UGANDA STANDARD
 
  US ISO 5566
     First Edition
        2009-09-04
 
    Reference numbe r
         US ISO 5566:1982
 © UNBS 2009
  
Turmeric — Determination of colouring power — 
Spectrophotometric method 
 US ISO 5566:1982 
 
© UNBS  2009 – All rights reserved ii Compliance with this standard does not, of itself confer immunity from legal obligations 
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2009 
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The Executive Director 
Uganda National Bureau of Standards 
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Uganda 
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      US ISO 5566:1982  
© UNBS  2009 - All rights rese rved                iii National foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 327, of the Laws of U ganda. UNBS is mandated to co-ordinate the elaboration 
of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council. 
This Uganda Standard, US ISO 5566, Turmeric — Determination of colouring power — 
Spectrophotometric method,  is identical with and has been reproduced from an International Standard, ISO 
5566:1982,  Turmeric — Determination of colour ing power — Spectrophotometric method, and adopted
as a Uganda Standard.  
This standard was developed by the Food and agricu lture Standards Technical Committee (UNBS/TC 2).  
Wherever the words, "International Standard" a ppear, they should be replaced by "Uganda Standard." 
 International Standard 
INTERNATIONAL ORGANIZATION FOR STANDARDIZATIONWlE~YHAPO~HAR OPrAHM3AlWl fl0 CTAHJJAPTM3ALWl6RGANISATION INTERNATIONALE DE NORMALISATION 
Turmeric - Determination of colouring power - 
Spectrophotometric method 
Curcuma - Determination du pouvoir colorant - Mbthode spectropho tomhtrique 
First edition - 1982-11-15 
UDC 664.59: 543.42 Ref. No. ISO 55664982 (E) 
Descriptors : turmeric, Chemical analysis, determination, colouring power, spectrophotometric analysis. 
Price based on 2 pages Foreword 
EIS0 (the International Organization for Standardization) is a worldwide federation of 
national Standards institutes (SS0 member bodies). The work of developing lnter- 
national Standards is carried out through ISO technical committees. Every member 
body interested in a subject for which a technicai committee has been set up has the 
right to be represented on that committee. International organizations, governmental 
and non-governmental, in liaison with ISO, also take part in the work. 
Draft International Standards adopted by the technical committees are circulated to 
the member bodies for approval before their acceptance as International Standards by 
the ISO Council. 
International Standard ISO 5566 was developed by Technical Committee ISO/TC 34, 
Agrieultwal food products, and was circulated to the member bodies in May 1981. 
lt has been approved by the member bodies of the following countries: 
Brazil 
Canada 
Czechoslovakia 
Egypt, Arab Rep. of 
Ethiopia 
France 
Hungary 
lndia 
Israel 
Italy Korea, Rep. of 
Malaysia 
Mexico 
Netherlands 
New Zealand 
Peru 
Poland 
Portugal 
Romania 
South Africa, Rep. of 
No member body expressed disapproval of the document. Spain 
Sri Lanka 
Tanzania 
Thailand 
Turkey 
United Kingdom 
USSR 
Yugoslavia 
International Organkation for Standardkation, 1982 
Printed in Switzerland INTERNATIONAL STANDARD ISO 55664982 (E) 
Turmeric - Determination of colouring power - 
Spectrophotom 
1 Scope and field of application 
This International Standard specifies a spectrophotometric 
method for the determination of the colouring power of tur- 
meric. 
2 Ref erences 
ISO 948, Spices and condiments - - Sampling. 
ISO 2825, Spices and condiments 
Sample for analysis. - - Preparation of a ground 
3 Definition 
colouring power of turmeric : The curcuminoids content of 
turmeric, expressed as curcumin as a percentage by mass. 
4 Principle 
Extraction of the Pigments of turmeric with hot ethanol, dilu- 
tion of the extract and spectrophotometric measurement at the 
wavelength of maximum absorption (i.e. 425 nm). 
5 Reagent 
5.1 Ethanol, 96 % (VW). 
6 Apparatus 
Usual laboratory apparatus, and in particular 
6.1 Round-bottomed extraction flask, of capacity 100 ml, 
fitted with a reflux condenser. 
6.2 Pipette, of capacity 5 mI. 
6.3 Qne-mark volumetric flasks, of capacities 100 and 
250 ml. 6.4 Spectrophotometer, suitable for making measure- 
ments of absorbance at 425 nm. 
6.5 Matched spectrophotometric cells (of silica), of op- 
tical path length 1 cm. 
6.6 Analytical balance. 
7 Sampling 
Sample the product by the method specified in ISO 948. 
8 Procedure 
8.1 Reparation of the test Sample 
Prepare the Sample by the method specified in ISO 2325. The 
degree of fineness of grinding used shall be about 500 pm. 
Ground (powdered) turmeric is analysed as received, without 
preparation, the degree of fineness usually being appropriate. 
8.2 Test Portion 
Weigh, to the nearest 0,001 g, about 0,5 g of the ground 
Sample. 
8.3 Determination 
Place the test Portion in the extraction flask (6. l), add 36 ml of 
the ethanol (5.1) and boil under reflux for 2,5 h. Allow the ex- 
tract to cool and filter qudntitatively into the 100 ml volumetric 
flask (6.3). Wash the residue on the filter thoroughly, collecting 
the washings in the volumetric flask. Dilute the contents of the 
flask to the mark with the ethanol (5.1). 
Transfer, by means of the pipette (6.21, 5 ml of the filtered ex- 
tract to the 250 ml volumetric flask (6.3). Dilute to the mark 
with the ethanol. Fill one of the spectrophotometric cells (6.5) 
with this Solution and fill the other with the ethanol. 
Measure the absorbance (R) at 425 nm using the ethanol as the 
reference liquid. 
1 ISO 55664982 (E) 
9 Expression of results 
The colouring power of turmeric, expressed as curcumin as a 
percentage by mass, is equal to 
A x D x 100 m is the mass, in grams, of the test Portion. 
NOTE - The result may also be expressed on the dry basis by means 
of the formula 
El % A x 50 x 100 x 100 
lcm’ m 1607 x rn x (100 - H) 
Ax50xloo 
= 
1607xm 
where 
A is the measured absorbance; 
D is the dilution of the extract, i.e. 
100 250 -= 
-x 100 5 50 
El % 
1 cm is the specific absorbance of a 1 % solution of cur- 
cumin measured at 425 nm in cells of Optical path length 
1 cm, i.e. 1 607; where His the moisture content of the Sample, expressed as a percen- 
tage by mass. 
10 Test report 
The test report shall show the method used and the results ob- 
tained. lt shall also mention all operating conditions not speci- 
fied in this International Standard, or regarded as optional, as 
weil as any circumstances likely to have influenced the results. 
The test report shall include all the information necessary for 
the complete identification of the Sample. 
2