Feed Analysis Standard Operation (Analysis) Procedure SOP
Feed Analysis Standard Operation (Analysis) Procedure SOP
Feed Analysis Standard Operation (Analysis) Procedure SOP
1. PURPOSE
To test proximate analysis of raw material finished feed, sales feed and incoming
samples to monitor and ensure high quality raw material and feed quality is done at
Laboratory Services department as per end user department requirements.
2. SCOPE
Proximate analysis (Moisture, crude protein, crude fat, crude ash, calcium,
phosphorus, crude fibre, soluble protein, nitrogen, physical test, particle size, water
durability) of raw material (as per SOP MMPD-FM-03), finished feed & sales feed (as
per SOP FM-010) and incoming samples to monitor and ensure high quality raw
material and feed quality is done.
3. DEFINITIONS
The wordings in this SOP are defined as follows
3.1. Analyte: The chemical substance or physical property being measured in a
sample.
3.2. Stock Standard Solution - A concentrated solution containing one analyte
prepared in the laboratory using an assayed reference compound or purchased
from a reputable commercial source.
3.3. Kjeldahl Method: Kjeldahl digestion in analytical chemistry is a method for the
Name of analysis
Moisture
Method of Analysis
Oven Drying method
4.2
Crude Protein
4.3
Crude Fat
References
AOAC Official method 930.15
AOAC Official methods of analysis
17th Edn (Chapter 4, p 2, Clause
4.1.06)
AOAC Official method 976.05
AOAC Official methods of analysis
17th Edn. (Chapter 4, p 23, Clause
4.2.05)
AOAC Official Method 920.39
AOAC Official methods of analysis
4.4
Crude Ash
Furnace method
4.5
Crude Fiber
4.6
Nitrogen Free
extract
By difference method
4.7
4.8
Acid Value
4.9
4.10
Acetone Insolubility
Calcium
4.11
Magnesium
Complexometric method /
spectrophotometric
4.12
Salt as NaCl
Argentometric
4.13
TVBN
Kjeldhls Method
4.14
4.15
Urease Activities
Sieve test
Indicator method
Mechanical Sieving
4.16
Bulk Density
By Weight
4.17
Peroxide Value
Iodometric method
4.18
Rancidity
Iodometric method
RESPONSIBILITY
4.1. Office of the Managing Director Has the sole responsibility of authorizing
the preparation of this Standard Operating Procedure, the approval of this SOP
and subsequent revision and amendments.
PROCEDURE
6.1.
Estimation of moisture
a. Equipment
Hot air oven
Instant moisture analyzer
b. Procedure
Regulate air oven to 135 + 2 C. Using low, covered glass dishes weigh about 10 15 g sample
into each dish and shake until the contents are evenly distributed. With covers removed, place
dishes and covers in hot air oven as quickly as possible and dry samples for 2 hrs. Place covers
on dishes and transfer to desiccators and cool. Take the weight. Calculate loss in weight as %
moisture.
Alternatively use instant moisture analyzer calibrated against samples tested in air oven at 135
+ 2 C.
6.2.
40% sodium hydroxide (LR) solution. Use 400 g NaOH per liter of solution. Commercially
available in concentrations up to 50%. Do not use concentrations above 40% as this will lead to
crystal formation impairing the function of the pumps.
iii. Receiver solution
Boric acid 1% with bromocresol green / methyl red indicator solution. Dissolve 100 g boric acid
in 10-lit de-ionized water, followed by addition of 100 ml of bromocresol green solution (100 mg
in 100 ml methanol) and 70 ml of methyl red solution (100 mg in100 ml of methanol). In order to
obtain accurate results the receiver solution is adjusted1 so that a small (0.05-0.15ml) positive
blank is obtained when running a blank sample.
iv. Titrant solution
0.2 M standard HCl. Standardization is done using the following method
Weigh approximately 10 g of anhydrous sodium carbonate (Na2CO3). Use mortar to make fine
powder. Dry it for 1 hr at 265 C or 2 hrs at 200 C. After cooling in a desiccator, transfer the
sodium carbonate to a beaker with a tight lid. Store it in a desiccator.
Dissolve 0.1 g methyl red in 100 ml ethanol.
Adjustment of the boric acid solution is made by the following procedure:Transfer 25 ml boric
acid solution to a receiver flask and add 100 ml of distilled water. If the solution in the flask is still
red, titrate with 0.1 M sodium hydroxide solution until a neutral gray color is obtained. Calculate
the amount of sodium hydroxide solution necessary to adjust the boric acid solution in the 10 lit
flask with the formula
Ml 1.0 M alkali = ml titrant x 40
2. Add the calculated amount of 1.0 M alkali solution to the boric acid solution. Mix. For
boric acid 1%, addition of 30 ml 0.1 M NaOH usually gives a good adjustment.
3. To check proceed as follows using 25 ml of the boric acid solution; Run a blank. If the
value of this blank is high (0.5 ml of 0.2 M HCl) the boric acid is incorrectly adjusted.
This might create irregular blanks. For correction add HCl directly into the boric acid
tank, mix it carefully and repeat until a reading of 0.05-0.15 ml HCl is obtained. If a
positive blank is not achieved, add further small quantities of 1M NaOH and repeat the
check until a satisfactory value is achieved.
The addition of alkali is to achieve a positive blank value. This should, however, be
kept between 0.05 0.15 ml titrant, to obtain good repeatability when testing blanks.
Weigh approximately 0.4 g of the standard substance, using an analytical balance; note the
weight (W1). Transfer the sodium carbonate to a receiver flask and add 40 ml of H20 (distilled
or de-ionized). Add 10 drops of the indicator solution. Titrate to pink. Note the amount in ml
used (A1). Boil this solution for a few minutes. The solution will turn green. Cool rapidly to room
temperature under running water. Continue the titration until the next pink color change occurs.
Note also this volume (A2). Boil the solution for a few minutes. Cool rapidly to room
temperature under running water. Continue the titration until the next pink color occurs. Note
also this volume (A3).
The color change of this official procedure (AOAC 936.15) may be difficult to see, therefore a
pH meter to a mixed indicator (e.g. 0.1 g methyl red and 0.1 g bromocresol green in 100 ml
ethanol) will make it much easier to perform.
Calculation
Molarity (M)
18.870 x W1
=
---------------(A1 + A2 +A3)
b. Apparatus
Digester DS 20 with exhaust manipulator and Kjeltec 2300 Analyzer
c. Procedure
i. Sample preparation
Analytical sample from the laboratory sample of the bulk product may involve one or more
treatments such as:
Physical treatments: shaking, stirring, mortaring, riffling, coning and quartering
Mechanical treatments: grinding, blending, homogenizing or milling. As a recommendation the
particle size should be equal or less than 1 mm.
ii. Sample size
Actual weight of the sample required is dependant on Nitrogen content and homogeneity.
Homogeneous samples (excluding water)
Non-homogeneous samples
Water samples (dependant on the N content)
0.1 1.0 g
1.0 3.0 g or more
1.0 100 ml
Using a titrant concentration of 0.2 N the analytical sample should ideally contain 10 100 mg
N and the appropriate sample weight can be calculated as follows.
Minimum weight in mg =
Where
1000
------X
x = approximate % N anticipated
iii. Digestion
During digestion the nitrogen or protein in the sample is converted to ammonium sulphate
according to the formula
Salt K2SO4
Protein + H2SO4
-------------
(NH2)2 SO4
Catalyst
Prepare a representative sample2 and weigh based on the nitrogen content to 0.1 mg accuracy
into a digestion tube. Add one kjeltab Cu 3.5 (alternatively 3.5 g K 2SO4 and 0.4 g CuSO4 x 5
H2O). Carefully add 10 ml of conc. sulphuric acid and gently shake to wet the sample with the
acid.
Place the samples in the preheated (420 C) digester with the exhaust manifold on the top and
heat shields in place. The water aspirator must operate at full flow the first five minutes of the
digestion. This is done to evacuate moisture. After five minutes it is essential to decrease the
aspirating effect to a minimum until the acid fumes are just contained within the exhaust head to
prevent acid losses.
Continue digestion until all samples are clear with a blue / green solution. This will normally be
after 30 60 minutes depending on the sample type. Remove the rack of he tubes with exhaust
still in place and put in the stand to cool for 10 20 mins.
iv.
Distillation
All samples after digestion will form ammonium sulphate ((NH4)2SO4). The distillation principle is
to convert ammonium (NH4) into ammonia (NH3) by using alkali (NaOH) and thereafter steam
distil it into a receiver flask containing boric acid and titrate with standard acid solution using
colorimetric end point detection.
Place the digestion tube in the distillation unit and close the safety door 3. Dispense 50 ml of
40% NaOH in to the tube4. Then the distillation cycle is controlled automatically.
v.Blank determination
Full chemical blanks should be run before each batch of analyses to compensate for any
contribution from the reagents used. Blanks should be treated identically to samples to be
meaningful.
vi.
Chemical check
% Recovery =
Actual % Nitrogen
------------------------ x 100
21.09
3 Dilution water is automatically added on the Kjeltec 2300 if the option is selected.
4 In general 4 times the amount of the acid = the amount of alkali to use with the
g sample
N = Normality of titrant to 4 places of decimal.
Actual % Nitrogen
% Recovery = -----------------------7.145
x 100
Please note that the above calculations must be adjusted if other purity levels of ammonium
salts are used. For a full check of your chemistry a substance like glycine can be digested and
used as a test sample.
d. Calculation of results
The most common ways of reporting Kjeldhal results are as % Nitrogen, % protein, mg N/liter
(ppm), g N/liter and mg N/100 ml. The calculations are as follows:
%N =
% Protein =
(T B) x N x 14.007 x 100
---------------------------------Weight of the sample in mg
%NxF
(T B) x N x 14.007 x 1000
mg N / liter = ----------------------------------Volume of the sample in ml
(T B) x N x 14.007
g N/liter = ------------------------------------Volume of the sample in ml
mg N/100 ml =
(T B) x N x 14.007 x 100
-------------------------------------Volume of the sample in ml
Where
T = Titration volume for the sample (ml)
B = Titration volume for blank (ml)
N = Normality of the acid to 4 places of decimal.
F = Conversion factor for Nitrogen to protein e.g. 6.25, 5.7, 6.38 depending on
sample.
6.3.
a. Regents
e. Instrument settings
Control unit / service unit is set at temperatures to get an even boiling of the solvent with a
reflux rate of about 3 5 drops / sec. This setting varies with the solvent used and the type of
extraction cups used (whether glass or aluminum). If too high temperature is used the boiling
of the solvent can become too vigorous which for some samples increases the risk for foaming.
The risk of oxidation of the extractable matter during the evaporation phase is also increased.
f.
Procedure
Press the mains button (switch lamp should light up). Set temperature to achieve a reflux of 3
5 drops of solvent per second. (See application sub note to achieve desired reflux of solvent).
Select the proper program and check time settings for boiling / rinsing / evaporation / pre-drying
on the control unit. Open the cold-water tap for the reflux condensers. With cooling water at
approximately 15 C the flow should be adjusted to 2 l/min to prevent solvent evaporation from
the condensers. Prepare the thimbles and attach them to adapters. Prepare and weigh sample
into thimbles with a precision of + 0.1 mg . Use the thimble support with the balance. Move the
thimbles to the thimble stand. Use thimble handler. Put a thin layer of de-fatted cotton on the
top of the sample and place the thimbles into thimble stand. Use the thimble handler and move
the thimbles to the thimble supports. Insert the thimbles in to the extraction unit. Attach them to
magnets. Remove the thimble supports.
Use the cup holder to insert the pre-dried extraction cups, tared with 5 10 glass pellets (5 6
mm) to prevent shock boiling, loaded with the solvent to be used. See ASN for recommended
volume. The buzzer signal will inform you when the temperature on the hot plate is sufficient for
lowering the thimbles with the handle. Boil the thimbles immersed according to boiling time in
the ASN. Make sure that the condenser valves are open.
position. Rinse according to rinsing time in the ASN. Also note that the condenser valves are
open. After rinsing, close the condenser valves by turning a quarter turn. Move the handle to
recovery position. When almost all the remaining solvent is collected, press the air button. The
last traces of solvent will now be collected in the condenser /solvent collection vessel. Remove
the cups. Dry the cups at 103 C for 120 150 mins. Cool the cups in the desiccator and weigh
them.
g. Calculation
W3 W2
Crude fat % =
-------------
x 100
W1
Where
6.4.
W1
W2
W3
a. Equipment
Muffle furnace
b. Procedure
Weigh 3g sample into silica crucible and place in temperature controlled furnace preheated to
600 C. Hold at this temperature for 2 hrs. Transfer crucible directly to desiccator, cool and
weigh immediately. Calculate the % of crude ash.
% Crude Ash =
6.5.
a. Equipment
Muffle furnace
b. Procedure
Moisten the contents with 5-10 ml of conc. HCl, after ashing as described in the procedure for
estimation of crude ash. Boil for 2 min, evaporate to dryness and heat on steam bath for 3 hrs
to render SiO2insoluble. Moisten residue with 5 ml conc. HCl, boil for 2 min, add about 50 ml
distilled water. Heat on a water bath for 5 min, filter through Whatman filter paper No. 1 and
wash thoroughly with distilled water. Then ignite at 500 550 C, cool and weigh to calculate
acid insoluble ash % by difference
Weight of acid insoluble ash
-------------------------------------- X 100
Weight of the sample
Estimation of crude fibre
a. Reagents
Sulphuric acid: 1.25 % (12.5 g of H2SO4 diluted to 1 lt and mixed)
Sodium hydroxide (NaOH) or potassium hydroxide (KOH) 1.25% (12.5 g of NaOH
or KOH dissolved in deionized water and diluted to 1 lit.
n-Octanol
Acetone
b. Equipment
Muffle furnace
Hot air oven
c. Procedure
Grind the sample to pass through 1 mm screen in a grinder. Weigh and transfer 2 g (Wo) of
defatted sample in to a beaker. Add 200 ml preheated 1.2% sulphuric acid and a few drops of
octanol to prevent foaming. And heat to boiling. Adjust heat and boil for 30 mins. Filter through a
200 micron cloath and wash with hot de-ionized water three times. Transfer again to the same
beaker and add 200 ml hot 1.25 % NaOH or KOH solution and boil for 30 min. Filter and then
wash with de-ionized hot water three times and then finally with acetone (25 ml each) three
times. Collect the residue, dry it in hot air oven at 100 C over night or at 130 C for 2 hrs. Cool
and weigh (W1) the material. Ash the sample in the crucibles at 550 C for 2 hrs. Cool the
crucibles to room temperature and weigh again (W2). Calculate the fibre content from the
formula
Crude fibre % =
W1 W2
-------------- x
Wo
100
Objective:
Cracks:
Cracks are the result of the pelletizing process. They are fine as
hairs and are visible under the microscope or when put into water.
Cracks are the entrance for penetration of water into pellets.
Disintegration: Due to absorption of water, the particles of the pellets fall off. Falling
off particles from the pellet is the beginning of the disintegration
3
Assay
Drop ~5 g feed sample, just enough to form one layer on the bottom of a 250 ml
glass beaker filled with water. This is stirred automatically and continuously so as to
simulate the pond water movement during aeration.
Procedure of judgment
Rating (judgment) is done at the end of 1 hour and 2 hours
Rating of the water durability is done by applying 1 to 10 points of fractions thereof,
preferably by three persons
Feed has to be observed carefully after putting into water for any quick changes with
reference to swelling, cracks and disintegration, especially at the end of the intervals
given above. Testing may be stopped if the samples get a failure rating as per
judgment chart given below.
Judgment chart
Chart for the judgment of the water durability of shrimp feed
Swelling:
Little to normal
Cracks 1
(in pellets)
None
Disintegration
None
Points
( 1 to 10 )
10
Standard
Normal
Normal
Normal
1/3 rd to 1/2
~ 15% 2
Normal
1/2 to 2/3 rd
~ 20 %
7.5
Normal to full
Normal to full
> 3/4 th
~ 50%
Full
Total
~ 75%
Full
Total
Full
Total
Total
8.5
Full (immediate)
Total (immediate)
Means number of pellets actually developed cracks but have not fallen apart
Visual estimation of fallen off particles in comparison to the volume of the feed present
6.8.
Estimation of calcium
a. Reagents
Where
W = Weight in g of Na2C2O4 taken
V= Titre volume of KMnO4
iii) Acetic acid Glacial
iv) Phenol Red indicator solution: 0.1g dissolved in 30ml 0.01N NaOH
solution and diluted to 250 ml with distilled water.
b.
Procedure
Nitric acid 1:1- Mixture of equal volumes of concentrated nitric acid and
water
Ammonium molybdate stock solution Take 200g of powdered ammonium
molybdate (AR grade) in a stoppered graduated cylinder of 1000 ml
capacity .Add to it 800 ml of distilled water and shake well for 25 minutes to
dissolve the ammonium molybdate. Add gradually 25 % (m/v) ammonium
hydroxide solution till the solution is clear (about 100 to 140 ml of
ammonium hydroxide may be required.) Avoid adding excess of ammonia.
Make up the volume to one liter, if necessary, filter the solution through a
filter paper and stock this solution.
Nitric acid solution 2 %
b. Procedure
Precipitation Take 10 ml aliquot of the prepared solution (general solution
as prepared for cal) In a 150ml beaker. In a dry baker, prepare ammonium molydbdate
solution by pouring into it, quickly and simultaneously. 10 ml of conc. nitric acid or take
10 ml of conc. nitric acid solution in the beaker and into thispour quickly 10 ml of
ammonium molybdate solution, whirling the beaker during addition. Pour this freshly
prepared clear liquid in to the beaker containing the aliquol and stir. But much better, if
the above analysis is done fast, so that the temp raised due to nitric acid will be enough
and if it is done slow , care should be taken .
Note: The temperature developed in the molydbdate solution is sufficient to
precipitate all the phosphorus present in the aliquant. Under no circumstances the
phosphomolybdate precipitate should be heated either on a water bath or directly over a
burner so as to avoid precipitation of molybdie anhydrate.
Filtration and Washing Allow the precipitate to stand overnight and then
filter through whatman filter paper no 42 over an ordinary funnel. As far as possible only
the supernatant liquid is passed thru the filter paper, retaining the precipitate in the
beaker. When the supernatant liquid is decanted off the precipitate is washed twice with
dilute nitric acid and then with potassium nitrate solution until the washings are free from
acid. Freedom from acidity may be tested by collecting sufficient filtrate in test tube to
which as few drops of phenolphthalein indicator solution and one drop of the standard
sodium hydroxide solution are added. If the pink color appears with one drop of the
standard alkali, the precipitate is free from acid.
Titration Transfer the precipitate with the filter paper back to the beaker in
which precipitation was carried out. Add sufficient quantity of the standard solution
hydroxide solution from a burette just to sufficient to dissolve the ppt and then add 5ml in
excess. See that no yellow ppt sticks to the filter paper. Note the total volume of the
standard sodium hydroxide solution added. Add about 2-3 drops of phenolphthalein
indicator solution and filtrate the excess of alkali with the standard nitric acid.
Calculation:
phosphorous
= 336.75(AN1- BN2)
--------------M x 100
Where,
A - Volume in ml of the standard sodium hydroxide solution used
N1- Normality of the standard sodium hydroxide solution
B - Volume in ml of the standard nitric acid used into neutralize the excess alkali.
N2- Normality of the standard nitric acid.
M Mass in gram of the material taken for the test (it means that total weight of
sample which is taken for ash)
6.10.
Reagents
Ferric sulphate solution: dissolve 60 g of ferric sulphate [Fe2(SO4)3] in one liter of
water.
Ammonium hydroxide solution: Prepared by mixing one volume of ammonium
hydroxide with 12 volumes of water.
Concentrated nitric acid.
Ferric sulphate indicator solution: Prepare as 25 % (m/v) solution. Filter and add
equal volume of nitric acid.
Standard silver nitrate solution: 0.1 N (follow procedure as described later).
Standard potassium thiocyanate solution: 0.1 n (follow procedure as described
later).
b.
Procedure
Weigh accurately about 1 g of the dried material and transfer to a 250 ml
volumetric flask. Add 50 ml of the ferric sulphate solution with a pipette, gently swirling the flask.
Add 100 ml of the ammonium hydroxide solution to bring it to the mark. Swirl the flask enough
to ensure through mixing but avoid vigorous shaking. Allow to settle for 10 min. filter through 11
cm Whatman filter paper # 41 or its equivalent. Transfer from the filtrate, an aliquot of 25 ml to a
250 ml beaker. Add 10 ml of nitric acid and 10 ml of the ferric sulphate indicator solution. Then
add with constant stirring, known quantity of the standard silver nitrate solution in slight excess.
Heat the solution to the boil and cool to room temperature and stir to coagulate the precipitate.
Titrate the excess of silver nitrate with the standard potassium thiocyanate solution. The end
point is indicated by the first appearance of reddish tint that persists for 15 seconds.
Where
A=
N1 =
B=
6.11.
N2 =
m=
Estimation of magnesium
a.
Reagents
Buffer solution pH 10: Dissolve 67.5 ammonium chloride in 200 ml distilled water. Add
570 ml ammonium hydroxide and dilute to 1 liter.
Potassium hydroxide (KOH) potassium cyanide (KCN) solution: dissolve 280 g KOH and
66 g KCN in 1 liter distilled water.
and 1.0 mg / ml :
magnesium turnings in HCL (1+10) and dilute each to 1 liter with distilled water.
Calcium standard solution 1mg / ml: Dissolve 2.4973 g calcium carbonate, AR grade,
previously dried for 2 hrs at 285 C, in HCL (1+10). Dilute to 1 liter with distilled water.
0.1%: Prepare as above (i), using 1 g Na2H2EDTA and standardize against 0.25 mg / ml
Mg standard solution.
b. Standardization:
For Calcium:
Pipet 10 ml standard Ca solution into 250 ml conical flask and add 10 ml distilled water.
Add 10 ml KOH-KCN solution and about 35 g pattons and reeders reagent. Titr with
0.4% EDTA standard solution till end point. Titr 3 aliquots and use average to calculate
titr Ca solution = 10 / ml EDTA solution.
For Magnesium:
Pipet 10 ml 0.25 and 1.00 mg / ml Mg standard solutions into 250 ml conical flasks and
add 150 ml distilled water. Add 7 ml pH 10 buffer, 2 ml 2% KCN solution, and 30 to 40
mg erichrome black T indicator. Titr. with 0.1 and 0.4% EDTA standard solutions
respectively, until color changes permanently from wine red to pure blue. Titr 3 aliquots
and use average to calculate titer Mg solution = 2.5. ml EDTA solution, or 10 / ml EDTA
solution, respectively.
c. Determination
Dry sample at 110 C to constant weight and cool to room temperature. Grind to pass #
60 or 80 ASTM sieve and mix thoroughly. Accurately weigh about 0.5 g into 250ml
beaker, add 20 ml HCL (1+1), and evaporate to dryness on hot plate. Dissolve residue
in 5 ml HCl (1+10), dilute to about 100 ml wit distilled water and digest over water bath
for 1 hr. Coll, transfer to 250 ml volumetric flask, dilute to volume, mix and let settle or
filter.
For Calcium: Pipette 10 ml aliquot into 250 ml conical flask and titer. As in II a,
observing end point thru solution and away from light. % Ca = (titer EDTA standard
solution for Ca x ml EDTA standard solution x 2 / g sample).
For Magnesium (for samples containing 4 % Mg) : For Ca + Mg, pipet 10 ml aliquot into
250 ml conical flask and titr. with 0.4% EDTA solution as in II b. % Mg = (Titer EDTA
standard solution for Mg ) x [(ml EDTA standard solution in Ca + Mg titrn) - (ml EDTA
standard solution in Ca titrn)] x 2 / g sample.
6.12.
Estimation of urease activity in soybean meal
a. Reagents
Urea crystals
Phenol red indicator (0.62 % solution in distilled water)
b. Procedure
Weigh 0.2 g soybean meal into a test tube, add 0.02 g urea crystals and 2 drops of phenol red
indicator. Finally add 2 3 ml distilled water into the test tube. Shake the test tube for 10
seconds and observe for the appearance of pink color in the test tube. Record the time span for
color development.
c.
Very strong
strong
Some activity
Reagents
Warm the sample to soften the product (do not heat over 60 C) and then mix
thoroughly.
c. Procedure
Weigh about 2 g of sample into a 250 ml conical flask. Dissolve in 50 ml of petroleum ether or
hexane by mixing gently. Then add 50 ml of neutral alcohol and mix. Add 4 drops of indicator
and while mixing titrate with 0.1 N NaOH to the first pink color, which persists for 5 sec. Adding
the bulk of the alkali solution rapidly until near the end point, and then slowing down to about 4,
then 1 2 drops fairly easily ascertain the end point, at a time.
Acid value (mg KOH / g ) of sample6 =
Reagents: Acetone
b.
Procedure
Weigh 5 g lecithin sample accurate to 0.001 g into the beaker. Weigh filter. When convinced, by
means of thermometer, that the acetone is at 0 C, add about 20 ml thereof to the lecithin and
start to knead with glass rod. Allow the solids to settle for a short period and filter off the oilcontaining acetone through the filter into the conical flask. Repeat the kneading step at least 5
times using in each case 20 ml acetone at 0 C. The initially greasy tacky material must
finally have disintegrated to a fine powder. Transfer as much as possible of the kneaded
lecithin to the filter and wash with cold acetone at 0 C until a drop of the filtrate evaporates on
a glass plate without leaving a residue. Then dry the filter together with the remainder of the
kneaded lecithin for 30 min in a hot air oven at 105 C. when the material is dried, cool it in a
desiccator, weigh it.
Acetone Insolubility % = [(F-E) x 100] W
Where F
6.15.
a.Reagents
Pepsin solution - % pepsin (activity 1:10,000) in 0.075N HCl, freshly prepared. Do not use
pepsin NF or pepsin of activity other than 1:10,000. Prepare just before use by diluting 6.1
ml HCl to 1 liter and heating to 42 45 C. Add pepsin and stir gently until dissolved. Do
not heat pepsin solution on hot plate or over heat.
b.
Equipment
Agitator continuous, slow speed (15 rpm), end-over-end type, to operate inside
incubator at 45 + 2 C and carry 250 ml screw cap prescription bottles, or equivalent.
Filtering device Buchner funnel or equivalent
Glass fiber filter paper, for indigestible residues.
45 angle settling rack
c.
Procedure
Grind sample to pass through # 20 ASTM sieve. Weigh accurately 1.000 g of material into the
thimble and extract with hexane as in procedure for determination of crude fat. Transfer the
defatted sample to 250 ml sample bottle. Add 150 ml freshly prepared 0.2% pepsin HCl
solution and heat to 42 to 45 C. Be sure sample is completely wetted by pepsin solution.
Stopper bottle, clamp in agitator, and incubate with constant agitation for 16 hrs at 45 + 2 C
remove bottles from agitator. Place in 45 angle settling rack and loosen the caps. Let residue
settle for 15 min or more.
Place weighed filter paper in funnel. Filter the sample and quantitatively transfer residue on to
filter washing properly with hot water. If filtration rate is slow it may be accelerated by adding
acetone coupled with suction. Add 15 ml acetone into the bottle. Hold thumb over bottleneck
7 Defatted sample is digested for hrs in the presence of warm acid solution of
pepsin under constant agitation. Insoluble residue is isolated by filtering, washed,
dried and weighed to determine % residue. Residue is analyzed for protein.
and shake vigorously. Release pressure, replace thumb over bottleneck and shake bottle in
inverted position over filter. Repeat rinse two or three times till the bottle is free from residue.
Dry the residue in the filter paper in a hot air oven as in the procedure of determination of
moisture. Calculate the % indigestible residue. Determine indigestible protein by transferring
filter-containing residue directly to Kjeldahl flask and determine crude protein by Kjeldahl
method as described previously.
Make blank determination on 1 sheet of glass filter and subtract from each sample
determination if necessary.
Calculate % of protein based on original sample weight. Result represents % indigestible
protein in sample.
% Indigestible crude protein in sample
% Protein indigestible = -------------------------------------------- x100
% Crude protein
% Pepsin digestibility = 100 - % protein indigestible.
6.18.
Take 10 g sample of wheat gluten, add 40 ml tap water and then soak it for 15 min in a
bowl. Then the contents are transferred into a filter paper in a funnel to let the excess
water filter out.
Wet gluten content in the filter paper is made into a ball and thoroughly washed over a
mesh (100 ASTM) for 20 30 min to remove excess of starch. Pure wet gluten ball is
then made free of adhering water over a cotton cloth and weighed for calculating the
percent gluten index.
Wet gluten index %
6.19.
Take 20 g pelletized feed in to a mesh of smeller pores than feed and place it in slowly
circulating fresh water in an aquarium. Water can be circulated with the help of aerator. After 2
hrs, collect the sample and dry it in hot air oven at 135 C till it is fully dried. Weigh dried feed
pellets and calculate the dry matter % retained in the mesh.
6.20.
Abrasion test
a. Equipment :
b. Procedure :
Place 500g pelletized feed in to the tumbler and rotate at slow speed ( about 30 to 50 rpm)
for15 min. Collect the sample and sieve it through smaller pore size mesh .The dust and fines
generated the period of tumbling are calculated as percent by weight .
6.21.
a.
ESTIMATION OF COARSENESS
Equipment : Test sieves ASTM-40, 60 and 80
b.
Procedure
10-20 g of sample is weighed and then sieved through any of the sieves in order to
find out the quality of coarse material. Depending on the type of material, particular sieve has to
be used. Quantity of coarse material retained over the sieve is weighed and calculated as
percent.
6.22.
prepare 0.1N solution. Boil the solution for 1 hr. Protect from dust and let stand overnight.
Standardization: For 0.1N solution, transfer 0.3g dried (1hr at 150c) Sodium oxalate
(Na2C2O4) to 500ml beaker. Add 250ml sulphuric acid (5+95) , previously boiled 10-15 min and
then cooled to 27-30C . Stir until sodium oxalates dissolved. Add 39-40ml KMnO4 solutions. If
too concentrated, discard and begin again, adding few ml less of KMnO4 solution. Heat to 5560c and complete titrn by adding KMnO4 solution until faint pink persists 30sec. Add last 0.5
1ml drop wise, letting each drop decolorize before adding next. Determine excess of KMnO4
solution required to turn soln pink by matching with color obtained by adding KMn O4 soln to
same vol, of boiled and cooled dil. sulphuric acid at 55- 60c. This correction is usually 0.03
0.05ml. From net vol, KMnO4, calculated normality.
Normality= g Sodium oxalate X 1000 / ml KMnO4 X66.999
6.23.
Titrate dilute nitric acid solution against 20 ml standard NaOH solution using phenolphthalein
indicator. Note down the volume of dilute nitric acid required to neutralize 20 ml standard NaOH.
Determine the normality of the nitric acid using the formula:
N2 =N1 V1 / V2
N1= Normality of standard NaOH
V1= Volume standard NaOH used
N2= Normality of standard nitric acid to be obtained
Dissolve slightly more than theoretical weight of silver nitrate (AgNO 3) in distilled water and
dilute to volume. Thoroughly clean glassware, avoid contact with dust and keep prepared
solution in amber glass stopper bottles away from light.
b. Reagents
Potassium chloride Dry KCl at 110c and then heat at about 500 C to
constant weight
Potassium chromate solution 5% solution of K2Cr2O4 in distilled water.
c. Standardization
Accurately weigh enough KCl to yield titration of about 40ml (approximately 0.03g for
0.01Nsolution) and titrate with AgNO3 solution until first perceptible pale red brown appears.
From titration volume subtract ml of the AgNO3 solution required to produce end point color in
75 ml distilled water containing 1ml K2CrO4 solution. From net volume AgNO3, calculate
normality.
Normality = g KCl x 1000/ml AgNO3 x 74.555.
6.25. Preparation of standard potassium thiocyanate solution
Preparation of about 0.1N solution using 9.718 g potassium thiocyanate (KSCN) / L.
Standardization:
Accurately weigh enough purified AgNO3 to give titration of about 40ml (about 0.7g for 0.1N
solution) and transfer with distilled water through glass funnel to 250ml conical flask. Dissolve in
about 75ml distilled water and add 5ml HNO3 (1+1 ) and 2ml Fe alum ( Ammonium Iron 111
sulphate or Ferric salt ) solution .Titrate with thiocyanate solution until titrated solution is reddish
brown .which remains after shaking vigorously 1 min. Record burette reading and set the flask
aside 5min ,shaking occasionally and maintaining end point color by addition of thiocyanate
solution as required .Then add additional thiocyanate solution , If necessary , to produce
permanent end point color, matching with color of reference solution . From total volume
thiocyanate solution used in titration, subtract volume, contained in the reference solution.
Normality =
The extract thereby obtained can be kept for at least seven days at a
temperature between approximately 2 6 0C
Blank test is carried out with 10mL aqueous solution (6.0%) of PCA.
10 ml of filtrates (6.1 clause ) taken in to digestion tube and set the Kjeltec
analyzer as mg N/100 gm. Enter the weight of sample ( filtrated solution )
taken for test.
After one week, the same filtrate is rechecked for TVB-N Value
6.27. The feed analysis is being carried out by laboratory services according to feed mill
requirements.
6.28. Apart from the chemical analysis physical examination of feed sample will be done
by visual observation.
7.0
DOCUMENTATION
7.1
7.2
7.3
All the document formats quoted here are given in Annexure I - III
8.0
REVISION HISTORY
Revision No.
& Date
Author(s)
Change
Reference
Issue 1, 01.08.2010
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9.0 APPROVALS
Prepared by:
Reviewed by:
Recommended by:
Process Control, LS
Department Manager,
Laboratory Service
Endorsed by:
Approved by: