Bsi bs en 12147 1997 scan

STD BSI B S EN 12147 ENGL 1777 1b24bb7 Ob217LL 1 2 2 BRITISH STANDARD Method for Determination of titratable acidity of fruit and vegetable juices BS EN 12147 1997 The European Stanhd EN 12147 1996 ha[.]

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S T D - B S I B S E N 1 2 1 4 7 - E N G L 1777 1 b 2 4 b b 7 O b 2 1 7 L L 1 2 2

BRITISH STANDARD

titratable acidity of fruit

BS EN

12147 : 1997

British Standard

ICs 67.160.20

NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW

Copyright European Committee for Standardization

Provided by IHS under license with CEN

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Amd No Date

BS EN 12147 : 1997

Text affected

Committees responsible for this British Standard

The preparation of this British Standard was entrusted to Technid Committee

represented:

British Fniit Juice Irnport~rs’ Association British Retail Consortium

British Soft Drinks Association Limited Campden and Chorleywood Food Research Association Department of ?iade and Industry (Laboratory of the Government Chemist) Leatherhead Food Research Associalion

Minishy of Agnculture, Fisheries and Food Royal Society of Chemistry

This British Standard, having

been prepared under the

direction of the Consumer

Products and Services Sector

Board, was published under the

authority of the Standards Board

and comes into effect on

15 June 1997

@ BSI 1997

Amendments issued since publication

The following B I references

relate to the work on this

standard

Committee reference Awl21

Draft for comment 91157094 DC

ISBN O 580 27424 1

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BS EN 12147 : 1997

Contents

page

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```,-`-`,,`,,`,`,,` -BS EN 12147 : 1997

National foreword

This British Standard has been prepared by Technid Committee AW/21, and is the English language version of EN 12147 : 1996 h i t and wgetablejukes -

Determ,imt.ion of titratubk acidity, published by the European Committee for

standardization (CEN) EN 12147 was produced as a result of ink&onal discussions

in which the United Kingdom took an active part

Cross-references Publication referred to

EN IS0 3696 : 1995

IS0 5725 : 1986, to which informative reference is made in the text, has been

superseded by IS0 57251 : 1994, IS0 57252 : 1994, IS0 57253 : 1994, IS0 5725-4 : 1994

and IS0 57254 : 1994 which are identical with BS IS0 5725 Accu- (trueness and

precision) of r n m s u m t methods and results, BS IS0 57251 : 1994 GerwmL

pinciples and definitions, BS IS0 57252 : 1994 B& method f o r îhe determination

of repeutubility aná reproducibility of a standard rneusurernent method,

BS IS0 57253 : 1994, Interrnedkte measures of the precìs.ion of a stu&rd

measurement method, BS IS0 5725-4 : 1994 B& method for the determination of the

Compliance with a British Standard does not of itself confer immunity from legal obligations

Corresponding British Standard

BS EN IS0 3696 : 1995 Spec&fht.ion f o r water f o r lubomtory

use

of accumc2/ values

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii, the

EN title page, pages 2 to 6, an inside back cover and a back cover

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NORMì3 EUR0PEE”E

1EuROP- NORM December 1996

ICs 67.160.20 Descriptors: Food products, beverages, fruit and vegetable juices, chemical anaiysis, determination, acidity, titration

English version

Fruit and vegetable juices - Determinaton of titratable acidity

Jus de fruits et de légumes - Dékmnimíion de i’aciditk titrable tittierbmn Saure

h c h t - und Gemusesaffe - Bestimmung der

This European Standard was approved by CEN on 1 W 5 - 0 9 CEN members are bound to compiy with the CENICENELEC h t e d Regulations which stipuiate the conditions for giving this European Standard the status of a nationai standard without any alteration

Uptodate lists and bibliographical references concerning such nationai standards may be obtained on application to the Central Secretariat or to any CEN member

This European Standard exists in three official vemions (English, French, German)

A version in any other ianguage made by translation under the responsibility of a CEN member into its own language and notified to the Centrai Secretariat has the same status as the officiai versions

CENmembers are the nationai standards bodies of Austria, Beigium, Denmark,

Finiand, h c e , Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom

CEN

European Committee for Standardization

Comité Européen de Normalisaton Europäisches Komitee für Normung

Central Secretariat: rue de Stassart 36, B-1060 Brussels

O 1996 Copyright reserved to CEN members

Ref No EN 12147 : 1996 E

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Page 2

Foreword

This European Standard has been prepared by

Technical Committee CENmC 174, the secretariat of

which is held by AFNOR

This European Standard shall be given the status of a

national standard, either by publication of an identical

text or by endorsement, at the latest by June 1997, and

conflicting national standards shall be withdrawn at

the latest by June 1997

According to the CENKENELEC interml Regulations,

the national standards organizations of the following

countries are bound to implement this European

Standad Austria, Belgium, Denmark, Fïnlmd, France,

Germany, Greece, Iceland, Ireland, Italy, Luxembourg,

Netherlands, Norway, Portugal, Spain, Sweden,

Switzerland and the United Kingdom

Contents

Foreword

1 Scope

2 Normative references

3 Defmition and symbol

4 Principle

6 Reagents

6 APP-

7 Procedure

8 Calculation

9 Precision

10 Testreport

Annexes

A (iormative) Bibliography

B inter-lab0mS-y test (ionnative) statistical resuits of the

page

2

3

4

5

O BSI 1997

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```,-`-`,,`,,`,`,,` -1 scope

This European Standard specifies a method for the determination of the tikitable acidity of fniit and vegetable juices and related products

2 Normative references

This European Standard incorporates by dated or undated reference, provisions from other publications

These normative references are cited at the appropriate piaces in the text and the publications are listeà hereafter For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard ordy

when incorporated in it by amendment or revision For undated references the laî.est edition of the publication referred to applies

EN EO 3696 : 1995 Water for analytkai l.abomtu?y

use - Specìfication and test

methods

Determination of repeatability

PrecLSum of test methods -

IS0 5725 : 1986

- and reproducibuity for a

= standard test method by

inter-labomtory tests

-

3 Deñnition and symbol

- *

m For the purposes of this standard the following

3.1 titratable acidity

A measure of the content of minerai and organic acids determined by titration, according to this standard

3.2 Symbol

For the purposes of this standard the following symbol applies:

* defmition applies

G substance concentration

4 Principle

Potentiometric titration with standard volumetric soàium hydroxide solution to a pH value of €41

5 Reagents

Use onìy reagents of recognized analyticai grade and

oniy degassed water in accordance with at least

grade 3 of EN IS0 3696 : 1995

6.1 Sodium hydm-, standard volumetric solution,

c (NaOH) = 0,25 moM

6.2 Buffer solutim, of suitable pH

Page 3

EN 12147 : 1996

6 Apparatus Usual laboratory apparatus and, in particular, the following:

6.1 p H meter, accurate to at least 0,Ol pH units 6.2 p H glass electrode

6.3 Refmme electrode, e.g calomel electrode

6.4 Combination g h s ekctmde, alternatively to 6.2

and 6.3

6.6 Magnetic s t i m

6.6 Burette, 25 mi capacity, graduated in 0,05 mi divisions

6.7 Lcnu fomt beaker (typically 50 mi)

6.8 One-mark pipette, 25 ml capacity

7 Procedure 7.1 Preparation of the test sample

Nonnally products shall not be pretreated and their anaiysis by this method shall be on a volumetric basis,

results being expressed per litre of sample Anaìysis of concentrated products may also be carried out on a volumetric basis, after dilution to a known relative density, in this case, the relative density shall be indicated Based on a weighed sample and taking the djiution factor for analysis into account, the results

may also be expressed per kilogram of product In products with a high viscosity and/or a very high

content of cells (for exampie pulp), a detemination on the basis of a weighed test sample is the usuitl

procedure

If the sample contains appreciable quantities of carbon

dioxide, degas it by shaking in a st~ppered conical

flask and removing the stopper from time to time, or

by using vacuum or ultrasound treatment untiì no more gas evolves

7.2 Calibration

Perform two-point calibration of the pH meter at 20 "C

using the buffer solution (6.2) with agitation and foliowing the instrument manufacturer's instructions If the pH meter is equipped with a temperature

compensation f a d @ , the caiibration can be &ed

out at a temperature other than 20 OC, but in any case

between 10 "C and 30 "C

7.3 Determination

'II.ansfer at 20 O C , by means of the pipette (6.8), 25 ml

of the test sample (Vo) into the beaker (6.7) Start the sikrer (6.6) and titrate by means of the burette (6.6)

with soàium hydroxide solution (6.1) una a pH

of 8,l is obtained Record the amount of solution (VI)

used if the pH meter is equipped with a temperature compensation facility, the determination can be carried

out at a temperature other than 20 OC, but in any case

between 10 "C and 30 "C

0 BSI 1997

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EN i2147 : 1996

Citric acid, anhydrous

8 Cdculation

8.1 Calculation as titratable acidity

The titratable acidity CH+, expressed in millimoles of

H+ per litre of product, is given by the form&

(1)

1Ooox v1xc

VO

c H + =

where

0,064

Vo is the volume, in milliiitres, of the test portion

(see 7.3) (as a rule 25 mi);

hydroxide solution (see 7.3) used for the

determination;

is the exact concentsaton, in moles per litre, of

the sodium hydroxide solution (6.1)

G

If Vo is 25 ml and c is 0,25 moM, as specified in this

expressed in millimoles of H+ per litre of product, is

given by the formuh

Report the result without a decimal place

8.2 Calculation as acid content

It is also possible to calculate the titratable acidity

conventionally as acid content expressed in grams per

litre of product, by multiplying the formula (8.1) by a

factor corresponding to the acid given in table 1

Tgble 1 Factors corresponding to different

10,075 0,067

9 Precision

Details of the inter-laboratory test on the precision of the method are given in annex B The d u e s derived from the inter-laboiatory test may not be applicable to

d y t e concentmiion ranges and matrices other thCui those given in annex B

9.1 Repeatability

The absolute difference between two single test results

found on identicai test material by one operator using

the same apparatus within the shortest feasible time

interval will exceed the repeaîability limit r in not more than 5 % of the cases

The d u e is:

9.2 Reproducibility

The absolute difference between two single test results

on identicai test material reported by two laboratories

w i l l exceed the reproducibility limit R in not more than5%ofthecases

The value is:

R = 2,28 mm01 H+A

10 l k s t report

The test report shall contain the following dah

- ali information necessary for the identification of the sample (kind of sample, origin of sample, designation);

- a reference to this European Standard -the date and type of sampling procedure (if -the date of receipt;

-the date of test;

- the test resuits and units in which they have been expressed;

-whether the repeatability of the method has been verified;

- any particular points observed in the course of the

test;

- any operation not specified in the method or regarded as optional, which might have affected the

results

Iniown);

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EN 12147 : 1996

39

72

Annex A (informative) Bibliography

Determimtion of titmtabie acidity : No 3,1991

In: The CouaCted Analyses of the Intenzat- Federation of h i t Juice Producers

Loose-leaf edition, as of 1991 Zug: Swiss Fniit Union

Annex B (informative)

S t a l i s t i d results of the inter-laboratory test

in accordance with IS0 5725 : 1986, the foliowing parameters have been defined in an inter-laboratory test (for

iiterature pertaining to the method see annex A) The test was conduced by the Max von Pettenkofer Institute of the Federal Health Office, Food Chemistry Department, Berlin, BRD

Year of interlaboratory test: 1993;

Number of laboratories: 14;

Number of samples: 5

I Sample

Number of laboratories retained after elhmaîmg outliers Number of outliers (laboratories)

Number of accepted results

Mean value (mmol H+A) Repeatability standard deviation (sr) (mm01 H+/l)

Repeatabiiity relative standard deviation (RSD,) (%)

I Repeatability limit (r) ( m o l H+A)

Reproducibility standad deviation (SR) ( m o l H+A)

Reproducibility relative standard deviation (RSDR) (%)

Rey>roducibility limit (R) (mmol H+A)

Sample types:

A: apple juice;

B apricotnectar;

C grapejuice;

D: orangejuice;

E grapefruitjuice

O BSI 1997

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BS EN 12147 : 1997

List of references

see national foreword

O BSI 1997

Tiêu đề	Method for determination of titratable acidity of fruit and vegetable juices
Trường học	British Standards Institution
Chuyên ngành	Standardization
Thể loại	British standard
Năm xuất bản	1997
Thành phố	London

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