2. Poultry and Eggs Flashcards
what counts as “poultry”?
domesticated birds of commercial value (eg. chicken, turkey, duck, goose)
globally, what are the 1st and 2nd major sources of animal protein?
1st: pork
2nd: poultry
what are some reasons that poultry consumption has become higher than other animal proteins?
- considered healthier than red meats
- less sat fats
- poultry fats are mostly located in the skin and is easy to remove prior to cooking
- cheap production costs
- smaller space requirement
what are the 6 classifications of market forms of poultry meat?
describe each one.
- broilers/fryers: 6-8 weeks old chicken. Wt = 2.5lbs
- capons: neutered male chicken. Wt = 6-8lbs
- cock/rooster: over 10 month old male. Wt = 6-8lbs
- fryers: 6-8 week old. Wt = 2.5-3.5lbs
- roasters: over 8 months. Wt = 3.5-5lbs
- stewing chicken: spent hens over 10 months old. Wt = 5-7lbs
what are classifications of poultry meat based on?
age and wt
what is a spent hen?
what kind of meat do they have?
hens who have stopped producing eggs
very tough meat
what factors does poultry meat composition depend on?
breed diet age sex growth environment
the breed of poultry meat depends on what two factors?
place of origin
physical traits
how is the protein content of poultry similar to that of red meat?
the muscle composition and structure is similar
what are 3 main poultry proteins?
sarcoplasmi
myofibrillar
connective tissue/stroma
describe the differences between the 3 main poultry proteins
the differences are mostly based on solubility
which poultry protein are H2O soluble. What is the importance of this?
sarcoplasmic proteins are H2O soluble
this makes them easy to be removed from the tissue with H2O
what are 2 forms of moisture found in poultry protein?
- tightly bound to protein via H bonds
2. held loosely within compartments in muscle tissue
what is WHC?
water holding capacity
what are conditions that enhance protein denaturation and reduces the WHC?
- cooking
- conditions that promote acid production and pH decline
- frozen storage
- condition that promotes protein oxidation
how do polyphosphates enhance WHC (water holding capacity) in poultry?
- polyphosphates promotes dissociation of actomyosin into actin and myosin
- actomyosin has low WHC, while actin and myosin both have higher WHC
- thus, polyphosphates enables water binding and retention
describe the lipid profile of duck and goose compared to chicken and turkey
duck and goose have:
- higher amounts of lipid since they have more dark meat, which has higher levels of fat per gram than white meat
- higher amounts of monounsat fats
- lower polyunsat fat (thus, more prone to oxidation)
what is the major monounsaturated FA in poultry?
oleic acid (18:1c)
what is the major PUFA in poultry?
linoleic (18:2c) linolenic acid (13:8c) arachidonic acid (20:4c)
is there higher moisture and fat content with the skin on of off of poultry meat?
skin on: higher fat content and lower moisture content
skin off: lower fat content and higher moisture content
what is MDPM?
- mechanically deboned poultry meat
- the meat separated from the carcass skeleton after removal of larger cuts of meat
describe the steps of how MDPM is obtained
- pressure is applied to the carcass or bone attached meat. This causes the soft tissues (protein, fat, skin) to separate from the bones
- pressure chamber has small holes, where the separated materials can pass through while bones are retained inside the barrel
what is the main goal of processing meats
- to increase product variety and convenience
- extend meat shelf life
- facilitate distribution
what are 3 categories of processed meats?
- minimally altered: eg. cured ham, bacon, corned beef
- moderately altered: eg. sectionned and restructure
- extensively altered: comminuted (broken down to small particles) and then re-formed (eg. sausage and luncheon meats
what is curing meat?
treating fresh meat with salt and nitrite/nitrate for the purpose of preservation and obtaining desirable color and flaour
describe the physical characteristics of cured meats
- pinkish color
- distinct aroma
what are the most common curing agents?
nitrite (NO2-) or nitrate (NO3-)
what is the immediate precursor for the actual curing agent?
nitric oxide (NO)
what are the functions of nitrite in curing meats?
- contributes to characteristic flavour of cured meat
- inhibits growth of spoilage and pathogenic microorganisms (especially clostridium botulinum)
- retards development of oxidative rancidity
- develops and stabilized pinkish red color
what are the steps of color development in cured meats?
- nitrate is dissolved in H2O. This forms nitrous acid (HNO2)
- HNO2 decomposes to nitric oxide (NO) under reducing conditions
- NO binds to heme iron in myoglobin to produce nitrosylmyoglobin (MbNO), which is pink. This reaction is reversible, thus, does not give permanent color.
- meat is heated, which converts MbNO to a more stable compound, nitrosylhemochromagen, as a result of globin denaturation
- reducing agents are added to reduce nitrite to nitric oxide and ferric ion of metmyoglobin to ferrous ion
what are 3 types of meat processing?
physical
chemical
thermal
describe deboning, in physical treatments of processing meat.
- involves spinning scraps in perforated drums with H2O under high pressure
- this causes the scraps of meat to separate from bones
- then, can restructure or mince
describe the function of salt in the chemical treatments of processing meat
- reduces H2O activity to control microbial growth and inactivate certain enzymes
- extracts salt soluble proteins
- flavouring
what are examples of antimicrobials used in chemical treatments of processing meat?
nitrates and nitrites, acidifies NaCl, chlorine dioxide, peroxy acidic acid, peroxy octamoic acid
what is NO3-? what is NO2-?
NO3- = nitrate NO2- = nitrite
how is NO3- converted to NO2-?
removal of H2O by Na erthorbate (vitC) or nitrate reductase (an enzyme naturally present in animal tissues) with NADH as the H donor
what compound MbO2 converted to?
is this conversion desirable or not?
MbNO
desirable because it is an antioxidant
what is MbNO?
what is MbO2?
MbNO is nitrosylmyoglobin:
- an antioxidant that protects against oxidation damage to preserve flavour and color
- pink color
- desirable compound
MbO2
- red color
- not desirable
what reaction is the conversion of MbO2 to MbNO coupled with?
NO to O2
what is the most commonly used reducing compound? describe this compound.
sodium erythorbate
- an isomer of ascorbate
- also an antioxidant that stabilizes color and flavor to decrease the formation of nitrosamines
what are some chemicals that improve water holding capacity?
starch
phosphates
texturizers
enzyme inhibitors (eg. potato powder and blood plasma protein)