GB/T 26634-2011Animal and vegetable fats and oils -- Determination of the deterioration of bleachability index (DOBI) (English PDF)

Foreword

This standard is identical with ISO 17932:2005 "Animalandvegetablefatsandoils-Determinationofthedete-riorationofbleachabilityindex (DOBI) ".

For ease of use, this standard ISO 17932:2005 includes the following editorial changes.

--- "This International Standard" by "this standard";

--- Deleted international standards foreword;

--- With a decimal point instead of the international standard as a decimal comma ",". ",";

--- Current national standard GB/T 15687 "Preparation of animal fat samples" with (GB/T 15687-2008, ISO 661.

2003, IDT) instead of ISO 661:2003 "Animalandvegetablefatsandoils-Preparationoftestsam-ple ".

The standard proposed by the National Food Authority.

This standard by the National Standardization Technical Committee OILS.

This standard was drafted. Nanjing University of Finance and Economics, Tianjin Grain and Oil Industry Co., Ltd. Long Wei.

Drafters of this standard. Yuan Jian, OILS, Yang Xiaorong, Wang Haifeng, Liao Shaohua.

Animal and vegetable fats Determination of decolorization Index (DOBI) of

1 Scope

This standard specifies the CPO decolorization Index (DOBI) measurement method.

This standard does not apply to oil contains large amounts of chlorophyll.

2 Normative references

Following standard terms of this standard reference and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 15687 animal and plant oils prepared sample (GB/T 15687-2008, ISO 661:2003, IDT)

3 Terms and Definitions

The following terms and definitions apply to this standard.

Decolorization index value DOBIvalue Determination Methods specified in this standard, the absorbance of the sample at 446nm under the ratio of absorbance at 269nm measured under.

Principle 4

After the sample is dissolved, in particular ultraviolet and visible wavelengths, the absorbance was measured with a spectrophotometer, and calculating 446nm 269nm Under absorbance ratio. It is a level for CPO refining method of determining when the oil is difficult to indicate a lower value oil DOBI Fat refining to lower Lovibond color.

5 Reagents

Warning. Note that the use of dangerous goods rules and take appropriate safety measures.

Unless otherwise indicated, the reagents used were of analytical grade.

5.1 isooctane (2,2,4-trimethyl pentane). distilled water as a reference, with 10mm cuvette at 230nm wavelength measured absorbance it should be less than 0.12, the absorbance at 250nm wavelength of less than 0.05.

If you can not meet the requirements of iso-octane, cyclohexane or n-hexane can be used to meet these requirements in place.

6 Equipment

Glass containers should be thoroughly washed before use and (5.1) rinsed with a solvent to remove possible absorption in the 220nm ~ 500nm Impurities.

In addition to conventional laboratory equipment, but also includes the following equipment.

6.1 Spectrophotometer. The best available recorders, before the recommendations in the following manner correct wavelength and absorbance.

Wavelength Calibration. according to the instrument instruction manual with mercury glass or holmium (maximum absorption peak at 287.5nm and 279.37nm) into Check the correct line. Holmium mercury or glass can be purchased from the instrument manufacturer.

Absorbance scale correction. Weigh 200mg of analytical grade potassium chromate dissolved in 1L, 0.05mol/L potassium hydroxide solution. Draw 25mL