fish and meat processing

1. MEATAND FISH
PROCESSING
Presented by
Karthik,S.K.
M.Tech (Agri. Engg)
PALB 3310

2. MEAT PROCESSING

3. INTRODUCTION
• The 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.

4. Cont.,
• 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.

5. MUSCLE
S
1. Striated muscles have transverse band
pattern as in skeletal and cardiac muscle.
2. 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.
Striated muscles Smooth
muscles
• 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.

6. STRUCTURE OF MEAT MUSCLE

7. Nutritional Composition of Meat
Carbohydrates: 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.

8.  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.

9. CLASSIFICATION OF
MEAT
1. Mutton
a) Lamb.
b) Yearling Mutton.
c) Mature Mutton.
2. Pork
3. Organs Meats
4. Sausages

11. AGIN
G
• The 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.

12. TENDERISATION OF
MEAT
The 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.

13. Natural
Method
 Natural 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

14. Artificial Methods
Many artificial methods have been developed to tenderise meat. They are
1. MECHANICAL ACTION: Tenderness is improved by reducing
the length of muscle fibres or breaking them. This is achieved by:
1. Pounding: This tears and breaks the surface meat fibres and
connective tissues. This method is used for individual portioned
cuts, steaks not whole joints.
2. 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.
3. Ultrasonic vibrations break the meat fibres.
4. Insertion of needles/blades into the meat has also been observed to
increase meat tenderness.

15. 2. Chemical Action
• Salt 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

16.  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:
o Tough cuts generally need a long, slow, moist method of
cooking, such as casseroling.
o 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.

17. CURING
 The 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.
SMOKING
 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.

18. Meat Cookery or Cooking
 It is the art of preparing food for the
nourishment of the body.
 Objectives of cooking meat are:
a) Develop or improve flavour, colour, aroma.
b) Make it delicious/appetising to eat.
c) Make it tenderer.
d) Make it easier to digest.
e) Make it safe to eat i.e., kill any harmful bacteria it
may have picked up during handling.

19.  During the process of cooking many chemical
changes occur, affecting the appearance, taste
and texture of meat.
1. Muscle proteins shrink and moisture is lost
2. Changes in colour
3. Connective tissue softens
4. Fat melts, browning occurs and flavour develops.

20. Cooking Methods
Dry heat methods: In this methods do not use liquid,
but can use fat or oil. Dry heat suits tender or medium-tender
meat cuts.
a) Roasting
b) Grilling (fan-grilling, pan-grilling)
c) Shallow frying (pan-frying, stir-frying)
d) Deep frying

21. Moist heat methods:
a) Braising
b) Pot-roasting
c) Stewing
d) Simmering
e) Poaching
f) Steaming
g) Pressure-cooking

22. The cooking method chosen depends on
1. Natural tenderness of meat cut.
2. The amount and type of connective tissue.
3. The leanness of the meat.
4. Size and thickness of the cut of meat.

23. CHILLING
• After 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 shortening
– Occurs 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

24. • 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 don’t fluctuate by more than
0.50c.
• Big temperature changes can mean a partial thaw which damages the
structure of the meat.
Freezing

25. Thawing
• The 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.
1) Place meat on a tray in a relatively cool room for 1-2hr before completing
thawing in the refrigerator.
2) Use a microwave oven set on defrost.
3) Place sealed vacuum-pack in a sink of cold running water.

26. Storage
Dried 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.

27. FISH PROCESSING

28. Introduction
O Fish is found abundantly in all natural
waters.
O It is a valuable source of food and has
been used by man from antiquity.
O Its popularity can be gauged by the
umpteen numbers of dishes with fish as
their base made in these states.

29.  Although there are over 25,000 species of fishes.
 Edible fishes are divided in two categories.
1) Fin fish
2) Shell fish
a) Mollusks (oysters, clams, scallops and mussels)
b) Crustaceans (lobsters, shrimps, crabs and cray fish)
• Classification of fish on the basis of their fat content
1) Lean: <2% (Bombay duck, halibut, cod perch and sole)
2) Medium: 2 – 5% (Generally fishes are white fleshed)
3) Fat: >5% and so the flesh is more pigmented and they
appear reddish. (Tuna, salmon, sardine and mackerel)

30. Nutritive
Value
 Protein: Fish is an excellent source of good quality
protein with about 20% protein. The main amino acids
are lysine and histidine. Methionine and tryptophan are
also present.
 Fats: variable and dependent on many factors like age,
season, sex and stage of maturity.
Fish type N-3 PUFA content (g/100 g
edible muscle)
Fresh water fish 0.07 – 0.28
Fish murrel 0.28
Marine fish 0.26 – 0.28
Fresh water fish (fat 1.7 g%) 0.26
Marine fish (1.8 g% fat) 0.39

31.  Carbohydrate: Fishes are not good sources of energy
since their fat and carbohydrate content is insignificant.
The main carbohydrate present in fish is glycogen from
muscles (3 – 5 % in shell fish).
 Vitamins: Fish oils are the richest sources of vitamins A
and D. They are fairly rich in thiamine, but due to the
presence of thiaminase in raw fish. Niacin is a vitamin
abundant in both fresh water and salt water fish.
 Minerals: The major minerals fishes contribute are iron,
copper, iodine, sulphur and phosphorus.
 Iodine content of marine fishes( 0.01 – 0.5 mg/100 g of
fish meat) is much better (30%) than fresh water fishes.
 Oysters are good sources of copper and iron.
 Fishes are specially rich in calcium, particularly small
fishes eaten with bones.

32. SELECTI
ON
Observed part Identifying characters
Skin Bright and shiny skin. No wrinkles and shrunken skin.
Eyes Convex eyes with black pupil and translucent cornea.
Bright, clear and bulging eyes.
Gills Bright red, not brown or with mucous.
Backbone Firmly attached backbone to the skin on splitting it
open
Surface Clean, free of dirt and grime
Flesh Firm to touch and not dry or brown.
Odour Absent
Taste Fresh and not sour as rancidity causes sour taste to
develop.
Yellow spots on
Rancid fish so not to be selected

33. SHELL FISH
SELECTION
Shell fish Characters for good quality
Prawns Fresh and firm
Scallops Pinkish or pale yellow in colour, with firm flesh and clear liquid
oozing out.
Clams Tightly closed with no entry points left open. Heavy to lift and no
foul odours emitting out.
Oysters Tightly closed with no entry points left open. Heavy to lift and no
smell of deterioration.
Mussels Difficult to open as the lids are tightly closed. The mussels
should be heavy to confirm no microbial spoilage and intact
flesh. No off odours should be coming out.

34. Spoilage
 Microbial spoilage: Till the time fishes are alive they
are sterile(microbiologically), but a number of microbes are
present on the body surface in the form of slime and in their
digestive tracts.
 Physiological spoilage: If there is no glycogen available
for conversion into lactic acid, pH does not decrease, this
condition accelerates spoilage.
 Biochemical spoilage: Odour is developed due to the
production of the compound tri-methyl amine formed when
bacteria react on phospholipids and choline of the fish cells.
Oxidative rancidity also is a major cause for
undesirable smell since the unsaturated fats undergo
oxidation.

35. Preservation Methods
1. Drying: Drying was done by exposure to sun or the
technique which resists bacterial and enzyme
putrefaction.
2. Pickling/salting: It is another primitive method which
uses salt as preservative (dry salting and wet salting).
3. Canning:
 Popular preservation method (John Eppurt). Salmon and
Tuna are the most popular varieties of canned fish.
 Canning is done by putting cleaned, dressed and cut fish
into a saline solution.
 Sterilize the cans at 1210c for 90 minutes, under steam
pressure.
 Sterilization is followed by cooling of the cans under
normal room temperature by running water.

36. 4. Low temperature treatment
For the effective preservation, very low temperature to
the tune of -400c and maintained at -230c approved. Freezing
is done rapidly and has to be properly maintained. This way,
fish stays in food condition for about 6 – 7 months.
Freezing causes some undesirable changes in the
quality of fish. It is the major reason for denaturation of fish
protein and desiccation of fish.
5. Denaturation: When water crystals are formed, salt
concentration of the muscle tissues goes on increasing. This
high salt concentration causes the denaturation of muscle
proteins and makes the flesh tough to chew and eat.

37. 6. Desiccation: Implying drying, this is another
problem with freezing fish. The loss of moisture due to
the fact that the air close to the fish in the storage area
is not as cold as that in the refrigeration pipes. As a
result it absorbs large amounts of moisture form the
surface of the fish.
The facet of desiccation is the evaporation of
water from flesh of the frozen fish to the air cavities
between muscle fibres. This can be avoided and
controlled by letting a weak saline solution to fill these
cavities prior to any evaporation.
7. Oxidation changes: Another aspect of freezing is
the development of oxidative rancidity. This is more
marked in fatty fish than lean ones. It can be avoided by
proper wrapping of the fish and adequate storage.

38. Fish Cookery
 With any food stuff the most important part comes
when it has to be cooked for consumption.
 Lot of factors like time, seasonings, cooking
method, additives etc. have to be considered to
make the perfect dish.
 Generally dry heating methods like broiling,
baking and frying are used to cook fish.
 Moist heating methods are also used as they
are effective in protecting the delicate flavour of
the fish.
 Some times a combination of both methods also
used.

39. Storage
 Fresh fish have 3 – 6 hours they are considered well
enough for consumption. But from the sixth hour their
journey to spoilage accelerates.
 It should be stored at frozen temperature(-180c or less) to
preserves the colour, texture, flavour and nutritive value of
fish. (max. 2 days)
 Canned fishes, pre-packed fish can keep well for a short
time.
 Cold storages are a viable storage option.
 If fish are kept with crushed ice they remain good for 2
days. Additionally, if stored in freezer with crushed ice, the
self-life increases to a week.
 For further long storage a media of crushed ice with salt is
good enough.