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Food Processing: Types, Objectives, Methods and Drawbacks of Food Processing!
Food processing is the set of methods and techniques used to transform raw ingredients into food or to transform food into other forms for consumption by human or animals either in the home or by the food processing industry. Food processing typically takes clean, harvested crops or slaughtered and butchered animal products and uses these to produce attractive, marketable and often long-life food products.
Types of Food Processing:
The common food processing techniques include:
1. Chopping or slicing, e.g., diced carrots.
2. Mincing and macerating
3. Liquefaction, such as to produce fruit juice
4. Fermentation, e.g., in beer breweries
5. Emulsification
6. Cooking, such as boiling, broiling, frying, steaming or grilling
7. Deep frying
8. Baking
9. Mixing
10. Addition of gas such as air entrainment for bread or gasification of soft drinks
11. Proofing
12. Spray drying
13. Pasteurization, and
14. Packaging.
Objectives of Food Processing:
The main aims and objectives of food processing are:
(a) Make available wholesome, nutritious and appetizing food at economic rates.
(b) Improve nutritive value and minimize loss of essential nutrients during processing and preservation.
(c) Ensure long term storage stability even at elevated temperature.
(d) Market the processed food of high caloric density in compact and easily reconstitutable form, in light weight and openable containers.
(e) Prevent food poisoning, contamination or adulteration.
(f) Fulfill the special dietary requirement of astronauts, patients, sports persons and children
(g) Improve the mechanical processing operations such as harvesting to replace or minimize labor Develop new varieties of instant or convenience food.
(h) Update processing, packaging and storage technologies for all major processed food products so that they meet international Standards.
(i) Standardization of various factors such as bacteriological standards, preservation standards, additives, pesticide residue etc. of meat and meat products, development of value added products of commercial importance.
(j) Development of processing technology for the production of intermediate and finished food product or production including design and building of prototype equipment or pilot plants.
(k) Fortification of cereals or cereal products for enhancing the nutritional level of our population, especially women and children.
(l) Traditional food items of various regions of the country.
(m) Development of new cost effective technologies for preservation and packaging for food products based on traditional food, common food grains, dairy products, etc. for both domestic and export purposes. Development and design of equipment for manufacture of such products, development of new inexpensive packaging techniques and equipments, analysis of existing packaging methods, materials processes, quality control norms studies about improvement in the currently used systems, studies about newer packaging possibilities.
(n) To check and maintain the performance parameters for food processing.
(o) When designing processes for the food industry the following performance parameters may be taken into account –
(1) Hygiene, e.g., measured by number of microorganisms per ml of finished product
(2) Energy consumption, measured, e.g., by “ton of steam per ton of sugar produced”
(3) Minimization of waste, measured, e.g., by “percentage of peeling loss during the peeling of potatoes”
(4) Labor used, measured, e.g., by “number of working hours per ton of finished product”
(5) Minimization of cleaning stops measured, e.g., by “number of hours between cleaning stops”.
Effect of Processing on Food Constituents:
Several factors will influence the nutritional content of the food and the type and level of losses due to processing.
These include the:
(1) Genetic make-up of the plant or animal,
(2) The soil in which it is grown,
(3) Use of fertilizer,
(4) Prevailing weather,
(5) Maturity at harvest,
(6) Packaging and storage conditions, and
(7) Method of preparation for processing.
The storage conditions and handling after processing are also important to the nutritive value of the food. The effect of food processing on nutrient content will depend on the sensitivity of the nutrient to the various conditions prevailing during the process, such as heat, oxygen, pH and light.
The nutrient retention may vary with a combination of conditions, such as the characteristics of the food being processed and the concentration of the nutrient in the food. For example, sensitivity of vitamin C to heat varies with pH. It should be noted that the macronutrient and vitamin content of food are more likely to be affected by processing than the mineral content.
In considering the effects of processing on nutrient content of specific food, it should be considered whether the food is one that serves as a worthwhile source of a particular nutrient. It is important that processing is done within the recommended guidelines, e.g., for heat and pH, as over processing will further destroy not only nutrient content but also taste and appearance.
Heat Processes:
Heating can be both beneficial and detrimental to nutrient content of food. It generally improves the digestibility of food, making some nutrients more available. A typical example is the protein in legumes, which is made more digestible by heating because of the inactivation of anti-nutrients such as trypsin inhibitors.
If the food contains reducing sugars, such as, glucose, fructose and lactose, there might be non-enzymatic (Maillard) browning, as the sugars reacts with certain amino acids to create an indigestible complex. This can reduce the protein quality of the food. Some nutrients such as vitamin C are destroyed by heating. Loss of this and other heat labile nutrients will depend on the extent of heating and the other prevailing conditions, such as pH.
There are two processes occurring during drying, the addition of heat and the removal of moisture from the food. Nutritional losses during drying are more due to the application of heat than to the removal of moisture. Generally, except for thiamine (vitamin B1), removal of moisture results in increased concentration of nutrients.
Losses during the drying process will depend on:
(i) Preparation procedures before drying, e.g., slicing, blanching.
(ii) Drying temperature.
(iii) Drying time.
(iv) Storage conditions.
Nutrient losses during drying can be decreased by drying at a low temperature and shortening drying time. After drying ensure that food is stored under dry conditions and at low oxygen levels.
Sulphite is added to food very often to act as an anti-oxidant and prevent browning. However, this will increase the loss of thiamine. Use of sulphite on meat is restricted in some countries and there is also a limit to the amount that is used in the preservation of fruits and seafood, as this may result in allergic reactions in some consumers.
Blanching:
One of the major objectives of blanching before freezing or drying is the destruction or inactivation of enzymes that can affect the color, texture, flavor and nutritive value of food during storage. However, the process itself can result in significant nutrient losses from fruits and vegetables.
The nutrient losses will depend on several factors:
(i) The food item
(ii) Surface area exposed
(iii) The method used (steam blanching or hot water blanching)
(iv) Contact time, and
(v) Amount of agitation.
Nutrient losses in blanching result from thermal degradation, oxidation and leaching. Losses due to thermal degradation and oxidation are similar for both methods (steam and hot water blanching), but hot water blanching results in more losses due to leaching of water-soluble vitamins, minerals and amino acids.
Salting is most commonly used for meat and fish. Salting results in liquid exuding from the flesh, taking with it some of the water- soluble proteins, vitamins and minerals. Some proteins are also denatured by the salt.
Smoking usually follows salting or curing. In addition to being bactericidal, the process has an antioxidative function. It reduces the oxidative changes that take place in fats, proteins and vitamins. However, smoking causes nutrient losses due to the associated heat, flow of gases and interaction of the smoke components with proteins.
The heat and smoke also cause denaturation of proteins, but the amino acid content is retained. Some of the substances deposited on food and absorbed during smoking are carcinogenic. These compounds increase the risk of gastrointestinal cancer in populations where there is a high intake of smoked food.
The nutrient changes that occur during concentration will depend on the contents of the mixture and the temperature at which the process takes place. Generally, there is decreased water content and corresponding increase in other nutrients. In the presence of heat and high concentration of salt and minerals, proteins can be denatured, which can result in gelling.
Methods of Food Processing:
There are several different ways in which food can be produced:
1. One off Production:
This method is used when customers make an order for something to be made to their own specifications, for example – a wedding cake. The making of one off products could take days depending on how intricate the design is and also the ability of the chef making the product.
This method is used when the size of the market for a product is not clear and where there is a range within a product line. A certain number of the same goods will be produced to make up a batch or run, for example, at Gregg’s bakery they will bake a certain number of chicken bakes. This method involves estimating the amount of customers that will want to buy that product.
This method is used when there is a mass market for a large number of identical products, for example, chocolate bars, ready meals and canned food. The product passes from one stage of production to another along a production line.
This method of production is mainly used in sandwich items, it is when all the components of the product are there and the customer chooses what they want in their product and it is made for them fresh in front of them
Advantages of Food Processing:
The most expected benefits of food processing include:
(i) It is possible to remove the toxin from natural food.
(ii) It can preserve the food more easy way by sophisticated methods.
(iii) Easy to market and distribute.
(iv) Food processing increase the consistency of food.
(v) It increases seasonal availability of many foods, enables transportation of delicate perishable food across long distances.
(vi) It is enable to make many kinds of food safe to eat by deactivating spoilage and pathogenic microorganisms.
(vii) Without food processing, the modern supermarkets are not feasible, long voyages would not be possible and military campaigns difficult to do.
(viii) It improves the quality of life for allergists, diabetic and other people who cannot consume some common food elements.
(ix) Food processing can also add extra-nutrients such as vitamins.
(x) Processed food is less susceptible to early spoilage than fresh food and is better suited for long distance transportation from the source to the consumer.
(xi) Processed materials are better because, fresh materials, such as raw meats, are more likely to harbor pathogenic microorganisms (e.g. Salmonella) capable of causing serious illnesses.
Drawbacks of Food Processing:
Like merits, the processing of food constituents has disadvantages also. Fresh food contains large amount of naturally-occurring vitamins, fiber and minerals. When we process the food they may be destroyed by the processing method. For example – Vitamin C is destroyed by heat and therefore canned fruits have a lower content of vitamin C than fresh ones.
Food processing can lower the nutritional value of food and introduce hazards to food products. Processed food often includes food additives, such as flavorings and texture-enhancing agents, which may have little or no nutritive value, or be unhealthy. Preservatives added during the processing of food helps to extend the ‘shelf-life’ of commercially-available food products but cause adverse health effects.
Use of low-cost ingredients that mimic the properties of natural ingredients (e.g. cheap chemically-hardened vegetable oils in place of more-expensive natural saturated oils) have been shown to cause severe health problems. Adequate government rules and regulation and food safety concepts are required for the production of generally-safe processed food by various technologies.