MEATAND FISH PROCESSINGPresented byKarthik,S.K.M.Tech (Agri. Engg)PALB 3310
INTRODUCTIONThe word meat comes form the old English word mete, in general which referred to food.
Meat is those animal tissues which are suitable for use as food by the man.
Technically it is the muscle portion of the animals body that is consumed as food.
It is composed of numerous types of tissues like muscle tissues, epithelial tissues and nervous tissues but the major component of meat is muscle.
The muscle and connective tissues are the major compositional components and contributes towards qualitative and quantitative characteristics of meat.
MUSCLESStriated musclesSmooth musclesStriated muscles have transverse band pattern as in skeletal and cardiac muscle.Smooth muscles do not show such pattern an mainly found as a component of blood vessels.
Skeletal Muscle: The muscles have direct attachment with bones but some of them are also attached with ligaments, fascia, cartilage and skin. Muscle fiber is a structural unit of skeletal muscle tissue and constitutes 75-92% of total muscle volume.
Smooth Muscle: It has little contribution to meat and found mainly in wall of arties, lymph vessels, gastrointestinal and reproductive tracts. Smooth muscle fiber is a single nucleus cell located mainly at the centre of the cell.
STRUCTURE OF MEAT MUSCLE
Nutritional Composition of MeatCarbohydrates: glycogen, glucose and glucose-6-phosphate is in meat.
Protein: Meat is rich in proteins and provides all the essential amino acids.15-20% of good quality protein, the percentage is higher in lean meat 20-22%.On dividing the total nitrogen content of meat we get 95% as protein and remaining 5% as smaller peptides and amino acids.Fat: Variable 5-40% depends on age, breed, feed and type of source animal.
Vitamins and minerals: found in the lean portions of meat.Meat are excellent sources of some vitamin B12, the liver is an excellent source of Vitamin A.Calcium and magnesium are the main minerals with important roles to play in the contraction of muscles.Iron as the component of the red pigment and zinc in enzymes.Hydrolysing enzymes: The enzymes help in the process of denaturation of the muscle proteins which in turn makes meat tender.
Pigments: Meat contain to pigments myoglobin and haemoglobin.
Water: it is the largest single component of muscles by weight.
CLASSIFICATION OF MEATMuttonLamb.Yearling Mutton.Mature Mutton.2. Pork3. Organs Meats4. Sausages
AGINGThe term ageing or ripening of meat, which implies the changes brought about by the resolution of rigor.
Resolution of rigor means improvement in flavour as well as juiciness, in cold conditions.
The method used for ageing is to keep the meat in a cold room with temperature between 0.50c to -20c for 1-4 weeks. Meat aged for 2-4 weeks has been found to be of best flavour and good tenderness.Events:Tenderization of meat.Development of better flavour and juiciness.Denaturation of proteins and their mild hydrolysis.Breakdown of the connective tissues present between muscle fibres by the action of cathepsins.
TENDERISATION OF MEATThe most important sensory qualities of meat is its tenderness and soft chewy feel.
Some meats are tender while others are hard to chew. This is due to the type of animal, its age, level of activity and the part of the animal eaten.
It can be improved by either natural methods or artificial methods, Mechanical action, Chemical action, Hydration and Cooking.
Natural MethodNatural method implies the natural ripening and tenderisation brought about by cathepsins present inside the meat.
They cause the denaturation and hydrolysis of muscle proteins and make the meat tender.
Cold room storage is effective in the natural ripening process.
Over tenderisation of meat is undesirable as it changes the texture of meat and results in loss of flavour and juiciness.
Artificial MethodsMany artificial methods have been developed to tenderise meat. They are1. MECHANICAL ACTION: Tenderness is improved by reducing the length of muscle fibres or breaking them. This is achieved by:
Pounding: This tears and breaks the surface meat fibres and connective tissues. This method is used for individual portioned cuts, steaks not whole joints.Grinding: Breaks and cuts all muscle fibres and connective tissues. Meat is put through a chopper, grinding machine to break up connective tissue and muscle tissue into small pieces.Ultrasonic vibrations break the meat fibres.Insertion of needles/blades into the meat has also been observed to increase meat tenderness.
2. Chemical ActionSalt increases tenderness because it softens the connective tissue.
Vegetable enzymes such as papain, bromelin, trypsin, ficin and fungal enzymes also tenderize meat
The tenderizing effect acts mainly at the surface, so a marinade or powder works better in small, thin cuts of meat.
Vegetable enzymes are limited though in that their action is sometimes restricted to the surface of the meat
Hydration: An acidic, alkaline or salt solution can increase the water holding capacity of meat and make it tenderer.Salts like sodium chloride, sodium bicarbonate and sodium/potassium phosphate used for solubilizes the meat proteins.Acid like lemon juice are often used to marinate meat before cooking.
Cooking: Tough cuts generally need a long, slow, moist method of cooking, such as casseroling. On heating, muscle fibres begin to shrink. A around 770c, shrinkage ceases and there are colour changes and loss of liquid. This liquid is mixture of meat extracts, water and fat.
SMOKINGThe process of curing refers to the treatments meted out to meat which helps in preserving meat as well as imparting it the unique flavour, colour and tenderness.Curing is a traditional art practised primarily to preserve meat and retard spoilage.Curing agents are salt, sugar, nitrite and spices.Occasionally cured meat is dried and smoked to impart a better flavour and cause protein coagulation. Smoking helps in destruction of microorganisms and prevents rancidity in meats. The sawdust from hardwood is the fuel for smoking.CURING
Meat Cookery or CookingIt is the art of preparing food for the nourishment of the body.Objectives of cooking meat are:Develop or improve flavour, colour, aroma.Make it delicious/appetising to eat.Make it tenderer.Make it easier to digest.Make it safe to eat i.e., kill any harmful bacteria it may have picked up during handling.
During the process of cooking many chemical changes occur, affecting the appearance, taste and texture of meat.
Muscle proteins shrink and moisture is lost
Changes in colour
Connective tissue softens
Fat melts, browning occurs and flavour develops.
Cooking MethodsDry heat methods: In this methods do not use liquid, but can use fat or oil. Dry heat suits tender or medium-tender meat cuts.RoastingGrilling (fan-grilling, pan-grilling)Shallow frying (pan-frying, stir-frying)Deep frying
Moist heat methods:BraisingPot-roastingStewingSimmeringPoachingSteamingPressure-cooking
The cooking method chosen depends onNatural tenderness of meat cut.
The amount and type of connective tissue.
The leanness of the meat.
Size and thickness of the cut of meat.
CHILLINGAfter slaughter many biological changes take place in the muscle that convert it to meat.
Chilling is used to prevent spoilage.
If chilling occurs rapidly the result is cold shorteningOccurs when the muscle is chilled to less than 150c before rigor mortis(Contraction and stiffening of the muscle) is complete.
If the carcass is frozen before rigor is complete the result is thaw rigor and the result is extremely tough meat
Before freezing, beef or lamb should be sufficiently aged, as meat does not continue to tenderise while frozen.
Frozen large cuts will keep better and longer, with less flavour change, than frozen smaller cuts, thin slices or mince.
It is important to make sure temperature dont fluctuate by more than 0.50c.
Big temperature changes can mean a partial thaw which damages the structure of the meat.Freezing
ThawingThe best way to maintain quality of frozen meat is by slow thawing in the refrigerator.
Thawing meat at room temperature is not recommended. The surface of the meat may reach warm temperatures which encourages spoilage.
If thawing is needed urgently there are some options. Leave the meat in its sealed freezer wrap or vacuum-pack for all the following speed-thaw methods.
Place meat on a tray in a relatively cool room for 1-2hr before completing thawing in the refrigerator.Use a microwave oven set on defrost.Place sealed vacuum-pack in a sink of cold running water.
StorageDried TVP should be kept cool, in an air-tight container away from direct sunlight. Tofu, tempeh and myco-protein should be kept in a refrigerator or freezer unit until needed.
IntroductionFish is found abundantly in all natural waters.It is a valuable source of food and has been used by man from antiquity.Its popularity can be gauged by the umpteen numbers of dishes with fish as their base made in these states.
ClassificationAlthough there are over 25,000 species of fishes.
Edible fishes are divided in two categories.Fin fishShell fishMollusks (oysters, clams, scallops and mussels)Crustaceans (lobsters, shrimps, crabs and cray fish)
Classification of fish on the basis of their fat contentLean: 5% and so the flesh is more pig