Exercise 7 - ham and korv

Question 1

Which are the positive and negative effects of salt in processed products?

Answer 1

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)

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

Question 2

Explain the different steps for the swelling of the myofilament lattice after addition of salt.

Answer 2

depolymerisation, löser upp myo lite - myosin tails can move

Question 3

Salt together with the pH-value of the meat has a large influence on water-holding capacity.
Explain the mechanism behind this.
In which products is this function most important?

Answer 3

Effect of NaCl on water holding capacity (WHC)
pH > isoelectric point (IP): addition of NaCl (2%) increases the WHC
pH < IP: addition of NaCl (2%) decreases the WHC.
Explanation: proteins interact preferentially with the Cl- ions and not Na+.
Below IP the positive charge of the proteins is neutralized by Cl- ions. This leads to decreased repulsive forces, a shrunk matrix and reduced WHC.
Above IP the Cl- ions neutralize the few positive charges, which leads to an increase in negative charges and swelling of the matrix.
At high ionic strength (above 5% NaCl) the opposite effect on the meat can be expected due to denaturation of proteins

Question 4

Explain a possible mechanism why Cl- and not Na+ has effect on water holding capacity

Answer 4

Protecting layer of water around Na+ ions will reduce its effect on neutralisation of negative protein charges

Question 5

Why do salt and phosphate act synergistically (i.e. increase the effect of each other) on water holding capacity in meat products?

Answer 5

• Improves water-holding capacity (WHC)
• Increases pH (~+0.6) and thus negative charges, leading to 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)

Question 6

Why synergistic effect of salt and phosphate

Answer 6

Effect of phosphate:

• Increase pH, increase negative charges
• Dissociate actomyosin complex
• Promotes myosin solubility Synergistic effect of salt + phosphate due to different mode of action.

Question 7

How do you get the pink colour of processed meat?

Answer 7

Nitrite

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

Question 8

Which mechanism can be involved when e.g. hamburgers are persistent red even when cooked to 70° C or higher?

Answer 8

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

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

At heating nitric oxide myoglobin is denatured and a bright pink pigment is formed: nitrosylhaemochromogen

• har varit i närhet av vegetabilier med hög nivå av detta, tex potatis

Question 9

Discuss the most important additives used both in whole meat products and sausages, and why they are used.

Answer 9

• Salt (NaCl)
• Nitrite (NaNO2) and nitrate (NaNO3)
• Phosphates
• Sodium Ascorbate
• Extenders and binders
• Spices and flavourings
• Sweeteners
• Antioxidants and antimicrobial agents

Question 10

Discuss the emulsion of sausage batter.

Answer 10

Lipid i vatten

Cooked Emulsion Sausage
An emulsion sausage is a complex mixture of different systems:
•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

Question 11

Describe how a fermented sausage is produced. Which specific ingredients are used and which are the critical steps during processing?

Answer 11

Sausage Production
A bowl cutter is used for preparation of the sausage mince.
1.
Meat and curing salt is added. The meat is chopped at low speed.
2.
Dry ingredients: sugar, ascorbate, spices and starter culture is added. Mixed at low speed.
3.
Fat (usually pork back fat) is added. Chopped and mixed at high speed. Short chopping time for sausage with large visible fat particles and longer chopping time for smaller fat particles in the sausage.
4.
The sausage mince is prepared under vacuum at low temperature.
5.
The mince is filled into casings
sen fermentation

Question 12

Which parameters are important for controlling the lactic acid production during fermentation of a fermented sausage?

Answer 12

socker innehållet