UNIT OPERATIONS IN FOOD PROCESSING.pptx

Unit operations in food processing

1. UNIT OPERATIONS IN FOOD PROCESSING SUBMITTED BY - SHIVAM DADWAL SUBMITTED TO - DR. DURGA SHANKAR BUNKAR ID NO. - 22412MFT006 SUBJECT CODE - FPT 501 SUBJECT - EMERGING TECHNOLOGIES IN FOOD PROCESSING

2. WHAT ARE UNIT OPERATIONS? The process/processes or steps used by the industries for converting the raw materials into desired and useful product or products is called unit operations. Examples of unit operations common to many food products include cleaning, coating, concentrating, controlling, disintegrating, drying, evaporating, fermentation, forming, heating/cooling (heat exchange), materials handling, mixing, packaging, pumping, separating, and others. Most unit operations are utilized in the making of a variety of food products. Heat exchanging, or heating, for example, is used in the manufacture of liquid and dry food products, in such diverse operations as pasteurizing milk, sterilizing foods in cans, roasting peanuts, and baking bread. Unit operations may include numerous different activities. The unit operation of mixing, for example, includes agitating, blending, diffusing, dispersing, emulsifying, homogenizing, kneading, stirring, whipping, and working. We may want to mix to beat in air, as in making an egg white foam, or to blend dry ingredients, as in preparing a ton of dry cake mix; or we may wish to mix to emulsify, as in the case of mayonnaise, or to homogenize to prevent fat separation in milk.

3. UNIT OPERATIONS IN FOOD PROCESSING MATERIAL HANDLING MIXING CLEANING CONCENTRATION SEPARATING/SORTING DRYING SIZE REDUCTION HEATING LOW TEMPERATURE MEMBRANE PROCESS PACKAGING

4. 1.MATERIAL HANDELING Efficient materials handling is ‘the organized movement of materials in the correct quantities, to and from the correct place, accomplished with a minimum of time, labor, wastage and expenditure, and with maximum safety’. Correct production planning should ensure that: raw materials, ingredients and packaging materials are scheduled to arrive at the factory at the correct time, in the correct quantities and in the required condition. storage facilities are sufficient for the anticipated stocks of materials and are suitable to maintain the quality of materials for the required time. handling equipment has sufficient capacity to move materials in the required amounts. staff levels are adequate to handle the required amounts of materials. processing and packaging equipment is selected to provide the required production throughput.

5. EQUIPMENTS USED FOR HANDLING 1.LOADING Automatic case formers Forklift Dimensioning, weighing and scanning systems Palletizers Automatic labelling machine Depalletizers 2.Transporataion Inside the warehouse AGV(Automated guided Vehicles) overhead trolleys sorting

6. PALLETIZER AND DEPPALETIZERS FORKLIFTS OVERHEAD TROLLEYS

7. LABELLING MACHINES AUTOMATIC CASE FORMERS AUTOMATIC GUIDED VEHICLES WEIGHING AND SCANNING SYTEMS

8. ADVANTAGES OF HANDLING

9. 2.CLEANING Cleaning is the unit operation in which contaminating materials are removed from the food and separated to leave the surface of the food in a stable condition for further processing. It uses: Brushes High velocity air Steam Water Vacuums Magnets Microfiltration Mechanical separation BLOWING MACHINES

10. CLEANING Wet procedures: Soaking, spraying, floatation, washing and ultrasonic cleaning. Dry procedures: Separation by air, magnetic attraction of metal contaminants or by physical methods depending upon the product and nature of the dirt. Fruit and vegetables are generally washed with water to remove dust, dirt and adhering surface micro-flora. Fruits like peach, apricot etc that are lye peeled are not washed before peeling. Washing after peeling removes vitamins and minerals and should be discouraged. Different methods of washing include soaking or agitating in water, washing with cold or hot water sprays etc. Mechanical washers involve agitating or tumbling the commodity on moving belts or revolving screens while they are immersed in water or subjected to water sprays. Washing by using high pressure sprays is most satisfactory. Detergents are frequently used in the wash or rinse water. Vegetables may be soaked in dilute solution of potassium permanganate or chlorine (25-50 ppm) for disinfection.

11. WASHERS MAGNET SEPARATORS

12. 3.SEPARATING It involve separating a solid from a solid like peeling of potatoes, separating a solid from a liquid as in filtration or a liquid from solid as in pressing of juice from a fruit. It might involve the separation of a liquid from a liquid as in centrifugation of oil from water. It might also involve removing gas from a solid or liquid as in vacuum removal or air from canned food during canning. Common separating methods used in fruit and vegetable processing are discussed as under: Sorting: Sorting is the separation of foods into different categories on the basis of a measurable physical property. Sorting and grading ensures the removal of inferior or damaged commodity. For sorting, inspection belt can be used, in addition to trained personnel who detect poor quality produce unsuitable for canning. Automatic color sorters can be used for sorting to reduce labor cost. Grading: After preliminary sorting, the fruit and vegetables are graded to obtain uniform quality with respect to size, color etc. Grading can be done either manually or with the help of mechanical graders. Different types of mechanical graders include screen grader, roller grader, rope or cable grader, conveyor grader etc.

13. SEPARATING Peeling, coring and pitting: These are the primary unit operations for preparing fruit and vegetables for processing. Peeling of fruit and vegetables is carried out to remove unwanted or inedible material and to improve the appearance of the final product. The main consideration for peeling is to minimize cost by removing as little of the underlying food as possible and reducing energy, labor and material cost to a minimum. The peeled surface should be clean and undamaged. Depending upon the commodity, peeling and coring methods can be selected such as 1) hand or knife peeling 2) machine/abrasive peeling 3) flash steam peeling 4) lye (caustic) peeling 5) flame peeling. Cores and pits in fruits like apple, peach, apricot etc are removed by hand or by machine (de-corer).

14. GRADERS SORTERS PEELING ,CORING AND PITTING MACHINE

15. 4.SIZE REDUCTION Size reduction is a unit operation in which the average size of solid pieces of food is reduced by the application of –Shearing, impact, compression forces etc. Uses of high-shear forces , grater, cutters, slicers, homogenizers, ball mill grinders etc. Size reduction machinery 1. Crushers: mostly used to break large pieces of solid materials into small lumps ,squeeze or press the materials until it breaks. Types: -Jaw crushers -Gyratory crushers

16. SIZE REDUCTION 2. GRINDERS : Used to mill the grains into powders Types: -Attrition mill -Hammer mill -Roller mill 3. CUTTING MACHINES : Size reducers used for meat, fruits, vegetables -Grinders -Bacon Slicers -Sausage stuffers -Verticals choppers

17. HAMMER MILL ATTRITION MILL GRINDERS JAW CRUSHERS

18. 5.HEATING Heating of foods is carried out to destroy the micro-organisms, to preserve the food as in case of pasteurized milk and canned peas and to make them more tender and palatable as in cooking operations. Foods are heated by conduction, convection, radiation or their combination. Most of the foods are sensitive to heat and prolonged heat may cause burnt flavor, dark color or nutrition loss. It is therefore desirable to heat such foods rapidly and cool immediately. Foods may be heated or cooked by using hot water toasters, direct steam, direct contact to flame or microwave cookers. a. Blanching: Treatment of fruit and vegetables by dipping in boiling water or steam for short periods followed by immediate cooling is called blanching. The basic objectives of blanching are: Inactivation of enzymes, to cleanse the product initially to decrease the microbial load. To preheat the product before processing. To soften the tissue for facilitating compact packing in the cans. To expel intercellular gases in the raw fruit. To prevent excessive pressure built up in the container. To allow improved heat transfer during heat processing. To ensure development of vacuum in the can and To reduce internal can corrosion.

19. HEATING b. PASTEURIZATION : Pasteurization is a relatively mild heat treatment in which the food is heated below 1000C to destroy selected vegetative microbial pathogens or to inactivate enzymes. The pasteurization of liquid foods (fruit juices, milk, milk products, liquid egg etc) is carried out in continuous heat exchanger. The product temperature is quickly raised to the pasteurization levels in the first heat exchanger, held for the required length of time in the holding tubes, and quickly cooked in a second heat exchanger. Flash pasteurization uses higher temperature and shorter times (HTST) for example 880 C for 1 s, 94 0 C for 0.1 sec or 100 0 C for 0.01 sec. for milk and is known as Higher heat shorter time processing. For milk pasteurization, inactivation of alkaline phosphatase is used as indicator of pasteurization. Liquid egg pasteurization is based of measurement of a- amylase activity.

20. CANNING : Canning is a method of preserving food by first sealing it in air-tight jars, cans or pouches, and then heating it to a temperature that destroys contaminating microorganisms that can either be of health or spoilage concern because of the danger posed by several spore-forming thermo-resistant microorganisms, such as Clostridium botulinum (the causative agent of botulism). STERILIZATION: Sterilization is a more severe heat treatment given to a food to destroy both spoilage and pathogenic micro-organisms, after packaging the food in a hermetically sealed container. The thermal processing criterion for acid and medium acid foods (pH<4.5) is the destruction of heat resistant vegetative micro-organisms or enzymes. The low acid foods such as mushrooms, potatoes, peas and other vegetables are processed at elevated temperatures (115-1210C). Acid foods like peaches, pears, pineapple and other fruits are processed at 1000C or lower for adequate inactivation of enzymes.

21. 6. DRYING THREE METHODS: Sun or Tray Spray Freeze Drying involves the removal of water with minimum damage to the food

22. SUN OR TRAY DRYING: one of the most least expensive drying method. Used with products that are already solid like fruits and vegetables. Drying is achieved through exposure to the sun or current of warm or hot air. Used to make grapes into raisins. FREEZE DRYING: Used with heat sensitive products moisture is removed without a phase change Commercially only instant coffee is widely freeze dried. SPRAY DRYING: widely Subdivision of a liquid is the basic principle behind the widely used spray driers. The liquid is atomized by a spray nozzle and at the same time the hot air is passed which results into drying. It is most commonly used for fluid products.

23. Tray drying Freeze drying Spray drying

24. 7.LOW TEMPERATURE Low temperature is applied to retard chemical and enzymatic reactions in food. In addition, reducing temperature retards or stops growth and activity of microorganisms in the food. Lower the temperature, the slower will be the rate of above natural activities. Cooling thus slows down or stops the spoilage of foods. Freezing and refrigeration are among the oldest methods of preservation. Mechanical ammonia refrigeration systems invented during 1875 allowed development of commercial refrigerated warehousing and freezing.

25. Low temperatures employed can be: Cellar storage temperature (15°C) It is usually used for the storage of surplus foods like root crops, potatoes, onions, apples, etc. for limited periods. Refrigeration/ chilling temperature (0 to 5°C) Foods kept at this temperature slow down the microbial activities and chemical changes resulting in spoilage. Mechanical refrigerator or cold storage is used for this purpose. Examples of this include meats, poultry, eggs, fish, fresh milk and milk products, fruits, vegetables, etc. which can be preserved for 2-7 days by refrigeration. Freezing (-18 to -40°C) In freezing, water in food turns into ice and hence, makes the water unavailable for reactions to occur and for microorganisms to grow. Most perishable foods like poultry, meats, fish, ice-creams, peas, vegetables, juice concentrates, etc. can be preserved for several months at this temperature. In vegetables, enzyme action may still produce undesirable effects on flavor and texture during freezing. Heating, like blanching, therefore, must destroy the enzymes before the vegetables are frozen.

26. Cellar storages Refrigerators Freezers

27. 8.MEMBRANE PROCESS FILTRATION : it is defined as the technique of separating suspended solid matter from a liquid by causing the latter to pass through the pores of a membrane , called a filter. REVERSE OSMOSIS : uses membranes of the smallest pores and separates water from solutes and it requires a high pressure pump. ULTRAFILTRATION : uses membrane with a large pores and will retain proteins, lipids and colloidal salts while allowing smaller molecules to pass through the membrane. It requires a low pressure pump. MICROFILTRATION: pores less than 0.1 microns are used to separate fat from proteins and to reduce microorganisms from fluid food systems. Requires a low pressure pump.

28. NANOFILTRATION: Nanofiltration is a filtration process using a nano porous membrane that is used in waters with low total dissolved solids. Nanofiltration is a membrane filtration-based method that uses nanometre sized pores through which particles smaller than 10 nanometres pass through the membrane. Nanofiltration membranes have pore sizes from 1-10 nanometres, smaller than that used in microfiltration and ultrafiltration, but a little bit bigger than that in reverse osmosis.

29. 9.CONCENTRATION AND EVAPORATION Concentration is achieved through evaporation and reverse osmosis Evaporation in food industry is used principally to concentrate foods by removal of water. All liquids boil at lower temperature under reduced pressure and are the key to modern evaporation. Vacuum evaporators multi stage evaporators can easily remove water.

30. 10.MIXING TWO MAJOR REASONS FOR MIXING: HEAT TRANSFER INGREDIENT INCORPORATION There are different types of mixers depending upon the type of material to be mixed. They maybe used for mixing solids with solids, liquids with liquids, liquids with solids, gases with liquids etc. A ribbon type blender with rotating mixing elements is used to mix sugars with other dry components to produce fluffy mix. Propeller type agitator mounted within stainless steel vat is used for mixing solids into liquids to dissolve them as case of salt and sugar solution

31. Ribbon blender Planetary Mixer

32. 11.PACAKGING Machines operate at high speed and automatically package food products in a step wise and automated fashion from forming the container, filling the container, labelling and stacking it. Use for a variety of materials.

33. CONCLUSION Unit operations are the processes which convert our physical or chemical raw products into useful products. Unit operations provides and aid to process the food with ease These processes are interrelated to each other e.g. concentration and evaporation. Unit operations could be simple or complex processes depending upon the product we desire. They helps to make our nutrients more available to us and to remove toxic substances which can cause harm to human health.

34. REFERENCES https://www.slideshare.net/PrathameshPawale/unit-operations-in-food-processing-241293875 http://ecoursesonline.iasri.res.in/mod/page/view.php?id=17057 http://ecoursesonline.iasri.res.in/mod/page/view.php?id=111435 http://ecoursesonline.iasri.res.in/mod/resource/view.php?id=147595 http://ecoursesonline.iasri.res.in/mod/page/view.php?id=17057#:~:text=Cleaning%20is%20the%20unit%20operation,floatation%2C%20washing%20and%20ultrasonic%20cleaning . https://pharmaguddu.com/hammer-mill-usage-construction-working-principles-and-types/ P.J fellows, Food processing Technology, principles and practice, second edition R.L. Earle Unit Operations In food Processing, Web edition Zeki Berk, Food Process Engineering And Technology

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