KENYA STANDARD KS 05-523: PART 1: 1986
ics 67.060
Specification for breakfast cereals
Part 1. Rolled/Flaked oats (quick-cooking type)
No copying of this standard without KEBS permission except as permitted by copyright law
TECHNICAL COMMITTEE REPRESENTATION
The following organizations were represented on the Technical Committee:
National Cereals and Produce Board
Ministry of Health
Wheat Board of Kenya
University of Nairobi ― Food Technology and Nutrition Department
Kenya National Mills Ltd.
Milling Corporation of Kenya Ltd.
Proctor and Allan Ltd.
Kenya Oatmeal Ltd.
Kenya Bureau of Standards — Secretariat
REVISION OF KENYA STANDARDS
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are welcome.
© Kenya Bureau of Standards, 1986
Copyright. Users are reminded that by virtue of section 6 of the Copyright Act, Cap. 130 of the Laws of Kenya, copyright subsists in all Kenya Standards and except as provided under section 7 of this Act, no Kenya Standard produced by Kenya Bureau of Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from the Managing Director.
Permission may be conditional on an appropriate royalty payment.
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ISBN 9966-07-255-1
©KEBS KS 05-523: PART 1: 1986
KENYA STANDARD KS 05-523: PART 1: 1986
ics 67.060
Specification for breakfast cereals
Part 1. Rolled/Flaked oats (quick-cooking type)
KENYA BUREAU OF STANDARDS (KEBS)
Head Office: P.O. Box 54974, Nairobi-00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020) 604031
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Coast RegionLakeRegion Rift Valley Region
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Tel.: (+254 041) 229563, 230939/4Tel.: (+254 057) 23549, 22396Tel.: (+254 051) 210553, 210555
Fax: (+254 041) 229448Fax: (+254 057) 21814
P R E F A C E
This Kenya Standard was prepared by the Processed Cereals and Pulses Technical Committee under the authority of the Food Industry Standards Committee and it is in accordance with the procedures of the Bureau.
Rolled/f laked oats form one of the commonly used breakfast foods, especially in catering establishments. In its manufacture, cleaned oats are kiln-dried, dehulled and then separated into various size groups. These dehulled oats, called 'groats', are treated with live steam at atmospheric pressure. This treatment inactivates enzymes and partially cooks the groats, which are then flaked by passage between two rolls. The quick-cooking type of oats are obtained by cutting the groats into pieces of a desired size before treatment with live steam. The size of the cut groats and thickness of the flakes govern the cooking properties of the product.
This standard is intended to improve the quality of rolled/flaked oats since it is a product with a fairly short shelf-life.
During the preparation of this standard, reference was made to the following documents:
Technology of cereals (with special reference to wheat), Second Edition ― By N. L. Kent.
IS: 1484-1974: Specification for rolled oats (quick-cooking type).
IS: 7219-1973: Method for determination of protein in food and feeds.
The chemical analysis of foods, Sixth Edition 1970 - By Pearson.
Acknowledgement is hereby made for the assistance received from these sources.
KENYA STANDARD
SPECIFICATION FOR BREAKFAST CEREALS
PART 1. ROLLED/FLAKED OATS (QUICK-COOKING TYPE)
- SCOPE
This Kenya Standard prescribes the requirements and the methods of test for rolled/flaked oats (quick-cooking type).
2.REQUIREMENTS
2.1Description
2.1.1The rolled/flaked oats shall be made from sound, hulled oats. It shall be in the form of thin flakes of uniform size, having uniform colour and an odour characteristic of good rolled oats.
2.1.2The material shall be free from rancid, musty, fermented or other undesirable taste and odour; added flavouring or colouring agents, or other adulterants.
2.2Oats Content ―When examined by the method prescribed in Appendix A, the proportion ofoats shall be not less than 99 per cent by mass, of which the proportion of unhulled oats shall be not more than 0.5 per cent by mass.
2.2.1Foreign Matter ― The proportion of food grains other than oats shall be not more than 0.5 per cent by mass.
2.3Flakes Powder ― When tested by the method prescribed in Appendix B, the proportion of the material passing through 850 micron sieve shall be not more than 12.5 per cent by mass.
2.4Cooking Time― The material shall pass the test prescribed in Appendix C.
2.5Lipase Inactivity― The cleaned oats used for the manufacture of rolled oats shall be well stabilized according to good manufacturing practice to inactivate the lipase enzyme. When tested by the method in Appendix D the enzyme (lipase) activity shall be negative.
2.6The material shall conform to the requirements given in Table 1.
TABLE 1. REQUIREMENTS FOR ROLLED OATS
SL No. / CHARACTERISTIC /REQUIREMENT
/ METHOD OF TEST (REF. TO APPENDIX)(i)
(ii)
(iii)
(iv)
(v) / Moisture, per cent by mass, max.
Total ash (on dry basis), per cent by mass, max.
Crude protein (N x 6.83), (on dry basis), per cent by mass, min.
Crude fibre (on dry basis), per cent by mass, max.
Fat, per cent by mass, max. / 10
1.8
12.0
1.5
10 / E
F
G
H
J
3.HYGIENE
3.1The material covered by the provisions of this standard shall be prepared in accordance with the appropriate codes of practice on food manufacture and hygiene as prepared by the Kenya Bureau of Standards, and other government regulations applicable to good manufacturing and handling.
3.2The rolled oats shall be free from dirt, insects, fungi, extraneous matter, micro-organisms, and other adulterants.
3.3When tested by appropriate methods as specified in various Kenya Standards, the material shall be free from pathogenic organisms.
3.4 When tested by appropriate methods, the material shall be free from heavy metals in amounts which may represent a hazard to health.
4.PACKAGING
4.1The material covered by this standard shall be packed in well-sealed moisture proof containers, with facilities for safe closure during usage of the product after the container has been opened.
4.2All food packaging containers and materials shall comply with the requirements of KS 05-348[*].
5. MARKING
5.1The containers shall be marked in compliance with the requirements of KS 05-40[†].
In addition to the above, the following shall be marked on the package:
(i) Recommended time for cooking the product;
(ii)Date of manufacture of the product;
(iii)Minimum date of durability of the product.
A P P E N D I X A
(Clause 2.2)
DETERMINATION OF OATS CONTENT
A1.PROCEDURE
Weigh about 100 g of the material. Spread it out on a large sheet of paper. Using forceps, pick out unhulled oat kernels (see 2.2) and food grains other than oats, and keep them in two separate groups. Weigh each group separately.
A2.CALCULATION
A2.1Per cent by mass, of each group =
where,
M2 = mass, in g of the group, and
M1 = mass, in g of the material taken for the test.
A2.2Oats content, per cent by mass = 100 - T - Y
where,
T = per cent of all foreign matter in the sample, and
Y = per cent unhulled oats in the sample.
A P P E N D I X B
(Clause 2.3)
DETERMINATION OF FLAKES POWDER CONTENT
B1.APPARATUS
B1.1850-Micro Sieve (Aperture 0.850 mm)―With a lid on top and receptacle below; of a type suitable for use in a sieve shaker (seeB1.2).
B1.2Steve Shaker― A Ro-Tap or other suitable mechanical sieve shaker.
B2.Procedure
Weigh about 100 g of the material. Place on the sieve in the sieve shaker for 2 minutes. At the end of this period, weigh the material that has passed through the sieve and is collected in the receptacle.
B3.CALCULATION
Material passing through the sieve, per cent by mass =
where,
M = mass, in g of the material passing through the sieve, and
M1 = mass, in g of the material taken for the test.
A P P E N D I X C
(Clause 2.4)
TEST FOR COOKING TIME
C1.PROCEDURE
C1.1Boil about 500 mL of water in an open vessel. Add to this about 60 g of the material. Allow to boil for exactly 5 minutes. At the end of this period, examine the material to determine whether it is cooked or not.
C1.2 The material shall be deemed to pass the test, if it is properly cooked for table use in 5 minutes.
A P P E N D I X D
DETERMINATION OF LIPASE ACTIVITY
D1.PRINCIPLE
Lipase serves no useful purpose in milled oat products and is inactivated during milling of the product. A check on the completeness of lipase inactivation is made by applying the catechol test. If after stabilization, a reddish or reddish brown colour develops, it follows, that the heat treatment used was insufficient to inactivate the dehydrogenase enzymes, and that other enzymes, in particular lipase, have survived also. This test should be negative for a good product.
D2.Preparation of the Sample
(i) Grind the rolled/flaked oats.
(ii) Make a 5 per cent solution of catechol (i.e. weigh 1 g of catechol to 20 mL distilled
water).
D3.PROCEDURE
Weigh about 1 g of the ground rolled/flaked oats and mix with15 mL distilled water in a test tube (carry out this in duplicate). In another test-tube add only 15 mL distilled water (no sample) as a control. Add 1 mL of the 5 per cent solution catechol and let stand.
D4.OBSERVATIONS
Note the development of a reddish or reddish brown colour, If the colour develops within 10 minutes lipase is positive.
NOTE:All equipment should be heat sterilized. Rinse with distilled water.
A P P E N D I X E
DETERMINATION OF MOISTURE
E1. PROCEDURE
Weigh about 5 g of the material in a dish made of porcelain, silica or platinum, previously dried in an electric oven maintained at 105 ± 1°C, for 5 hours. Cool the dish in a desiccator and weigh with the lid on. Repeat the process of heating, cooling and weighing at half-hour intervals until the loss in weight between two successive weighings is less than one milligram. Record the lowest weight obtained.
NOTE: Preserve the dish containing this dried material for the determination of total ash
(see F1) and crude fibre (see H2)
E2.CALCULATION
Moisture, per cent by mass
where,
M1 = mass, in g of the dish with the material before drying,
M2 = mass, in g of the dish with the material after drying, and
M = weight, in g of the empty dish.
A P P E N D I X F
DATERMINATION OF TOTAL ASH
F1.PROCEDURE
Ignite the dried material in the dish (see E1) with the flame of a suitable burner for about one hour. Complete the ignition by keeping in a muffle furnace at 550 °C to 600 °C until grey ash results. Cool in a desiccator and weigh. Repeat the process of igniting, cooling and weighing at half-hour intervals until the difference in weight between two successive weighings is less than one milligram.
Note the lowest weight.
A P P E N D I X G
DETERMINATION OF CRUDE PROTEIN
G1. PRINCIPLE
The sample is oxidized in the presence of sulphuric acid and nitrogenous compounds are converted into ammonium sulphate. Mercury is added to the digestion mixture as a catalyst and alkali sulphate as a boiling point elevator. Ammonia is liberated by adding an excess of alkali and is quantitatively distilled into a measured volume of standard hydrochloric or sulphuric acid. The acid not neutralized by ammonia is backtitrated with standard alkali.
G2. APPARATUS
G2.1For Digestion― Use 500 mL to 800 mL Kjeldahl flasks. Conduct digestion over a heating device adjusted to bring 250 mL water at 25 °C to boil in about 5 minutes. To test heaters, preheat for 10 minutes, if gas, or for 30 minutes if electric. Add 3 to 4 boiling chips or glass beads to prevent superheating.
G2.2For Distillation ― Fit the flask with a rubber stopper through which passes the lower end of an efficient scrubber trap or bulb to prevent mechanical carryover of alkali during distillation. Connect the upper end of the trap to a condenser by rubber or glass tubing. Immerse the trap outlet of the condenser in such a way as to ensure complete absorption of ammonia distilled over into acid in a 500-mL Erlenmeyer flask.
G3.REAGENTS
G3.1Concentrated Sulphuric Acid― 93 to 98 per cent by mass, nitrogen free.
G3.2Mercuric Oxide or Metallic Mercury ― Nitrogen free.
G3.3Potassium Sulphate or Anhydrous Sodium Sulphate ― Nitrogen free.
G3.4Zinc Granules
G3.5Sulphite or Thiosulphate Solution ― Dissolve 40 g potassium sulphide or 80 g hydrated sodium thiosulphate in 1 litre distilled water.
G3.6Sodium Hydroxide ― Pellets, flakes or solution; nitrogen free. For solution, dissolve about 450 g solid sodium hydroxide in distilled water, cool and dilute to 1 litre. The specific gravity should be at least 1.36 at 20 °C.
G3.7Hydrochloric or Sulphuric Acid, Standard Solution ― 0.1 N or 0.5 N. Standardize against primary standard and against sodium hydroxide standard solution (see G3.8).
G3.8Sodium Hydroxide Standard Solution– (0.1 N) ― Standardize against primary standard and against standard acid solution (seeG3.7).
G3.9Methyl Red Indtcator ― Dissolve 1 g methyl red in 200 mL alcohol.
G4.PROCEDURE
G4.1 Digestion ― Accurately weigh 0.7 g to 2.2 g of the sample into the digestion flask. Add 0.7 g mercury oxide or 0.65 g mercury and 15 g powdered potassium sulphate or anhydrous sodium sulphate, and 25 mL sulphuric acid (seeG3.1). Ratio of salt to acid (m/v) should be about 1:1 at the end of digestion for proper temperature control. Digestion may be incomplete at a lower ratio and nitrogen may be lost at a higher ratio.
G4.1.1 Each gram of fat consumes 10 mL sulphuric acid and each gram of carbohydrate 4 mL sulphuric acid during digestion. Place the flask in an inclined position on a heater and heat gently until foaming ceases (see G2.1). A small amount of paraffin or silicon antiform may be added to reduce foaming. Boil vigorously until the solution becomes clear and then continue boiling it for 1 or 2 hours.
G4.2Distillation― Cool, add about 200 mL distilled water, and in order to avoid complex formation, add 25 mL of the sulphide or thiosulphate solution. Mix to precipitate mercury. Add a few zinc granules to prevent bumping, incline flask, and add without agitation 25 g of sodium hydroxide as solid, or equivalent as solution, to make solution strongly alkaline (the thiosulphate or sulphide solution may be mixed with the sodium hydroxide solution before addition to the flask). Immediately connect the flask to distillation bulb or trap on condenser, and, with tip of the condenser immersed in a measured quantity standard acid (usually 50 mL, 0.5 N or an appropriate quantity of 0.1 N) in the receiver, rotate the flask to mix the contents thoroughly then heat immediately until all ammonia has distilled over (at least 150 mL distillate). Lower the receiver before stopping distillation and wash the tip of the condenser with distilled water. Back-titrate excess acid with standard 0.1 N sodium hydroxide, using methyl red as indicator. Correct for blank determinations in reagents.
G4.3Blank― Conduct determinations using all reagents and 2 g of sugar.
G5. CALCULATION, EXPRESSION AND INTERPRETATION OF RESULTS
G5.1 Methods of Calculation and Formulas
G5.1.1Calculation of Nitrogen Content
Nitrogen content (N) in g = (A - B) - (C - D) X 0.0014.
where,
A = volume, in mL 0.1 N acid measured for main distillation;
B = volume, in mL 0.1 N alkali used for back-titrating A;
C = volume, in mL 0.1 N acid measured for blank distillation; and
D = volume, in mL 0.1 N alkali used for back-titrating C.
G5.1.2Calculation of Total Protein ― Protein, per cent by mass
where,
N = mass of nitrogen content, in g of original sample, and
W = mass of sample, in g.
G5.2 Reporting ― Report nitrogen to the nearest 0.01 per cent and protein to nearest 0.05 per cent.
G5.3Precision of Method ― Duplicate determinations of the nitrogen should agree within 0.05 per cent nitrogen.
A P P E N D I X H
DETERMINATION OF CRUDE FIBRE REAGENTS
H1. REAGENTS
H1.1 Dilute Sulphuric Acid ― 1.25 per cent (w/v), accurately prepared.
H1.2Sodium Hydroxide Solution ― 1.25 per cent (w/v), accurately prepared.
H1.3 Ethyl Alcohol ― 95 per cent by volume
H2.PROCEDURE
Weigh about 2.5 g of the material preserved in Clause E1 and transfer it to a one litre flask. Take 200 mL of dilute sulphuric acid in a beaker and bring to the boil. Transfer the whole of the boiling acid to the flask containing the fatfree material and immediately connect the flask with a water-cooled reflux condenser and heat, so that the contents of the flask begin to boil within one minute. Rotate the flask frequently, taking care to keep the material from remaining on the sides of the flask and out of contact with the acid. Continue boiling for exactly 30 minutes. Remove the flask and filter through the fine linen (about 18 threads to the centimetre) held in a funnel, and wash with boiling water until the washings are no longer acid to litmus. Bring to the boil some quantity of sodium hydroxide solution under a reflux condenser. Wash the residue on the liner into the flask with 200 mL of the boiling sodium hydroxide solution. Immediately connect the flask with reflux condenser and boil for exactly 30 minutes. Remove the flask and immediately filter through the filtering cloth.
Thoroughly wash the residue with boiling water and transfer to a Gooch crucible prepared with a thin but compact layer of ignited asbestos. Wash the residue thoroughly first with hot water and then with about 15 mL of ethyl alcohol, 95 per cent by volume.
Dry the Gooch crucible and contents at 105 ± 2 °C in an air-oven to constant weight. Cool and weigh. Incinerate contents of the Gooch crucible in an electric muffle furnace at 600 ± 20 °C until all the carbonaceous matter is burnt. Cool the Gooch crucible containing the ash in a desiccator and weigh.
H3.CALCULATION
Crude fibre (on dry basis), per cent by mass =
where,
M1 = mass, in g of Gooch crucible and contents before ashing;
M2 = mass, in g of Gooch crucible containing asbestos and ash; and
M = mass, in g of the dried material taken for the test.
A P P E N D I X J
DETERMINATION OF TOTAL FAT CONTENT
J1. DEFINITION
J1.1 Total Fat Content ― The whole of the substances extracted by hexane under the operating conditions specified in this standard, and expressed as a percentage by mass of the product as received.
J2.PRINCIPLE
After any grinding required, hydrolysis of a test portion by hydrochloric acid in the presence of ethanol and formic acid, thus releasing lipids bound to proteins and sugars and producing in situ ethyl formate which is a lipid solvent. Extraction of the fat by hexane in a special flask, removal of the solvent and weighing the residue thus obtained.
J3. REAGENTS
The reagents used shall be of recognized analytical purity and the water used shall be distilled water of at least equivalent quality.