During food processing various substances are added to the food products during food processing for a number of purposes that may be intentionally or unintentionally added. These substances affect positively or negatively the quality and quantity of food. These substances may be in the form of
· Food adulterants
· Chemical additives
Contaminants is not intentionally added to the food products and causes a negative effect on the quality of the food and thus on the health quality of the consumers. Such as stones, soil, and metallic pieces.
Food adulterants added to the food intentionally to the food products during processing to get more profit from it. It can decrease the quality of the food product or quality may be. Such as the addition of milk in the water to get more profit or the removal of the cream from the milk.
A chemical additive is a substance or a mixture of substances, added intentionally for technological purposes during manufacture, processing, preparation, treatment, packing, transport, or storage. This facilitates enhancing the qualities of the foodstuff. These may help to
· Prevent Microbial spoilage
· Avoid toxic development
· Reduce nutritionally
· Reduce nutritional losses
· Retard aesthetic changes
Functions of food additives:
· Increase agricultural yield through enhancing feed utilization in poultry and livestock.
· Facilitates handling, distribution and preparation of foodstuffs.
· Control physical, chemical and microbial changes to reduce health hazards and preserve quality.
· Improve sensory and nutritive qualities.
Chemical additives can act as a
Chemical additives as preservatives
In addition to the use of chemicals for various purposes, some are using to increase the shelf life of food commodities. Among these are anti-ripening, sprout inhibitors, anti-microbial, and anti-oxidants.
1) Anti-ripening agent
Fruits continue their normal physiological functions even after being detached from the tree and ripen after harvesting. Sometimes during cold storage of such commodities, it is essential to control the ripening process. Chemical compounds such as Purafil and 2, 4, 5-trichlorophenoxy acetic acid help to retard ripening in plantain and mango respectively.
2) Sprout inhibitors
Many foods of plant origin like onions, carrots, and potatoes that grow beneath the soil surface sprout during storage. Potatoes are especially vulnerable when the storage temperature is moderate (25-300C) and relative humidity is between (50-80%). In order to prevent sprouting following chemicals are used such as
· Methyl esters of the naphthalene acetic acid
· Maleic acid
· Popham and chlorophyll
· Phenyl carbamate
· Vapors of nonyl-alcohol
Anti-oxidants are substances that prevent the reaction of various food constituents with oxygen thereby avoiding deterioration caused by simple oxidative chemical reactions. Oxidative changes occur in un-saturated food components that include fats and oils, carotenoids, and porphyrin-like compounds such as chlorophyll and hemoglobin.
Anti-oxidants such as
· Butylated hydroxyl toluene (BHT)
· Butylated hydroxyl anisole (BHA)
· Isopropyl citrate mixture
· Propyl gallate
4) Anti-microbial agent
Microorganisms are present on the surface of fresh food commodities. If these are not inhibited, they will grow and cause spoilage. Whole fruit may be treated with fungicide solution such as di-thane M45 to prevent fungal growth on their surface. The sodium salt of O-phenyl phenol is used as a spray or dip for citrus fruits.
The choice of anti-microbial agent depends upon several factors. These include properties, safety, and cost of the compound as well as the properties of the food and possible effect of the chemical on its quality.
Anti-microbial agent such as
· Sorbic acid
· Potassium and sodium metabisulphite
· Benzoic acid
Natural the anti-microbial agent includes such as
· Organic acid
· Medium-chain fatty acids
· Hydrogen peroxide
Chemical additives as non-preservative
As non-preservative, several substances are add in foods to improve the color, taste, flavor, nutritional value or functional properties.
1) Improve color
Many natural substances and synthetic chemicals are added to improve the color of foodstuffs. Food-grade permitted colors are used in fruit products, carbonated beverages, bakery products as well as candies, and others. Some chemicals bleach the natural color of food materials, thereby giving them a superior look. In flour production, for example, benzoyl peroxide, an oxidizing substance, bleaches out any residual natural yellow color in freshly milled wheat flour. Hydrogen peroxide is used to whiten the color of fresh whole milk for the production of some kind of cheese. Sulfur dioxide improves the color of many fruits and vegetable products.
2) Improve flavor
Natural flavoring substances include spices, herbs, essential oils, and plant extracts. Currently, there are over 12,000 different flavoring materials
Used in food, making this the largest single group of food additives. A number of food flavoring compounds are extracted from natural raw materials, while still large numbers are synthesized. The extracted flavor from plant materials in the form of essential oils and oleoresins finds applications as food flavoring agents. Flavors derived from orange and lime peels are common ingredients In orange and lime-based products.
Synthetic flavors are most commonly add to the food materials.
· Ethyl butyrate is the base in the pineapple flavor.
· Methyl anthranilate in grape flavor.
· Iso-amyl acetate in banana flavor.
· Benzaldehyde is the base material for almond material.
Additionally some substances called Flavor enhancers are added to accentuate the original flavor of the foodstuff. They may not have a flavor of their own but are efficient in bringing out the natural flavor of food. Such as monosodium glutamate (MSG) is a common flavor improver employed in meats, gravies, sauces, and food rich in protein.
Its excessive use results in toxicity in which a burning sensation in the back of the neck spreading to forearms and subdermal comfort.
3) Taste improver
The basic quality of food material for human consumption is that, in addition to its appearance, it should have a good taste. All foods have a natural taste of their own. However, several additives are employs to improve the taste of foods. These substances such as sugar, salt, and spices are common substances that bring the desirable taste. Some synthetic low-calorie sweeteners such as sorbitol and cyclamates are, likewise is used to impart a sweet taste to the products, particularly for diabetic and obese individuals.