FOOD CONSERVATIONS AND METHODS TO CONSERVE FOOD

FOOD CONSERVATION IMPORTANCE, HOW TO CONSERVE FOOD, WHAT ARE THE DIFFERENT METHODS TO CONSERVE FOODS AND WHAT ARE THE WAYS TO CONSUME WITH PROPER CONSERVATION.

1. Food preservation & CONSERVATION Basic principles of preservation methods of food preservation .

2. Basic principles of preservation Making food safe for consumption –  Some food contains natural toxins which need to be inactivated, i.e., trypsin inhibitor in soya bean, fungal toxin such as aflatoxin in groundnut & grains, infected portions of food materials, green portion of potato is removed by visual examination, & chemical toxin & poison are discarded. Ensure the safety of food by using a process to remove toxins & heat to develop microorganism& their toxins. Safe processing prevents contamination.

3. Basic principles of preservation Increased digestibility –  most foods are difficult to digest unless they are cooked. Cooking softens fiber , gelatinized starch, denatures protein, & makes food easier to digest. Foods need special kind of processing for preservation. Enhance flavor color & taste –  The acceptability of food depends on its organoleptic qualities. Processing techniques enhance the appearance of food & many techniques make food more tasteful. The browning crust is formed due to Miller reaction which gives bakery items its baked flavor aroma & taste. Processing such as caramelization; fermentation etc gives food a different flavour.

4. Basic principles of preservation Improving texture & consistency –  Processes such as emulsification, gel formation & increase in viscosity are aimed to improve the texture &consistency of ready to eat food. Minimized nutrients loss –  Nutrition is better retained by controlled processing conditions such as autoclaving, freezer drying & controlled heat. Nutrients loss due to processing is managed by adding extra vitamins. Processed margarine, butter, etc are fortified by vitamins. Other processed food often enriched with vitamins, minerals & lysine.

5. Basic principles of preservation Extending the self-life –  Processing extends the self-life because apart from removing unwanted, spoilt,& harmful matter & subjecting the food to temperatures outside the danger zone, all processes such as dehydration, cold storage, canning & pasteurization are aimed at preservation to food. Increased acceptability through fabricated foods –  New products of uniform sizes & shape are been introduced in the market. They are made from low- grade commodities which are plentiful or good for health.

6. Basic principles of preservation Removal of micro-organisms or inactivating them- This is done by removing air, water (moisture), lowering or increasing temperature, increasing the concentration of salt or sugar or acid in foods. If you want to preserve green leafy vegetables, you have to remove the water from the leaves so that micro organisms cannot survive. You do this by drying the green leaves till all the moisture evaporates.

7. Basic principles of preservation Inactivating enzymes - Enzymes found in foods can be inactivated by changing their conditions such as temperature and moisture, when you preserve peas, one of the methods of preservations is to put them for a few minutes in boiling water. This method also known as blanching inactivates enzymes and thus, helps in preserving the food. Removal of insects, worms and rats : By storing foods in dry, air tight containers the insects, worms or rats are prevented from destroying it.

8. Methods of Food Preservation Preservation of food is achieved by application of physical, chemical and/or biological methods are as follows: A good method of food preservation is one that slows down or prevents altogether the action of the agents of spoilage. Also, during the process of food preservation, the food should not be damaged. In order to achieve this, certain basic methods were applied on different types of foods. For example in earlier days, in very cold weather condition, ice was used to preserve foods. Thus, very low temperature became an efficient method for preventing food spoilage.

9. Methods of Food Preservation Physical methods Cooling to → Low temperature refrigeration (0 to 7°C) - preserves for shorter period (days) → Freezing - preserves for several months • Heating → pasteurization, cooking, sterilization etc • Exposure to ionizing radiation → U.V., γ, etc • Application of high pressure • Drying → removal of water to a level which does not support the growth of microorganism

10. Methods of Food Preservation Chemical methods Quite often it is either impossible or undesirable to employ conventional physical methods of the preservation. • In such situation one has to opt for chemical methods of preservation. • It involves application of chemical additives which act as antimicrobial agents. Biological methods Souring (fermentation) lactic and acetic acid, e.g. cheese and cultured milk.

11. Methods of Food Preservation The principles of various methods for food preservation are as 1) Prevention or delay of microbial decomposition • By keeping out microorganisms (asepsis) • By removal of microorganisms • By hindering the growth and activity of microorganisms (e.g. by low temperatures, drying, anaerobic conditions, or chemicals) • By killing the microorganisms (e.g. by heat or radiation) 2) Prevention or delay of self-decomposition of the food • By destruction or inactivation of food enzymes (by blanching) • By prevention or delay of chemical reactions (By using antioxidant)

12. Several methods are available for preservation of food based on the above principles, the method include: Preventing the accessibility of food to microorganism by asepsis and packaging Physical removal of microorganisms from food by filtration or centrifugation Hindering the growth and activity of microorganism by use of preservatives, use of low temperatures atmospheric control in packaging and storing of foods and decreasing water activity in foods by drying or evaporation Killing the microorganism by use of high temperature and ionizing radiation Inactivation of endogenous enzymes by moderate heating Inhibition of chemical reaction through the use of chemical additives Fermentation of foods to yield more stable or less perishable food product Food preservation as it is practiced in the industry always involves the use of combination of methods for achieving maximum effectiveness.

13. Methods of Food Preservation Asepsis or preventing the accessibility of food to microorganisms is well exemplified in nature, the protective covering in natural foods such as skins on fruits and vegetables, shells on eggs and nuts and skins and membranes on livestock and fish prevent the attack by microorganisms and maintain the living tissues in healthy condition. Microbial attack is facilitated only after the death of the animal or when the skin is physically damaged. Packaging of foods and food products in a variety of materials such as metal cans, plastic films pouches, bags or boxes, paper bags or cartons and glass bottles provide effective protection against microbial attack. Filtration or centrifugation is adopted to physically remove microorganisms particularly in liquid foods such as milk, soft drinks, fruits juices and alcoholic beverages such as wine and beer.

14. , Trypsin inhibitor in soybeans:   This protein inhibits digestion, and it can be reduced by proper cooking methods like soaking and heating soybeans during processing to deactivate the trypsin inhibitor, making the protein more digestible.  Aflatoxin in groundnuts and grains:   These mycotoxins, produced by molds, can be significantly reduced by proper storage conditions, including controlling moisture levels and temperature, as well as sorting out and removing contaminated grains before processing.  Infected portions of food materials:   visually inspecting and removing spoiled or moldy parts of fruits, vegetables, and meat helps eliminate potential contamination with harmful bacteria or toxins.  Green portion of potato:   Solanine, a toxic glycoalkaloid, is concentrated in the green parts of potatoes, so removing the green skin and sprouts before consumption is crucial to minimize exposure.  Other methods to inactivate or reduce toxins include: Fermentation:   Certain fermentation processes can help reduce the levels of toxins in certain foods, like the use of probiotics in soy sauce production.  Heat treatment:   Cooking at high temperatures can effectively inactivate many toxins, including some mycotoxin s

15. . Vegetables like broccoli, green beans, and spinach, which are blanched to preserve color and texture for freezing, and fruits such as tomatoes and peaches, blanched to easily remove their skins. Other examples include nuts like almonds, blanched to remove their skins for recipes like marzipan, and avocados to prevent browning. 

16. k .REMOVAL OF TOXINS FOR CONSERVATION