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REFERENCE TILES FOR THE CALIBRATION OF MEASUREMENT OF COLOUR OF TOMATO PASTE AND SIMILAR PRODUCTS

Objective


Subjective methods for assessing colour of tomato paste by visual comparison with colour cards are being replaced by objective methods employing colorimeters. These devices measure colour by mimicking the response of the human eye to the 3 primary colours, red, blue and green and allow any colour and shade to be expressed numerically in terms of tri-stimulus or colour values. Consultation with major users of tomato paste confirmed the need for reference tiles specifically for the calibration of colorimeters used for industrial purposes.

A batch of 1200 tiles having a colour very close to the target values and a narrow range of L, a and b values (26(+/-0.5), 32.8(+/-0.5), 14.4(+/-0.4)respectively) has been produced. Individual colour values have been assigned to each tile by one institute using an instrument whose calibration is directly traceable to a national metrology institute. The tile was shown in a study involving 52 European Laboratories to virtually eliminate calibration errors in the measurement of tomato colour.
The annual European production of tomato paste is valued at some 600 MECU, its principal usage being as an ingredient in food. Among several attributes, the colour of tomato paste is tightly specified by the purchasers who need to ensure that their food products have a consistent appearance. Increasingly, subjective methods for assessing colour of tomato paste by visual comparison with colour-cards are being replaced by objective methods employing colorimeters. These devices measure colour by mimicking the response of the human eye to the three primary colours, red, blue and green and allow any colour and shade to be expressed numerically in terms of "tri-stimulus" or colour values (e.g. Judd-Hunter L.a.b. values).
The colour sub-group of COST 90 Bis (Physical Properties of Foods) investigated sources of disagreement in measurement of food colour.
Consultation with major users of tomato paste confirmed the need for reference tiles specifically for the calibration of colorimeters used for industrial purposes.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Ministry of Agriculture, Fisheries and Food (MAFF)
Address
135 Abbey Road
AB9 8DG Aberdeen
United Kingdom

Participants (15)

AB Marabou
Sweden
Address

17285 Sundbyberg
AB Slotts
Sweden
Address

Uppsala
BRITISH CERAMIC RESEARCH LTD.
United Kingdom
Address
Penkhull, Queens Road
ST4 7LQ Stoke-on-trent
CSIC - Instituto Agroquimico de Tecnologia de Alimentos (IATA)
Spain
Address
11,Calle Jaime Roig
46010 Valencia
Campden and Chorleywood Food Research Association (CCFRA)
United Kingdom
Address
Station Road
GL55 6LD Chipping Campden
Danish Research Service for Plant & Soil Science
Denmark
Address
12,Kirstinebjergvej
5792 Arslev
ENSIA
France
Address
1 Avenue Des Olympiades
91300 Massy
F. HOFFMANN LA ROCHE
Switzerland
Address
124,Grenzacherstrasse
4002 Basel
FEDERAL INSTITUTE FOR MATERIAL RESEARCH AND TESTING
Germany
Address
87,Unter Der Eichen 87
12205 Berlin
HENGSTENBERG
Germany
Address
Mettinger Straße 109
73728 Esslingen Am Neckar
Ministry of Agriculture in Athens
Greece
Address
1,S. Venizelou
14123 Lykovrissi Athens
Ministère des Affaires Economiques
Belgium
Address
17A,rue De La Senne
1000 Bruxelles
Nordreco AB
Sweden
Address

26755 Bjuv
STAZIONE SPERIMENTALE PER L'INDUSTRIA DELLE CONSERVE ALIMENTARI
Italy
Address
Viale Faustino Tanara 31/A
Parma
TEAGASC - National Food Centre
Ireland
Address
Dunsinea, Castleknock
15 Dublin