《BS-ISO-23275-1-2006.pdf》由会员分享，可在线阅读，更多相关《BS-ISO-23275-1-2006.pdf（22页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS ISO 23275-1:2006 Animal and vegetable fats and oils Cocoa butter equivalents in cocoa butter and plain chocolate Part 1: Determination of the presence of cocoa butter equivalents ICS 67.190; 67.200.10 ? Licensed Copy: London South Bank University, London South Bank University, Su
2、n Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 23275-1:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 BSI 2006 ISBN 0 580 49708 9 National foreword This British Standard was published by BSI. It is
3、the UK implementation of ISO 23275-1:2006. The UK participation in its preparation was entrusted to Technical Committee AW/307, Oil seeds, animal and vegetable fats and oils and their by products. A list of organizations represented on AW/307 can be obtained on request to its secretary. This publica
4、tion does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank
5、 University, London South Bank University, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Reference number ISO 23275-1:2006(E) INTERNATIONAL STANDARD ISO 23275-1 First edition 2006-11-01 Animal and vegetable fats and oils Cocoa butter equivalents in cocoa butter and plain chocolate P
6、art 1: Determination of the presence of cocoa butter equivalents Corps gras dorigines animale et vgtale quivalents au beurre de cacao dans le beurre de cacao et dans le chocolat de mnage Partie 1: Dtermination de la prsence dquivalents au beurre de cacao BS ISO 23275-1:2006 Licensed Copy: London Sou
7、th Bank University, London South Bank University, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iii Contents Page Foreword iv Introduction v 1
8、 Scope 1 2 Terms and definitions .1 3 Principle1 4 Reagents and materials 1 5 Apparatus .2 6 Sampling.2 7 Preparation of test sample3 7.1 Preparation of cocoa butter CRM for calibration purposes and system suitability check3 7.2 Preparation of chocolate sample.3 8 Procedure .3 8.1 Fat extraction .3
9、8.2 Separation of individual triacylglycerols by HR-GC 3 8.3 Identification.3 9 Calculation4 9.1 Determination of response factors4 9.2 Calculation of percentages of triacylglycerols.4 9.3 Decision if sample is pure cocoa butter4 10 Procedural requirements 5 10.1 General considerations.5 10.2 System
10、 suitability 5 11 Precision.5 11.1 Interlaboratory test5 11.2 Repeatability.6 11.3 Reproducibility.6 12 Test report6 Annex A (informative) Results of interlaboratory test.7 Bibliography12 BS ISO 23275-1:2006 Licensed Copy: London South Bank University, London South Bank University, Sun Dec 24 04:44:
11、04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each
12、member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
13、 Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards
14、adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of
15、patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 23275-1 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 11, Animal and vegetable fats and oils. ISO 23275 consists of the following parts, under the general title Animal
16、and vegetable fats and oils Cocoa butter equivalents in cocoa butter and plain chocolate: Part 1: Determination of the presence of cocoa butter equivalents Part 2: Quantification of cocoa butter equivalents BS ISO 23275-1:2006 Licensed Copy: London South Bank University, London South Bank University
17、, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI v Introduction “Cocoa butter equivalents” is the general term for fats used to replace cocoa butter in chocolate. They resemble the chemical composition and physical properties of cocoa butter very closely, making them therefore extrem
18、ely difficult to quantify and even in some cases to detect. In principle, cocoa butter equivalents must by definition be fats low in lauric acid, rich in symmetrical mono-unsaturated triacylglycerols of the type 1,3-dipalmitoyl-2-oleoylglycerol, 1-palmitoyl-2-oleoyl-3-stearoylglycerol and 1,3-distea
19、royl-2- oleoylglycerol, miscible with cocoa butter, and obtained only by refining and fractionation. Within the European Union, the following vegetable fats, obtained from the plants listed below, may be used singly or in blends, according to Directive 2000/36/EC 1: illip, Borneo tallow or tengkawan
20、g (Shorea spp.), palm oil (Elaeis guineensis, Elaeis olifera), sal (Shorea robusta), shea (Butyrospermum parkii), kokum gurgi (Garcinia indica), and mango kernel (Mangifera indica). This part of ISO 23275 specifies a procedure for the detection of these fats (restrictions are only made for pure illi
21、p fat samples) in cocoa butter and plain chocolate. ISO 23275-2 specifies a procedure allowing a reliable quantification of these fats at the level of 5 %, complying with the statutory limit laid down in Directive 2000/36/EC 1 of the European Parliament and the Council. To facilitate the usage of bo
22、th parts of ISO 23275, an analytical toolbox named “CoCal-1” has been established. “CoCal-1” contains the validated methods for detection (part 1) and quantification (part 2) of CBEs in plain chocolate, and also a certified cocoa butter reference material (IRMM-801) to calibrate the analysts instrum
23、ents and an electronic evaluation sheet for Microsoft Excel to calculate the final result. An analyst working on CBE detection and quantification has only to calibrate the gas chromatographic separation system using IRMM-801, separate the triglyceride fractions of the sample in question, and use the
24、 electronic evaluation sheet for subsequent data treatment to detect and quantify CBEs. Information on “CoCal-1” is available on the website of the Institute for Reference Materials and Measurements: http:/www.irmm.jrc.be. BS ISO 23275-1:2006 Licensed Copy: London South Bank University, London South
25、 Bank University, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 1 Animal and vegetable fats and oils Cocoa butter equivalents in cocoa butt
26、er and plain chocolate Part 1: Determination of the presence of cocoa butter equivalents 1 Scope This part of ISO 23275 specifies a procedure for the detection of cocoa butter equivalents (CBEs) in cocoa butter (CB) and plain chocolate by high-resolution capillary gas liquid chromatography (HR-GC) o
27、f triacylglycerols and subsequent data evaluation by regression analysis. The method is applicable for the detection of 2 % CBE admixture to cocoa butter, corresponding to about 0,6 % CBE in chocolate (i.e. the assumed fat content of chocolate is 30 %). 2 Terms and definitions For the purposes of th
28、is document, the following terms and definitions apply. 2.1 cocoa butter equivalents CBEs fats detected in cocoa butter and plain chocolate according the procedure specified in this part of ISO 23275 NOTE The result is expressed as a qualitative result, i.e. CBEs present/CBEs not present (YES/NO). 3
29、 Principle Cocoa butter, or the fat obtained by solvent extraction from plain chocolate, is separated by HR-GC into triacylglycerol fractions according to their molecular mass and degree of unsaturation. The presence of CBEs is detected by linear regression analysis applied to individual triacylglyc
30、erol fractions of the fat analysed. 4 Reagents and materials Use only reagents of recognized analytical grade, unless otherwise stated. WARNING Attention is drawn to the regulations which specify the handling of dangerous matter. Technical, organizational and personal safety measures shall be follow
31、ed. 4.1 Cocoa butter Certified Reference Material (CRM) IRMM-801 2, for calibration purposes and system suitability check. 4.2 Fat solvent, non-chlorinated solvents (e.g. diethyl ether, n-heptane, iso-octane). BS ISO 23275-1:2006 Licensed Copy: London South Bank University, London South Bank Univers
32、ity, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 5 Apparatus 5.1 Analytical balance, with a readability of 0,1 mg. 5.2 Drying oven, maintained at 55 C. A dry heater block may be used. 5.3 Food grater, i.e. a kitchen blender with a design featuring the motor above the receiving c
33、ontainer to avoid melting the samples1). 5.4 Rotary evaporator. Alternative evaporation procedures may be used. 5.5 Pipettes, of capacity 1 ml. 5.6 Volumetric flasks, of capacity 20 ml. 5.7 Microsyringe, with maximum volume 10 l, graduated to 0,1 l, or automatic sampler. 5.8 Gas chromatograph (GC),
34、fitted with a cold on-column injection system and a flame ionization detector (FID). Alternative injection systems e.g. a split injector, a programmed-temperature vaporizer (PTV) or a moving- needle injector may be used provided the same results are obtained as indicated in 10.2. The separation and
35、detection have been found to be satisfactory if the following experimental conditions are followed: GC column: 25 m to 30 m length, with 0,25 mm i.d., fused silica coated with thermostable 50 % phenylmethylpolysiloxane to a film thickness of 0,1 m to 0,15 m. temperature programme: 100 C (initial tem
36、perature), programme rate 30 C/min to 340 C (final temperature). carrier gas: helium or hydrogen (purity W 99,999 %). NOTE Suitable columns and alternative experimental conditions, used in an international collaborative study, are listed in Annex A. Operating conditions may be changed to obtain opti
37、mum separation of cocoa butter triacylglycerols. 5.9 Chromatographic data system. 6 Sampling A representative sample should have been sent to the laboratory. It should not have been damaged or changed during transport or storage. Sampling is not part of the method specified in this part of ISO 23275
38、. A recommended sampling method is given in ISO 5555. 1) Philips HR2833 is an example of suitable equipment available commercially. This information is given for the convenience of the users of this part of ISO 23275 and does not constitute an endorsement by ISO of this product. BS ISO 23275-1:2006
39、Licensed Copy: London South Bank University, London South Bank University, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 7 Preparation of test sample 7.1 Preparation of cocoa butter CRM for calibration purposes and system suitability check Before opening and using the cocoa butter
40、 CRM (4.1), the ampoule shall be warmed in a drying oven (5.2) until the contents have melted. When a clear solution is obtained, mix the contents by repeated inversion for not less than 20 s. Then open and transfer the contents to a clean vial, which can be tightly sealed and preserved in a cool pl
41、ace for future usage. 7.2 Preparation of chocolate sample Chill approx. 200 g of chocolate until hard, and grate to fine granular condition using a mechanical device (5.3). Mix thoroughly and preserve in tightly stoppered bottle in a cool place. 8 Procedure 8.1 Fat extraction Separate the fat from 1
42、0 g to 40 g of grated chocolate (as described in 7.2) by extracting with two or three 100 ml portions of a fat solvent (4.2). Centrifuge and decant. Combine the extracts and evaporate most of the fat solvent (5.4) then finally dry it under a stream of nitrogen. Alternative extraction procedures may
43、be used (e.g. by Soxhlet, by supercritical carbon dioxide or by using microwaves) provided that the same results are obtained. 8.2 Separation of individual triacylglycerols by HR-GC The test samples cocoa butter, fat extracted from chocolate, cocoa butter CRM (4.1) shall be warmed in a drying oven (
44、5.2) until completely melted. If the liquid sample contains sediment, filter the sample inside the oven to obtain a clear filtrate. Pipettes (or similar equipment) used for transferring the sample during weighing operations should be brought to a temperature of ca. 55 C in a drying oven (5.2) in ord
45、er to avoid partial fat fractionation. Weigh ca. 0,2 g of test sample in a 20 ml volumetric flask (5.6) and dilute to the mark with a suitable fat solvent (4.2). Pipette (5.5) 1 ml of the resulting solution into another 20 ml volumetric flask and dilute to the mark with the same solvent. Inject 0,5
46、l to 1,0 l of the final test solution (fat = 0,5 mg/ml) into the HR-GC system using the cold on- column injection system. Alternative sample amounts and injectors may be used provided that the detection system employed gives a linear response and the system suitability criteria (10.2) are met. 8.3 I
47、dentification Identification of the five major triacylglycerol fractions 1,3-dipalmitoyl-2-oleoylglycerol (POP), 1-palmitoyl-2- oleoyl-3-stearoylglycerol (POS), 1-palmitoyl-2,3-dioleoylglycerol (POO), 1,3-distearoyl-2-oleoylglycerol (SOS), and 1-stearoyl-2,3-dioleoylglycerol (SOO) is made by compari
48、son of the retention times of the test samples with those of the cocoa butter CRM (4.1). In general, triacylglycerols appear in order of increasing number of carbon atoms and of increasing unsaturation for the same number of carbon atoms. The elution order of the triacylglycerols of the cocoa butter
49、 CRM is given in the example chromatogram (Figure A.1). BS ISO 23275-1:2006 Licensed Copy: London South Bank University, London South Bank University, Sun Dec 24 04:44:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 9 Calculation 9.1 Determination of response factors Determine the response factors of the triacylglycerols POP, POS, POO, SOS and SOO by injection of the cocoa butter CRM solution using experimental conditions identical to those us