Meat Flashcards
Meat types
Red meat species = cattle, sheep & goats - White meat species = chickens & pigs
Other meat species = deer, ducks, buffaloes, horses, camels, dogs, kangaroos, emus
Pig & poultry are becoming more popular: why?
Are cheaper to produce than beef & mutton
- Intensification growth practices
- Perceived to be healthier by affluent consumers:
Leaner meats = little or no visible fat in skinless pork &
chicken
Redder meats associated with large fat amounts
Meat carcases sold as
- Sides
- quarters (hinds or fores)
- wholesale cuts (large cuts such as entire rounds, loins, ribs or chucks)
boxed beef
- removing more bone & fat from carcase as it’s cut into smaller portions
- vacuum-packed to reduce spoilage & shrinkage - placed into boxes for easy shipping & handling
- Boxed beef reduces shipping costs, labour costs & provides increased value of fat & bone to packer
Meat grading
Establishes & maintains uniform trading standards & aids in determination of value of various meat cuts
- Carcases are given a quality grade (yield grade is used for lamb; Australia Pork also uses yield grade for pork).
Dentition (number of teeth), weight & fat depth used to define animal’s meat class & grading
Meat quality depends on breed, heredity, sex, feeding, pre- slaughter & slaughtering conditions, dressing, carcass cooling & storage conditions
Meat Structure & Composition
skeletal muscle from the animal carcase – beef & veal (cattle), pork (pigs) & lamb (sheep)
General composition:
- ~70% water
- ~21% protein
- ~8% fat - contributes to product “juiciness”, tenderness & flavour of meat & processed
meats (& reduces their formulation costs)
- ~1% minerals (ash)
- provide complete protein sources containing all essential amino acids in favourable quantities
- The protein has high biological value (BV)
Contains all amino acids essential for human health
excellent source of iron as more biologically available than plant sources, or added fortification
BV
measure of proportion of absorbed protein from a food which becomes incorporated into the proteins of an organism’s body
main animal classes slaughtered in Australia
cattle & calves = bovine
- sheep & lambs = ovine
- pigs = porcine
Other slaughtered animals in lesser numbers = goats (caprice) & horses (equine)
Slaughtering systems
vary according to animal class & abattoir sophistication
- Methods used to slaughter animals can influence
- Carcass and meat quality
- Animals’ welfare
- Safety of personnel operating the system
Australia slaughter law
“The slaughter of animals for food must be carried out in a humane manner. Regardless of religious or cultural beliefs, animals must be humanely rendered unconscious via stunning prior to slaughter.”
Slaughtering steps
- handling of livestock
- stunning - renders animal unconscious prevents pain or distress during
exsanguination. - sticking = cuts major blood vessels in neck or thorax = animal bleeds to death
- skinning and dehariing and evisceration = removing non edible parts. done in a way to prevent contact of carcass with dirt
- inspection - identify abnormalities or disease that would make the meat and edible offal unfit for human consumption
- carried out by specially licenced veterinarians or meat inspectors (other roles = animal welfare and hygiene standards, grading) - washing and grading - done with a fine spray of water to remove surface blood & bone dust
- effectiveness may be increased by using hot (80°C) water or by including low concentrations of organic acids, chlorine or other agents in water - refrigeration = done after being bled, skinned & eviscerated (removal of internal organs),
- carcases are chilled for 24-48h before grading & processing
chilling
Chilling done immediately after slaughter to prevent carcase spoilage
If carcase chilled too quickly = cold shortening occurs & subsequent toughness
* Cold shortening = occurs when muscle chilled to <16°C before rigor mortis completion
* If carcase frozen before rigor mortis completion = results in “thaw rigor” & subsequently extremely tough meat
Rigor mortis
Many changes take place in muscle immediately after slaughter, that convert muscle to meat
* Muscle contract & stiffen = rigor mortis
* At time of slaughter muscle very tender -> but as rigor
mortis begins, becomes progressively less tender until rigor
mortis completed
- Beef = 6-12h required for completion of rigor mortis
Pork = 1-6h
Meat Aging
After rigor mortis completion, more changes take place resulting in beef becoming progressively more tender
* Beef holding in the refrigerator = aging period
* Increased tenderness due to natural enzymatic changes taking place in muscle
* Tenderness increase continues only for ~7-10 d after slaughter – beef held at ~2°C
* Beef held at higher temperatures tenderise more quickly BUT may also spoil & develop off flavours
* Pork & lamb rarely aged = lack of tenderness not encountered as lamb & pork relatively young age when slaughtered
Meat Tenderising
Tenderness, juiciness & flavour = components of meat palatability
- Juiciness & flavour normally don’t vary a great deal but tenderness can considerably vary from one cut to next
- Most cause of beef, pork, lamb & veal tenderness variation
genetics
species & age = beef>lamb>pork>veal, 9-30 months
feeding = indirect effects
muscle type,
carcase suspension
electrical stimulation - Done to “hot” carcases immediately after slaughter increases
tenderness
chilling rate,
quality grade= Carcases from young animals (up to 40 months of age) are eligible for MLA grading
aging,
mechanical tenderising= Grinding is very popular means of increasing
meat tenderness (esp. beef)
chemical tenderising,
freezing & thawing,
cooking & carving
Salt concentrations and meat tenderness
- Salt at certain concentrations increases meat
tenderness
Salt tenderises by softening connective tissue protein (collagen) into more tender form
Hence cured meats (e.g. hams) more tender than uncured meats
Marinading
- Improves tenderness & adds taste variety
- Basic ingredients include salt (or soy sauce), acid (vinegar, lemon, Italian salad dressing, or soy sauce), & enzymes
(papain, bromelin, ficin or fresh ginger root) - Sometimes alcohol (wine or brandy) added for flavour
- Addition of several tablespoonfuls of olive oil seal surfaces from air & thus result in meat staying fresher & brighter in colour for longer period of time
Thawing
Done slowly in refrigerator generally results in greater
tenderness compared with cooking from frozen state
- Slow thawing minimises toughness effect from cold shortening (when present) & reduces moisture loss amount
- Microwave thawing should be done on lower power setting or manually alternating cooking & standing times
Freezing
Rate of freezing plays small role in tenderness
- When meat frozen very quickly = small ice crystals form
- When meat frozen very slowly = large ice crystals from = disrupt components of meat muscle fibres & slightly increase tenderness
BUT also increase juice loss upon thawing
Juice loss = meat less juicy upon cooking & perceived as being less
tender
Cooking + tenderising
- As progresses, contractile meat proteins become less tender & major
connective tissue protein (collagen) become more tender
Carving and tenderising
Muscles, muscle bundles & muscle fibres surrounded by connective tissue
- For carcase cuts & wholesale cuts = cut at right angles to length of muscle = severs maximum amount of connective tissue & bone more evenly distributed in that area
- Consumers should carve cooked meat at right angles to length of the muscle fibre or “against the grain” to achieve maximum tenderness
Cutting “with the grain” = “stringiness” & thus less tenderness
Meat curing
Was used as a preservative method * Now used more for flavour & colour
enhancement
* Some curing agents:
- Salt = added to preserve & add flavour
- Sodium nitrate & sodium nitrite = fix red colour of meat, acts as a preservative & prevent botulism
- Sugar = provides colour stability & flavour - Spices = produce desired flavour
Meat colour
- Myoglobin = protein that is the primary colour pigment of meat
- Function is to store oxygen in muscle tissue
- Denatured by prolonged air exposure or by cooking (goes from red to brown)
- Oxygen present = meat is bright red colour
- Oxygen absent = meat is purplish in colour
Meat smoking
Smoke
- Protects fat from rancidity
- Contributes to colour characteristics
- Creates unique flavours in processed meats
* Highly smoked products of past have largely given way to milder smoking methods = reduced but not eliminated smoke effectiveness as microbial growth inhibitor
* Smoke most effective microbial growth inhibitor when used with other preservation techniques
Meat specialities
Dry sausages = salami or pepperoni
- May or may not be characterised by bacterial
fermentation
- When fermented = intentional encouragement of lactic acid bacterial growth = useful as meat preservative & producing typical tangy flavour
- Ingredients mixed with spices & curing materials, stuffed into casings & put through carefully controlled long continuous air-drying process
Semi-dry sausages = mortadella, devon, bologna
- Usually mildly seasoned & heated in smokehouse to fully cook product & partially dry it
- Are semi-soft sausages with good keeping qualities due to lactic acid fermentation
Salami
cured sausage, fermented & air-dried meat
Pepperoni
an American variety of salami, usually made from cured pork & beef mixed together
Meat freezing
Properly wrapped, fresh meat cuts held at -18°C
or less for months if cut is a fatty meat like pork
- Storage time limited because at freezer temperatures, fat gradually oxidizes, producing off-flavours
* Beef can be held for years
* Once frozen, meat should not be thawed &
refrozen
* Few cured meats or sausages frozen = salt in their formulation increases rate of rancid flavour development, & spice flavours may change during frozen storage
Meat storage (months)
Beef: Mince, Roast, Steaks: 4,12, 12
Lamb:Steaks Roast; 9
Pork:Cured, Fresh roasts Fresh sausages: 2,8,2
Veal:Chops/cutlets Roasts: 9
Cooked meat: Meat dinners Meat pie: 3
Meat Cooking
Method depends on cut
* Cuts low in connective tissue = steaks & chops from rib & loin = dry heat cooking including pan frying, broiling, roasting, or grilling or BBQ
- Dry heat rises temperature very quickly = meat flavour develops before contractile proteins have opportunity to become significantly less tender
