For food processing

1. TECHNOLOGY OF MEAT, POULTRY AND FISH
PROCESSING
UNIT I
• Meat composition from different sources; muscle structure and
compositions; post-mortem muscle chemistry; meat colour and
flavours; meat microbiology and safety.
UNIT II
• Modern abattoirs, typical layout and features, abattoir equipment
and utilities, ante-mortem handling and design of handling facilities;
hoisting rail and traveling pulley system; stunning methods; steps in
slaughtering and dressing; offal handling and inspection; inedible by-
products; operational factors affecting meat quality; effects of
processing on meat tenderization.
UNIT III
• Chilling and freezing of carcass and meat; canning, cooking, drying,
pickling, curing and smoking; prepared meat products like salami,
kebabs, sausages, sliced, minced, corned; intermediate moisture and
dried meat products; meat plant hygiene – GMP and HACCP.
Packaging of meat products

2. TECHNOLOGY OF MEAT, POULTRY AND FISH
PROCESSING
UNIT IV
• Poultry industry in India, measuring the yields and quality
characteristics of poultry products, microbiology of poultry meat,
spoilage factors; lay-out and design of poultry processing plants, plant
sanitation; poultry meat processing operations, equipment used –
defeathering, bleeding, scalding etc.; packaging of poultry products,
refrigerated storage of poultry meat, by products – eggs, egg
products, whole egg powder, egg yolk products, their manufacture,
packaging and storage.
UNIT V
• Commercially important marine products from India; product export
and its sustenance; basic biochemistry and microbiology;
preservation of postharvest fish freshness; transportation in
refrigerated vehicles; deodorization of transport systems; design of
refrigerated and insulated trucks; grading and preservation of shell
fish; pickling and preparation of fish protein concentrate, fish oil and
other by products.

3. Meat
• Meat consumption in developing countries has
been continuously increasing
• Average annual per capita consumption
– 10 kg in the 1960s
– 26 kg in 2000
– 37 kg around the year 2030 (FAO projections)
• Global meat production
– 267 million tons (2006)
– 320 million tons (2016)
 India – 6.2 million tons (2014)

4. Sources of Meat
Meat products are mainly derived from the domesticated
animal species like sheep, goats, cattle, buffaloes, pigs and
poultry.
• Beef- from cattle > 1 yr. of age
• Veal - calves ( 3 months. or
younger)
• Pork - swine
• Mutton-mature sheep
• Lamb -young sheep (< 1 year)
• Chevon -goats (goat meat)

5. Meat
• Meat can be defined as “the muscle tissue of slaughter
animals”.
• The skeletal muscle is the principal muscle tissue in meat,
although very little of smooth tissue is also present.
• The other important tissue used for further processing is fat.
• Other edible parts of the slaughtered animal and often used
in further processing are the internal organs (liver, kidneys,
lungs, tongue, heart, diaphragm, oesophagus, intestines) and
other slaughter byproducts (blood, soft tissues from feet,
head).

6. Skeletal
w Voluntary muscle; controlled consciously
w forms the bulk of meat
Cardiac
w Controls itself with assistance from the nervous
and endocrine systems
w Found only in the heart
Smooth
w Involuntary muscle; controlled unconsciously
w Found in the walls of blood vessels and internal
organs
Types of Muscles
There are more than 300 muscles in the animal body. These
muscles constitute about 35-60% of the carcass weight of meat
animals

7. Skeletal Muscle
• Skeletal muscles are muscles which are
attached to the skeleton.
• Approx. 40% of animal body mass
• Skeletal muscles are mainly responsible for
locomotion, and voluntary contraction and
relaxation.
• skeletal muscles are directly attached to the
bones, although some attach indirectly via
ligament, cartilage, fascia and skin.
• Each muscle is surrounded by a sheath of
connective tissue known as epimysium.
• From the inner surface of epimysium, a
septum of connective tissue penetrates into
muscle and surrounds the bundles of muscle
fibres or fasciculi. This connective tissue is
called perimysium . It contains major blood
vessels and nerves.
• Each muscle fibre is surrounded by a
connective tissue layer called endomysium
Cross-section of a typical muscle
depicting arrangement of connective
tissues and muscle fibres

9. • An individual muscle cell is called a
muscle fiber.
• Muscle fibres are usually 10-100μ
in diameter with conical or
tapering ends and their length
ranges from 1-40 mm
• A muscle fiber is enclosed by a
plasma membrane called the
sarcolemma.
• The cytoplasm of a muscle fiber is
called a sarcoplasm.
• Within the sarcoplasm, the T-
tubules allow transport of
substances throughout the muscle
fiber and the sarcoplasmic
reticulum stores calcium.
Structure of single muscle fibre

10. Chemical composition of muscle meat
• Muscle tissue contains approximately 75% water and 25%
solids, of which 19% are proteins. Lipids constitute about
2.5 to 5% of muscle
• In general, meat is composed of water, fat, protein,
minerals and a small proportion of carbohydrate.
• The most valuable component from the nutritional and
processing point of view is protein.
• Protein contents and values define the quality of the raw
meat material and its suitability for further processing.

11. Chemical composition of muscle meat
Water
• This is the largest component comprising two
third to three fourth of the muscle tissue.
• Due to polar behavior, water molecules are
attached with the electrically charged groups of
muscle proteins.
• About 40 % of the total water in muscle is so
tightly bound that it is almost impossible to
dislocate it.

12. Protein
• Muscle proteins have been broadly classified into
three categories:
i) Myofibrillar proteins -- soluble in dilute salt
solution
ii) Sarcoplasmic proteins -- soluble in water or
very dilute salt solution.
iii) Stroma or connective tissue proteins –
almost insoluble

13. Chemical composition of a typical
animal muscle

15. Composition of different meat

16. The nutritional value of meat and meat
products
Protein
• The nutritional value of meat is essentially related to the content of
high quality protein. High quality proteins are characterized by the
content of essential amino acids which cannot be synthesized by our
body but must be supplied through our food.
• The myofibrillar proteins are quantitatively the most important (some
65%) and are also qualitatively important as they have the highest
biological value.
• Connective tissues contain mainly collagen, which has a low biological
value. Elastin is completely indigestible. Collagen is digestible but is
devoid of the essential amino acid tryptophan.
• Blood proteins have a high content of tryptophan but are nevertheless
of a lower biological value than meat due to their deficiency of the
essential amino acid isoleucine

17. Fats
• Animal fats are principally triglycerides.
• The fatty acid composition of the fatty tissues is very different in
different locations.
• External fat (body fat) is much softer than the internal fat
surrounding organs due to a higher content of unsaturated fat in
the external parts.
• Meat and meat products are relatively good sources of unsaturated
fatty acids (linoleic, linolenic and arachidonic acid), which are
physiologically and nutritionally important

18. Vitamins
• Meat and meat products are excellent sources of the B-
complex vitamins. The daily requirement for humans of
this rarely occurring vitamin is 1-1.5 mg.
• Plant foods have no vitamin B12, hence meat is a good
source of this vitamin.
• Internal organs, especially liver and kidney generally
contain an appreciable percentage of vitamin A, C, D, E
and K.
• Most of the vitamins in meat are relatively stable during
cooking or processing, although substantial amounts may
be leached out in the drippings.

19. Minerals
• The mineral contents of meat include calcium,
phosphorus, sodium, potassium, chlorine, magnesium
with the level of each of these minerals above 0.1%,
and trace elements such as iron, copper, zinc and many
others.
• Blood, liver, kidney, other red organs and to a lesser
extent lean meat, in particular beef are good sources of
iron.
• Iron in meat has a higher bio-availability, better
resorption and metabolism than iron in plant products

20. • The red pigment that provides the characteristic colour of
meat is called myoglobin.
• Similar to the blood pigment haemoglobin it transports oxygen
in the tissues of the live animal.
• Oxygen is needed for the biochemical process that causes
muscle contraction in the live animal.
• Specifically, the myoglobin is the oxygen reserve for the
muscle cells or muscle fibres.
• The greater the myoglobin concentration, the more intense
the colour of the muscle.
• This difference in myoglobin concentration is the reason why
there is often one muscle group lighter or darker than another
in the same carcass
Meat Color

21. Meat colour
• Myoglobin concentration in muscles also differs
among animal species.
• Beef has considerably more myoglobin than pork,
veal or lamb, thus giving beef a more intense
colour .
• The maturity of the animal also influences
pigment intensity, with older animals having
darker pigmentation.
• Myoglobin is denatured by prolonged exposure
to air or by cooking

22. The water holding capacity
• The capacity of meat to retain its water during the application of
physical forces (during cutting, grinding, filling, pressing, or heating) is
known as water holding capacity (WHC).
• WHC of meat is one of the most important factors of meat quality both
from the consumer and processor point of view. it contributes to the
juiciness of cooked meat besides influencing the texture and colour
• Fresh meat with a good water holding capacity is less prone to
shrinkage during storage
• Muscle proteins are capable of holding many water molecules to their
surface.
• As the muscle tissue develops acidity (decrease of pH) the water
holding capacity decreases.
• Water holding capacity varies greatly among the muscles of the body
and among animal species.
• Beef has the greatest capacity to retain water, followed by pork, with
poultry having the least.

23. Tenderness
• Meat tenderness plays an important role, where entire pieces of meat are
cooked, fried or barbecued.
Factors Responsible for Tenderness in Meat
1. Genetics: In Beef it has been noticed that 45% of observed variation in tenderness
of cooked Beef is due to genetics /parents of the animal.
2. Species & Age:
• Tenderness – Variations in tenderness is observed to a great extent in Beef
followed by lamb & pork.
• Tenderness depends on age of the animal at the time of slaughter
Beef – 20 month,
Lamb – 8 month
Pork – 5month
• The decrease in tenderness with increasing age is due to charging nature of
collagen (gristle), connective tissue protein found in meat.
• Collagen becomes complex & stronger with advancing age

24. Tenderness
• In these cases some types of
meat, in particular beef, have
to undergo a certain ripening
or ageing period before
cooking and consumption in
order to achieve the
necessary tenderness.
– beef's natural enzymes break
down the connective tissue in
the muscle, which leads to
more tender meat
Ageing of meat

25. Taste and flavour
• The typical desirable taste and odor of meat is to a
great extend the result of the formation of lactic acid
(resulting from glycogen breakdown in the muscle
tissue) and organic compounds like amino acids and di-
and tripeptides broken down from the meat proteins.
• In particular the aged (“matured”) meat obtains its
characteristic taste from the breakdown to such
substances.
• The “meaty” taste can be further enhanced by adding
monosodium glutamate (MSG) (0.05- 0.1%), which can
reinforce the meat taste of certain products.

26. Post mortem Muscle chemistry
Glycolysis and pH Decline
• Immediately post-mortem the muscle contains a small amount of
muscle specific carbohydrate, called glycogen
• In the live animal glycogen is the energy reserve for the muscles
used as fuel for muscle contraction
In life: Glycogen + O2 CO2 + H2O + ATP (energy)
After death: Glycogen CH3 CH(OH)COOH (lactic acid)
• Glycogen is broken down to lactic acid in the muscle meat after
slaughtering.
Aerobic
conditions
Anaerobic
conditions

27. Post mortem Muscle chemistry
Glycolysis and pH Decline
• The build up of lactic acid in the muscle produces an increase
in its acidity, as measured by the pH.
• The pH of normal muscle at slaughter is about 7.0
• In a normal animal, the ultimate pH (expressed as pH24 = 24
hours after slaughter) falls to around pH 5.8-5.4.
• The drop in pH is a desirable features as a low pH slows down
growth of microorganism, and enhances flavour, juiciness and
colour of the meat.
• The typical taste and flavour of meat is only achieved after
sufficient drop in pH down to 5.8 to 5.4.

28. Post mortem Muscle chemistry
Glycolysis and pH Decline
• The degree of reduction of muscle pH after slaughter is related to the
amount of glycogen present in the muscle .
• Animals are held at rest before slaughter to make sure that they are
not stressed prior to slaughter, as stress causes them to burn up their
glycogen reserves.
• Meat of animals, which had depleted their glycogen reserves before
slaughtering (after stressful transport/handling in holding pens) will not
have a sufficient fall in pH and will be highly prone to bacterial
deterioration.
• Meat from stressed animals has a high pH, causing it to be dark in
colour, firm in texture and dry in taste (known as DFD meat).
• Sharp decline in postmortem pH may cause denaturation of muscle
proteins. So, the muscles depict pale, soft and exudative condition
(PSE meat) .

29. Post mortem Muscle chemistry
Rigor Mortis
• It refers to stiffening of muscles after death.
• The phenomenon of rigor mortis resembles that of muscle
contraction in a living animal muscle except that rigor mortis
is irreversible under normal conditions.
• A particular level or concentration of ATP complexed with
Mg++ is required for breaking the actomyosin bond and
bringing the muscle to a relaxed state
• As the conc. of ATP drops, permanent actomyosin cross
bridges begin to form and muscle gradually becomes less and
less extensible under an externally applied force.
• When postmortem pH decline is very slow or very fast, the
onset and completion of rigor mortis is rapid. The onset of
rigor mortis is enhanced at ambient temperature above 200C.

30. Post mortem Muscle chemistry
Degradation due to Proteolytic Enzymes
• Several autolytic lysosomal enzymes called
cathepsins which remain inactive in a living
muscle tissue, are activated as the muscle pH
declines.
• These enzymes initiate the degradation of
muscle protein structure.
• In fact, catheptic enzymes are capable of
breaking down even collagenous connective
tissue of the muscle and cause tenderization of
meat during aging.

31. Post mortem Muscle chemistry
Loss of Protection from Invading Microorganisms
• During postmortem period, body defence
mechanism stops operating and membrane
properties are altered.
• So, during conversion to meat, muscle is quite
susceptible to invading microorganisms.
• Except for low pH, most of the other postmortem
changes favour bacterial growth. Hence, utmost
handling precautions are necessary to prevent
contamination of meat