- Soap = sodium salts (RCOO-Na+) / potassium salts (RCOO-K+) of long-chain fatty acids
- Alkalis react with fatty acids –> soap
- Fatty acids = animal fats or vegetable oils
- Soap preparation: hydrolysing fats or oils under alkaline condition
- Saponification – alkaline hydrolysis
- Saponification process – boiling fats / oils with concentrated sodium hydroxide solution or concentrated potassium hydroxide solution to produce glycerol + salts of fatty acids (soap)
- Saponification steps: 1. Hydrolysis of fats / oils –> glycerol + fatty acids. 2. Neutralisation of fatty acids + concentrated alkali –> soap + water
- Overall equation: Fats / oils + alkali –> glycerol + soap
- Sodium chloride – reduces the solubility of soap in water
|Liquid soap||Solid soap|
|Sodium hydroxide + saturated oils (coconut oil)||Potassium hydroxide + unsaturated oil (sunflower oil / olive oil)|
|Uses: bathing purposes||Uses: shaving cream|
- Detergent = sodium salt of sulphonic acid
- Alkalis react with sulphonic acid –> detergent
- Common detergent: sodium alkyl sulphate & sodium alkylbenzene sulphonate.
- Detergent preparation: 2 processes – 1. Sulphonation. 2. Neutralisation.
- Sulphonation: Petroleum fraction (long chain hydrocarbon compounds) converted into sulphonic acid with the present of concentration sulphuric acid. Water molecule is removed.
- Neutralisation: sulphonic acid neutralised with sodium hydroxide to form detergent (water molecule is formed).
- Other type of detergents: 1. Anionic detergent (dishwashing liquid detergent). 2. Cationic detergent (hair conditioner). 3. Non-ionic detergent (car washing detergent).
Cleansing action of soap and detergent
- Soap and detergent are surfactants. Surfactants are organic compounds that lower the surface tension of a liquid.
- Surfactants act as emulsifiers and foaming agents.
- Anion soap consists of carboxylate ion (hydrophilic = soluble in water) and long hydrocarbon tail (hydrophobic = soluble in grease /oils).
- Anion detergent consists of sulphate ion / sulphonate ion (hydrophilic = soluable in water) and long hydrocarbon tail (hydrophobic = soluble in grease / oils).
The action process
- Soap or detergent is added to water.
- This has lower the surface tension of water and increases the wetting ability of water.
- Hydrophilic part of the anion dissolves in water.
- Hydrophobic part dissolves in grease.
- Scrubbing helps to pull the grease free and break the grease into small droplets.
- These droplets do not coagulate and redeposit on the surface of the cloth. It is because therepulsion between negative charges on the surface.
- The droplets are suspended in water forming an emulsion.
- Foam produces to float the emulsion.
- Rinsing helps to remove these droplets.
The effectiveness of the cleansing action of soap and detergent
|Hard water (contain calcium & magnesium ion)||Form an insoluble precipitate = soap scum (formation of soap scum causes wastage of soap)||Detergent is effective cleaner. Form soluble substances = calcium or magnesium salts (do not form scum)|
|Soft water (do not contain calcium & magnesium ion)||Soap is effective cleaner.||Detergent is effective cleaner.|
|Acidic water (contain hydrogen ion)||Form insoluble long-chain fatty acids (reduces the amount of soap used for cleaning)||Detergent is effective cleaner. Form soluble substances (Do not form scum)|
|Environment||Soap is biodegradable||Soap is non-biodegradable|
Additives in detergent
|Biological enzyme||Remove protein stains||Amylase, lipase & protease|
|Foam control agent||Control foaming in detergent||Silicones|
|Builder||Enhance the surfactant efficiency||Sodium phosphate|
|Filler||Make the solid detergent dry and enable the liquid detergent to be poured easily||Sodium silicate|
|Optical brightener||Add brightness by convert UV radiation to blue light and whiteness||Fluorescent dye|
|Stabilising agent||Lower the production of foam||Silicones|
|Suspension agent||Prevent the dirt particles removed from redepositing onto cleaned fabrics||Sodium carboxymethylcellulose|
|Whitening agent||Bleach stains||Sodium hypochlorite|
Food additive = a natural / synthetic substance that is added to food to
- prevent spoilage
- extend food storage life
- improve food appearance
- improve food taste
- improve food texture
- slow down / prevent the growth of microorganisms / bacteria / fungi
- extend food storage life
|Salt||Draws the water out of the cells of microorganisms. Retards the growth of microorganisms.||Salted vegetables||Increase the risk of cardiovascular diseases|
|Sugar||Draws the water out of the cells of microorganisms. Retards the growth of microorganisms.||Fruit jam||Tooth decay, diabetes and obesity|
|Vinegar||Inhibits the growth of microorganisms.||Pickled cucumber|
|Sodium nitrite / sodium nitrate||Slows down the growth of microorganisms. Stabilise red colour in meats.||Sausage||Carcinogenic|
|Benzoic acid / sodium benzoate||Slows down the growth of microorganisms.||Tomato sauce|
|Sulphur dioxide||Slows down the growth of microorganisms.||Grape juice||Asthma and allergies|
Alternative ways: freezing and refrigeration
- prevent oxidation (causes rancid fats and brown fruits)
|Vitamin E||Prevent oils from turns rancid||Palm oil & sunflower oil||No|
|Vitamin C||Preserve the colour of fruit juice and the formation of nitrosamines||Fruit juice & cured meat||No|
|Sodium citrate||Stop rancidity in fats||Ice-cream||-|
|BHA (Butylated hydroxyanisole) BHT (Butylated hydroxytoluene)||Retard rancidity in fats, oils and oil-containing foods||Margarine & cereal||Carcinogenic|
- improve the taste
- improve the smell
- restore taste loss due to food process
|MSG (monosodium glutamate)||Bring out the flavor||Salad dressing & canned soup||Headache, thirsty, nausea & chest pain.|
|Aspartame (non-sugar sweetener)||Sweeten food (about 180 – 200 times than sugar)||Soft drinks & diet drinks||Increase the risk of leukaemia, cancer and neurological problems|
|Synthetic essences (esters)||Produce artificial flavours = natural flavour. Cheaper to use than the real fruits||Methyl butanoate (apple flavour) & octyl ethanoate (orange flavour)||-|
- prevent an emulsion from separating out
|Monoglycerides of fatty acids||Mix oil and water||Ice-cream, chewing gum, beverages, whipped topping and margarine|
|Acacia gum||Mix two liquids that do not mix together. Forms an emulsion.||Marshmallow, gumdrop, edible glitter, carbonated drink syrup & gummy candies|
|Lecithin||Reduces viscosity. Replaces more expensive ingredients. Controls sugar crystallisation and the flow properties of chocolate. Helps in the homogeneous mixing of ingredients. Uses as a coating.||Margarine, dough, candy bar & cocoa powder|
|Gelatin||Mixture of peptides and proteins of collagen extracted from the boiled bones, connective tissues, organs and some intestines of animals||Fruit jam, jelly babies, shells of pharmaceutical capsules, margarine & yogurt|
- thicken food
- give the food dense, smooth and uniform texture
|Acacia gum||Reduces the surface tension of liquid. Leads to increased fizzing. Mix two liquids that do not mix together. Forms an emulsion.||Marshmallow, gumdrop, edible glitter, carbonated drink syrup & gummy candies||-|
|Gelatin||Mixture of peptides and proteins of collagen extracted from the boiled bones, connective tissues, organs and some intestines of animals||Fruit jam, jelly babies, shells of pharmaceutical capsules, margarine & yogurt||-|
|Pectin||Dietary fiber||Fruit jam||-|
|Starch||Thicken food||Soup, custard, pudding, noodles and pasta||-|
|Modified starch||Increase their visco-stability||Instant soups & cheese sauce granules||-|
|Xanthan gum||Helps to prevent oil separation. Increase in the viscosity of a liquid||Sauce & salad dressing||Allergies|
F. Dyes or Colourings
- add colour vanished during food processing
- replace colour vanished during food processing
- make food appear more attractive
|Dyes / Colourings||Function||Examples||Side effect|
|Tartrazine E102 / Sunset yellow E110 (artificial dye)||Yellow azo dye||Orange drinks, sweet & custard powder||Hyperactive in children|
|Brilliant blue FCF Blue 1 (artificial dye)||Blue triphenyl dye||Ice-cream, beverages, jellies & blue raspberries flavoured product.||Allergic|
|Carmosine E122/ Azorubine (artificial dye)||Red azo dye||Sweet, jellies & confections||Carcinogenic & allergic|
|Anthocyanin (natural dye – red grape, red cabbages, sweet potatoes and tomatoes)||Natural red colouring||Ice-cream & sweet||-|
|Carotenoids / saffron (natural dye – carrots, sweet potatoes and palm oil)||Natural red colouring||Cooking oil & confections||-|
|Paprika||Natural red colouring||Dessert food||-|
|Butterfly pea (clitoria ternatea)||A blue food dye||Dessert food & confections||-|
|Pandan (pandanus amaryllifolius)||A green food dye||Noodles & confections||-|
A. Traditional medicine
Source: living thing – animals, plants & minerals
|Garlic||To treat colds and asthma, lowers the blood pressure, antibiotics||Eaten raw or cooked|
|Cocaine||Anaesthetic||Drug is processed from the leave|
|Ginseng||Strengthen the body||Boiled with water to produce juice|
|Quinine||Treat malaria||Produced from the bark|
|Ginger||Treat stomach ache, treat diarrhea, prevent flu||Boiled with water to produce juice|
|Peppermint||Increase the body metabolism, treat nausea, indigestion and flu, to treat headaches, muscles and nerve pain||Boiled with water to produce juice or taken in capsule|
|Eurycoma longifolia(Tongkat Ali)||Treat wounds, relieve headaches, to lower the body temperature, increase male virility||Dried and boiled with water to produce juice, served as a hot drink / beverage or made into tablets / capsules|
|Tamarind (Asam Jawa)||Reduce malaria fever, reduce cough, medicine for gastric problem||Dried and served as a cold drink|
|Lemon grass (Serai)||Mosquito repellent, treat cough, headaches and stomach aches||Made into juice|
|Centella asiatica (Daun pegaga)||Help maintain youthfulness, relieve hypertension, aid wound healing||Eaten raw or made into juice|
|Green tea||Prevent breast, stomach and skin cancers, improve mental alertness, lower the cholesterol levels||Drink as beverage|
|Aloe vera (Lidah buaya)||Heal wounds and skin disease, laxative, treat diabetes, osteoarthritis and sunburn||Eaten cooked or leaves produce juice and rub on body|
B. Modern medicine
Source: synthesised by scientists
|Common analgesics||Uses||Side effect|
|Aspirin (acetylsalicylic acid) (cannot be given to pregnant mother and children)||Relieve pain, reduce inflammation, reduce ability of blood to clot||Stomach (internal) bleeding, kidney damage, ulceration|
|Paracetamol (can be given to children)||Relieve mild to moderate pain, does not irritate stomach or cause internal bleeding||Skin rashes, blood disorders, acute inflammation of the pancreas, liver damage (overdose)|
|Codeine (synthesised from morphine / opium)||Relieve headache and used in cough medicines||Drowsiness, irregular heartbeat, hallucination, lead addiction, depression and nausea|