Paper and board intended to come into contact with foodstuffs - Calibration of the odour test - Part 1: Odour

This Technical Report specifies a written protocol to prepare calibration samples for assessment of odour released by a paper or board sample, and how to train the panel in the use of these calibration samples.
The general outline of the testing procedure consists of sensory assessment of the odour samples without formal training by a selected panel, followed by training of the panel, and finally sensory assessment of the odour samples after training by the same sensory panel.

Papier und Pappe vorgesehen für den Kontakt mit Lebensmitteln - Kalibrierung der Geruchsprüfung - Teil 1: Geruch und Aroma

Papiers et cartons destinés en entrer en contact avec les denrées alimentaires - Etalonnage de l'essai de flaveur atypique - Partie 1: Odeur

Le présent rapport technique spécifie une formule écrite de préparation des échantillons d'étalonnage utilisés pour procéder aux analyses sensorielles olfactives des échantillons de papier et de carton, il spécifie également une méthode d’entraînement à l’utilisation de ces échantillons d'étalonnage par le jury d’analyse sensorielle.
De manière générale, le mode opératoire d’essai se décompose comme suit : une analyse sensorielle des échantillons olfactifs, sans entraînement formel préalable du jury d’analyse sensorielle, suivie d’un entraînement du jury et finalement une analyse sensorielle des échantillons olfactifs par le jury préalablement entraîné.

Papir, karton in lepenka v neposrednem stiku z živili - Umerjanje za preskus vonja - 1. del: Vonj

General Information

Status
Published
Publication Date
04-Mar-2008
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
04-Feb-2008
Due Date
10-Apr-2008
Completion Date
05-Mar-2008

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SLOVENSKI STANDARD
SIST-TP CEN/TR 15645-1:2008
01-april-2008

Papir, karton in lepenka v neposrednem stiku z živili - Umerjanje za preskus vonja

- 1. del: Vonj

Paper and board intended to come into contact with foodstuffs - Calibration of the odour

test - Part 1: Odour
Papier und Pappe vorgesehen für den Kontakt mit Lebensmitteln - Kalibrierung der
Geruchsprüfung - Teil 1: Geruch und Aroma
Papiers et cartons destinés en entrer en contact avec les denrées alimentaires -
Etalonnage de l'essai de flaveur atypique - Partie 1: Odeur
Ta slovenski standard je istoveten z: CEN/TR 15645-1:2008
ICS:
67.250
85.060
SIST-TP CEN/TR 15645-1:2008 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
TECHNICAL REPORT
CEN/TR 15645-1
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
January 2008
ICS 67.250; 85.060
English Version
Paper and board intended to come into contact with foodstuffs -
Calibration of the odour test - Part 1: Odour

Papiers et cartons destinés en entrer en contact avec les Papier und Pappe vorgesehen für den Kontakt mit

denrées alimentaires - Etalonnage de l'essai de flaveur Lebensmitteln - Kalibrierung der Geschmacksprüfung - Teil

atypique - Partie 1: Odeur 1: Geruch und Aroma

This Technical Report was approved by CEN on 13 August 2007. It has been drawn up by the Technical Committee CEN/TC 172.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,

Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15645-1:2008: E

worldwide for CEN national Members.
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CEN/TR 15645-1:2008 (E)
Contents Page

Foreword..............................................................................................................................................................4

Introduction .........................................................................................................................................................5

1 Scope ......................................................................................................................................................6

2 Normative references ............................................................................................................................6

3 Terms and definitions ...........................................................................................................................6

4 Principle..................................................................................................................................................7

5 Materials and reagents..........................................................................................................................8

5.1 General....................................................................................................................................................8

5.2 Base paper..............................................................................................................................................8

5.3 Spiking compound.................................................................................................................................8

5.4 Solvent ....................................................................................................................................................8

6 Equipment ..............................................................................................................................................8

6.1 General....................................................................................................................................................8

6.2 Micro-syringes .......................................................................................................................................8

6.3 Glass flasks ............................................................................................................................................8

6.4 Aluminium foil........................................................................................................................................9

7 Preparation of calibration samples......................................................................................................9

7.1 General....................................................................................................................................................9

7.2 Preparation of the spiking solutions ...................................................................................................9

7.2.1 General....................................................................................................................................................9

7.2.2 Stock solution K (800 mg/l)...................................................................................................................9

7.2.3 Solution K 2 (40 mg/l) ..........................................................................................................................10

7.2.4 Spiking solutions.................................................................................................................................10

7.3 Preparation of calibration samples....................................................................................................10

8 Sensory tests .......................................................................................................................................11

8.1 General test conditions.......................................................................................................................11

8.2 Sensory panel ......................................................................................................................................11

8.3 Sample presentation ...........................................................................................................................11

8.4 Sensory evaluation of odour ..............................................................................................................11

9 Test procedure for sensory panel......................................................................................................12

9.1 General..................................................................................................................................................12

9.2 First step: Assessment before training.............................................................................................12

9.3 Second step: Training of the panel....................................................................................................13

9.4 Third step: Assessment after training...............................................................................................14

10 Data collection and reporting.............................................................................................................15

10.1 General..................................................................................................................................................15

10.2 Data Format ..........................................................................................................................................15

11 Data analysis........................................................................................................................................15

Annex A (informative) Experimental design for sample evaluation before training (Rep 1) .....................16

Annex B (informative) Experimental design for sample evaluation before training (Rep 2) .....................17

Annex C (informative) Example of evaluation form for use during assessments (first step and

third step) .............................................................................................................................................18

Annex D (informative) Example of evaluation form for use during training (second step).......................19

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CEN/TR 15645-1:2008 (E)

Annex E (informative) Experimental design for sample evaluation after training (Rep 1) ........................20

Annex F (informative) Experimental design for sample evaluation after training (Rep 2) ........................21

Annex G (informative) Example of data entry sheets for the first step .......................................................22

Annex H (informative) Example of data entry sheets for the third step ......................................................26

Annex I (informative) Mood’s median test......................................................................................................30

Annex J (informative) Tukey's Quick (Pocket) Test ......................................................................................33

Bibliography......................................................................................................................................................34

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CEN/TR 15645-1:2008 (E)
Foreword

This document (CEN/TR 15645-1:2008) has been prepared by Technical Committee CEN/TC 172 “Pulp,

paper and board”, the secretariat of which is held by DIN.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

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CEN/TR 15645-1:2008 (E)
Introduction

Paper and board, intended to be in contact with food, may have characteristic odour that can migrate via the

airspace to the food packed in it. The purpose of testing the odour of paper and board is to establish whether

the material to be tested possesses an inherent odour when kept at room temperature.

In order to gain reliable results from the sensory evaluation, the performance of a sensory panel assessing the

odour of paper and board needs to be validated. This can be implemented through a training procedure by

using spiked calibration samples prepared according to the given instructions.
This document consists of:

 protocol to prepare the calibration samples (spiked paper) for sensory evaluation of odour;

 description of the training procedure for a sensory panel in the use of the calibration samples;

 instructions for sensory evaluation of calibration samples before and after training.

This guide is meant to be used in connection with the European Standard EN 1230-1. The guidance given in

this document is only a recommendation. Please note that the calibration samples, the preparation of which is

described, can be also applied in other ways than described in this document.

This guide has been devised and collaboratively tested in the context of the EU research project

CALIBSENSORY (Growth programme, Measurement and Testing activity, GRD2-2000-30015) and it is the

sole responsibility of its authors. It does in no way represent the views of the Commission or its services.

Published results of the project are available at http://www1.kcl.fi/euproj/calib.html .

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CEN/TR 15645-1:2008 (E)
1 Scope

This Technical Report specifies a written protocol to prepare calibration samples for assessment of odour

released by a paper or board sample, and how to train the panel in the use of these calibration samples.

The general outline of the testing procedure consists of sensory assessment of the odour samples without

formal training by a selected panel, followed by training of the panel, and finally sensory assessment of the

odour samples after training by the same sensory panel.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.

ISO 5496, Sensory analysis — Methodology — Initiation and training of assessors in the detection and

recognition of odours
ISO 6658, Sensory analysis — Methodology — General guidance

ISO 8586-1, Sensory analysis — General guidance for the selection, training and monitoring of assessors —

Part 1: Selected assessors
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
assessor
any person taking part in a sensory test
[see ISO 5492:1992]
3.2
base paper
paper that has minimal number of sensory properties
3.3
calibration procedure

protocol of calibration samples and written instructions to train selected assessors with calibration samples i.e.

calibrate the panel
3.4
calibration sample
base paper that is spiked with spiking compounds at a certain concentration
3.5
control sample

a hidden reference sample served blind coded to the assessors among the calibration samples, and prepared

according to the procedure of the calibration samples but without the spiking compound

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CEN/TR 15645-1:2008 (E)
3.6
odour

organoleptic attribute perceptible by the olfactory organ on sniffing certain volatile substances

[ISO 5492:1992]
3.7
multicomparison test

test where the assessor is asked to give a rating of the intensity of the difference in taste or odour between

test portions for analysis and a known reference sample
3.8
reference sample
calibration sample without any spiking compound

NOTE This is presented to the assessors labelled as "Reference" and served to the assessors before the calibration

samples.
3.9
selected assessor
assessor chosen for his/her ability to perform a sensory test
[see ISO 5492:1992]
3.10
spiking compound
a volatile chemical compound having a specific odour
NOTE In this case hexanal is the selected spiking compound.
3.11
spiking method
a method for spiking the base paper with spiking compounds
4 Principle

A training process validation for a sensory panel has to be conducted with freshly made calibration samples,

prepared by spiking an odourless base paper with different concentrations of hexanal. The panel performance

in evaluating the odour intensity of hexanal is determined before and after a formal training step. The

effectiveness of training can then be determined.
The test procedure consists of 3 steps:
a) first step: assessment of calibration samples before training;
b) second step: training procedure;
c) third step: assessment of calibration samples after training.

Detailed instructions for general test procedure, sample preparation and sensory evaluation are provided

within this Technical Report, and must be carefully followed to ensure validity of results.

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CEN/TR 15645-1:2008 (E)
5 Materials and reagents
5.1 General

Odourless base paper is used as a carrier for different concentrations of the spiking compound diluted with the

solvent. In this Technical Report, hexanal is used as the spiking compound and triacetin as the solvent.

5.2 Base paper

The base paper used in the odour test shall be suitable for food use. The paper shall respect the following

criteria:
 odourless
 porous.

One example for the base paper is coffee filter paper made of bleached chemical pulp, including wet strength

resin and grammage of approximately 52 g/m .
5.3 Spiking compound

Hexanal (CAS number 66-25-1, 98 %) is used as the spiking agent in the odour test. The odour of hexanal is

described as being green, fruity, bitter and grassy. Hexanal is often found in rancid fats (in foods) and in fibre-

based materials.
5.4 Solvent

Triacetin (CAS number 102-76-1) shall be used as a solvent for diluting the spiking compound. It is assessed

to be almost odourless, and related to its other characteristics, suitable for this purpose.

6 Equipment
6.1 General

All equipment used shall be free from odour and only in use for sensory analysis (see ISO 6658). Special care

is required to ensure that lids, seals and inserts do not become a source of odour.

Equipment and glass flasks shall be cleaned between sessions. Any glassware used shall be washed with

minimum-odour cleaning agents and dried by placement in oven at a temperature > 100 C and left to

evaporate for at least 2 h. All other equipment shall be washed with minimum-odour cleaning agents and left

to dry at room temperature.
6.2 Micro-syringes
Micro-syringes in capacity from 20 µl to 100 µl.
6.3 Glass flasks

Glass flasks in 500 ml in capacity. The shape of the flask is not as essential as the volume. Brown glass

bottles with lids of polytetrafluorethylen or Erlenmeyer flasks with narrow neck and conical ground joint and

stopper may be used.
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CEN/TR 15645-1:2008 (E)

The flasks (if needed) are covered by aluminium foil for preventing the influence of the appearance of the

sample. Each sample is served to each assessor in a separate flask, therefore 5 flasks are required for each

assessors at each session.
6.4 Aluminium foil

Aluminium foil used for wrapping the glass flasks (if needed) shall be free from odour.

7 Preparation of calibration samples
7.1 General

Prepare for each five sessions five samples: the reference sample plus four samples for assessment. These

are summarised, along with their concentrations, in table 1.

Table 1 — Calibration samples and concentrations of hexanal (µg hexanal/paper sample)

sample µg/sample
reference 0
N 0 (control sample) 0
N 1 0,04
N 2 0,80
N 3 8,0

For the three spiked samples, base paper should be spiked at various concentrations of hexanal diluted in

triacetin, the concentrations being 0,04 µg, 0,8 µg and 8 µg hexanal/sample. The reference (given reference)

and control samples (hidden reference) shall be odour flasks with base paper and triacetin but without hexanal.

For each of the five samples, the number of prepared test portions (flasks) has to be equal to the number of

assessors on the panel, the recommended panel size varying between 10 and 12. The flasks should be

covered with aluminium foil and coded with three-digit random numbers prior to preparing the individual test

portions. These have to be presented individually to each assessor. Examples for blinding codes and

experimental designs for each session are presented in the annexes.
7.2 Preparation of the spiking solutions
7.2.1 General

The following sets of stock solutions will be needed. Stock solution K can be used over three consecutive

days only. The other stock solution K 2 and the batch solutions for each sample have to be freshly made each

day.
7.2.2 Stock solution K (800 mg/l)

Dissolve 80 mg (100 µl) of hexanal in about 50 ml of triacetin, then fill up with triacetin to make total volume of

100 ml.

Stock solution K has to be stored at + 4 °C, and can be used for three consecutive days.

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CEN/TR 15645-1:2008 (E)
7.2.3 Solution K 2 (40 mg/l)

Dilute 1 ml of stock solution K in 20 ml of triacetin (i.e. 1 ml K/20 ml triacetin).

Stock solution K 2 has to be stored at + 4 °C and shall be prepared daily.
7.2.4 Spiking solutions

To create batch solutions for the spiked samples, dilute solution K 2 as presented in Table 2.

Table 2 — Preparation of batch solutions for spiking the calibration samples
sample K 2 triacetin description
ml ml
N1 0,1 9,9 to create a batch of N1 solution, dilute 0.1 ml of K 2
stock solution with 9.9 ml triacetin
N2 1 4 to create a batch of N2 solution, dilute 1 ml of K 2 stock
solution with 4 ml triacetin
K, ml
N3 1 9 to create a batch of N3 solution, dilute 1 ml of K stock
solution with 9 ml triacetin
Sample batches for N1 to N3 shall be prepared daily.

The reference and control samples, also presented to the assessors during the sensory assessment, will be

prepared using triacetin without any added hexanal.
7.3 Preparation of calibration samples

The sample flasks should be prepared in a completely odourfree space (see ISO 6658). To prepare the

calibration samples the following scheme has to be followed:

1) Reference test paper must first be prepared by cutting into squares of 1 dm² (10 cm × 10 cm) cm.

For each session, five pieces of test paper (each 1 dm²) for each assessor (one for each sample)

will be needed.

2) Reference test paper (1 dm²) shall be folded in double thickness and bent in accordion style. Place

the bent paper into the flask.

3) Sample solution has to be pipetted onto the test paper. The amount of solution per paper is 100 µl,

and should be pipetted in four drops, 25 µl each, to guarantee even distribution of the spiking

solution on the paper. Close the flask immediately.

4) Store the flasks for 3 h at (22 ± 3) ºC in the dark, wrapped in aluminium foil (or use brown coloured

bottles) to avoid the possibility of any chemical reactions prior to the sensory assessments.

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CEN/TR 15645-1:2008 (E)
8 Sensory tests
8.1 General test conditions

Basic information on general requirements, test methods and analysis of results in sensory evaluation is given

in ISO 6658 as a general guidance.

For the design of, and the conditions in, the room in which tests are conducted ISO 8589 should be consulted.

In general, the evaluation shall be carried out at room temperature in a quiet, well-ventilated room that is free

from odours. The relative humidity of the room shall be constant and controllable approximately 50 % r.h.

The containers and equipment used shall be odourless and should not have any influence on the test results.

8.2 Sensory panel

Guidelines concerning the selection and training of assessors are given in ISO 8586-1. The assessors shall

be in good health and shall not suffer from the common cold at the time of the test. ISO 5496 in particular may

be used to train the panel members to assess odour.

Only selected, trained assessors shall be used in the sensory evaluations. The availability of assessors, their

interest and motivation, and capacity to concentrate should be ascertained prior the training procedure. The

recommended panel size is from 10 assessors to 12 assessors. A minimum number of 8 assessors should be

used. The panel members may not change during the test procedure. If the panel members are not

equivalent at each step, the missing assessors may not be replaced with other assessors.

In addition to the general rules for sensory assessors given in ISO 6658, the assessors participating in

evaluation of odour intensity shall not have carried out any other sensory analysis concerned with odour

assessment within the 20 min prior to the test (see ISO 5496).
8.3 Sample presentation

Except during the training procedure, all samples must be served to the assessors in randomised order

following an experimental design. Suggested designs are provided in the Annexes.

Each assessor must receive the reference plus four test samples presented in separate flasks. Samples are

labelled with 3-digit random numbers and served (at room temperature) in random order according to the

appropriate experimental design. The presentation order will thus be different for each assessor.

NOTE For each session, ensure that panellist numbers are consistent (e.g. panellist number "1" is the same person

each time).
8.4 Sensory evaluation of odour

The perceived odour of hexanal within the samples shall be evaluated by using the multiple comparison

method. The reference sample must be available at all times, while the four samples are presented one at a

time following the design order.

Assessors shall be instructed to sniff the reference sample, and then sniff the samples in the order provided.

Assessors are required to have a one-minute break between samples, and should sniff the reference sample

before each test sample.

For each sample, the assessors shall be instructed to turn the flask once up and down, carefully remove the

stopper, and sniff shallowly the vapour phase over the sample immediately after opening the flask. After

sniffing, the assessor shall be instructed to close the flask immediately, and this must be kept closed for at

least 2 min, if they wish to sniff again from the same flask.
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CEN/TR 15645-1:2008 (E)

Each assessor has his/her own sample set and an evaluation form at each session. Examples of evaluation

forms for each step of the test procedure can be found in the Annexes, as described in clause 9.

For each sample, the assessor records the intensity of the perceived odour, relative to the reference sample,

using the 0 to 4 scale shown below.
 0 = no perceptible odour, same as reference
 1 = odour just perceptible (difficult to define)
 2 = weak odour
 3 = clear odour
 4 = strong odour

In addition to the whole numbers (0, 1, 2, 3, 4), ½ scores may be given but only within the range of 0 to 4 (i.e.

0.5, 1.5, 2.5 and 3.5). The reference sample is defined as 0 and a blind-coded control sample is presented

among the other samples.
9 Test procedure for sensory panel
9.1 General
The test procedure for the sensory panel consists of three steps:
a) first step: assessment before training (two sessions);
b) second step: training of the panel (one session);
c) third step: assessment after training (two sessions).
9.2 First step: Assessment before training

The first step of the test procedure is the sensory assessment of samples before training by a selected

sensory panel. Two replicate sessions are required for this step. The replicate sessions should not be closer

than on sequential days.
For each replication:

 prepare stock solutions, test samples (N0 to N3) and the reference sample as described in clause 7;

 present the samples to assessors following the procedure described in 8.3. Each assessor has to make

individual assessments from their own sample set coded with three-digit blinding codes;

 samples should be presented to the assessors following a randomised experimental design. Suggested

designs for each replicate, including blinding codes, are given in Annex A and Annex B;

 assessors shall evaluate the samples as described in 8.4. An example of a questionnaire, which includes

instructions for the assessors, is shown in Annex C;

 data may also be collected using a computerised data capture systems. If using a computerised data

capture system, a 5-point category scale from 0 to 4 should be used, which allows ½ scores to be

recorded. The one-minute break between samples may also be controlled using a computerised data

capture systems;
---------------------- Page: 13 ----------------------
CEN/TR 15645-1:2008 (E)

 data from paper or computerised evaluation forms could be transferred to the Excel Data Entry Sheet

(Annex G) provided, as described in clause 10.
9.3 Second step: Training of the panel

The second step of the test procedure is the training of the sensory panel. The training should take place in a

single session. During the training process all samples should be evaluated by the same selected assessors

as in the first step. If the panel members are not all present in each step, the missing assessors may not be

replaced by other assessors and should be disregarded from the training procedure.

The samples used for training are shown in Table 3. Prepare the samples following the procedure described

in clause 7. Samples should be presented labelled as shown in Table 3.
Table 3 — Samples and labels used for training
sample label shown
reference reference
N1 A
N2 B
N3 C
The training procedure consists of three activities.
a) evaluation of samples by assessors;
b) table discussion and teaching by panel leader;
c) re-evaluation of samples and consolidation of learning.
Activity 1 Evaluation of samples by assessors

 Present the four samples to the assessors. Present the samples to each assessor in the same order:

reference, A, B, C.

 Each assessor should make individual assessments from their own sample set. The assessors evaluate

the samples as described in 8.4, sniffing the reference sample before each sample and with a one-minute

break between samples.

 An example of an evaluation form that can be used during the training session, which includes

instructions for the participants, is shown in Annex D.

 For this training step, data should be collected using paper ballots, as the assessors will be working

together in the same room.
Activity 2 Table discussion and teaching by panel leader

 Round table discussions related to the calibration samples have to be performed immediately after the

evaluation. The panel leader has to initiate discussion amongst the assessors regarding the perceived

odour intensity of each samples, and the scores given by the assessors.

 Assessors should be trained to the reference points by teaching them which score should be given for

each calibration sample. The panel leader has to use the information in Table 4 to guide the discuss

...

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