1、DD CEN/TS15465:2008ICS 67.060NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWDRAFT FOR DEVELOPMENTCereals and cerealproducts Durumwheat (T. durum Desf.) General guidelinesfor instrumentalmethods measurementof semolina colourThis Draft for Developmentwas published under theautho
2、rity of the StandardsPolicy and StrategyCommittee on 32008 BSI 2008ISBN 978 0 580 56620 2Amendments/corrigenda issued since publicationDate CommentsDD CEN/TS 15465:2008National forewordThis Draft for Development is the UK implementation of CEN/TS15465:2008.This publication is not to be regarded as a
3、 British Standard.It is being issued in the Draft for Development series of publications andis of a provisional nature. It should be applied on this provisional basis,so that information and experience of its practical application can beobtained.Comments arising from the use of this Draft for Develo
4、pment arerequested so that UK experience can be reported to the internationalorganization responsible for its conversion to an international standard.A review of this publication will be initiated not later than 3 years afterits publication by the international organization so that a decision can be
5、taken on its status. Notification of the start of the review period will bemade in an announcement in the appropriate issue of Update Standards.According to the replies received by the end of the review period,the responsible BSI Committee will decide whether to support theconversion into an interna
6、tional Standard, to extend the life of theTechnical Specification or to withdraw it. Comments should be sent tothe Secretary of the responsible BSI Technical Committee at BritishStandards House, 389 Chiswick High Road, London W4 4AL.The UK participation in its preparation was entrusted to TechnicalC
7、ommittee AW/4, Cereals and pulses.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Stand
8、ard cannot confer immunityfrom legal obligations.0 SeptemberDD CEN/TS 15465:2008TECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN/TS 15465August 2008ICS 67.060English VersionCereals and cereal products - Durum wheat (T. durum Desf.) -General guidelines for instrumental methods
9、 measurement ofsemolina colourCrales et produits craliers - Bl dur (T. durum Desf.) -Lignes directrices pour la mesure de la couleur dessemoules par des mthodes instrumentalesGetreide und Getreideerzeugnisse - Hartweizen (T.durumDesf.) - Allgemeine Leitlinien fr die Messung derGriefarbe mit instrume
10、ntellen VerfahrenThis Technical Specification (CEN/TS) was approved by CEN on 28 January 2008 for provisional application.The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit theircomments, particularly on the quest
11、ion whether the CEN/TS can be converted into a European Standard.CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS availablepromptly at national level in an appropriate form. It is permissible to keep conflicting national standards
12、in force (in parallel to the CEN/TS)until the final decision about the possible conversion of the CEN/TS into an EN is reached.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ire
13、land, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36
14、 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN/TS 15465:2008: EDD CEN/TS 15465:2008CEN/TS 15465:2008 (E) 2 Contents Page Foreword3 Introduction .4 1 Scope 5 2 Terms and definitions .5 3 Apparatus .5 3.1 Genera
15、l5 3.2 Spectrocolorimeters6 3.3 Colorimeters.6 4 Procedure for sample preparation.6 4.1 General6 4.1.1 Introduction6 4.1.2 Dry semolina 6 4.1.3 Wet semolina6 5 Measurements6 5.1 General6 5.2 Dry semolina 7 5.3 Wet semolina7 6 Test report 7 Bibliography 8 DD CEN/TS 15465:2008CEN/TS 15465:2008 (E) 3 F
16、oreword This document (CEN/TS 15465:2008) has been prepared by Technical Committee CEN/TC 338 “Cereals and cereal products”, the secretariat of which is held by AFNOR. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not
17、be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Eston
18、ia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DD CEN/TS 15465:2008CEN/TS 15465:2008 (E) 4 Introduction The colour mea
19、surement of a milled product like semolina is an important characteristic for its end use; it is the ability of a durum wheat or a semolina to give a coloured final product. The indirect measurement of potential colour of semolina by chemical determination of carotenoid pigments (see EN ISO 11052) i
20、s not the same colour perceived by the human eye. The instrumental measure of yellow index and lightness allows to obtain a better evaluation of colour. DD CEN/TS 15465:2008CEN/TS 15465:2008 (E) 5 1 Scope This standard defines general guidelines for the instruments used to determine colorimetric cha
21、racteristics of semolina samples in the dry or wet form. 2 Terms and definitions 2.1 colour of semolina result of measurement performed by using a spectrocolorimeter or colorimeter in the conditions indicated in this European Standard 2.2 colour space expression of the colour of an object or of a li
22、ght source by some parameters expressed by figures NOTE Among the different systems, two are considered here: a) the tri-stimulus values x, y, z: which are at basis of existing colour space of CIE (Commission Internationale de lEclairage - International Commission on Illumination). These values repr
23、oduce the theory of colour perception by the human eye based on three components. b) the colour space CIELAB (1976) : this system is the most used for measuring the colour of objects. L* indicates the lightness and extend from 0 (black) to 100 (white); a* and b* are chromaticity indexes, respectivel
24、y: - +a* towards red and a* towards green; - +b* towards yellow and b* towards blue/ 2.3 illuminants light source characterized by a spectral curve, whose energy relative distribution is defined in the field of wavelengths which are able to influence the object colour vision NOTE The illuminants nor
25、malized by the CIE 1, are the following: a) Illuminant A: representing the light emitted by the integral radiator at the absolute temperature of 2856 K (approximately); b) Illuminant B: representing the direct light of sun of a proximal colour temperature similar to 4874 K; c) Illuminant C: represen
26、ting a medium day-light with a proximal colour temperature similar to 6774 K; d) Illuminant D65: representing one of the relative spectral distribution of the day-light energy which corresponds to a proximal colour temperature similar to 6504 K; It is recommended for obtaining the results to select
27、colour space CIE LAB and illuminant D65. 3 Apparatus 3.1 General There are two different types of instruments: spectrocolorimeters and filter colorimeters. NOTE The word “colorimeter” is also a generic appellation which can be applied to any colour measuring instrument based on any principle. DD CEN
28、/TS 15465:2008CEN/TS 15465:2008 (E) 6 3.2 Spectrocolorimeters Spectrocolorimeters enable the measuring of the luminance spectral factor, of reflection or transmission, and the determination of the colorimetric characteristics. They provide, in function of wavelength, the properties of reflection or
29、transmission of considered materials. A dispersive device position related to the sample defines two lighting ways: - lighting by monochromatic light (monochromator placed between source and sample); - lighting by polychromatic light (monochromator placed between sample and detector). 3.3 Colorimete
30、rs The filter colorimeters, as indicated by the name, use some appropriate filters, generally three, whose spectral transmission band covers a great part of the visible domain. These filters are determined by the manufacturer to obtain a measuring result corresponding to that which should be obtaine
31、d if the object was lighted by the light source specified. 4 Procedure for sample preparation 4.1 General 4.1.1 Introduction Colorimetric measurements are very sensitive to semolina granulometry and to the instrument used. The preparation protocol shall be clearly defined and controlled. 4.1.2 Dry s
32、emolina Before the analysis, the samples shall be homogenised. The measure may be made either on semolina as received or on a defined fraction of the semolina. In this last case, by sieving adequately the sample, a better homogeneity for a defined semolina sample can be obtained, reducing the variab
33、ility of particle size range. 4.1.3 Wet semolina With the aim of reducing the interferences on the colour measures due to the normal particle size distribution of semolina, it is possible to wet the semolina to obtain a sheet of fresh pasta and to perform colour measures on the surface of this sheet
34、. 5 Measurements 5.1 General Before every measures series, the apparatus shall be calibrated. The colorimeter calibration shall be made through opaque stable materials (as ceramics, glaze, ) sampled and supplied by manufacturers. When the colorimeter is used, a further calibration for better measure
35、 accuracy can be performed using references next to the colour of samples to be measured. DD CEN/TS 15465:2008CEN/TS 15465:2008 (E) 7 5.2 Dry semolina The semolina sample shall be posed in a container with a plane surface, optically neutral, equal or greater than the measurement surface of the instr
36、ument. The measure will be performed on this plane surface against which the semolina is posed, and to avoid any parasite light source, a black opaque screen shall cover both the sample-holder and the measure window of instrument. Sample-holders for the measure of granular material are provided as a
37、ttachment by apparatus manufacturers. 5.3 Wet semolina The pasta obtained from wet semolina will be posed directly in front of the measure window of instrument on a black background. To avoid the dehydration of surface sample, the time between the pasta preparation and the colour measurement should
38、be limited as much as possible (it should not exceed 60 s). 6 Test report The test report (colorimetric characteristics of a sample) shall contain the following information. a) apparatus : trade-mark, type, diameter of opening of measure window; b) sample : for dry semolina: milling process, particl
39、e size, conditions used for obtaining sample; for wet semolina: conditions used for obtaining pasta, hydration rate of the fresh pasta, time elapsed between pasta making and measure; c) general conditions of measurements: illuminant used (illuminant D65 is recommended), type of references used for c
40、alibration, room temperature; d) values obtained : colorimetric system ( L*, a*, b*); number of measures and relative standard deviation. The test report shall include all information necessary for a complete description of the sample and the measurement details which could affect the final result.
41、DD CEN/TS 15465:2008CEN/TS 15465:2008 (E) 8 Bibliography 1 CIE 15:2004, Colorimetry, 3rd Edition 2 EN ISO 11052:2006, Durum wheat flour and semolina - Determination of yellow pigment content (ISO 11052:1994) DD CEN/TS 15465:2008This page has been intentionally left blank DD CEN/TS15465:2008BSI Group
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