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Materials Used In Daily Life- Grade 10
5
Materials Used In Daily Life
Presented by:-
- Prabesh Shrestha
- Divyesh Bajracharya
- Anumesh Shrestha
- Manjeet Rokaha
Materials Used In Daily Life
There are various differejnt materials that we use in our household or in other areas. The us of chemical subtances makes human life easier, more comfortable and more luxious. We use diffeft chemical subtances or diffent materials in our daily life that make our life easier.
Food Preservatives
Preservatives and Preservation
Preservatives
Preservatives are the chemicals which are added to food to prevent it from being spoilt by bacteria and fungi, maintain the nutritional quality of food and keep food fresh for a long time.They also prevent changes in the food's colour, flavour, texture and delay rancidity.
The process of treating food in orderto slow down spoilage and prolong the shelf life is called food preservation.
Food preservatives
Food Preservatives and their types
Food preservatives are subtances that are added to food to prevent or delay spoilage, microbial growth, and chemical changes caused by chemical reaction. They are used to extend the shelf life of these products and maintain their quality and safety. Food preservatives are classified into:-
- First grade preservatives
- Second Grade preservatives
First Grade Preservatives
First Grade Preservatives are typically those preservatives that are considered safe for consumption in the amount used in food products. Thesemay include natural preservatives such as salt, vinegar and critic acid, spices, honey, sugar etc.
First Grade Preservatives
Second Grade preservatives
Second Grade Preservatives are those preservatives which are considered safe for consumpotion only when recommended the amount of them is used in food stuff. This may include systhetic preservatives such as sodiumk benzoate and potassium sorbate, sodium nitrate.
Second Grade Preservatives
Types of food Preservatives
- Natural Food Preservatives
- Chemical Food Preservatives
- Induced ripening food preservatives
Types of Food Preservatives
Natural Food Preservaties
Natural Food Preservatives
Natural food preservatives are the organic chemicals that are used to prevent food spoilage caused by bacteria, molds and fungi; they can keep food fresh, thereby extending its shelf life. Some common natural preservatives are table salt, sugar, vinegar, vegetable oil and mustard powder. Sometimes, drying in sunlight, storing in cold places, using ash and turmeric powder and dipping in oil may be some safest natural safety measures. Some of the natural food preservatives are-
Salt
Table salt (NaCl) serves to be an excellent food preservative since ancient times, especially for amala (gooseberry), raw mango, meat and fish. The sodium chloride salt dehydrates the food items as it absorbs moisture from food, making it dry and uninhabitable for microbes. It prolongs the shelf life.
Sugar
Sugar is a natural preservative which is used to preserve the food items such as jams, murabbas, squashes and jellies. Adding correct proportion of sugar in such food items reduces the water contents and inhibits the growth of the harmful microbes such as bacteria and fungi which spoil food.
Vinegar
Vinegar is commonly used for preserving tomatoes for ketchup, vegetables, fruits, fish, meat and pickles. This maintains the acidic nature in food items and prevents the growth and activity of micro-organisms that spoil food. Besides, citric acid and lemon juice can also be used as food preservatives.
Oils
Edible vegetable oils are used as preservatives in fried food, vegetables and pickles as bacteria and fungi cannot live in an environment provided by oil.
Oils
Mustard Powder
Mustard powder is a spice that prevents growth of micro-organisms in pickles and other preserves. It prevents the contact of food with air having micro- organisms so that micro-organisms cannot grow.
Mustard Powder
Chemical Food Preservatives
Chemical or synthetic food preservatives are the chemicals that inhibit or delay the growth of bacteria, moulds, fungi, spoilage and discolouration in the food. They can be added to the food or sprayed on the food. They are effective in small amount. Some examples are sodium benzoate, sodium nitrate, potassium sorbate, calcium propionate, sodium metabishulphite, benzoic acid, etc. Some of the preservative ingredients and the products normally preserves are as follows:
a. sorbic acid, sodium sorbate, sorbates: cheese, wine, baked goods, and more
b. benzoic acid, sodium benzoate, benzoates: jams, salad dressing, juices, pickles, carbonated drinks, soy sauce, and more
c. sulphur dioxide, sodium metabisulphites: fruits, wines, vegetables, syrups and fruit juices
d. nitrites, nitrates: meats
e.lactic acid: yogurt, cottage cheeses, and more
f. propionic acid, sodium propionate: baked goods, and more
Similarly, common antioxidants are also used as preservatives to prevent oxidation. Some of the antioxidant ingredients and the products it normally preserves are as follows:
a. ascorbic acid, sodium ascorbate: cheese, chips, and more
b. butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA): oils, packaging food, and more
c. gallic acid, sodium gallate: wines and more
d. sulphur dioxide, sulphites: beverages, wines, and more
e. tocopherols (Vitamin E): oils, cereals, etc.
Induced ripening food preservatives
Induced ripening is a method of artificially ripening matured fruits using chemicals such as calcium carbide, ethylene gas and ethephon. Ethylene is safe and commonly used in the food industry. However, calcium carbide is controversial and banned in many countries due to the formation of carcinogenic compounds. Excessive use of ripening agents can cause health issues such as skin itching, burning, and rashes, water accumulation in the lungs, and eye irritation. Ethylene is a natural plant hormone produced by fruits as they ripen, and it can be produced artificially and used to ripen fruits quickly. Ripening agents, including ethylene, can also help ripen fruits such as avocados that would otherwise be difficult to ripen them naturally. Though induced ripening has some benefits, it is important to be aware of the potential risks associated with the chemicals used. We should choose naturally ripened fruits whenever possible
Following points:
Harmful Effects of Food Preservatives
Harmful Effects of Food Preservatives
The majority of preservatives used today are artificial rather than natural. Several of them are toxic and several others have potentially life-threatening side effects. However, consumption of a small amount of some preservatives is not harmful.
Following points 2:
1. Preservatives such as nitrites or nitrates used in processed meats has been shown to increase the risk of colon cancer.
Regular and excessive consumption of certain preservatives have the following negative effects.
2. Preservatives such as sodium benzoate used in beverages react with ascorbie acid (vitamin C) of beverages to form a chemical benzene that causes leukemia.
3. Regular and excessive consumption of man-made preservatives may cause food allergies, food intolerance, attention deficit hyperactivity disorder (ADHD), brain damage, nausea and cardiac diseases..
4.Consumption of sodium benzoate may also cause hyperactivitv, allergies, asthma and skin rashes.
5.Sorbates preservatives added to foods may cause urticaria (nettle rashes).
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