UGANDA STANDARD 
        US ISO 1955
First Edition
2009-mm-dd
 
Reference numbe r 
     US ISO 1955:1982
 © UNBS 2009
  
Citrus fruits and derived products — Determination of essential 
oils content (Reference method) 
 US ISO 1955: 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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      US ISO 1955:1982  
© 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 1955, Citrus fruits and derived products — Determination of essential oils
content (Reference method), is identical with and has been reproduced from an International Standard, ISO
1955:1982, Citrus fruits and derived products — Determination of essential oils content (Reference
 method), and  adopted as a Uganda Standard.  
This standard was developed under the subcommittee on fruits and vegetables by the Food and agriculture 
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 STANDARDIZATION.MEIKjJYHAPOJJHAR OPI-AHM3ALWlR fl0 CTAHflAPTbl3AL(MM.ORGANISATION INTERNATIONALE DE NORMALISATION 
Citrus fruits and derived products - Determination of 
essential oils content (Reference method) 
Agrumes et produits dkrivks - Determination de Ia teneur en huiles essentielles (Methode de rkfkrence) 
First edition - 1982-12-01 
UDC 643.3 : 543.862 : 665.52 Ref. No. ISO 19554982 (E) 
Descriptors : agricultural products, fruits, citrus fruits, tests, determination of content, essential oh. 
Price based on 3 pages Fsreword 
ISO (the international Organization for Standardization) is a worldwide federation of 
national Standards institutes (ISO member bodies). The work of developing Inter- 
national Standards is carried out through ISO technical committees. Every member 
body interested in a subject for which a technical 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 1955 was developed by Technical Committee ISO/TC 34, 
Agriculturalfoodproducts, and was circulated to the member bodies in August 1980. 
lt has been approved by the member bodies of the following countries : 
The member body 
tech nical gro unds 
0 Australia India 
Brazil Israel 
Canada Kenya 
Czechoslovakia Netherlands 
Egypt, Arab Rep. of New Zealand 
France Peru 
Germany, F. R. Philippines 
Hungary Roland 
of the following country expressed disapproval of the document on Romania 
South Africa, Rep. of 
Spain 
Thailand 
Turkey 
USSR 
Y ugoslavia 
USA 
International Organization for Standardization, 1982 
Printed in Switzerland INTERNATIONAL STANDARD ISO 1955-1982 (E) 
Citrus fruits and derived products - Determination of 
essential oils content (Reference method) 
1 Scope and field of application 
This International Standard specifies the reference method for 
the determination of the total essential oils content of citrus 
fruits and their derived products (whole fruits, fruits tut into 
small pieces, skins, juices, concentrates, beverage bases, 
sweetened products etc.). 
2 Principle 
Boiling of a test Portion, diluted or undiluted, and steam en- 
trainment of the essential oils which are collected in a 
graduated tube; after cooling, direct reading from this tube of 
the volume of essential oils separated from the distillate. Citrus fruit juices, for example, shall be used after simply stir- 
ring; thick, pulpy or syrupy products shall be thoroughly mixed 
with an equal mass of water. 
4.1.2 Products rich in essential oils2) 
Suitably dilute the test Sample to obtain an essential oils con- 
tent of less than 0,l ml per 100 ml or per 100 g of product. 
4.1.3 Products very rich in essential oils (used as bases for 
carbonated drink# 
Mix thoroughly by diluting with water in the Proportion in- 
dicated in 4.12, operating in a high-speed mechanical mill in 
Order to avoid Separation. 
4.1.4 Whole fruits, fruits tut into small pieces, and skins 
3 Apparatus 
Grind the Sample finely and proceed as specified in 4.1.3. 
3.1 Apparatusl), for entrainment and recovery of essential 
oils, comprising a condenser and a trap terminating in a tube, 
of diameter 8 to 10 mm, graduated in 0,05 ml divisions, having 
a capacity of 4 ml. 
3.2 Flask, of capacity 3 litres, suitable for connection to the 
apparatus (3.1). 
3.3 Graduated measuring cylinders, of capacity 2 Iitres. 
3.4 Boiling aid. 
4 Procedure 4.2 Preparation of apparatus (3.1) 
Start the circulation of water through the condenser and, if 
possible, moisten the inside of the condenser with a wetting 
agent, for example sodium secondary alkylsulphate. 
Fill the trap with distilled water. If possible, immerse the trap 
itself in a large beaker of cold water during the test. 
4.3 Test Portion21 
Transfer 2 litres of the test Sample (4.11, measured by means of 
the graduated measuring cylinder (3.3) and corresponding to a 
volume V0 or a mass m of the product before dilution, to the 
flask (3.2). If necessary, add the boiling aid (3.4). 
4.1 Preparation sf the test Sample 
4.4 Determination 
NOTE - Sufficient test Sample is required to provide test portions of 
2 litres. 
4.1.1 Products having low essential oils content (less 
than 0,l ml per 100 ml or per 100 g of product) Connect the flask to the apparatus (3.1) and Start heating. 
When the liquid begins to boil, reduce the rate of heating so 
that only about one drop of distillate falls from the condenser 
per second. 
1) An apparatus of the modified Clevenger type is illustrated, for information only, in the annex. 
2) For products which are rich, or very rich, in essential oils (4.1.2 and 4.13, it is possible to reduce the volume of the test Portion to 1 litre, modify- 
ing the capacity of the apparatus and the degree of dilution accordingly. 
1 ISO 1955-1982 (El 
Allow to boil for 1 to 3 h; the essential oils accumulate in the 
trap. When the volume of essential oils has not increased for 15 
to 30 min, stop heating and allow the trap to cool. 5.1.2 Samples taken by mass 
The essential oils content, expressed 
prod uct, is given by the formula in millilitres per 100 g of 
lf possible, rinse the condenser with water from a wash-bottle, 
then bring the lower boundary of the essential oils Phase to the 
“0” mark of the graduated tube, by running out water through 
the tap. Allow the trap to drain for at least 5 min, then read the 
volume, to the nearest half-division, indicated by the upper VI -x 100 
n-l 
where 
menrscus. 
m is the mass, in grams, of product present in the test por- 
tion (4.3); 
4.5 Number of determinations 
has the same meaning as in 5.1.1. 
Carry out two determinations on the same test Sample. 
5.1.3 Result 
Take as the result the arithmetic mean of the values obtained in 
the two determinations (4.51, provided that the requirement for 
repeatability (see 5.2) is fulfifled. 5 Expression of results 
5.1 Method of calculation and formula 
5.2 Repeatability 
5.1.1 Samples taken by volume 
The differente between the values obtained in the two deter- 
minations (4.5), carried out simultaneously or in rapid succes- 
sion by the same analyst, shall not exceed 5 % (relative) of the 
mean. The essential oils content, expressed as 
volume of product, is given by the formula percentage by 
6 Test report 
The test report shall show the method used and the result ob- 
tained. It shall also mention any operating conditions not 
specified in this International Standard, or regarded as op- 
tional, as weil as any circumstances that may have influenced 
the result. V. is the volume, 
rtion (4.3); in millilitres, of product present in the 
test po 
The test report shall include all the information 
the complete identification of the sa mple. necessary for V, is the 
in 4.4. volume, in millilitres, of essential oils, measured Annex ISO 19554982 0 
Example of suitable apparatus (modified Clevenger type) 
Graduated tube - 
M 
Bulb 8 - 
- 4 ml 
3 ml 
2 ml 
1 ml Dimensions in millimetres Phis page intentionally left blank This page intentionally left blank This page intentionally left blank