PDF GB/T 5538-2005 English (GB/T 5538-1995: Older version)
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Animal and vegetable fats and oils -- Determination of peroxide value
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| GB/T 5538-1995 | English | 199 |
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Oils and fats--Determination of peroxide value
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| GB 5538-1985 | English | 199 |
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Inspection of vegetable oils--Rancidity test of oils and methods for determination of peroxide value
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GB/T 5538-2005: PDF in English (GBT 5538-2005) GB/T 5538-2005
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.200.10
X 14
GB/T 5538-2005 / ISO 3960:2001
Replacing GB/T 5538-1995
Animal and Vegetable Fats and Oils – Determination of
Peroxide Value
(ISO 3960:2001, IDT)
ISSUED ON: NOVEMBER 11, 2005
IMPLEMENTED ON: DECEMBER 1, 2006
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Replaced
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Principle ... 5
5 Reagents ... 5
6 Apparatus ... 6
7 Sampling ... 6
8 Preparation of Test Sample ... 6
9 Analytical Procedures ... 7
10 Expression of Results ... 8
11 Precision ... 8
12 Test Report ... 9
Annex A (Informative) Results of Interlaboratory Tests ... 10
Bibliography ... 12
Foreword
This Standard equivalently adopts ISO 3960:2001 Animal and Vegetable Fats and Oils –
Determination of Peroxide Value (English Version).
This Standard replaced GB/T 5538-1995 Animal and Vegetable Fats and Oils – Determination
of Peroxide Value.
For the benefit of use, this Standard made the following editorial modifications:
a) Change “this International Standard” into “this Standard”;
b) Use decimal point “.” to replace the comma “,” that is used as decimal point;
c) Use GB/T 15687 Oils and Fats - Preparation of Test Sample to replace ISO 661:1989
Animal and Vegetable fats and Oils – Preparation of Test Sample;
d) Use GB/T 6682-1992 Water for Laboratory Use – Specifications to replace ISO
3696:1987 Water for Analytical Laboratory Use – Specification and Test Methods.
e) Delete the Foreword of the international standard;
f) Add SN in 9.3 according to the test sequence, making the test procedures clearer;
g) Change the unit "milligram equivalent" in the original international standard into China's
legal measurement unit "millimoles per kilogram"; and the value in the original
international standard in the unit of "milligram equivalent" is placed in parentheses after
it for readers' reference;
h) After the units of the experimental test results in Annex A are converted, the data have
the same significant figures as the original data; and the data in the original international
standard are placed in brackets after them.
The major technical difference between this Standard and GB/T 5538-1995 is the change of
solvent; this Standard uses isooctane to replace chloroform in the original standard.
Annex A of this Standard is informative.
This Standard was proposed by and under the jurisdiction of State Administration of Grain.
Drafting organization of this Standard: Xi'an Oil Food and Feed Quality Supervision,
Inspection and Testing Center, State Administration of Grain.
The chief drafting staffs of this Standard: Xue Yalin, Zhang Ying, and Liu Jiantao.
Animal and Vegetable Fats and Oils – Determination of
Peroxide Value
1 Scope
This Standard specifies a method for the determination of the peroxide value of animal and
vegetable fats and oils.
2 Normative References
The provisions in the following documents become the provisions of this Standard
through reference in this Standard. For dated references, the subsequent amendments
(excluding corrigendum) or revisions do not apply to this Standard, however, parties
who reach an agreement based on this Standard are encouraged to study if the latest
versions of these documents are applicable. For undated references, the latest edition of
the referenced document applies.
GB/T 6682-1992 Water for laboratory use – Specifications (neq ISO 3696:1987)
GB/T 15687 Oils and fats - Preparation of test sample (GB/T 15687-1995, eqv ISO
661:1989)
3 Terms and Definitions
For the purposes of this Document, the following terms and definitions apply.
3.1 Peroxide value
Quantity of those substances in the sample, expressed in terms of active oxygen, which oxidize
potassium iodide under the conditions specified in this Standard, divided by the mass of the test
portion.
NOTE 1: Peroxide value is usually expressed in industry as milliequivalents per kilogram.
NOTE 2: Peroxide value may also be expressed (in SI units) as millimoles per kilogram. The value
expressed in millimoles per kilogram is half that expressed in milliequivalents per kilogram (see Clause
10).
5.8 Starch solution, 5 g/L.
Mix 1 g of starch and a small amount of cold distilled water. Add this mixture, while stirring,
to 200 mL of boiling water. Add 250 mg of salicylic acid as preservative and boil for 3 min.
Immediately remove from the heat and cool.
If long storage is required, keep the solution in a refrigerator at between 4 °C and 10 °C for 2
weeks to 3weeks. A fresh starch solution shall be prepared when the endpoint of the titration
from blue to colorless fails to be sharp.
The sensitivity of the starch solution may be tested as follows. To 5 mL of the starch solution
in 100 mL of water; add 0.05 % of potassium iodide solution (5.5) and 1 drop of 0.05 % sodium
hypochlorite solution. When titrating more than 0.05mL of sodium thiosulfate solution (5.6), if
the deep blue color disappears, it shall indicate that the sensitivity is insufficient.
6 Apparatus
All used equipment shall be free from reducing or oxidizing substances. Do not grease ground
glass surfaces.
Usual laboratory apparatus and, in particular, the following.
6.1 Conical flasks, of 250 mL capacity, with ground glass stoppers.
7 Sampling
It is important that the laboratory receive a sample that is truly representative and has not been
damaged or changed during transport or storage.
Sampling is not part of the method specified in this Standard. A recommended sampling method
is given in ISO 5555.
Ensure that the sample is taken and stored away from strong light, kept cold, and contained in
completely filled dark-colored glass containers, hermetically sealed with ground glass stoppers.
8 Preparation of Test Sample
Ensure that the packaging of the sample is not damaged, and is well closed. When parameters
other than the peroxide value have to be investigated, the test portion for the peroxide value
shall be taken first from the laboratory sample.
Prepare the test sample in accordance with GB/T 15687.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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