Paper and board intended to come into contact with foodstuffs - Calibration of the off flavour test - Part 2: Fatty food

This Technical Report specifies a written protocol to prepare calibration samples for assessing off-flavour (given by benzaldehyde) in a test substance representative of fatty food products (coconut oil). Essentially, this is meant to simulate the transfer of off-flavours from paper and board to a fatty food product.
This Technical Report also specifies how to train the panel in the use of the calibration samples.

Papier und Pappe vorgesehen für den Kontakt mit Lebensmitteln - Kalibrierung für die Geschmacksprüfung - Teil 2: Fettende Lebensmittel

Papiers et cartons destinés en entrer en contact avec les denrées alimentaires - Étalonnage des essais de flaveur atypique - Partie 2 : Aliments gras

Le présent Rapport technique spécifie une formule écrite pour la préparation d'échantillons d'étalonnage en vue de l'évaluation de la flaveur atypique (fournie par le benzaldéhyde) dans une substance d'essai représentative des produits alimentaires gras (huile de coco). Pour l'essentiel, ceci vise à simuler le transfert des flaveurs atypiques du papier et du carton vers un produit alimentaire gras.
Le présent Rapport technique spécifie également le mode d'entraînement du jury à l'utilisation des échantillons d'étalonnage.

Papir, karton in lepenka v stiku z živili - Umerjanje za preskus neprimernega vonja ali okusa - 2. del: Maščobna živila

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 15645-2:2008
01-april-2008

3DSLUNDUWRQLQOHSHQNDYVWLNX]åLYLOL8PHUMDQMH]DSUHVNXVQHSULPHUQHJDYRQMD

DOLRNXVDGHO0DãþREQDåLYLOD

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

flavour test - Part 2: Fatty food

Papier und Pappe vorgesehen für den Kontakt mit Lebensmitteln - Kalibrierung für die

Geschmacksprüfung - Teil 2: Fettende Lebensmittel
Papiers et cartons destinés en entrer en contact avec les denrées alimentaires -
Étalonnage des essais de flaveur atypique - Partie 2 : Aliments gras
Ta slovenski standard je istoveten z: CEN/TR 15645-2:2008
ICS:
67.250 Materiali in predmeti v stiku z Materials and articles in
živili contact with foodstuffs
85.060 Papir, karton in lepenka Paper and board
SIST-TP CEN/TR 15645-2:2008 en,fr,de

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

---------------------- Page: 1 ----------------------
TECHNICAL REPORT
CEN/TR 15645-2
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 off flavour test - Part 2: Fatty food

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

denrées alimentaires - Étalonnage des essais de flaveur Lebensmitteln - Kalibrierung für die Geschmacksprüfung -

atypique - Partie 2 : Aliments gras Teil 2: Fettende Lebensmittel

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 15645-2:2008: E

worldwide for CEN national Members.
---------------------- Page: 2 ----------------------
CEN/TR 15645-2:2008 (E)
Contents Page

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

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

1 Scope ......................................................................................................................................................5

2 Normative references ............................................................................................................................5

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

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

5 Materials an reagents ............................................................................................................................8

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

5.2 Test substance.......................................................................................................................................8

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

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

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

6.2 Aluminium foil........................................................................................................................................8

6.3 Petri dishes.............................................................................................................................................8

6.4 Plates for serving the test portions .....................................................................................................8

6.5 Plastic spoons or plastic toothpicks ...................................................................................................8

6.6 Glass flasks ............................................................................................................................................8

6.7 Moulds for preparation of test portions ..............................................................................................9

6.8 Other laboratory equipment .................................................................................................................9

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

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

7.2 Preparation of the calibration samples ...............................................................................................9

7.3 Preparation of test portions from a calibration sample...................................................................10

7.3.1 General..................................................................................................................................................10

8 Sensory tests .......................................................................................................................................12

8.1 General test conditions.......................................................................................................................12

8.2 Sensory Panel ......................................................................................................................................12

8.3 Sample presentation ...........................................................................................................................12

8.4 Sensory evaluation of off-flavour.......................................................................................................12

9 Test procedure for sensory panel......................................................................................................13

9.1 General..................................................................................................................................................13

9.2 First step: Assessment before training.............................................................................................13

9.3 Second step: Training of the panel....................................................................................................14

9.4 Third step: Assessment after training...............................................................................................15

10 Data collection and reporting.............................................................................................................16

10.1 General..................................................................................................................................................16

10.2 Data format ...........................................................................................................................................16

11 Data analysis........................................................................................................................................16

Annex A (informative) Specification of coconut oil .......................................................................................17

Annex B (informative) Experimental design for sample evaluation before training (Rep 1 and Rep

2)............................................................................................................................................................18

Annex C (informative) Example of evaluation form to be used during assessments (first step

and third step)......................................................................................................................................19

Annex D (informative) Example of evaluations form to be used during training (second step)...............20

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CEN/TR 15645-2:2008 (E)

Annex E (informative) Experimental design for sample evaluation after training (Rep1 and Rep2).......21

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

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

Annex H (informative) Method of chemical analysis.....................................................................................30

Annex I (informative) Mood's median test......................................................................................................32

Annex J (informative) Tukey's Quick (Pocket) Test ......................................................................................35

Bibliography......................................................................................................................................................36

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CEN/TR 15645-2:2008 (E)
Foreword

This document (CEN/TR 15645-2:2008) 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 15645-2:2008 (E)
Introduction

Paper and board, intended to be in contact with food, may have characteristic off-flavours that can migrate via

airspace to the food packed in it. The purpose of testing the off-flavour of food in contact with paper and board

is to establish whether the material to be tested possesses an inherent off-flavour when kept at room

temperature.

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

off-flavour within test material 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 coconut fat) for sensory evaluation of off-flavour;

 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 1230-2. The guidance given in

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

described, can be applied also 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 .

1 Scope

This Technical Report specifies a written protocol to prepare calibration samples for assessing off-flavour

(given by benzaldehyde) in a test substance representative of fatty food products (coconut oil). Essentially,

this is meant to simulate the transfer of off-flavours from paper and board to a fatty food product.

This Technical Report also specifies how to train the panel in the use of the calibration samples.

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 6658, Sensory analysis – Methodology – General guidance

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

Part1: Selected assessors
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CEN/TR 15645-2:2008 (E)
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
calibration procedure

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

calibrate the panel
3.3
control sample

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

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

3.4
flavour

complex combination of the olfactory, gustatory and trigeminal sensations perceived during tasting

NOTE The flavour may be influenced by tactile, thermal, painful and/or kinaesthesic effects

[see ISO 5492:1992]
3.5
multicomparison test

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

portions for analysis and a known reference sample
3.6
off-flavour

a typical flavour often associated with deterioration or transformation of the product

[see ISO 5492:1992]
3.7
reference sample
calibration sample without any spiking compound, i.e. pure coconut oil

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

samples.
3.8
selected assessor
assessor chosen for his/her ability to perform a sensory test
[see ISO 5492:1992]
3.9
spiking compound
a volatile chemical compound having a specific flavour
NOTE In this case benzaldehyde is the selected spiking compound
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CEN/TR 15645-2:2008 (E)
3.10
spiking method
a method for spiking the test substance with spiking compounds
3.11
taint
taste or odour foreign to the product
[see ISO 5492:1992]
3.12
taste

sensations perceived by the taste organ when stimulated by certain soluble substances

[see ISO 5492]

NOTE For simplicity, taste and flavour are used as synonyms in the European standard 1230-2, though this is not

exactly in accordance with ISO 5492. The same regards taint and off-flavour.
3.13
test portion
portion of the test sample, which is directly tested by the assessor
[see ISO 5492:1992]
3.14
test substance
substance to be assessed by the assessor

NOTE It may be the food product intended to be packed, or a suitable simulant that may absorb compounds from the

packaging materials. In this case coconut oil is the selected test substance.
4 Principle

A validation of the training process has to be conducted with calibration samples. The calibration samples

have to be prepared by spiking the test substance (coconut oil) with direct addition of the spiking compound

(benzaldehyde) followed by dilution in pure coconut oil until required concentrations are reached. From these

calibration samples, test portions have to be made and evaluated by the panel. The panel performance in

evaluating the off-flavour intensity 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 15645-2:2008 (E)
5 Materials an reagents
5.1 General

Coconut oil is the test substance used to absorb different concentrations of the spiking compound diluted with

itself (coconut oil). In this Technical Report, benzaldehyde shall be used as the spiking compound.

Every substance and reagent shall be certified for use in foodstuffs in accordance with European Standards.

5.2 Test substance

Coconut oil obtained from coconut followed by purification and deodorisation is used as the test food.

Specifications for the coconut oil are presented in Annex A.
5.3 Spiking compound

Benzaldehyde for food purpose with purity of > 99%. Benzaldehyde is a flavouring. Risk assessments have

been carried out on the levels within the samples, and the results ensure the safety of participants.

6 Equipment
6.1 General

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

odour cleaning agents for cleaning and left to dry at room temperature shall be used. 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.
6.2 Aluminium foil

Aluminium foil used for wrapping shall be free from odour and introduce no off-taste into the test food. (i.e. the

foil shall not be varnished or coated).
6.3 Petri dishes

At least 5 Petri dishes are required, preferably with a diameter of approximately 200 mm made of glass and

equipped with lid. The dishes should be used for storing the test portions.
6.4 Plates for serving the test portions

The test portions should be served to the assessors using glassware, or plates that do not alter the sensory

characteristics of the test portions. Example of proper equipment: glass plates, small Petri dishes or plates

made of polystyrene.
6.5 Plastic spoons or plastic toothpicks

Assessors should use plastic spoons or plastic toothpicks to evaluate test portions.

6.6 Glass flasks

Glass flask, 500 ml, equipped with ground glass cap has to be used for melting coconut oil (50 C).

Glass flasks, 100 ml, equipped with effective sealing (e.g. screw cap) have to be used for preparation and

storage of spiked coconut oil.
---------------------- Page: 9 ----------------------
CEN/TR 15645-2:2008 (E)
6.7 Moulds for preparation of test portions

Moulds made of inert plastic intended for preparing test portions (see an example in Figure 1).

6.8 Other laboratory equipment
 balance suitable for weighing the test portions (approximately 0,3 g);
 freezer (< -18 °C) for solidifying and storing test portions;
 refrigerator (< 8 °C) for cooling Petri dishes;
 oven (50 °C) to melt the calibration samples.
7 Preparation of calibration samples
7.1 General

After preparation the calibration samples may be stored in glass bottles for up to four weeks at room

temperature or in a refrigerator. During a period of four weeks there is no significant (5 %) decrease in

benzaldehyde concentration and no significant (5 %) sensory difference neither when stored at room

temperature nor when stored in refrigerator.
NOTE 5 % comes from the statistical tables to evaluate the results.

In general, six samples are needed to be prepared. These are summarised, along with their concentrations of

benzaldehyde, in Table 1.

During the assessment sessions (first and third step), all six calibration samples are needed to be prepared.

During the training session (second step), only four of the samples are needed to be prepared (reference, C1,

C2 and C4). This will impact on the amount of test portions that is needed to be prepared.

Table 1 — Samples and their concentrations of benzaldehyde (ppm = µg benzaldehyde/g coconut oil

sample)
sample benzaldehyde concentration, ppm first step second third
step step
reference 0 x x x
C0 (control sample) 0 x x
C1 10 x x x
C2 40 x x x
C3 160 x x
C4 660 x x x
7.2 Preparation of the calibration samples

To prepare each desired calibration sample, the following scheme has to be followed:

1) Melt the pure coconut oil in a glass bottle, 500 ml, at 50 C (oven);
2) Prepare the calibration samples using the following procedure:
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CEN/TR 15645-2:2008 (E)

 add 30 g to 40 g melted coconut oil into an empty glass bottle, 100 ml, on a balance (0,01 g).

 move the bottle to a precision balance (0,1 mg) and tare off the weight to zero.

 add W g of solution S.
 move the bottle back to the first balance (0,01 g).
 add melted coconut oil up to 100,0 g achieving the calibration sample c.
 seal the bottle and homogenise by handshaking.
In this way, prepare sequentially the calibration samples C4, C3, C2 and C1:
Table 2 — Preparation of calibration samples
W Solution S calibration sample c
6,7 benzaldehyde Stock solution
1,0 stock solution C4
24,3 C4 C3
25,0 C3 C2
25,0 C2 C1
provided that the purity is assumed to be 99 %.
7.3 Preparation of test portions from a calibration sample
7.3.1 General
Prepare the test portions from calibration samples using the moulds.
For preparing test portions, the following procedure shall be applied.

7.3.2 Take the glass flask containing the actual calibration sample out of the refrigerator and gently heat it

until the content has melted (use an oven maximum temperature of 50 ºC for approximately 45 min in the

case of a filled up flask). Keep the cap tightly screwed.

7.3.3 Take the sealed glass flask out of the oven, carefully mix the melted oil by gently turning the flask

upside down two to three times and let it stand at room temperature for 5 min to 10 min.

7.3.4 Unscrew the cap and gently pour melted calibration sample into the holes of the mould (see Figure 1).

Hold the edge of the flask in contact with the mould. Do not overfill but see to it that all holes are filled up

(approximately 15 ml will be used).
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CEN/TR 15645-2:2008 (E)
Figure 1 — Pouring the melted calibration sample

7.3.5 Re-screw the cap of the glass flask tightly immediately after filling the mould and put it back into

refrigerator.

7.3.6 Put the filled mould into the freezer for 20 min to solidify the test portions.

7.3.7 Put a Petri dish (intended for storing the test portions) into the refrigerator.

7.3.8 Take the mould out of the freezer and the Petri dish out of the refrigerator. Place the filled mould

upside down over the open cooled Petri dish. Grip one short side edge of the mould with you hand and gently

knock the other short side edge on the side of the Petri dish so that the formed test portions drop down into

the dish (see Figure 2). Test portions of different calibration solutions should be placed separately while

several test portions of the same type (like the 0-samples) may be placed together.

Figure 2 — Removing test portions from mould
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CEN/TR 15645-2:2008 (E)

7.3.9 Step 3 to step 7 will make about 30 test portions of each sample, depending on the mould used. Each

assessor has to receive two pieces of each sample. Step 3 to step 7 may be repeated (but only once) if there

are more than 15 assessors, or if more test portions are desired per assessor. Ensure that there is enough

coconut oil to make two moulds worth of test portions for each replicate. Pay attention that approximately half

of the calibration sample shall be saved for replicate 2. Moulds do not need to be cleaned between making

these two sets of test portions.

7.3.10 The mass of some of the test portions at random has to be checked and noted. Arrange them in the

Petri dish in such a way that they are separated from each other (not stacked), put the lid on, wrap with

aluminium foil, mark it with the appropriate label, and store in the freezer for no more than 24 h before

assessment.
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 a temperature below the melting point of coconut oil (25 °C) in

a quiet, well ventilated room that is free from odours.

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.

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, and due to the restricted amount of sample material, a maximum of 20 assessors is imposed. The

panel members may not change during the test procedure.
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.

The test portions for each sample have to be placed onto serving plates (see 6.4) that are coded according to

the test design. The best results will be achieved if the time between removing the test portions from the

freeze storage and assessing is between 5 min and 10 min.

Each assessor must receive two test portions of each sample, and two test portions of the reference sample.

8.4 Sensory evaluation of off-flavour

Assessors shall be instructed to taste the reference sample once, and then taste the samples in the order

provided. Assessors should cleanse their palate between each sample tasted by rinsing the mouth with water

(preferably warm water) and/or eating a piece of dry cracker.

For each sample, the assessor records the intensity of the off-flavour relative to the reference sample using

the 0 to 4 scale shown below. Assessors are allowed to re-taste the reference sample if needed.

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CEN/TR 15645-2:2008 (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. The

assessor should use a plastic toothpick or a plastic spoon to place one test portion on the tongue for 5 s to

10 s prior to rubbing the tongue gently around the mouth followed by swallowing. If a repetition is necessary,

another sample should be evaluated in the same manner as before. The assessor has to record the intensity

of the perceived off flavour on the scale 0 to 4 on the evaluation form using the multiple comparison test

method.
It is strongly recommended that the following scale is used:
 0 = no perceptible off-flavour;
 1 = just perceptible off-flavour (difficult to define);
 2 = weak off-flavour;
 3 = clear off-flavour;
 4 = strong off-flavour.

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 test portions of the calibration samples (C0 to C4) and the reference sample using a mould,

as described in clause 7;

The test portions for replicate one as well as those for replicate two shall be made of the same calibration

material.

 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. A

suggested design including sample blinding codes is given in Annex B;
---------------------- Page: 14 ----------------------
CEN/TR 15645-2:2008 (E)

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

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