Safety of food - lecture 10: salting & curing | Quizlet

Curing options

Dry salting

Injection

Soaks/brining

Salting definition

Addition of salt to meats for the purpose of preservation

Rarely done without nitrite

Curing definition

The addition of salt, nitrite or nitrate and sugar for the purposes of preservation, flavour and colour

History of salting and curing

Use:

- preservation

- important trading activity

- means to export far away

Why do we need salt?

1. Control the fluid balance in out body

2. Make sure our muscles and nerves work properly

3. Maintains blood pressure

Too little = muscle cramps

Too much = increase risk of high blood pressure = hypertension

High blood pressure = increase risk of developing heart disease and stroke

Untreated can also lead to kidney failure and eye damage

What are the ingredients used in curing?

Salt

Nitrite/nitrate

Sugar (sucrose, dextrose)

Natural sugars

Ascorbate's/Erythorbates

Phosphates

Spices and flavourings

Binders and extenders

MSG (monosodium glutamate)

How does salt affect curing?

- enhances flavour

- increases binding (extracts salt-soluble proteins)

- increases water holding capacity (WHC)

- lowering the water activity = will improve shelf life

- preservative

- tenderises

How does Nitrate/Nitrite affect curing?

- Preserves (reduces food spoiling micro orgs)

- stops oxidative rancidity

- reduces warmed-over flavour

- flavour enhancement

- cured colour development

How does Phosphates affect curing?

- increase water holding capacity (WHC) = increases the tendency for water binding

- increase juiciness

- enhance colour development

- helps reduce oxidative rancidity

How does phosphate affect water holding capacity

When added to meat products the alkaline phosphate raises the pH away from the isoelectric point of meat proteins which increases the tendency for water binding

Ascorbate's and erythorbates functions

Accelerate the curing process

Aid in preventing the formation of nitrosamines

Act as antioxidants

Dry curing method is best used for

All types of sausages, bacon and hams that will be air-dried

Best for people living in hot climates or when have no fridge

What happens after curing

After curing, meats go for smoking, then for air drying

No cooking involved

Different names for wet curing

Brine (salt & water)

Sweet pickle (sugar added)

Immersion curing

Wet curing used for larger cuts of meat

How to apply wet cure into meat

1. Immersing meat in curing solution (water, salt, nitrite)

2. Spray pumping meats with needles and curing solution

Disadvantages of wet immersing curing

- time consuming method

- Danger of meat spoiling from within the center where the bone is located

Better method for smaller cuts of meat that will have shorter curing time (require 3-14 days of curing time at 4ºC)

Purpose of soaking - wet curing

- Purpose of soaking is to provide more even salt distribution inside the meat

Large piece of meat (ham/shoulder) when fully cured will not have a uniform salt distribution

When pumping meat with a brine injector we achieve? (Wet curing)

- more uniform salt distribution

- soaking can be eliminated

- speeds up the curing process - can inject brine under the fat layer

What advantages does needle pumping in wet curing have?

- curing sln can be precisely introduced where needed most (most areas and fatty tissues)

- shorter curing time

- spices & flavourings can be injected inside

What are the two methods of needle pumping?

1. Artery pumping

- long needle pump brine into artery (arterial blood system = pipeline)

2. Commercial curing methods - stitch pumping

- pumping w needle injectors > massaging meats in tumblers

- pumped under pressure

- stitch pumping machines

- ham ready for the smoker in 24 hours

Advantages of curing meat?

1. Obtain the desired, permanent pink colour of meat, which remains after heat treatment

2. Distinctive and desirable flavor

3. Improve the shelf-life of meat

4. Inhibit the growth of bacterial pathogens - esp C. Botulinum

What agent effect the colour of curing meats?

Nitrite is the active meat-curing agent responsible for cured colour development.

Nitrate & nitrites (sodium nitrate reduced by ascorbate's and microbes to sodium nitrite)

What is the red colour of fresh meat caused by?

Myoglobin (70% of meat pigments)

Hemoglobin (30% of pigments)

What is the average content of myoglobin in beef, pork, veal?

Beef = 250-350 mg/100g

Pork = 130-180 mg/100g

Veal = 50-100 mg/100g

Colour changes in fresh (unheated) meat = Interconversion of meat pigments

Myoglobin when oxygenated is bring red in color = oxymyoglobin

Both myoglobin and oxymyoglobin can undergo oxidation (loss of an electron) to form metmyoglobin (dark brownish)

What is the natural effect of heating on the change of colour of meat?

At 65ºC myoglobin denatures + presence of air = grey-tan cooked meat colour (hemichrome)

Myoglobin > cooked > hemichrome

Eg. Beef

Nitric oxide formation?

1. Nitrate (NO3) > Nitrite (NO2) > Nitric oxide (NO)

2.

- add just NO2 = faster

- NO2 > NO

- preferred method - react imm w muscle pigment and w microbes

How does Nitric Oxide (NO) affect meat?

1. NO reacts w myoglobin or metmyoglobin forming nitrosylmyoglobin

2. After heat treatment form nitrosylhaemochrome (pink colour of cured meat)

Eg. Cured ham

Effect salt curing has on meat flavour?

- most important ingredient

- should be highest grade possible

- enhances flavour

- tenderises

Effect of curing with Nitrate/Nitrite has on meat flavour?

- do not directly impart much flavour

- NO plays an important role in controlling lipid oxidation

Concentration of NaCl in water phase formula?

X = a/a+b * 100

X = conc of NaCl in water phase (%)

A = content of NaCl in meat (%)

B = content of water in meat (%)

What are the effects of natural sugars on meat flavour?

- maple, brown sugar, honey and molasses

- acts as flavouring agent

- Counteracts harshness of salt

- Enhance browning properties

- modified sweeteners = corn syrup solids, dextrose and crystalline fructose are used for their binding qualities and lighter sweetening power

Effects of MSG on meat flavour & normal level

- flavour potentiator, flavour body = makes taste buds more sensitive

- umami taste

- normal level of use is 60-180 g/100kg

What ingredients are used as meat extenders? What is a meat extender?

Meat extenders are non meat substances with a substantial protein content

- soy ingredients

- milk ingredients

- starch ingredients

- gums and hydrocolloids

- animal derived extender ingredients (gelatine)

What is the best measure of the availability of water for bacteria?

Water activity

Aw = P/Po

P = is the Vapor pressure of water in the substance

Po = is the Vapor pressure of pure water at the same temp

The activity of pure water = 1

Relative humidity = 100%, Aw = 1.00

Relative humidity = 97%, Aw = 0.97

Eg. Clostridium botulinum a, b = 0.97 aw

What is water activity (Aw)?

The amount of water available (unbound) for chemical and biochemical reactions, and for microbial growth to occur.

Helps to make predictions about food quality and processing (salting, curing, freezing, dehydration, conc, sugaring)

Water activity calculation

Water can be calculated based on conc of salt and water in the food product

Y = a/a+b * 100

Y = conc of NaCl in water phase (%)

A = content of NaCl in meat (%)

B = content of water in meat (%)