Presentation on theme: "Food Processing. The Food Industry b Three Main Sectors Primary producers Food Processing Food Retailing b The food production complex is called."— Presentation transcript:
The Food Industry b Three Main Sectors Primary producers Food Processing Food Retailing b The food production complex is called the food chain.
The food chain Materials & Equipment Cash Food Animals Crops Material & Energy inputs Land Food processing and distributionConsumer System Banking System Ancillary Industries Cash Flow
The food industry b Purpose of food processing is to produce foods that Between them provide constituents of a balanced diet Are free from contamination Are appealing in colour, taste and texture. b But remember The primary aim of a food company is to make money and stay in business
Food processing b Why process foods? Safety Nutritional reasons Improve storage (shelf) life Improve flavours, colour, texture etc.
Food processing operations b Ambient temperature processes b Mechanical processes b High temperature processes b Low temperature processes b Fermentation processes b Post processing
Ambient temperature processes b Include Cleaning and sorting Peeling, shredding, chopping and milling Mixing, blending and forming b Are often preparation processes for subsequent operations.
Physical Separations b Include Filtration, centrifuging, Expression and extraction Membrane separations b These often involve recovering a particular component from a raw material.
High temperature processes b Two major purposes Safety; pasteurisation and sterilisation Cooking; modifies flavour, texture, nutritional qualities. b A single process may serve both functions simultaneously.
High temperature processes include b Sterilisation and pasteurisation b Blanching b Baking & Roasting b Frying b Microwave and infra red heating
Blanching b Purpose: As a pre-treatment, esp. for Dehydration Sterilisation Freezing b Heat is sufficient to inactivate enzymes but not to cook but Under processing is as bad as over processing
Baking and Roasting b These are essentially the same process involving dry heating in hot air. Baking usually refers to dough products Roasting usually refers to meat, nuts & vegetables. b Surface undergoes chemical changes developing colour and flavour b The heat has nutritional effects Food easier to eat and digest loss of vitamins
Frying b Frying is cooking in hot oil b Its purpose is to improve eating quality of the food (flavour, texture) b Effects of frying are similar to those of baking b Because of direct contact between hot oil and food, frying is generally quicker than roasting or baking
Microwave and infra red heating b Microwave and infra red heating use electromagnetic radiation for heating. b Microwave heating involves short wavelength radiation. The frequency of the waves coincides with the natural vibration frequency of water molecules. b Infra red is radiation just beyond the visible light region of the spectrum b The energy is dependant on Temperature surface properties shape of the bodies
Processing at low temperatures b Low temperature slows the rate of microbial growth, but does not kill microbes b Up to a point, the lower the temperature, the longer the shelf life b Below -10 o C, all microbial growth stops, but some residual enzyme activity may remain b The main function of chilling and freezing, therefore, is for storage and prolonged shelf life.
Fermentation b Fermented foods have been around for a long time b Fermentation serves a number of purposes, including; Preservation Improve nutritional quality Improve digestibility Health Benefits Increase variety b There is a wide variety of fermented foods including Dairy products Fermented Meat and vegetables Beverages Bread, etc.
Post processing operations b These include packaging and storage. b Purposes include Protection Display Increase storage life. b Increasingly modified atmospheres are being used to increase shelf life, often by reducing oxygen and increasing nitrogen content.