Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 1 - MINISTRY OF THE ECONOMY  
DRAFT Official Mexican Standard PROY -NOM -173-SCFI -2008, Pre -packaged fruit juices – 
Trade descriptions, physico -chemical specifications, commercial information and test 
methods  
 In the margin is a seal bearing the national coat of arms, with the words: United Mexican 
States – Ministry of the Economy  
DRAFT OFFICIAL MEXICAN STANDARD PROY -NOM -173-SCFI -2008, PRE -
PACKAGED FRUIT JUICES. TRADE DESCRIPTIONS, PHYSICO -CHEMICAL 
SPECIFICATIONS, COMMERCIAL INFORMATION AND TEST METHODS.  
The Min istry of the Economy, through the General Directorate of Standards, on the basis of 
Articles 34 sections XIII and XXXI of the Organic Law of the Federal Public Administration; 
39 section V, 40 sections I and XII, 47 section I of the Federal Law on Metrolog y and 
Standardisation, 33 of its Regulation and 19 sections I, XIV and XV of this Ministry’s Rules 
of Procedure, hereby submits for public consultation the following Draft Official Mexican 
Standard PROY -NOM -173-SCFI -2008 “Pre -packaged fruit juices – Trade descriptions, 
physico -chemical specifications, commercial information and test methods”, to enable 
interested parties to submit their comments within 60 calendar days to the National Advisory 
Committee on Standardization for User Safety, Commercial Informa tion and Trade Practices, 
located at Avenida Puente de Tecamachalco number 6, colonia Lomas de Tecamachalco, 
Sección Fuentes, Naucalpan de Juárez, post code 53950, Mexico State, telephone 57 29 93 
00, Ext. 43222, Fax 55 20 97 15 or e -mail addresses jvazque @economia.gob.mx; 
amedina@economia.gob.mx and/or francos@economia.gob.mx, to enable them to be 
considered in the proposing committee as required by law.  
Mexico City, 14 November 2008. Director -General for Standards and Chairman of the 
National Advisory Co mmittee on Standardization for User Safety, Commercial Information 
and Trade Practices, Francisco Ramos Gómez. - Initialled .  
DRAFT OFFICIAL MEXICAN STANDARD PROY -NOM -173-SCFI -2008, PRE -
PACKAGED FRUIT JUICES – TRADE DESCRIPTIONS, PHYSICO -CHEMICAL 
SPECIFICAT IONS, COMMERCIAL INFORMATION AND TEST METHODS  
INTRODUCTION  
The following firms and institutions took part in the drafting of this draft official Mexican 
standard:  
ALMACENADORA ACCEL, S.A. DE C.V.  
ASOCIACIÓN NACIONAL DE PRODUCTORES CITRICOLAS, A.C. (Natio nal 
Association of Citrus Growers)  
ASOCIACIÓN NACIONAL DE VITIVINICULTORES, A.C. (National Association of Wine 
Growers)  
CÁMARA NACIONAL DE LA INDUSTRIA DE CONSERVAS ALIMENTICIAS 
(National Chamber for the Food Preserving Industry)  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 2 - CENTRO DE CONTROL TOTAL D E CALIDADES, S.A. DE C.V. (Total Quality Control 
Centre)  
COCA -COLA DE MEXICO, S.A. DE C.V.  
CONFEDERACIÓN DE CÁMARAS INDUSTRIALES DE LOS ESTADOS UNIDOS 
MEXICANOS (Confederation of Chambers of Industry of the United Mexican States)  
CONSEJO CITRICOLA MEXICAN O (Mexican Citrus Growers’ Council)  
CONSEJO MEXICANO DE LA INDUSTRIA DE PRODUCTOS DE CONSUMO, A. C. 
(Mexican Council of the Consumer Products Industry)  
GERBER, S.A. DE C.V.  
GRUPO JUMEX  
HECA, S.A.  
HERDEZ, S.A. DE C.V.  
JUGOS DEL VALLE, S.A. DE C.V.  
LEFI X Y ASOCIADOS  
PROCONSUMIDORES, A.C.  
PROCURADURIA FEDERAL DEL CONSUMIDOR (Federal Attorney for Consumer 
Affairs)  
Laboratorio Nacional de Pruebas (National Testing Laboratory)  
Dirección General de Verificación y Vigilancia (Directorate -General for Testing and 
Monitoring)  
SABRITAS, S.A. DE C.V.  
SECRETARIA DE SALUD (Ministry of Health)  
Comisión Federal de Protección contra Riesgos Sanitarios (Federal Commission for 
Protection against Health Hazards)  
SECRETARIA DE AGRICULTURA, GANADERIA, DESARROLLO RURAL, PES CA Y 
ALIMENTACION (Ministry of Agriculture, Livestock, Rural Development, Fisheries and 
Food)  
Dirección General de Fomento a la Agricultura (Directorate -General for Agricultural 
Development)  
SECRETARIA DE HACIENDA Y CREDITO PUBLICO (Ministry of the Treasur y and 
Public Credit)  
Sistema de Administración Tributaria (Tax Administration System)  
SIGMA ALIMENTOS, S.A. DE C.V.  
SOCIEDAD COOPERATIVA TRABAJADORES PASCUAL, S.A.  
SOCIEDAD MEXICANA DE NORMALIZACION Y CERTIFICACION, S. C. (Mexican 
Standardisation and Cer tification Company)  
UNILEVER DE MEXICO, S.A. DE C.V.  
UNIVERSIDAD DE LAS AMERICAS DE PUEBLA (University of the Americas, Puebla)  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 3 - UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO (National Autonomous 
University of Mexico City)  
Instituto de Química (Institute of Chem istry)  
Instituto de Geología (Institute of Geology)  
VALLE REDONDO, S.A. DE C.V.  
CONTENTS  
Chapter   
Objective and scope  
References  
Definitions  
Classification and trade description  
Product specifications  
Sampling  
Commercial information  
Monitoring  
Bibliography  
Concordance with international standards  
1. Objective and scope  
This official Mexican standard establishes the characteristics of processed and pre -packaged 
products and the minimum requirements that they must satisfy in order to be described as fruit 
juices, and also the commercial information that they are required to display.  
This standard applies to products marketed as fruit juices on Mexican territory.  
2. References  
This Mexican standard is complemented by the following current officia l Mexican standards 
and Mexican standards:  
NOM -002-SCFI -1993  Pre-packaged products. Net contents, tolerance and checking 
methods, published in the Official Journal of the Federation on 13 October 1993.  
NOM -030-SCFI -2006  Commercial information – Declara tion of the quantity on the 
label – Specifications, published in the Official Journal of the Federation on 6  November 
2006.  
NOM -051-SCFI -1994  General specifications for labelling pre -packaged foodstuffs and non -
alcoholic beverages, published in the Offici al Journal of the Federation on 24  January 1996.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 4 - NOM -086-SSAI -1994  Goods and services. Foodstuffs and non -alcoholic beverages 
with modified composition. Nutritional specifications, published in the Official Journal of the 
Federation on 26  June 1996.  
NOM -130-SSA1 -1995  Goods and services. Foodstuffs packaged in hermetically sealed 
containers and subjected to heat treatment. Health provisions and specifications, published in 
the Official Journal of the Federation on 21 November 1997.  
NMX -F-103-1982  Foodstu ffs – Fruit and derivatives – determination of degrees Brix. 
Declaration of validity published in the Official Journal of the Federation on 14  October 
1982.  
NMX -F-309-NORMEX -2001  Determination of benzoates, salicylates and sorbates in 
foodstuffs. Declara tion of validity published in the Official Journal of the Federation on 26 
July 2001.  
3. Definitions  
For the purposes of this standard, the following definitions shall apply:  
3.1 Adulteration  
Product of a nature not matching its labelling, advertising,  sale or supply or the authorised 
specification, even where it has been processed to conceal those circumstances or conceal 
defects in processing or the health quality of the raw materials used in it.  
3.2 Citrus fruit  
Fruit of the Rutaceae family that is  damaged at low temperatures, characterised by oils and 
pigments in the peel.  
3.3 Sound fruit  
Fruit free of disease, cuts, rot, damage by inspects or other pests, containing no live or dead 
inspects or larvae thereof.  
3.4 Ripe fruit  
Fruit that is in se ason or at maturity.  
3.5 Degrees Brix  
Percentage of solids dissolved in a product derived from fruit or a liquid of sugar.  
3.6 Fruit juice  
The unfermented but fermentable liquid product obtained by pressing fully ripened and fresh 
fruit in good conditi on, or fruit that has been kept in good condition using appropriate 
procedures, including surface treatments applied after harvesting, clarified or otherwise, and 
subject to appropriate treatment to ensure that it is preserved in the packaging. It must not  
contain peel or seeds or inadmissible foreign material.  
Juice must be prepared using procedures that preserve the essential physical, chemical, 
organoleptic and nutritional properties of the original fruit. Pulp and cells obtained by means 
of physical pr ocesses appropriate to the type of fruit may be added. In the case of citrus fruit, 
the pulp and cells are the juice sacs obtained from the endocarp.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 5 - This product may be made from frozen fruit juice and/or reconstituted concentrated fruit 
juice, provided that it meets the specifications laid down in this standard.  
3.7 Concentrated fruit juice  
Fruit juice from which water has been physically removed in an amount sufficient to raise the 
Brix level to a value of at least 50% greater than the Brix value esta blished for the liquid 
product obtained by pressing  healthy and ripe fruit that has been subjected to physical 
treatment or stored under appropriate conditions that ensure it is preserved in the container. It 
must not contain peel or seeds or inadmissible foreign material.  
3.8 Juice of multiple fruits (mix)  
A blend of two or more liquid products obtained by pressing  healthy and ripe fruit of the 
relevant variety, clarified or not, unfermented and suitably treated to preserve it in the 
container. It must n ot contain peel or seeds or inadmissible foreign material.  
This product may be produced by blending two or more frozen juices and/or purées, and/or 
concentrated juices and/or purées reconstituted from various kinds of fruit.  
Juice must be prepared using procedures that preserve the essential physical, chemical, 
organoleptic and nutritional properties of the original fruit. Pulp and cells obtained by means 
of physical processes appropriate to the type of fruit may be added. In the case of citrus fruit, 
the pulp and cells are the juice sacs obtained from the endocarp.  
3.9 Frozen juice  
Fruit juice that has undergone a thermal treatment by means of appropriate equipment until 
the product reaches a temperature of -15°C at the thermal centre.  
3.10 Pre -package d products  
Foodstuffs and non -alcoholic beverages packaged in a container of any kind in the absence of 
the consumer, where the quantity of product contained cannot be altered without opening or 
altering the container in a noticeable way.  
3.11 Fruit pulp   
The fleshy and often juicy mass of the fruit (insoluble solids). In the case of citrus fruit, the 
pulp consists of a considerable number of segments full of juice.  
3.12 Fruit purée  
The fermentable but unfermented product obtained by appropriate procedu res, such as 
sieving, crushing or crumbling the edible part of whole or peeled fruit without removing the 
juice. The fruit must be in good condition, fully ripened and fresh, or preserved by means of 
physical procedures or treatments applied in accordance with the relevant provisions of the 
competent authority.  
3.13 Concentrated fruit purée  
The product obtained by physical removal of a sufficient quantity of water from fruit purée to 
raise the Brix level to a value at least 50% greater than the Brix value  established for juice 
reconstituted from the same fruit.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 6 - 3.14 Dissolved fruit solids  
Soluble solids from fruit, quantified in degrees Brix.  
4. Symbols and abbreviations  
°Bx degrees Brix  
% per cent  
g gram  
mg milligram  
µg microgram  
kg  kilogram  
L or l  litre  
mL or ml  millilitre  
µL or µl  microlitre  
mm  millimetre  
cm   centimetre  
m3  cubic metre  
GMP  good manufacturing practice  
pH  hydrogen potential  
m/v  solids/total volume  
m/m  mass/mass  
13C  total number of atoms of carbon -13  
12C  total number of atoms of carbon -12  
13C  delta carbon 13  
VPDB  Vienna Peedee  belemnite  
‰  parts per mille  
g  acceleration of gravity  
mol  mole  
rpm  revolutions per minute  
h  hour  
min  minute  
s  second  
°C  degrees Celsius  
K  Kelvin  
Pa  pascal  
kPa  kilopascal  
mbar  millibar  
amu  atomic mass unit  
σ standard deviation  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 7 - 5. Classification and trade description  
5.1 Juices  
Juices covered by this standard shall be described with the same character size in accordance 
with the following.  
5.1.1 Fruit ju ices as defined in 3.6 shall be described as follows:  
__________ JUICE  
The name of the fruit concerned shall be written in the blank space.  
5.1.2 Concentrated fruit juices as defined in 3.7 shall be described as follows:  
CONCENTRATED ____________ JUICE   
The name of the fruit concerned shall be written in the blank space.  
5.1.3 Juices of multiple fruits as defined in section 3.8 shall be described as follows:  
5.1.3.1 Where juice of multiple fruit consists of a blend of two fruit juices, it shall be 
described as:  
__________ JUICE  
The name of the two fruits concerned shall be written in the blank space, beginning with the 
one of higher content.  
5.1.3.2 Where the blend consists of juices and/or purées of three or more fruit it shall be 
described as:  
__________ JUICE  
The name of the fruit concerned shall be written in the blank space.  
6. Product specifications  
6.1 Juices  
6.1.1 Sensory characteristics  
Colour:  Characteristic similar to the variety used.  
Smell:  Characteristic of the juice concerned.  
Taste:  Characteristic of the juice concerned, without off -flavours.  
It must not contain peel or seeds or inadmissible foreign material.  
6.1.2 Physical and chemical properties  
Juices covered by this standard must comply with the physical and chemical sp ecifications set 
out in Table 1.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 8 - Table 1  
Specifications for juices and reconstituted concentrated juices  
Parameter  Orange  Mandarine  Apple  Grapefruit  Pineapple  Grape  Multiple 
fruits  Test 
methods  
* Minimum 
dissolved 
solids of the 
fruit 
concerned 
(°Brix)  11.2 11.8 11.5 10 12.8 16 10 Ref. 
section 
8.1 and 
NMX F -
103-1982  
Isotope ratio 
of carbon 
(13C/12C), 
expressed in 
13CVPDB 
(‰).  <-24 to -
28 -24 to -28 --24 to 
-28 --24 to -28 N.A.  --24 to 
-28  Ref. 
section 
8.1  
* This specification shall be complied wit h even if the product composition is altered.  
N.A.: Not applicable  
It is prohibited to add both sugars and acidifying agents to the same fruit juice since it is 
regarded as an adulteration of the composition of the product, as established in the Codex 
Alimentarius.  
Note : Where a juice comes from a fruit not mentioned in this table, the minimum Brix level 
of the fruit shall be as laid down internationally by the Codex Alimentarius.  
**Additives for Table 1  
Permitted additives and preservatives shall be t hose referred to in NOM -130-SSA1, Goods 
and services. Foodstuffs packaged in hermetically sealed containers and subjected to heat 
treatment. Health provisions and specifications.  
7. Sampling  
For official purposes, sampling shall be subject to the applica ble statutory and regulatory 
provisions.  
8. Test method  
Determination of the addition of cane sugar or corn syrup using the carbon isotope ratio 
(13C/12C) in sugars from fruit of C 3 plants using stable -isotope mass spectroscopy.  
8.1 Objective and field of application  
This methodology aims to quantify the addition of exogenous industrial sweeteners such as 
those listed in CODEX Standard for Sugars CODEX STAN 212 -1999 amendment 1 -2) to the 
various classifications of industrial fruit juices from C3 plants,  produced from sound and ripe 
fruit or prepared from fruit concentrates obtained by means of an industrial process for 
removing the water contained in the juices. This method is not applicable to pineapple juice.  
The following exogenous sugars may be cons idered: cane sugar, corn syrups with a high 
fructose or glucose content.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 9 - 8.2 Basis  
The method is based on determining the carbon isotope ratios (13C/12C) using stable -isotope 
mass spectrometry, expressed as the quotients of the abundances of stable carbo n-12 and -13 
atoms as (13C/12C) using 13CVPDB units (‰), which are referred to an international standard 
that is physically a calcium carbonate (CaCO 3) of marine origin, taken from the Peedee 
cretaceous formation in South Carolina, known as PDB (Peedee belemnite limestone). The 
repor ting unit is , expressed in parts per mille (‰), in accordance with the following 
equation (Craig, 1957):  
∂13CVPDB=(13C/12C)Sample
(13C/12C)VPVD−1 
   
  •103 Eq. 1  
The bodies internationally responsible for establishing, maintaining and developing the 
metrology of stable isotopes a re the International Union of Pure and Applied Chemistry 
(IUPAC), Commission on Isotopic Abundances and Atomic Weights (CIAAW); IUPAC has 
designated the Subcommittee on Isotope Abundance Measurements (SIAM) as operationally 
responsible for the metrology of  stable isotopes, which is composed of a group of experts who 
publish reports and issue metrological recommendations on isotopic abundances and atomic 
weights. At its recent meeting in the context of the 43rd General Assembly of the IUPAC that 
took place i n August 2005 in Beijing, China, it made the following recommendations: that 
delta carbon -13 values of all carbon -bearing materials be measured and expressed relative to 
VPDB (Vienna Peedee belemnite), b) the VPDB scale be normalised using the reference 
materials NBS -19 and L -SVEC by assigning the consensus values of 13CVPDB = -46.6‰ 
relative to L -SVEC lithium carbonate and 13CVPDB = +1.95‰ relative to NBS 19 calcium 
carbonate. c) authors analysing these materials should clearly state so in their reports.  
(Coplen, T et al 2006).  
8.3 Principle of the method  
All organic compounds forming living beings contain the chemical element carbon. Two 
stable carbon atoms exist in nature that differ among themselves only in their atomic mass, all 
their other chemical  properties being identical. These atoms are known as isotopes and are 
represented as carbon -13 (13C) and carbon -12 (12C).  
The proportion of stable isotopes (13C/12C) contained in foodstuffs is typical and set mainly 
by their origin or provenance and to a  much lesser extent by the industrial processes they 
subsequently undergo. The original isotope proportion is generally maintained, which enables 
us to identify their source.  
The basis of the method consists of relating the quantity of stable isotopes of a given product , 
expressed in delta units,  to the corresponding photosynthesis cycle of the plant from which 
the raw material originates. The reason for this is that plants have three different 
photosynthesis mechanisms for fixing atmospheric CO 2.  
The var ious types of origin of plants are established on the basis of photosynthesis, and are 
classified in three main groups depending on the photosynthesis process they use to fix 
atmospheric CO 2, namely: type C 3 plants which use the Calvin cycle, type C 4 plant s which 
follow the Hatch Slack cycle and Crasulacean acid metabolism (CAM) plants.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 10 - In nature, the Calvin cycle is used by type C 3 plants; members of this photosynthesis cycle are 
trees, shrubs and some fruits such as: apple, pear, peach, banana, grape, ma ngo, guava, plum, 
apricot, cherry, bilberry, orange, grapefruit, mandarine, lemon, tomato, etc. The vast majority 
of industrially -produced juices and nectars are extracted from these fruits.  
In nature, the Hatch Slack cycle is used by C 4 plants, such as s ugar cane and maize. Plants of 
this type are used to make industrial sweeteners such as cane sugar and corn syrup with a high 
fructose or glucose content; such sweeteners are mostly used as exogenous sugars for adding 
to juices and nectars.  
The third grou p of plants is called Crasulacean Acid Metabolism (CAM). This group contains 
agaves, vanilla and plants such as the pineapple.  
There is a considerable and measurable difference in the proportion of stable 13C isotopes 
(13C/12C) contained in plants of gro ups C 3 and C 4. Therefore, by measuring it in juices or 
concentrated juices it is possible to identify the photosynthesis process of the original plant 
and quantify the blend, if any.  
The proportion of a blend of sugars from C 3 plants with C 4 plants (exoge nous sugars from 
cane sugar or corn syrup) can be quantified using a linear proportion constructed by taking as 
extremes the 13C isotope composition of the exogenous sugars and the 13C isotope 
composition of the soluble solids contained in the fruit juic e.  
8.4 Description of test method  
The 13CVPDB is determined in a stable -isotope mass spectrometer using the CO 2 obtained 
from the combustion of the main organic material contained in a sample of juice such as 
dissolved solids and pulp. The results obtai ned from both are reported as 13CVPDB expressed 
as ‰ evaluated in accordance with equation 1.  
To carry out the analysis,  an aliquot of juice is taken and the pulp and dissolved solids are 
separated out mechanically (by centrifuging); once the organic mat erial has been separated it 
is oxidised by quantitative combustion to form mainly CO 2 and H 2O. The CO 2 produced by 
the oxidation reaction is purified by means of a cryogenic separation process and using 
vacuum systems as per section 8.7.2.1.1) or a separat ion process using a chromatography 
column such as an elemental analyser for separating the N 2 from the CO 2.  
International literature reports three basic quantitative combustion methods. The first uses 
dynamic combustion. The second method is the most accu rate of the three  and uses high -
temperature  combustion in a sealed quartz tube; the combustion products are taken to a 
vacuum line where the CO 2 is separated and purified quantitatively; the vacuum line has been 
purpose -designed for this method; the 13CVPDB is determined using the CO 2, cryogenically 
purified using the spectrometer’s dual gas inlet system. The third method is a fast quantitative 
combustion and purification system using an elemental analyser and the continuous flow 
technique with helium with  an interface that leads the CO 2 from the sample to the stable -
isotope mass spectrometer for determining the 13CVPDB.  
8.5 Instrumentation  
The equipment needed to implement this method is a mass spectrometer to determine stable -
isotope ratios with the analysis capability to determine t he 13CVPDB in the range of natural 
abundances in CO 2 with an internal accuracy of the order of 0.02‰ (defined here as the Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 11 - difference between two consecutive measurements of isotope ratios of a CO 2 sample) and is 
the external accuracy of 0.05‰ (expressed i n delta values – Eq 1). The linearity must be 
< 0.05‰ per nanoampere of ion current. While the spectrometer is operating, the plateaus of 
the peaks for universal CNOS collector must be m/ Δm = 95 (10% trough).  
The mass spectrometer must be capable of carry ing out isotope determinations by 
simultaneously reading molecular masses 44, 45 and 46 amu. The spectrometer must have a 
dual sample inlet system for simultaneous determinations between the sample gas and the gas 
of a calibration standard. The dual -inlet method is intrinsically more accurate. However, 
specific instrumentation has been developed to connect an elemental analyser and an analysis 
method has been devised for it that uses a continuous flow of helium to transport the CO 2 
combustion product into t he isotope -ratio mass spectrometer. The results of this technique are 
just as reliable, but it requires a set of aliquots of reference materials to be analysed in series 
with the samples.  
Where the elemental analyser (EA) is used in line with the stable -isotope mass spectrometer, 
the EA must be connected directly to the spectrometer by means of an interface specially 
designed for this method. The EA must be capable of handling both the combustion gases 
from the sample or reference materials and the gas use d as a calibration standard at the same 
time. The EA must also be capable of quantitatively converting all the carbon in the sample 
into carbon dioxide and of eliminating the other combustion products of the sample, 
principally oxides of nitrogen, oxides o f sulphur and water.  
8.6 Other equipment needed for the method  
Centrifuge for physically separating the dissolved solids of the fruit and the pulp; a centrifuge 
must be used with a rotor of 45o. for six centrifuge tubes with a volumetric capacity in each  
arm of at least 50  ml with a force of at least 1400 G.  
Electric grill with magnetic stirrer: with temperature control and stirring control.  
Drying oven with a temperature of 50°C to 60°C.  
Hand refractometer for determining °Brix.  
Sample preparation as  described in section 8.7 is applicable to all types of juices, whether in 
fresh natural form or in commercial presentations. Concentrated juices must be diluted to 50% 
with distilled water. The procedure is as follows.  
8.7 Procedures  
8.7.1 Preparing the  sample  
8.7.1.1 Reagents and materials  
Only the following analysis -grade reagents must be used to prepare the sample:  
• Calcium hydroxide {Ca(OH) 2}, analysis grade. A 25% solution is prepared with grade 
III water.  
• Sulphuric acid (H 2SO 4) 95-97%, analysis grade. Concentration 1M  
• Water of at least grade III as per EN ISO 3696:1995  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 12 - • pH paper  
• Centrifuge tubes, 40 ml or 50 ml  
• Graduated pipettes, 10 ml  
• Propipette  
• Precipitation beaker, 100 ml  
• Precipitation beaker, 1 l  
• Agate mortar and pestle  
8.7.1.2 Proce dure for separating and preparing soluble solids (sugars) and insoluble solids 
(pulp) for isotope analysis  
To physically separate the constituents of a juice into dissolved solids and pulp, take 50 ml of 
juice of any specification and place in a centrifug e tube, centrifuging at 1400 g for 
10 minutes.  
a) Preparing soluble solids (sugars) for isotope analysis  
• After centrifuging as above the soluble solids are contained in the supernatant, so this 
supernatant is decanted and 10 ml of it is placed in a 100 m l precipitation beaker.  
• Add 25% calcium hydroxide solution until the pH is adjusted to between 8.5 and 9. 
Heat the mixture in a bain -marie at 90°C for 10 minutes while stirring.  
• The organic acids, amino acids and other components are precipitated in this  step; 
centrifuge the solution for 10 minutes at 1400 g to separate them.  
• Decant the supernatant and place it in a 100 ml precipitation beaker, acidify with 1M 
H2SO 4 until the pH is 5, namely approximately when the solution changes colour and 
check the pH  by placing a drop of the solution onto pH paper, being careful not to 
bring the paper into contact with the sample.  
• Refrigerate at 4°C for 12 hours and decant the supernatant liquid.  
• Take an aliquot of supernatant for 13C isotope analysis. The approximate 
concentration in °Brix of the dissolved solids containing mainly the sugars of the juice 
can be measured with a hand refractometer.  
b) Preparing insoluble solids (pulp)  
The insolub le solids (pulp) obtained from the first centrifuging are precipitated on the bottom 
of the centrifuging tube, are separated and prepared as follows:  
• The pulp is washed with hot distilled water at 90°C in the centrifuging tube, and is 
centrifuged for a fu rther 10 minutes at 1400 G. The supernatant is decanted and 
broken up; this step should be repeated five times.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 13 - • The pulp is washed a second time, with 40 ml of acetone, is centrifuged for 10 
minutes at 1400 g; the supernatant is decanted and broken up (th is step should be 
repeated at least twice). Once the pulp has been washed with water and acetone, it is 
freeze -dried or may be dried in an oven at 60°C –80°C for a whole night.  
• The dry pulp is homogenised, pulverising it in an agate mortar.  
• Weigh out an a liquot of pulp to determ ine the 13C.  
8.7.2 Techniques for combustion of samples of dissolved solids or pulp from the juice 
samples for subsequent determination of 13CVPDB in the stable -isotope mass spectrometer  
8.7.2.1 Purpose of combustion  
The purpose of the various combust ion techniques is to transform quantitatively the carbon 
from the organic material (dissolved solids or pulp) prepared as per 8.7.1.2 a) and 8.7.1.2 b) 
from the juice samples with carbon dioxide CO 2. After combustion and subsequent separation 
of the other combustion products, the carbon dioxide CO 2 is purified to measure their 
13CVPDB in the stable -isotope mass spectrometer.  
Two methods of quantitative combustion of the organic material can be used, the first method 
uses a sealed quartz tube, combustion of the gases produced taking place at a temp erature of 
950°C; the CO 2 is separated and purified and the pure CO 2 is passed into the dual gas inlet 
system of the stable -isotope mass spectrometer. The second combustion and purification 
method uses an elemental analyser connected in line with the mass spectrometer.  
A detailed description of each method is given below.  
8.7.2.1.1 Combustion in quartz tube  
Reagents and materials for combustion in quartz tube  
• Reference materials: see Table 2.  
• Tank of CO 2 with minimum purity 99.995% in a 7 l cylinder, c ontained in a metal 
tank at a maximum pressure of 5860 kPa at 294 K (21ºC) with a two -stage regulator 
having a delivery pressure of 5.0 ml/minute, to operate with cylinders having a 
maximum pressure of 100 kPa. For use as a calibration standard in the isot ope-ratio 
mass spectrometer.  
• Cupric oxide wire, analysis reagent grade. The cupric oxide is passed through a 40 
gauge mesh to remove the dust. It is then burned in a muffle at 850°C for three hours 
to oxidise all the organic material it contains.  
• Silver,  99.9994% pure. It is rolled to a thickness of 0.1 to 0.4 mm and cut into sections 
1 mm wide and 7  mm long. The sections are cleaned in 1% nitric acid solution and 
then washed in distilled water and heated in a muffle at 400°C for one hour. The silver 
is used as a catalyst in the combustion tube.  
• Activated metallic copper (granules) analysis reagent grade  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 14 - • A gas -oxygen blowtorch capable of reaching the melting temperature of quartz, for 
sealing the quartz tubes  
• A tank of industrial oxygen, with regulator and valves for use with the blowtorch  
• Butane gas for domestic use, with tubing for use with the blowtorch  
• Dry ice  
• Absolute industrial ethanol, 95% alcohol by volume  
• Liquid nitrogen  
• High vacuum grease, type Apiezon N or M  
• Pointed -nosed tweezers and st ainless -steel spatula for handling 10 mg samples  
• Industrial hot -air dryer capable of reaching 500°C, with 1500 rpm squirrel -cage fan  
• Laboratory screw clamps of various sizes  
• Tesla generator for detecting leaks in glass vacuum systems  
• Quartz tube, exter nal diameter 9 mm, internal diameter 7 mm and 20 cm long, sealed 
at one end with a blowtorch. For use as a combustion tube.  
• Quartz tube, external diameter 6 mm, internal diameter 4 mm and approximately 2 cm 
long, sealed at one end with a blowtorch. Used t o keep the cupric oxide separate from 
the metallic copper and as a container for solid organic samples.  
• Quartz tube, external diameter 4 mm, internal diameter 2 mm and approximately 2 cm 
long, with a point at one end for use as a capillary tube to contain  samples of organic 
liquids.  
• Quartz tube, external diameter 4 mm, internal diameter 2 mm and approximately 2 cm 
long; a silver filament 1 mm x 7 mm long is placed inside and both ends are sealed 
leaving a small hole to support the silver filament.  
• All th e quartz apparatus used in this method is placed in a muffle at 600°C for one 
hour to remove any particles of organic matter; once purified it is kept in containers 
and must be kept in a drying oven between 40°C and 60°C to drive out any moisture.  
• Pyrex g lass flasks with high -vacuum valve and Teflon or glass piston. These flasks are 
used to transport the CO 2 from the sample preparation line to the inlet system of the 
isotope -ratio mass spectrometer.  
• Pyrex glass thermos flasks of various sizes (1, 1/2 and 1/4 l) for liquid nitrogen.  
• 50 litre stainless -steel thermos flask for holding liquid nitrogen.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 15 - • Ultra -Torr vacuum unions size 3/8, part number SS -6-UT-6 and gas filter 
SS4VCR25M.  
• A system is required to break the quartz tube containing the CO 2 gas from the sample; 
it is made up of the following parts: a) an Ultra -Torr vacuum reducer size 1/2 to 1/4, 
part number SS -8-UT-6-4, b) flexible vacuum tube size 1/2, part number 321 -8X-1, c) 
two stainless -steel cones 304 -8-XOA, d) one Ultra -Torr vacuum reducer siz e 1/2 to 
3/8 and one gas filter SS4VCR25M. The equipment in this paragraph is for a single 
breaker. (Vacuum unions: Swagelok Companies). Described in the article by 
DesMaris and Hayes, 1976.  
• Micropipettes of various volumes: 0 to 200 µl; 0 to 50 µl and 0 to 10 µl with 
removable plastic tips.  
Equipment needed to achieve combustion in a quartz tube  
• Muffle. The combustion of the organic material in a sealed quartz tube takes place in a 
muffle with a maximum operating temperature of 1100.0ºC equipped with a digital 
temperature control with an error not exceeding ± 5ºC and a time control with a 
resolution of 1 minute.  
• Vacuum line 1. For de -gassing the samples. Fitted with two vacuum pumps with a 
throughput of 4 m3/h and a diffusing pump with a liquid nitrogen  trap with a 
throughput of 100 l/s capable of reaching a pressure of 0.1 Pa or 10-4 mbar.  
• Vacuum line 2. For cryogenic purification of the samples. Fitted with two vacuum 
pumps with a pumping capacity of 4 m3/h and a diffusing pump with a liquid nitrogen 
trap with a pumping rate of 100 l/s capable of reaching a pressure of 0.1 Pa or 10-4 
mbar.  
• Analysis balance: capacity 200 g, precision 0.1 mg.  
• Drying oven. That maintains a constant temperature. Maximum variation ± 0.1 
degrees Celsius achieved by a measu ring and control system based on a thermocouple 
over a temperature range of 50°C –60°C.  
Preparation and packaging of the material and the sample for combustion in a sealed 
quartz tube   
a) Preparing the combustion tube. The quartz tube is heated to 600°C an d 3 g of cupric oxide 
and a small capillary with a filament of silver are placed inside. The whole assembly is heated 
for one hour at 600°C in a muffle to eliminate any remaining organic material. The prepared 
tubes are stored in a sealed glass container i n an oven at 40° -60°C that maintains a constant 
temperature varying no more than ±1.0 degrees Celsius.  
b) Preparing samples of dissolved sugars of pulp from juices, nectars and juice concentrates 
for isotope analysis. Proceed as per 8.7.1.2 a) and 8.7.1.2  b).  
c) Take between 40 and 90 µl of dissolved solids or 8 -10 mg of dry pulp and place in a small 
6 mm external diameter quartz tube and place upside down in the 9 mm external diameter 
quartz combustion tube containing CuO, the silver filament and the sam ple; finally add 3 g of Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 16 - metallic copper with a funnel. The sample is combusted using the oxygen released by the 
cupric oxide; the silver acts as a catalyst for the reaction while the metallic copper allows the 
oxides of nitrogen to convert into N 2 at a tem perature of 650°C.  
d) The combustion tubes prepared as per the previous paragraph are placed in the vacuum line 
using an Ultra -Torr 3/8" union. The samples are freeze -dried at a pressure of 1.33 Pa and are 
finally evacuated until a pressure of 0.133 Pa is  reached, whereupon the quartz tube is sealed 
with a high -temperature blowtorch.  
e) Every time a set of samples is prepared for 13C isotope analysis, at least two 
internationally agreed reference materials are prepared, such as: NBS22 (5 µl), IAEA -CH-7 
(4 mg) or IAEA -CH6 (8 mg) for calibrating the mass spectrometer.  
Combustion  
The samples in their respective sealed quartz tubes are heated up to 900ºC and maintained at 
temperature for two hours in a muffle, after which the temperature is lowered to 650ºC  and 
maintained at that level for one hour. The tubes are then allowed to cool slowly until they 
reach ambient temperature.  
Cryogenic purification of CO 2  
The CO 2 combustion product of the sample is separated and purified cryogenically, beginning 
by separ ating the water by means of a cooling mixture (a mixture of dry ice and 80% alcohol 
or acetone). For purification another trap is used cooled with liquid nitrogen ( -190ºC) that 
traps the CO 2 while the non -condensable gases are removed with a vacuum line.  
The flasks of purified CO 2 are placed in the automatic dual gas inlet system of the stable -
isotope mass spectroscope to determine the 13C of the samples.  
8.7.2.1.2 Method for combusting samples of dissolved solids or pulp using an elemental 
analyser coupled to a stable -isotope ma ss spectrometer.  
Reagents and materials   
• Tin capsules, 5 mm x 9 mm  
• Microspatula  
• Tweezers  
• Micropipette with volume variable from 0 to 10 µl with removable plastic tips  
• Reference materials  
• The materials used for correct operation of the elemental analy ser are described in the 
manuals of the respective manufacturers of the equipment.  
• Helium, 99.999% pure or helium, 99.995% pure with purification traps for water and 
hydrocarbons.  
• Oxygen, 99.996% pure  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 17 - • CO 2, 99.995% pure  
• N2, 99.999% pure  
Equipment  
• Micr obalance with a capacity of 5 g, sensitivity 1.0 µg  
• Elemental analyser and interface: see section 8.5 “Instrumentation”  
• Stable -isotope mass spectrometer: see section 8.5 “Instrumentation”  
8.7.3 Obtaining 13CVPDB results for CO 2 produced by any of the c ombustion methods.  
The CO 2 resulting from combustion of the samples of dissolved solids and/or pulp described 
in sub -sections 8.7.1.2 a) and b) is used to determine the 13C/12C isotope ratios using a mass 
spectrometer with the characteristics described in  section 8.5.  
The isotope ratios are determined with the isotope species 13C16O16O/12C16O16O from the 
corresponding intensities of molecular ion clusters of mass 44 and 45 amu corrected for 17O 
content as per Santrock et al 1985.  
8.7.4 Obtaining 15NAIR results for N 2 from organic material produced by any of the 
combustion methods and reduction with metallic copper.  
Using the elemental analyser, the oxides of nitrogen obtained from combustion of the pulp are 
converted to N 2 by reduction with meta llic copper. The spectrometer parameters must be 
programmed to obtain the isotope analysis of N 2 produced by the pulp used to determine the 
isotope ratios of 14N/15N by means of a mass spectrometer with the characteristics set out in 
section 8.5.  
The isot ope ratios are determined using isotope species 14N14N/14N15N from the corresponding 
intensities of the molecular ion clusters of mass 28 and 29 uma .  
8.7.5 Calculations  
The recording unit  is the system of units most commonly used to indicate the isotope 
content. The  values are used to indicate variations in isotope abundance.  
The 13C of a compound is expressed by means of the isotope ratios of the sample with the 
isotope ratio of the standard in accordance with equation 1 in parts per mille (‰).  
∂13CVPDB=(13C/12C)Sample
(13C/12C)VPDB−1 
   
  •103 (Eq. 1)  
Where 13C is expressed by the quotients of the stable isotopes (13C/12C) of the sample in 
relation to the international standard VPDB which is a carbonate of marine origin from the 
Peedee cretaceous formation in South Carolina (Craig, 1957). Its absolute isotope ratio is 
(13C/12C)PDB = 0.0112372. This value is the reference point on the PDB scale of  calculated 
using equation 1 (Eq. 1).  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 18 - The stable -isotope mass spectrometer gives the result of each analysis, directly in 13C units 
including various corrections in the result, including corrections due to pressure, parasite 
masses, memory effect, residual gas, mixture of gases owing to valve cha nges and isotope 
abundance (Mook, W.G. and Grootes P.M. 1973).  
As mentioned previously the result given by the spectrometer will be on the VPDB scale if, 
and only if, the CO 2 used as an internal standard is previously calibrated in relation to VPDB. 
Howev er, to comply with the IUPAC recommendation of 2005, the result of the 13C analysis 
is subsequently normalised using the L -SVEC and NBS 19 scale, and the normalisation is 
verified using at least three of the reference materials in table 2, with the sole requirement that 
they cover the measurement scale of the samples concerned.  
In the case of fruit juices, the reference materials may be IAEA -CH7 (polyethylene), NBS -22 
(oil) and IAEA -CH6 (sucrose). Both normalisation and verification are carried out using a 
least-squares reg ression in which the experimental results obtained from the isotope -ratio 
mass spectrometer are plotted on the “x” axis and on the “y” axis the values of 13CVPDV 
assigned to each of the reference materials shown in table 2. The linear correlation coeffici ent 
R2 may not be less than 0.9999. For example, a calibration equation resulting from this 
normalisation might be: 13CVPDB = 1.004* 13CVPDB(experimental)  + 0.06. Based on this verified 
calibration the final result of the value of 13CVPDB normalised in a ccordance with the IUPAC 
recommendation of 2005.  
In the same way as for carbon, IUPAC recommends that the isotope ratio of any material 
containing nitrogen should be measured and expressed in d15NAIR which is calculated by the 
quotients of the stable isot opes (15N/14N) of the sample relative to the international standard, 
namely air, in accordance with equation 2, the reporting units being parts per mille (‰). In 
the same way as for carbon, normalisation  is carried out using USGS 24; USGS 25 is used to 
verify the scale of d15NAIR as in the previous example based on the reference materials in table 
2.  
∂15NAIR=(15N/14N)Sample
(15N/14N)AIR−1 
   
  •103 (Eq. 2)  
8.7.6 Reference materials  
The reference materials in Table 2 have been approved by the IUPAC Subcommittee on 
Isotope Abundanc e Measurements (SIAM) and are acquired from the International Atomic 
Energy Agency (IAEA) or the National Institute of Standards and Technology (NIST).  
The reference materials for calibrating CO 2 to be used as a calibration standard and to 
determine 13CVPDB and 18OVPDB are NBS -19, L -SVEC and NBS -18 which are prepared 
using the technique by J. M. McCrea (1950) and normalised as per Tyler Coplen, 1988 and 
2006.  
A tank of calibrated CO 2 or N 2 may be u sed, such as those made by Oztech Trading 
Corporation.  
Table 2  
Reference materials  13CVPDB. (‰) ± σ 15NAIR (‰) ± σ 
NBS-19 calcium carbonate  +1.95   Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 19 - L-SVEC lithium carbonate  -46.6  
NBS-18 calcium carbonate  -5.01 ± 0.06   
IAEA -CO-1 calcium carbonate  +2.49 ± 0.06   
IAEA -CO-8 calcium carbonate  -5.76 ± 0.06   
IAEA -CO-9 barium carbonate  -47.32 ± 0.06   
NBS-22 oil  -30.03 ± 0.09   
IAEA CH7 polyurethane  -32.15 ± 0.1   
USGS24 graphite  -16.05 ± 0.07   
IAEA CH6 sucrose  -10.45 ± 0.09   
USGS40 L -glutamic acid  -26.39 ± 0.08  -4.52 ± 0.12  
USGS41 L -glutamic acid  +37.63 ± 0.1  +47.57 ± 0.22  
IAEA -CH3 cellulose  -24.72 ± 0.08   
IAEA -600 caffeine  -27.77 ± 0.09  +1 ± 0.2  
IAEA -601 benzoic acid  -28.81 ± 0.09   
IAEA -602 benzoic acid  -28.85 ± 0.09   
IAEA -N1 (NH 4)2SO 4  +0.43 ± 0. 07 
IAEA -N2 (NH 4)2SO 4  +20.32 ± 0.09  
IAEA -NO-3 KNO 3  +4.69 ± 0.09  
USGS32 KNO 3  +180  
USGS34 KNO 3  -1.8 ± 0.2  
USGS35 KNO 3  +2.7 ± 0.2  
USGS 25 (NH 4)2SO 4  -30.25 ± 0.38  
USGS 26 (NH 4)2SO 4  +53.62 ± 0.25  
 
Accuracy  
The accuracy of the method for a particu lar juice can be derived from the results obtained via 
a validations study of the method carried out between several laboratories. The results of the 
validation can be found in European standards ENV 12140 and ENV 13070.  
Repeatability (of measurement resu lts)  
This is defined as the closeness of agreement between the results of successive measurements 
of the same parameter, carried out applying all the same conditions, i.e. in two analyses for 
the same sample, the same measuring instrument used under the s ame conditions, in the same 
place and repeated with a short period of time.  
The isotope analysis of 13CVPDB in organic material has a repeatability as follows:  
For dissolved solids the repeatability limit is 0.21‰.  
For pulp the repeatability limit is 0.38‰.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 20 - This means that if a sample were sent to the laboratory again for a 13CVPDB analysis, there is 
a 95% probability  that the new result for the sample submitted would be within a range of 
±0.21‰ for dissolved solids and ±0.38‰ for pulp.  
Reproducibility (of the measurement results)  
This is defined as the closeness of agreemen t between the results of measurements of the 
same parameter, carried out under varying measurement conditions by different laboratories.  
For the isotope analysis of 13CVPDB on organic material reproducibility should be less than 
the following values:  
For dissolved solids the reproducibility limit is ±0.25‰.  
For pulp the reproducibility limit is ±0.68‰.  
Reporting of results  
The results shal l be reported using the format suggested in NMX -EC-17025 -IMNC -2006 
“General requirements for laboratory competence of assays and calibration”, section 
8.16.5.10.  
Expression of results   
C3 plants (orange, apple, grapefruit, grape, mandarine, mango, pear, p lum, peach, apricot, 
guava, papaya, soursop, strawberry, tamarind) have a range of dissolved solids of -24‰ to -
28‰, in pulp of -24‰ to -28‰ and in ethanol derived from the fermentation of the 
corresponding dissolved solids of -25.5‰ to -28‰. These ranges of 13CVPDB do not apply to 
the pineapple as it is a CAM plant and must therefore be treated separately.  
To estimate more accurately the percentage of fruit a juice contains, remember that this 
requires the 13CVPDB in dissolved solids and the 13CVPDB in pulp to be determined on the 
same sample, this last parameter being included for use as an internal standard.  
This is designed to correct the results of 13CVPDB in dissolved solids due to various factors 
such as change in the type of fruit or change in the various environmental conditions in which 
the fruit was grown. This is based on the fact that in fruit both the soluble carbohydrates 
contained in the juice and other more complex organic molecules that form the pulp are 
generated simultaneously during  the growing process of a given type of fruit and therefore 
have an almost identical value of 13CVPDB, which can be expressed in the following equation.  
%Fruit=∂13CDissolvedSOlid sinJuice−∂13CAverage (CaneSugar /Maize )
∂13CPulp+0.24−∂13CAverage (CaneSugar /Maize )∗100 Eq. 3  
In a large number of analyses reported in the international literature a nd from samples 
analysed in the laboratory it has been found that the value of –11.45‰ is a good estimate for 
the average 13Caverage(CaneSugar/Maize)  to be used in equations 3 and 4. These represent the 
historical average of various types of carbohydrates  from C 4 plants (cane sugar and/or 
sweeteners derived from maize) used as exogenous sweeteners commonly added to juices.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 21 - The 13CVPDB for dissolved solids of fruit is denoted as 13CDissolvedSolidsinJuice . Finally the 
13CVPDB for pulp is represented as 13CPulpJuice . Lastly, the values of +0.24 in the denominator 
of equations 3 and 4 is a constant that was obtained experimentally from the results of 
analyses carried out on various types of fruit; it is related to the average value of 13CVPDB for 
dissolve d solids of the fruit and the 13CVPDB for pulp which has a correlation close to 1. This 
constant is used in equation 3 as follows:  
%Fruit=∂13CDissolvedSolid sinJuice−(−11.45)
(∂13CPulp+0.24)−(−11.45)∗100 Eq. 4  
Applying equation 4 using the methodology described, validation studies have shown that 
there  is a probable maximum error up to 5% in the determination of % Fruit.  
For the special case of clarified juices and which are processed to contain no pulp, such as 
apple and grape juices, the percentage of dissolved solids in fruit can be calculated using  
equation 4:  
%Fruit=∂13CDissolvedSolid sinJuice−(−11.45)
−11.45∗100 Eq. 5  
Applying equation 5 using the methodology described, validation studies have shown that 
there is a probable maximum error up to 10% in the determination of % dissolved solids in 
fruit.  
Criteria for interpreting the results of 13CVPDB in fruit  
The criteria for interpreting the results of applying equations 3 and 4 for the % of dissolved 
solids in fruit are as follows:  
The application of equation 4 for juices containing pulp requires the pulp to be described as 
an internal standard for which the following conditions apply:  
• The 13CVPDB in pulp must be in the range for C 3 plants ( -28.5‰ a –24‰)  
• The analysis of d15NAIR in pulp must be detectable and have a value greater than zero.  
• Once pulp is accepted as an int ernal standard, the following considerations must be 
taken into account:  
• If the numerical difference ( 13CVPDB in pulp - 13CVPDB in dissolved solids) is less 
than 1, and the values of 13CVPDB in dissolved solids and pulp are in the ranges for C 3 
plants the product can be considered as one in which 100% of the dissolved solids 
come from fruit and it can be regarded as authentic. In this case, applying equation 
gives a value of 98% or even slightly higher than 100%.  
• If the numerical difference of 13CVPDB in pulp - 13CVPDB in dissolved solids is greater 
than 1, equation 4 is applied to determine the % of dissolved solids of the fruit which 
may have an error of 5%.  
• If the 13CVPDB in pulp is not in the interval for C 3 plants and/or there is no value 
d15NAIR for the presence of nitrogen then the pulp may not be used as an internal Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 22 - standard and equation 3 may not be used. However, equation 5 may be used to 
determine the % of dissolved solids of fruit, which may have an error of 10%. This 
implies that thicken ers or cellulose have been added, which is prohibited under section 
6.1.2 “Stabilisers and thickeners”  of this standard.  
To calculate the °Brix of dissolved solids of fruit, equation 6 may be applied:  
°BrixFruit =°BrixProduct∗%Fruit
100 Eq. 6  
°Brix Product  values are  determined by direct measurement of °Brix levels of the product being 
analysed.  
9. Commercial information  
Labelling of products covered by this standard must comply with the provisions of NOM -
051-SCFI -1994, identified in the references section.  
The tra de description must be printed in the same font and type size.  
10. Monitoring  
This official Mexican standard is not certifiable, and compliance will be monitored by the 
Ministry of the Economy and the Federal Attorney for Consumer Affairs, in line with t heir 
respective powers.  
11. Bibliography  
11.1 Cienfuegos Edith, Casar Isabel and Morales Pedro, (1998). “Carbon isotopic 
composition of Mexican honey”. Journal of Apicultural Research 36(3/4): 169 – 179.  
11.2 Craig Harmon. (1953). The geochemistry of st able carbon isotopes. Geochimica et 
Cosmochimica Acta, 3: 53 – 92.  
11.3 Craig Harmon (1957). Isotopic standards for carbon and oxygen and correction factors 
for mass –spectrometric analysis of carbon dioxide. Geochimica et Cosmochimica Acta, 
12:133 – 149.  
11.4 DesMaris, D.J. and Hayes J.M. (1976). Tube cracker for opening glass Sealed ampoules 
under vacuum. Analytical Chem. 48: 1651 – 1652.  
11.5 Mook, W.G. and Grootes P.M. (1973). The measuring procedure and corrections for the 
high precision mass –spectro metric analysis of isotopic abundance ratios, especially referring 
to carbon, oxygen and nitrogen. International Journal of Mass Spectrometry and Ion Physics. 
Vol 12, 273 – 298.  
11.6 A.O.A.C. Official Method 981.09 Corn Syrup in Apple Juice Carbon Ratio M ass 
Spectrometric Method. Chapter 37, P. 19, Fruit and Fruit Products. A.O.A.C. 16th Edition, 
Vol. II. 1995.  
11.7 A.O.A.C. Official Method 982.21 Corn Syrup in Orange Juice Carbon Ratio Mass 
Spectrometric Method. Chapter 37, P. 20, Fruit and Fruit Product s. A.O.A.C. 16th Edition, 
Vol. II. 1995.  Wednesday 3 December 2008  OFFICIAL JOURNAL   (Section One)  
 - 23 - 11.8 J. Bricout & J. Koziet (1987). Control of the Authenticity of Orange Juices by Isotopic 
Analysis. J. Agric. Food Chem. 35, 758 -780.  
11.9 Doner Landis & Bills Donald. (1982). Mass Spectrometric 13C/12C Determi nations to 
detect High Fructose Corn Syrup in Orange Juice: Collaborative Study”. J. Assoc. OFF. Anal. 
Chem 65 (3): 608 – 610.  
11.10 J. Koziet, A. Rossmann, G.J. Martin & P.R. Ashurst (1993). Determination of carbon -
13 content of sugar of fruit and vegeta ble juices. Analytica Chimica Acta, 271, 31 -38  
11.11 G.G. Martin, V. Hanote, M. Lees, Y.L. Martin (1996) Interpretation of combined 2H 
SNIF/NMR and 13C SIRA/MS analyses of fruit juices to detect added sugar, Journal of 
AOAC International, Vol. 79, No. 1 6 2-72.  
11.12 M. Gensler & H. L. Schmidt. (1994). Isolation of the main organic acid from fruit 
juices and nectars for carbon isotope ratio measurements. Analytica Chimica Acta, 299, 231 -
237.  
11.13 E. Jamin, J. González, G. Remaud, N. Naulet & G. Martin. ( 1997). Detection of 
Exogenous Sugar or Organic Acid Addition in Pineapple Juices and concentrates by 13C 
IRMS Analysis. J. Agric. Food Chem. 45, 3961 -3967.  
11.14 J. Koziet, A. Rossmann, G.J. Martin, P. Johnson. (1995). Determination of the oxygen -
18 and d euterium content of fruit and vegetable juice water an European inter -laboratory 
comparison study, Analytica Chimica Acta 302 (1) pp. 29 -37. Anal. Chim. Acta. (1995), 302, 
29-37.  
11.15 UNE -EN-12140:1997 Zumos de frutas y hortalizas. Determinación de la re lación de los 
isótopos estables del carbono (13C/12C) en los azúcares de los zumos de fruta. Método por 
Espectrometría de Masas de Relaciones Isotópicas.  
11.16 PNE -ENV -13070 Zumos de fruta y hortalizas. Determinación de la relación de los 
isótopos estable s de carbono (13C/12C) en la pulpa de los zumos de fruta. Método por 
espectrometría de masas de relaciones isotópicas.  
11.17 Code of Practice published by the AINJ – Association of the Juice and Nectar 
producing Industry.  
11.18 Handbook of indices of Foo d Quality and Authenticity. Woodhead Publishing, 1997.  
11.19 Reglamento de Control Sanitario de Productos y Servicios VII.1  
12. Concordance with international standards  
This official Mexican standard concords partially with international standard CODEX STAN 
247-2005, Codex general standard for fruit juices and nectars.  
Mexico City, 14 November 2008. - Director -General for Standards and Chairman of the 
National Advisory Committee on Standardization for User Safety, Commercial Information 
and Trade Practic es, Francisco Ramos Gómez. - Initialled .