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Animal food sience - meat > Induvidual studies - korv > Flashcards

Induvidual studies - korv Flashcards

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1
Q

An emulsion sausage is a complex mixture of different systems:

A
  • Solution of dissolved materials, such as protein and salts
  • Suspensions of larger particles in added water
  • Gel made from muscular proteins
  • Emulsion containing stabilized fat in a gel made from protein and fat, which is partially present in liquid form
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2
Q

Sausage Production - hur går det till?

A
  1. Meat, curing salt and phosphate are added. The meat is chopped at low speed.
  2. Water and ice are added. Ice is used to keep low temperature.
  3. Dry ingredients: potato starch, ascorbate and spices are added.
  4. Fat (usually pork back fat) is added. Chopped and emulsified at high speed.
  5. The sausage batter is prepared under vacuum at low temperature.
  6. The batter is filled into casings
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3
Q

Sausage Production Smoking and Cooking - hur går det till?

A
  1. Conditioning with water shower (1-2 min) to get an even surface moisture
  2. Alternative: Reddening step at 50-55ºC with high relative humidity (RH, 90%)
  3. Drying at 60-65ºC, 20-40% RH
  4. Smoking at 60-70ºC, 40-60% RH
  5. Steam cooking to 70-72ºC core temperature
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4
Q

Vad för salt används?

Varför används salt och hur mycket?

A
  • Usually nitrite salt (sodium chloride with max. 0.6% sodium nitrite) is used
  • Salt is added in the beginning of the chopping process to solubilise (activate) proteins
  • Minimum 1.2 % salt to activate protein effectively
  • Maximum salt content – depends on taste
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5
Q

Formation of a typical meat batter consists of two related transformations, vilka?

A
  • Swelling of proteins and formation of a viscous matrix

- Emulsification of solubilized proteins, fat globules and water

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6
Q

Emulsification - hur går detta till?

A
  • Mechanical energy from cutting and shearing forces destroys the meat fibres
  • Salt and phosphates activate (solubilise) the released protein
  • Added water is emulsified and bound (or immobilized) with the activated protein
  • The solubilised protein creates a thin layer around the finely cut fat particles preventing fat separation during thermal treatment
  • Added water and fat is stabilized in a three-dimensional matrix, a protein network
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7
Q

Hur skiljer sig salt lösliga proteiner ifrån andra?

Vilka är de saltlösliga

A

Salt soluble proteins, such as myosin and actin, has a 300% stronger WHC and ability to emulsify fat than water-soluble sarcoplasmic proteins

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8
Q

Vilka muskelproteiner binder vatten?

A

Myosin, actin and partly tropomyosin are responsible for binding water

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9
Q

Vad är en korv emulsion?

A

Lipider i vatten med emulsifying agents

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10
Q

Var finns den emulsifying agenten någonstans?

A

The emulsifying agent is located at the interface between the lipid and water phases. The emulsifying agent forms a monomolecular layer surrounding the lipid droplet.

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11
Q

sausage Emulsions - vad gör den stabil?

A

Emulsions are generally unstable unless another component, known as an emulsifying agents (soluble proteins), is present.

If enough of the emulsifying agent is present, it will form a continuous layer between the two phases, thereby helping to stabilize the emulsion by separating the two phases.

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12
Q

Quality of Raw Material

vad för krav finns på råvaran?

A

Low bacterial numbers of meat and fat is important 102 – 104 per gram

pH – optimal between 5.7 and 6.0 - high WHC and enhanced protein solubility

Chilled meat: 0 - 4ºC - Low temperature optimizes the solubility of myofibrillar proteins and delay bacterial growth

Frozen meat may be used - short storage period – risk of rancidity

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13
Q

PSE kött och DFD kött i emulsion korv

går det?

A

PSE-meat – not suitable because - partially denaturated proteins - low WHC - reduced ability to emulsify fat

DFD-meat with high pH - would be beneficial due to high WHC and good protein solubility - but negative due to poor curing colour and reduced shelf life

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14
Q

Fatty Tissue doing in emulsion tissue?

A

Stabilizes the solubilised protein network

  • Contributes to succulence and texture
  • Prevent shrinkage of the protein during cooking by acting as a filler
  • Fatty acid composition - unsaturated fat – higher risk of fat separation
  • Pork fat most common – often used frozen to keep low temperature during emulsification
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15
Q

Definition of fermentation in food

A

The conversion of carbohydrates into alcohols or acids under anaerobic conditions used for making certain foods

A cured minced meat product with specific qualities (flavour, consistency, shelf life & safety) mainly due to bacterial activity

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16
Q

Traditionally Fermented Sausage

. hur gjorde man förr?

A

Chopped meat was presalted in order to promote the development of lactic acid bacteria for fermentation.

The ”back-slopping” method was used. A small part of the fermented sausage mince was inoculated back in the new batch

This method resulted in sausages fermented by lactic acid bacteria from the house flora of the producer.

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17
Q

Starter Cultures

  • varför
  • vilken typ används
A

Large scale industrial production requires uniform and accelerated processing, which has led to the present general use of starter cultures.

Commercial starter cultures are frozen or freeze dried concentrates.

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18
Q

Fermentation - hur går det till, vad görs för att hjälpa till i processen?

A

-Lowering pH through the formation of lactic acid by bacterial activity

  • Bacteria from the meat or added starter cultures
  • Addition of salt promotes the growth of lactic acid bacteria
  • Lowering the water activity (Aw) by drying
  • Drying is facilitated by salting and pH-decline
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19
Q

Sausage Production

Fermentation - hur går denna produktion till?

A

1.
Conditioning at 15-25°C, low relative humidity (RH) % and low air flow for 12 hours
2.
Fermentation. Smoking at 25-30°C, 95-85% RH, and high air flow for 5 days
3.
Drying at 12-18°C, < 85% RH and low air flow for 1 week

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20
Q

Drying

Vad är viktigt i det här steget?

A

It is important that the drying procedure, controlled by RH and temperature, is rather slow.

The water have to diffuse all the way from the center of the sausage to the surface before this becomes dry and hard.

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21
Q

Vad är sol, vad är det viktigt för?

A

The sausage mass should be slightly tacky with a small degree of protein activated by the salt.

This tiny amont of activated protein is a ’sol’ (a solid dispersed in a liquid) and consists of salt, acivated protein and water (from the meat itself).

The sol is needed for slice coherency during fermentation as well as subsequent drying and it is a colloidal system where particles within are moving freely. A ’gel’ in contrast is a solid substance in which particles do not move freely.

At pH 5.2 the activated protein within the sol coagulates and the sausage becomes sliceable

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22
Q

Effects of salt and pH on WHC

A

Salted meat has lower WHC than unsalted meat at the isoelecrtic point or lower pH.

Drying is faciltated at the low pH in fermented sausage

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23
Q

The sugar for fermentation may come from

A

Glycogen and glucose in the meat - beef, pork, lamb, horse, deer

Added sugars

  • glucose is fermented directly to lactic acid
  • sucrose, lactose, maltose has to be hydrolysed to monosaccarides before fermentation to lactic acid
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24
Q

Hur påverkar temperatur fermentationen?

A

Faster pH-drop and lower pH is reached with higher fermentation temperature

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25
Q

Hur påverkar nitrit färgen?

Varföpr används nitrit?

A

Nitrite from the curing salt is reduced to nitric oxide (NO) by sodium ascorbate

NO reacts with myoglobin to form a red pigment, which is denatured by the pH-drop forming the pink pigment of cured meat colour

Some of the nitrite (NO2-) is oxidized to nitrate (NO3-) in the process. This nitrate can be reduced back to nitrite by bacterial nitrate reductase present in some starter cultures. This reduction stabilises the cured meat colour

Används som mo inhibitor

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26
Q

Bacterial quality krav vid produktion av fermenterad korv

Varför är detta viktigt?

A

Low bacterial contamination of meat and fat - not more than 102-103 bacteria/g

Low bacterial numbers are important to

  • provide safety, since there is no heat treatment in the process
  • avoid ”wrong” fermentation from other bacteria in the meat than the starter culture
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27
Q

Meat quality vid fermentering

  • ph krav
  • dfd och pse, går dessa använda?
A

Meat with pH below 5.7-5.8 should be used since - Water loss during fermentation is facilitated at low pH
- Colour development is optimal at low pH

No DFD meat in fermented sausage due to its high WHC

PSE meat may partly be used since - Reduced WHC aids weight loss - but Pale colour may be a problem

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28
Q

Fat Tissue – vikla krav finns på detta?

A

Colour of the fat is important - pork fat is white - beef fat is more yellow

Fatty acid composition - fat with high content of PUFA is too soft

No rancid fat should be used

Fat has higher pH value than muscle tissues - may increase pH of the sausage mince

Fat has low water content which lowers water activity

29
Q

Starter Cultures i ferment meat - vilka används?

A

Lactic acid bacteria (LAB) – for acidification Lactobacillus - Pediococcus

Micrococcaceae – for colour and flavour Staphylococcus - Micrococcus

Mould – for white surface colour and flavour
Penicillium spp

Yeasts – for surface colour and characteristic flavour Debaromyces, Candida

30
Q

Flavour from fermented - vilka smaker får man ut?

A

Fast fermented sausages (sold after 5-21 days) - Acidity, spices & smoke give flavour

Medium-fast fermented sausages (sold after 3-5 weeks) - Combination of acidity, spices & some degree of proteolysis. lipolysis (+ smoke) that give flavour

Slow-fermented salami (several months of maturation)
- Komplex processes of proteolysis and lipolysis together with spices result in specific flavours

31
Q

Safety of Fermented Sausages - hur säkerhetsställer man detta?

A

A fermented sausage is not heated and different hurdles against unwanted bactrial growth is used to provide safety

  1. Low bacterial counts in raw material
  2. Nitrite in the salt provides initial protection against pathogens
  3. Content of oxygen is reduced by bacteria inside the sausage which lowers the redox potential
  4. Growth of lactic acid bacteria acts competetive against pathogens
  5. Decrease in pH by the growth of lactic acid bactria
  6. Drying lowers the water activity (aw)
32
Q

Hur kan pH variera mellan olika korvar?

A

Fast acidification - pH should reach ≤ 5.2 within 24-48h

Medium-fast acidification - pH should reach ≤ 5.2 within 48-96h

Slow acidification in slow fermented salami – pH-drop too slow and protecting bacterila cultures are added

33
Q

Fermented versus Emulsion Sausage

A

Sol/gel between meat particles - ferment

Protein network - emulsion

34
Q

Additives in meat processes - vilka finns?

A 
Salt (NaCl)
nitrite (NaNO2) and nitrate (NaNO3)
Phosphates
Sodium Ascorbate
Extenders and binders
Spices and flavourings
Sweeteners
Antioxidants and antimicrobial agents
35
Q

Vad betyder curning?

A

Processing starts with curing = salting the raw meat

Curing salt is NaCl, usually with maximum 0.6% sodium nitrite (NaNO2)

36
Q

Function of salt:

A
  • preservation
  • solubilises proteins
  • accelerates swelling of proteins
  • gives salty taste & enhance meat flavour
37
Q

Sodium chloride posetiv effekt - ge exempel

A 
Positive effects
Water binding
Shelf-life
Flavour
Colour (nitrite salt)
Fat binding in sausages
Texture and bite
Decreases water activity (Aw-value)
Economy (salt cheap)
38
Q

Sodium chloride negativ effekt - ge exempel

A

Negative effects
Nutritional aspects (effect of Na+ on blood pressure)
Rancidity

39
Q

Water holding capacity (WHC) depend on?

A

WHC depends on the space within the muscle fibre

Lack of space reduces WHC by different mechanisms

  • Steric effect
  • actomyosin complex + PSE
  • pH
  • net charge effect
  • Contraction
40
Q

Hur hålls vatten i kött?

A

Charged hydrophilic groups on the muscle proteins attract water, forming a tightly bound layer the molecules of which are oriented by their own polarity and that of the charged group.

An immobilized layer is formed that has a less orderly molecular orientation toward the charged group.

The free water molecules are held only by capillary forces, and their orientation is dependent of the charged group.

41
Q

Hur ser distansen mellan actin myosin ut efter rigor mortis

A

Lateral shrinkage of a myofibril due to attachment of cross-bridges at rigor onset
- de har krympt och bunditi ihop sig

42
Q

Hur påverkar salt WHC, hur?

A

Salt increases WHC by:

  • ökar proteinets negativa laddning
  • myosin gallret sväller
  • sänker Lowering the protein isoelectric point while raising pH of meat slightly.
43
Q

Hur mycket salt i köttet?

A

Usually around 2-3% is used in meat products; some countries such as Finland have lower concentrations due to health reasons and >1.9% salt is marked as highly salted.
Difficult to have less than 1.4%

44
Q

Swelling of the myofilament lattice - hur går det till

A

a) rigor innan salt treatment
b) depolymerisation av de tjocka filamenten innan swelling
c) efter swelling så kan inte längre myosin svansarna röra sig

45
Q

Vilka krafter genererar the swelling tycket?

Hur och hur stor betydelse har dessa krafter?

A
  1. Electrostatic.
    Probably of limited importance. The electrostatic repulsive forces between the tails are high when they are close. However, when they have moved apart the electrostatic swelling pressure is small.
  2. Osmotic.
    The osmotic contribution to the swelling pressure could be considerable. More easy as the mechanical constraint exerted by the cross-bridges is removed when the thick filament shaft depolymerises.
46
Q

Effect of NaCl on water holding capacity (WHC) beroende på ip

A

pH > (IP):
addition of NaCl (2%) increases the WHC

pH < IP:
addition of NaCl (2%) decreases the WHC.

Detta pga proteinerna föredrar att interagera med Cl- och inte Na+ joner

47
Q

Effect of NaCl on water holding capacity (WHC) - below och över ip respektive

A

Below IP the + charge of the proteins is neutralized by Cl- ions.
Decreased repulsive forces, a shrunk matrix and reduced WHC.

Above IP the Cl- ions neutralize the few positive charges, increase in negative charges and swelling of the matrix.

48
Q

Why Na+ doesn’t have any effect on water holding capacity but Cl- does?

A

Na+ ions are small and have concentrated charge. Therefore they will get a protecting layer of water that reduces their charge and will have a limited effect on the negative protein groups.
Cl- ions have more diffuse charge and weaker effect on water molecules

49
Q

Phosphates in korv - hur mycket och vad tillför det?

Vad sker om har för mycket?

A

0.2-0.3% common, too much gives metallic and soapy taste and rubbery consistency

Different phosphates have different properties such as buffer capacity and solubility in cold water – mixtures are often used
Max 0.5% expressed as P2O5 (phosphorus pentoxide)

50
Q

Effects of Phosphate on korv

A
  • Improves water-holding capacity (WHC)
  • Increases pH (~+0.6) - mer neg - swelling and higher WHC
  • Improves the solubility of fibrillar proteins
  • Synergistic effect with salt
  • Improves the aroma stability
  • Antioxidative effect - binds Fe and Cu (chelate binding)
51
Q

Specific protein solubility effects of phosphates?

A
  • Improved emulsion stability
  • better protein binding performance
  • Releases some actomyosin crossbridges induced by rigor
  • Partially solubilises other structural proteins gives greater swelling of sarcomeres.
52
Q

Effect of phosphate:

A
  • Increase pH, increase negative charges
  • Dissociate actomyosin complex
  • Promotes myosin solubility
53
Q

Nitrite - vad gör detta i produkten? Bra som dåligt

A

Promotes the red/pink curing colour
- 30-50 ppm needed

Provides the curing flavour – positive for taste
- NO reacts with aldehydes, alcohols, inosin, sulphuric compounds

Antioxidant

  • forms complex with Fe in myoglobin (20-60 ppm needed)
  • konserverande

Bacteriostatic effect

  • higher amount needed than for colour formation – ca 150 ppm
  • Salmonella spp - Staphylococcus aureus - Clostridium botulinum

Risk of nitrosamine formation (carcinogenic)

54
Q

Cured Colour Formation - hur går det till

A

Nitrite oxidises the iron in myoglobin to
(MetMb) and nitric oxide (NO)

NO reacts with MetMb to form nitric oxide metmyoglobin (or nitrosylmetmyoglobin) which is reduced to nitrosylmyoglobin;
red pigment

The process is accelerated by reducing agents such as ascorbate

Heating nitric oxide myoglobin - denaturation and bright pink colous is formed (nitrosylhaemochromogen)

55
Q

Ge exempel på grönsaker som innehåller Nitrate (NO3-)

A
  • Celery
  • Beetroot
  • Spinach
  • Potato
  • Onion
56
Q

Sodium Ascorbate - användning, varför använda detta?

A

Use of ascorbate and not ascorbic acid due to risk of formation of nitrous gases

Accelerating the rate of curing by helping the metomyoglobin to myoglobin

Reacts with nitrite - increase the yield of nitric oxide from nitrous acid

Acts as an antioxidant, stabilising colour and flavour

prevents development of rancidity

Prevents fading of sliced meats when exposed to light

Prevents hemecatalysed lipid oxidation as long as there is an excess of ascorbate
(degraded heme pigments catalyse lipid oxidation).

57
Q

Extenders and Binders

Vad gör de, vilka finns och varför används dessa?

A

Binds water: potato flour, wheat flour, fibres, bread or rusk (‘skorpsmulor’)

Binds water + fat: caseinate, soybean protein, albumin, egg, dry milk, blood plasma

For more course consistency and for low fat products: soybean protein, fibres from potatoes, peas and beets

58
Q

Varför tillsätts socker?

A

Sugar is added:

  • to counteract the salty taste
  • to give flavour
  • to serve as a substrate for bacterial acid production in fermented sausages
  • Important for Maillard reactions (brown crust)
59
Q

Hur går curding till?

- dry vs wet curding

A

Dry curing = rubbing with salt, used for e.g. Parma ham. Takes time for the salt to diffuse evenly into the ham.

Wet curing (also called pickle curing) - ligga i Brine Takes time.

Injection curing = injection of brine into the meat
Fast method.

A combination of them dry and wet can be used.

60
Q

varför används Tumbling?

Hur går det till?

A

Tumbling is a method used after brine injection to get evenly distributed salt in the muscle.

The tumbler rotates and baffles inside let the meat fall down again during the rotation. (tänk torktumlare)

61
Q

why tumbling?

A

Causes cellular disruption of the muscle tissue increases the water-holding capacity

Extracts salt soluble proteins to the meat surface creating a sticky crust enhances muscle cohesion

Promotes migration of salt and nitrite favours even distribution of brine in the meat

Gives a more tender meat

62
Q

Why tumbeling under vaccum

A
  • Supports swelling of proteins giving higher cooking yield, slice coherency and firmness
  • Supports formation of curing colour
  • growth of aerobic poilage bacteria
  • Helps to keep the temperature low
  • Reduces formation of foam.
63
Q

Heat Treatment - why?

A

Destroys considerably number of micro-organisms and improves the shelf-life of the meat product

Protein denaturation ─ resulting in firm texture and enhanced sensory properties

Stabilises the red colour of cured meats

64
Q

Smoking

Positive effects

A
  • Gives stable and pleasant surface colour
  • Gives a characteristic smoke flavour
  • Contains antibacterial substances
  • Delays fat rancidity
65
Q

Smoking

Negative effect

A

The smoke contains carcinogens such as 3,4-benzpyrene and other polynuclear aromatic compounds

66
Q

Hot-smoking - hur går det till

A
  • during short period

* 40-90 °C

67
Q

Cold-smoking - hur går det till

A
  • during a long period

* 20-35 °C

68
Q

Raw Material – Quality Aspects - processmeat

  • PSD/DFD
  • viket ph?
A

High pH meat (5.7-6.1) - beneficial for WHC and processing yield - beneficial for protein solubility - problem with colour formation

PSE-meat - problem with WHC and processing yield - pale colour

Muscles differing in pigment content (or some muscles being PSE or DFD) - twotoned hams

Animal food sience - meat (18 decks)

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