HOW TO DETERMINE THE GLAZING WATER CONTENTS
IN DEEP-FROZEN OR FROZEN PRODUCTS
1. IMPLEMENTATION
The aim of this method is to determine the quantity of ice used to protect the meat against outer drying/dehydration which causes a quick damaging of the quality.
The method is to be used only for the frozen or deep frozen products
and for the following individually glazed products :
- whole or headed fish
- fish fillets
- scallops
- big shell-on crustaceans
- cooked shell-off shrimp :
* use the method Nr. 2 for the routine checkings
* use the method Nr. 3 in case of claims
This method does not enable one to determine the net content of blocks of products with ice inside, nor the soaking rate.
2. HOW TO PROCEED
Allow the ice coating layer to thaw by dipping the product into water, remove the water excess and weigh the still frozen product.
3. EQUIPMENT
3.1 - A 1 decigram sensitive precision balance
3.2 - A water bucket that can contain a volume of water equal to
10 times or more the sample weight
3.3 - A spatula
3.4 - Absorbing paper
3.5 - A thermometer
3.6 - A hand operated household wringer
4. METHODS
NB. 1 GENERAL METHOD
=====================
4.1 - SAMPLING
One must make sure that the temperature of the product is lower or equal to minus 18 degrees C.
If not, keep the product at that temperature before starting the determining process.
Weigh the selling unit (or each piece). We’ll call ‘’MG’’ the weighed mass.
Take a sample. It consists of :
- Selling units of announced
net mass One selling unit
between 500 G and 1000 G
- Selling units of announced
net Mass One or several
above 1000 G pieces the total
One or several pieces mass of which is
above 1000 G
For example : Take 4 dabs from one 10 KG selling unit
of dabs with an unit mass of 250 to 300 G.
- Pieces of announced net mass Several pieces
below or equal to 500 G the total mass of
which is above
1000 G
- Pieces of announced net mass
above 500 G 1 piece
weigh to within about 1 G. We’ll call this mass ‘’M0’’
4.2 - DEGLAZING
4.2.1. - Place the sample in a water bucket at 25 degrees C
plus or minus 5 degrees C. Hold the sample constantly under
water, with a spatula for example (the water volume must be
10 times higher than the volume of the sample).
Make sure, when touching the sample, that all the ice has
disappeared from its surface and inside holes that could
eventually be present.
4.2.2. - Take the product/sample out of the water and quickly dry it
with absorbing paper, making sure to also dry the inner part
of the holes that could eventually be present.
Immediately weigh to within about 1 G. We’ll call this
mass ‘’M1’’.
METHOD NB. 2 : For cooked peeled shrimp
============= (To use in routing checkings)
4.3 - SAMPLING
One must make sure that the product/sample is at a temperature
lower or equal to 18 degrees C.
If not, keep it at that temperature before starting the determining
process.
Weigh the selling unit. We’ll call that mass ‘’MG’’.
Take a sample. It consist of :
- Selling units of announced 1 selling unit
net mass
below or equal to 250 G
- Selling units of announced Around 250 G,
net mass a whole number
above 250 G of pieces
Weigh to within about 1 G. We’ll call this mass ‘’M0’’.
4.4 - DEGLAZING
- Split the samples into portions of around 50 G.
- Weigh to within about 1 G.
- Place the first portion in the wringer basket.
- Fill up the water receiving tub of the wringer with tap
water at 25 degrees C plus or minus 5 degrees C temperature.
- Dip the wringer basket containing the shrimp 10 times in
a row in the tub filled up with water.
- Empty the tub water.
- Then wring the shrimp in the wringer by giving it 10 crank
rotations.
- Wipe the water that could eventually remain on the surface
of the product with absorbing paper.
- Then weigh immediately the deglazed shrimp to within about
1 G.
- Repeat the operation to obtain result for he whole of the
samples.
- Work out the sum of deglazed shrimp masses. This gives a
mass called ‘’M1’’.
METHOD NB. 3 : For cooked and peeled shrimp
============= (To use in case of claims)
4.5 - SAMPLING
One must make sure that the temperature of the product is lower
or equal to minus 18 degrees C.
If not, keep the product at that temperature before starting
the determining process.
Weigh the selling unit. We call this mass ‘’MG’’.
Take a sample. It consists of :
- Selling units of announced One selling Unit
net mass
below or equal to 250 G
- Selling units of announced Around 250 G,
net mass a whole quantity of
above 250 G pieces
4.6 - DEGLAZING
Take a quantity of pieces (around 100 G).
Weigh to within about 1 G. We’ll call this mass ‘’M0’’.
Take one shrimp and dip it in the water at 25 degrees C
plus or minus 5 degrees C until, when touching it, the ice has
completely disappeared from the surface. Take the shrimp out
of the water and immediately dry it with absorbing paper.
Place the shrimp in a receptacle weighed to within about 1 G.
Repeat the process for each shrimp of the sampling.
Weigh the receptacle containing the shrimp to within
about 1 G and work out the mass of deglazed shrimp
(this mass being called ‘’M1’’).
5. RESULT FORMULA
The glazing rate expressed in G for 100 G of frozen deglazed
product is as follows :
M0 - M1
G = ------------- X 100
M1
MO = The mass of frozen glazed sample
M1 = The mass of frozen deglazed sample
6. WORKING OUT THE NET MASS
Net mass 100 MG
of the = ----------------
selling unit 100 + G
MG = The mass of the selling unit or piece with glazing
G = Percentage of glazing rate
For example :
Net mass of 1000 G (M1) with 20 % glazing (200 G)
Mass of the glazed selling unit : 1200 G (M0 or MG)
1200 - 1000 M0 - M1
G = ---------------- X 100 = -------------- X 100 = 20 %
1000 M1
Net mass of 100 X 1200
the selling = --------------------- = 1000 G
unit 100 + 20
