Many food materials contain naturally occurring organic acids, such as citric acid in oranges and lactic acid in cheese. Food acids are essential to providing some food products with their characteristic sharpness. Food acids can also act as preservatives and antioxidants.

Examples of common food acids are acetic acid (E260), citric acid (E330), malic acid (E296), tartaric acid (E334) and lactic acid (E270).

Acidity regulators are used to control or adjust the pH (the acidity or alkalinity) of foods.

For example, acetic acid (the acid found in vinegar) can be added to salad dressings to provide a sharp acid flavour and to aid with the preservation of the products.

Some powdered food materials have a tendency to cake: a phenomenon caused by powder particles sticking together.

Anticaking agents prevent this from happening.

Some food materials have the tendency to produce foams which can cause difficulties during processing and use.

Antifoaming agents are used to suppress foams, thereby enabling trouble-free food production.

Oxygen can be problematic in the manufacture and storage of food products, especially when fats and oils are oxidised to produce off-flavours and vitamins are degraded by oxidation.

Antioxidants such as ascorbic acid (vitamin C) (E300) and alpha-tocopherol (vitamin E) (E307) can be added to foods to ‘mop up’ oxygen and prevent oxidation.

Sometimes in the formulation of food products it is necessary to make up space by adding an material that does not affect the overall quality or characteristics of the product.

This is where bulking agents such as starch can be very useful, as they do not significantly affect taste and appearance.

The colour of food is incredibly important to consumers as we most often select and buy foods with our eyes.

The appearance of food will affect our perceptions of acceptability and colour is the characteristic that most strongly influences appearance.

Food colourings can be used to enhance the attractiveness and aesthetics of food products as will cakes decorated with coloured icing, or they can be used to compensate for colour lost during processing, as will canned peas.

During the processing of some food materials oxidation can cause the loss of colour and colour retention agents such as ascorbic acid can be added to limit or prevent the problem.

Water and oils are known as immiscible food materials. They do not mix – unless an emulsifier is added.

Emulsifiers help to create and stabilise food emulsions and products such as ice cream and mayonnaise would not exist without the use of emulsifying agents in their manufacture.

Acetic acid - acidity regulator
Pectin - stabiliser

The flavour of food products is of critical importance to consumers.

The taste of foods that consumers found so attractive are created by the flavour compounds in food materials.

Flavour also helps in the recognition and identification of foodstuffs, and it helps consumers to know whether food products are suitable to eat or have gone off.

Flavours can be added to food to establish the character of a product, eg. strawberry ice cream, or they can be added to enhance the character of existing flavours.

Flavour enhancers can be used to emphasise or magnify a food material’s existing flavour.

Many flavour enhancers are derived from natural foodstuffs and some are created synthetically from naturally occurring compounds.

At times it is desirable to improve the appearance of flour e.g. to make it whiter, or to improve the functionality of bread dough.

Flour treatment agents, also known as bread improvers, dough conditioners and dough improvers, can be used to enhance the quality of flour based products and also to help control production costs.

Flour treatment agents are categorised as: flour bleaching agents, flour oxidising agents, flour reducing agents and enzymes.

Glazing agents are used to impart a shiny, gloss appearance to food products, such as baked goods and some confectionery products, and also to provide protective coatings.

Some food products have a tendency to dry out.

Humectants can be added to the recipe to bind water and prevent its loss to the atmosphere, thereby retaining the moist character of the product.

Food products can be spoiled as a consequence of the growth of microorganisms (bacteria, yeasts and fungi) and chemical reactions such as oxidation.

Preservatives can be added to some food products to inhibit microbial growth, or to prevent or slow chemical reactions that might lead to spoilage.

In some cases the use of preservatives is important to ensure food safety, such as the addition of sodium nitrate (E250) and sodium nitrite (E251) to cured meats, as these prevent the growth of Clostridium botulinum, as serious food poisoning bacterium.

Jam makers know that when they make plum jam they usually get a good set. This is because of the high levels of naturally occurring pectin in plums.

Pectin is one of a class of substances known as hydrocolloids, or more commonly, thickening or gelling agents.

These substances can be used in a wide range of food applications to provide body and texture, and to bind and stabilise water.

They also work in combination with emulsifiers to help create stable emulsions.

Sugar has been the traditional sweetener in foods and before that it was honey.

However, modern concerns about the over consumption of sugar have created opportunities for low-calorie sweeteners.

These can be beneficial in low-calorie food products and for those who need to control type 2 diabetes.

Some food products, particularly some beverages, soups and sauces, are characterised by their viscosity.

Thickening agents such as modified starches can be very useful to the creation of texture, viscosity and mouthfeel in food products without substantially altering other product characteristics.