Rendering of slaughterhouse by-products.ppt
- 1. Rendering Mohammad Hafizur Rahman Assistant Professor Dept. Animal Products and By-products Technology
- 2. • Historically, “rendering” has been defined as separation of fat from animal tissues by the application of heat. • Rendering can refer to any processing of animal products into more useful materials, or more narrowly to the rendering of whole animal fatty tissue into purified fats like tallow or lard. • Rendering is the recycling of raw animal tissue from food animals, and waste cooking fats and oils from all types of eating establishments into a variety of value-added products. During the rendering process, heat, separation technology, and filtering are applied to the material to destroy microbial populations, remove moisture, extract fat from the protein, and remove moisture and proteinaceous material from the fat. What is Rendering?
- 3. • Rendering is a process of both physical and chemical transformation using a variety of equipment and processes. All of the rendering processes involve the application of heat, the extraction of moisture, and the separation of fat. • According to Romans and others, rendering involves the heating or cooking of raw materials, with complex or simple mixtures of protein, minerals, and fatty substances, to liquefy fats and break down membranes or other structures that may hold fat.
- 4. • According to Kumar the goals of carcass rendering are elimination of water, separation of fat from other materials (mainly protein substances), sterilization of the final products, and production of MBM from a variety of condemned, fallen, culled, and experimental animals. • Romans and other defined rendering as a process of using high temperature and pressure to convert whole animal and poultry carcasses or their by-products with no or very low value to safe, nutritional, and economically valuable products. • “Meat and bone meal, meat meal, poultry meal, hydrolyzed feather meal, blood meal, fish meal, and animal fats are the primary products resulting from the rendering process”.
- 5. Unique Features of Rendering process: • Prevents environment pollution by disposing of all biological waste. • Offers optimum utilization of animal resources since meat meal is used for making animal feed. • More effective and profitable than any other waste disposal method. • Converts entire poultry/cattle waste into high protein sterilized meat meal.
- 6. The Rendering Process • Rendering is a process of both physical and chemical transformation using a variety of equipment and processes. All of the rendering processes involve the application of heat, the extraction of moisture, and the separation of fat. The methods to accomplish this are schematically illustrated in Figure 1. • The temperature and length of time of the cooking process are critical and are the primary determinant of the quality of the finished product. The processes vary according to the raw material composition. • All rendering system technologies include the collection and sanitary transport of raw material to a facility where it is ground into a consistent particle size and conveyed to a cooking vessel, either continuous-flow or batch configuration.
- 7. Figure 1. The Basic Production Process of Rendering.
- 8. • Cooking is generally accomplished with steam at temperatures of 240º to 290ºF (approximately 115º to 145ºC) for 40 to 90 minutes depending upon the type of system and materials (133ºC for at least 20 min at a pressure of at least 300 kPa). • Regardless of the type of cooking, the melted fat is separated from the protein and bone solids and a large portion of the moisture is removed. • Most importantly, cooking inactivates bacteria, viruses, protozoa, and parasites. Alternative methods of raw material disposal such as burial, composting, or landfill applications do not routinely achieve inactivation of microorganisms.
- 9. • Fat is separated from the cooked material via a screw press within a closed vessel. • Following the cooking and fat separation, the “cracklings” or “crax,” which includes protein, minerals, and some residual fat, are then further processed by additional moisture removal and grinding, then transferred for storage or shipment. • Storage of the protein is either in feed bin structures or enclosed buildings. • The fat is stored and transported in tanks.
- 10. The essence of rendering −Removes water from meat by-products to produce meat meal Meat by-products Meat meal Energy Wate r Fat/oil Rendering
- 11. Rendering Systems There are probably as many rendering systems, differing slightly from one another. However, all these different systems can generally fit into one of four categories: (1)autoclave (wet rendering), (2) dry batch, (3) dry continuous, or (4) continuous low-temperature systems.
- 12. Wet Rendering • Wet rendering is a system which leaves a high amount of moisture in the product, until, or if, it is to be dried. • It is most commonly applied today in the rendering of edible fats and oils and in the production of items such as partially defatted chopped beef or condensed beef. • Open kettle/pressure cooker wet rendering was quite common on a small scale. Figure: Wet Rendering System with Autoclaves
- 13. Dry rendering − A simple process with minimum quality concerns Dry rendering is done with or without an initial pressurization stage (sterilization) and it is the most common system used today. The most common process to transform animal by-products into stable, usable proteins and fat •A very industrial non-sanitary process •Uses significant quantities of energy •Require long processing times •At high temperatures of up to 140°C •Produces brown fat or grease and burnt meal that has undergone oxidation
- 14. Batch Rendering • When a system is operating in a batch manner, it becomes a batch system. • Even a continuous cooker can be operated in a batch mode. • A batch cooker is designed to be loaded, processed to a percentage dry, and then discharged for fat separation. • A batch cooker can function as a cooker, dryer, hydrolyzer, or processor, yet it is still the same piece of equipment. • With minor modifications, and with or without internal pressurization, a batch cooker can be used for each purpose.
- 15. Continuous Rendering • Generally defined as continuous in-feed and continuous out-feed with many still in use, there have been a number of continuous systems employed in the past. • One of the first was the Anco Strata-Flow system. • By connecting a series of modified batch cookers in a unique fashion, this became the first real continuous system.
- 16. Comparison between batch and continuous • A continuous rendering system normally consists of a single continuous cooker, whereas the batch cooker system consists of multiple cooker units. • A continuous system usually has a higher capacity than the batch cooker system it replaces. This increased capacity provides for more efficient processing of the raw material by processing more material in less time. • Continuous rendering also has a number of other inherent advantages over the batch system. • Since a continuous process requires less cooking time or exposure to heat, improved product quality normally results.
- 17. • Further, the continuous system occupies considerably less space than a batch cooker system with equivalent capacity, thus saving building construction costs. • Finally, a single cooker unit is inherently more efficient than multiple cooker units in terms of steam consumption and achieves a significant saving in fuel usage by the boilers. • Likewise, less electrical power is consumed for agitation in the single continuous cooker unit. • The only advantage of the batch cooker is that it can work under pressure so it can process feathers and hair.
- 19. Preparation of Blood Meal
- 20. • Blood Blood is a liquid connective tissue that is specialized to deliver necessary substances to the body's cells and remove wastes from them. • Composition of blood -Red blood cells, also called "erythrocytes," carry oxygen throughout th blood. -White blood cells, called "leukocytes," are part of the body's immune system and help defend the body against pathogens. -Platelets are cells that aid in blood clotting.
- 21. • -Hemoglobin the iron-containing substance in red blood cells that transports oxygen from the lungs to the rest of the body; it consists of a protein (globulin), and harem (a porphyrin ring with an atom of iron at its center). -Plasma A clear component of blood or lymph containing fibrin Source of blood From slaughter house, different meat industry
- 22. Blood meal Blood meal is a dry, inert powder made from blood used as a high- nitrogen fertilizer and a high protein animal feed. N = 13.25%, P = 1.0%, K = 0.6%. It is one of the highest non-synthetic sources of nitrogen. It usually comes from cattle as a slaughterhouse by-product. Whole blood meal is produced by spray drying at low temperatures, the fresh whole blood from animal processing plants.
- 24. Process of blood meal preparation Different production methods are applied in the industry, but some of the main processes are following: 1) by-products from slaughterhouses (blood) are transported to the factories in closed containers 2) the products are minced 3) the "mincemeat" is coagulated by heating (80-90o C) 4) liquid and solid material is separated by pressing, 5A) the solid fraction is dried (110o C), 5b) the wet fraction is heated (105o C) and fat is separated,
- 25. 6a) the dry product is screened, sterilized (133o C), packed and stored for distribution, 6b) fat is sterilized (125o C), packed and stored for distribution. 7) the wastewater generated during the process is either treated completely and emitted to recipient or treated to some extent and diverted to further in municipal wastewater treatment plants. 8) ventilation air is treated in bio-filters. 9) blood meal from healthy animals has traditionally been used for animal feed.
- 26. Function of blood meal 1. It can be spread on gardens to deter animals such as rabbits 2. It can be spread on gardens as a composting activator 3. It may also be used as an animal food supplement for cattle, fish and poultry and is in fact widely used due to the high lysine content. 4. It is mixed with molasses before use as animal feed. 5. Blood meal is permitted in certified organic production as soil amendments. 6. Applying blood meal will help plants become green again 7.It is use as a poultry feed source of high protein.
- 28. Important glands and their biochemicals/ pharmaceutical uses Important glands Pancreas Supra renal, thyroid and pituitary glands Ovaries, testes, stomach glands and gall bladder
- 29. Pancreas • Insulin (Pharmaceutical) and other enzymes, which are used by tanneries (industry), are obtained from pancreas. • It is a mixed type of gland. • It remains attached to liver and embedded in fat. • Insulin is the main hormone, an antidiabetic, which is extracted from the b-cells of this gland with the help of acidified methanol. • One kg of fresh bovine or pig pancreas yields about 150 mg of crystalline insulin with an activity of 254 IU/mg of insulin.
- 30. • Other biochemicals extracted from pancreas are: • Pancreatin – (Extract of pancreas) • Trypsin • Chymotrypsin • Amylase • Glucagon (a-cells) • Pancreas also contains several enzymes, which are used in the tannery or cleaner industries. • For this purpose, glands can be preserved for a week or so with some application of salt. These are packed in drums with a cover of salt.
- 31. Supra renal, Thyroid and Pituitary glands •Supra renal or adrenal • This gland is of two parts – outer cortex and inner medulla. • Cortex of adrenal gland yields corticosteroids, which are used in the treatment of Edison’s disease, to overcome shock in surgery and as a non-specific treatment. • Medulla of adrenal glands yields adrenaline (epinephrine) nor- adrenaline hormones. • Yield of adrenaline is 0.2% on fresh weight basis and 1% on dry weight basis. It is extracted in water or alcohol.
- 32. Thyroid gland •These are two maroon colored bodies situated on either side of trachea. •Acetone dried powder of this gland is used to extract thyroxin hormone with the help of Barium hydroxide. •Yield of the hormone is 0.08%.
- 33. Parathyroid gland •These are located near thyroid gland. •Parathromone is extracted from them. •It is used in the prevention of tetany and increase to the rate of calcium excretion.
- 34. Pituitary gland • It is a very small gland and has to be carefully collected. • From the anterior lobe the following hormones can be prepared • Growth hormone, FSH, LH, ACTH (Adrenocorticotropic Hormone) and MSH (Melanocyte-stimulating hormone) • From the posterior lobe the following hormones can be extracted • Oxytocin: • This can be extracted in 2 % acetic acid. • It initiates the uterine contraction and also milk-ejecting factor. • Vasopressin •Anterior lobe and Posterior lobe •Posterior lobe is an important vasoconstrictor and also an antidiuretic hormone.
- 35. Ovaries, Testes, Stomach glands and Gall bladder Ovaries •These are collected only from mature animals i.e. those having corpus lutea. •Ovaries are irregular, lobulated in appearance with large follicles projecting like small grapes. •All ovaries with cysts are discarded. •Sex hormones – estrogen and progesterone are extracted from ovaries.
- 36. Testes •These are also collected from mature animals that have been passed in antemortem examination and postmortem inspection. •Testosterone, a sex hormone is extracted from testes. •Hyaluronidase enzyme is made from bull or rams testes. •It is a very good spreading factor and used in several drugs to intensify their effect.
- 37. Stomach glands •Rennin or rennet: • This is an enzyme obtained from the lining of fourth stomach (abomasum) of milkfed and unweaned buffalo or cow calf. • The abomasum is cut out, packed and frozen without any washing. •Pepsin: • This is an enzyme obtained from the mucosal lining of the hog stomach. • Pink-red colour wrinkles and folds distinguish this part of hog stomach. • The glands are situated between the folds.
- 38. • The hog stomach is cut and the glandular linings are pulled away from the stomach wall and frozen as quickly as possible. • These can be preserved in 1% H2SO4 or the acetone-dried powder of the glands can be stored at room temperature but very low temperature is required during its preparation. • Peptone can be prepared from the remainder part of the hog stomach.
- 39. Gall bladder •It is attached to liver and contains bile, a dark golden-greenish viscous fluid of bitter taste. •Bile is slightly alkaline (pH 7.15) and has a specific gravity of 1.025. •It can be used as detergent in slaughter in slaughterhouses by dissolving in warm water (1:5 v/v). •Dried bile has medicinal use as a substitute in secretion deficiencies. •One kg of bile can be obtained from the gall bladder of 6 buffaloes or 55 sheep/goats, stored frozen.
Editor's Notes
- #10: Here is an overview of the basic of a rendering process. Rendering is a process that reduces a meat by-product by removing water to generate the dry and stable protein meal and fat. The meat by-products used as raw material going into the process is composed mainly of water (typically up to 68%). The meat by-products are usually collected from the meat processing facility and driven to a central rendering facility. The water is removed for discharge through evaporation. The process uses significant amount of energy (steam). After rendering, the meat meal contains 65% protein and only 6% water, a higher mineral content, and roughly the same amount of fat.
- #13: Dry rendering is the most common process to transform animal by-products into stable, usable materials. It separates water, fat and protein components (blood, bone and other meat materials) from animal by-products into dry and stable protein meal and fat for commercial use. Dry rendering is a very industrial and non-sanitary process. It uses significant energy quantities. It requires long processing times at high temperatures of up to 140°C. It produces brown fat or grease and burnt protein meal that has undergone oxidation. Although dry and stable, the burnt protein meal and fat are less in line with the trends for high-end pet food.