{\oplus}Na^{\oplus}\] | Household detergent, additive in toothpaste |
| Cationic detergents | \[\mathrm{CH_{3}(CH_{2})_{15}-N^{\oplus}(CH_{3})_{3}Br^{\oplus}}\] (Cetyltrimethyl ammonium bromide) | Hair conditioner, germicide |
| Non-ionic detergents |
\[CH_{3}\left(CH_{2}\right)_{16}-COO\left(CH_{2}CH_{2}O\right)_{n}CH_{2}CH_{2}OH\] (an ester) | Liquid dishwash |
 |
liquid detergent |
