Food Technology

Food Technology

Food Technology

I INTRODUCTION

Food Technology, application of physical, chemical, and biological sciences to food processing and preservation, and to the development of new and improved food products.

Food Technology

The food technologist is concerned with the composition, properties, and behaviour of food from the point of production through to its eating quality at the point of consumption. Food is a complex biological and chemical material. Food technology is a multidisciplinary science subject, involving chemistry, biochemistry, microbiology, physics, process engineering, and industrial management. Food scientists and technologists are responsible for ensuring that food items produced are safe, nutritious, and of the quality and substance demanded by the consumer. Everyone needs to eat, so there will be a continuing demand for food technologists.

As part of the National Curriculum in British schools, food technology can be defined as “using knowledge and skills to design and make good quality food products”. Essential skills and knowledge for food technology include learning about ingredients, food products, and nutrition, using tools and equipment accurately and hygienically, understanding systems and control, designing and adapting recipes, creating product specifications, carrying out a sensory evaluation, and knowing about industrial practice. Food technology within the curriculum is different to home economics since it focuses on the industrial knowledge of making food products, and less on preparing family meals, looking after children, and consumer studies. Within the design and technology curriculum, pupils may study food safety and microbiology. The science curriculum places strong emphasis on these areas

II QUALITY ASSURANCE

In the food industry, large numbers and quantities of food products are produced for distribution and sale, often in several different countries. It would be impossible, and often destructive, to test each individual item of food to ensure that it complies with all safety and quality requirements. Instead, the food technologist applies quality assurance schemes to ensure that the food products made meet the required standards of quality and safety, and comply with all the necessary food legislation.

Quality assurance relies on the use of systems that employ the technique of Hazard Analysis Critical Control Points. In this, the food material and its processing have to be sufficiently understood and the hazards associated with each step in the process identified to pinpoint the critical control points. At these points, food control can be applied and implemented to ensure that the particular hazard is eliminated or reduced sufficiently. For example, milk, as a high-protein food, is nutritious both for ourselves and for micro-organisms. Some of these organisms are harmless, while others may cause illness such as tuberculosis. Dangerous bacteria are, however, killed by heat, and so by law, milk must be heated to 63° C (145.4° F) for 30 minutes, or more commonly to the equivalent of 72° C (161.6° F) for 15 seconds, as part of the pasteurization process, named after the French microbiologist Louis Pasteur.

Eggs are known to be a possible source of the food poisoning organism Salmonella, so eggs prepared at home must be cooked thoroughly. The scale and risk of contamination in the food industry, where many eggs are bulked together into the liquid egg as a food ingredient, making it both a critical control point and a legal requirement that eggs be pasteurized. In this case, to prevent the egg from turning brown during the heat treatment, the enzyme glucose oxidase is used to remove any free glucose, and a lower temperature is used for the pasteurization. This is an interesting example of the application of food technology, involving food chemistry, biochemistry, physics, and food microbiology to ensure the safety and high quality of an important, nutritious food ingredient.

Much food is preserved by the use of heat or dehydration. The food technologist, therefore, studies the principles of heat and mass transfer. Food technology thus involves both the understanding and application of many operations, including particle size reduction and mixing.

Not all microorganisms in food are harmful or will cause spoilage, however. One of the original uses of biotechnology was in its application to food in the production of fermented foods. These are foods in which microorganisms, such as lactic acid bacteria or some yeasts and moulds, are deliberately added or encouraged to grow in foods so that their enzymes can modify the food to give new products and flavours. Examples include wine made by the yeast fermentation of grapes, yoghurt and cheeses made by the fermentation of milk by lactic acid bacteria, and moulds for some ripened cheeses, such as Camembert.

III HISTORY OF FOOD TECHNOLOGY

Early on, human beings discovered how to grind wheat between stones to give stoneground flour. Much later, in Hungary, roller milling was developed, which is used to produce much of our refined flour. Flour is made into dough, fermented, and oven-baked to produce a wide variety of bread, an original convenience food. The high-volume production of loaves of bread depends on the unique properties of the protein gluten found in wheat and to a lesser extent in rye. Gluten gives the dough its elastic properties and allows it to expand during baking.

In the United States, technology was applied to maize, rice, and wheat to produce breakfast cereals, now consumed throughout the world as an ideal convenience breakfast food, which needs no further preparation in the home. In the United Kingdom, the combination of the skills of the baker, with the expertise of the food engineer, and the manufacture of packaging allowed the commercial production of another convenience cereal food, the biscuit. Biscuits are baked to a final low-moisture content or water activity, and in airtight packaging are able to last many months and be exported throughout the world.

Only in the past half-century, following the work of Clarence Birdseye, has another success of food technologists become commercially available—the use of rapid freezing to produce whole ranges of frozen foods. In fast freezing, large numbers of small ice crystals are formed which cause only minor damage to cell structure when the food is later thawed. Rapid freezing has increased the availability of, for example, fish and vegetables, notably frozen green peas, which are more tender and sweeter than is possible by sending fresh peas in pod through markets and shops to consumers.

If peas and other vegetables were frozen directly, enzymes present naturally would cause slow deterioration in colour and flavour, even at low temperatures. To prevent this, hot water (80-90° C/176-194° F), or steam blanching is used before freezing to destroy enzyme activity. Commercial rapid freezing technology has increased the seasons and availability of valuable nutrients from these foods.

Another success of food technology came with ice cream. This popular foodstuff, thousands of years old, is produced from an oil-in-water emulsion, which is partially destabilized during freezing, to give some fat-clumping, which helps in giving a smoother texture. Today, emulsifiers and stabilizers are used to help keep some of the aqueous phases from freezing, preventing graininess in texture. Freeze-drying is a useful process in which foods are frozen and then held in a vacuum with the ice being removed by converting it directly into vapour (sublimation). It is used where the expense of the process can be justified by the benefits it provides in retaining good flavour and convenience, as, for example, in freeze-dried instant coffee.

IV FOOD QUALITY AND HEALTH

Food technology involves not just the study and application of processing to foodstuffs, but also the study of how the processing and composition of food affects its appearance, texture, flavour, or nutritional value. In recent times we have become much more aware of the need to eat a healthy, balanced diet. Food technologists have been busy in developing a wide range of low-fat spreads, which are water-in-oil emulsions, and which, when kept cool, have the firm texture of butter but are more spreadable on bread. Consumers can now choose from a wider range of vegetable oils and butters made into a range of products that can meet their needs for essential fatty acids without providing an excess of fat in the diet.

Diet does not just consist of the three major nutrients of fat, carbohydrates, and protein, but also provides a range of essential micronutrients, in the form of dietary fibre, minerals, and vitamins. For good health and vitality, a range of micronutrients is needed, in sufficient but not excessive quantities, combined with the absence, or minimization, of toxic components in food, whether naturally present or as contaminants.

Japanese food technologists have led the way in producing a range of functional foods, in which these micronutrients are supplied in specific products, such as sports drinks. In Japan, too, there is great interest in the application of high pressures, thousands of normal atmospheres, to foods, as an alternative preservation process to heat processing, such as in canning.

Another area where food technologists have been active is in the application of chilling, alone or in combination with modified atmospheres, to increase the keeping quality or shelf-life of foods. By reducing the oxygen content of the atmosphere, and increasing the level of carbon dioxide, the rate of respiration of living plant foods can be slowed down. This use of controlled or modified atmospheres has allowed fruit, such as apples, to be kept in good condition before being eaten as “fresh” many months later, perhaps on the other side of the world from where they were harvested.

The food technologist is also aware of the vital role played by the packaging of food products. Modern packaging does not just provide a convenient and attractive container, but if well sealed and made of the correct materials, it acts as a suitable barrier, for example, to keep fresh high-quality long-life milk for several months, to keep bread mould-free for weeks, or to maintain the bright red colour of chilled beef for many days.

Food technology is an international, multidisciplinary science subject that can be studied as a degree in certain universities around the world. Graduates work with food retailers and manufacturers to develop new food products and to ensure the safety and quality of the food that is produced. Other food scientists and technologists work in research institutes, universities, or for large companies, while others are employed by international agencies and government-controlled laboratories and agencies to ensure that foodstuffs are nutritious and safe for people to eat and enjoy.

Food Technology

Contributed By:
Geoffrey Campbell-Platt