SIST EN ISO 5377:1998
(Main)Starch hydrolysis products - Determination of reducing power and dextrose equivalent - Lane and Eynon constant titre method (ISO 5377:1981)
Starch hydrolysis products - Determination of reducing power and dextrose equivalent - Lane and Eynon constant titre method (ISO 5377:1981)
Titration of a prescribed volume of mixed Fehling's solution with a solution of a test portion under specified conditions, using methylene blue as internal indicator. An informative annex provides a metod for testing standard reference anhydrous D-glucose, necessary for the procedure.
Stärkehydrolyseprodukte - Bestimmung des Reduktionsvermögens und des Dextroseäquivalents - Verfahren mit konstantem Titer nach Lane und Eynon (ISO 5377:1981)
Diese Internationale Norm legt ein mit konstantem Titer arbeitendes Verfahren nach Lane und Eynon zur Bestimmung des Reduktionsvermögens und des Dextroseäquivalents sämtlicher Stärkehydrolysate fest.
Produits d'hydrolyse de l'amidon ou de la fécule - Détermination du pouvoir réducteur et de l'équivalent en dextrose - Méthode Lane et Eynon a titre constant (ISO 5377:1981)
La présente Norme internationale spécifie la méthode Lane et Eynon à titre constant, pour la détermination du pouvoir réducteur et de l'équivalent en dextrose pour tous les produits d'hydrolyse de l'amidon ou de la fécule.
Škrobni hidrolizati - Določevanje redukcijske moči in dekstroznega ekvivalenta - Titrimetrijska metoda po Lanu in Eynonu
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 5377:1998
01-november-1998
âNUREQLKLGUROL]DWL'RORþHYDQMHUHGXNFLMVNHPRþLLQGHNVWUR]QHJDHNYLYDOHQWD
7LWULPHWULMVNDPHWRGDSR/DQXLQ(\QRQX
Starch hydrolysis products - Determination of reducing power and dextrose equivalent -
Lane and Eynon constant titre method (ISO 5377:1981)
Stärkehydrolyseprodukte - Bestimmung des Reduktionsvermögens und des
Dextroseäquivalents - Verfahren mit konstantem Titer nach Lane und Eynon (ISO
5377:1981)
Produits d'hydrolyse de l'amidon ou de la fécule - Détermination du pouvoir réducteur et
de l'équivalent en dextrose - Méthode Lane et Eynon a titre constant (ISO 5377:1981)
Ta slovenski standard je istoveten z: EN ISO 5377:1994
ICS:
67.180.20 Škrob in izdelki iz njega Starch and derived products
SIST EN ISO 5377:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 5377:1998
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SIST EN ISO 5377:1998
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SIST EN ISO 5377:1998
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SIST EN ISO 5377:1998
International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDlZATION.ME)I(C1YHAPOC1HAF OPrAHM3ALWlR fl0 CTAH&APTl43ALWlkl~ORGANISATlON INTERNATIONALE DE NORMALISATION
Starch hydrolysis products - Determination of reducing
power and dextrose equivalent - Lane and Eynon
constant titre method
Determination du pouvoir rbducteur et de l’equivalent en dextrose -
Produits d’hydrolyse de l’amidon ou de Ia f&ule -
Methode Lane et Eynon 6 titre constant
First edition - 1981-12-15
UDC 664.28 : 664.162.036 : 543.24 Ref. No. ISO 5377-1981 (E)
Descriptors : starches, tests, determination, mass losses, dry matter, titration.
Price based on 6 pages
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SIST EN ISO 5377:1998
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of
national Standards institutes (ISO member bodies). The work of developing Inter-
national Standards is carried out through ISO technical committees. Every member
body interested in a subject for which a technical committee has been set up 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.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the ISO Council.
International Standard ISO 5377 was developed by Technical Committee ISO/TC 93,
Starch (including derivatives and by-productsl, and was circulated to the member
bodies in November 1980.
lt has been approved by the member bodies of the following countries :
Australia Netherlands
Austria Romania
Egypt, Arab Rep. of South Africa, Rep. of
France USA
Iran USSR
No member body expressed disapproval of the document.
0 International Organkation for Standardkation, 1981
Printed in Switzerland
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SIST EN ISO 5377:1998
ISO 5377-1981 (E)
INTERNATIONAL STANDARD
Starch hydrolysis products - Determination of reducing
power and dextrose equivalent - Lane and Eynon
constant titre method
4 Principle
1 Scope and field of application
This International Standard specifies a Lane and Eynon cons- Titration of a prescribed volume of mixed Fehling’s Solution
with a Solution of a test Portion under specified conditions,
tant titre method for the determination of the reducing power
using methylene blue as internal indicator.
and dextrose equivalent of all starch hydrolysis products.
2 References
5 Reagents
ISO 38511, Laboratory glassware - Burettes - Part 7:
During the analysis, use only reagents of recognized analytical
General reguiremen ts. 1)
grade and only distilled water or water of equivalent purity.
ISO 38512, Laboratory glassware - Part 2: Burettes for wbich
no waiting time is specified. l)
5.1 Fehling’s stock solutions
ISO 648, Laboratory glassware - One-mark pipettes.
Prepare the following solutions, using apparatus in accordance
with clause 6.
ISO 1042, Laboratory glassware - One-mark volumetric flasks.
ISO 1741, Dextrose - Determination of loss in mass on drying
5.1.1 Stock Solution A
- Vacuum oven method.
CopperU sulphate pentahydrate
69,3 g
ISO 1742, Glucose syrup - Determination of dry matter con-
(CUSOJ-~H~O)
tent - Vacuum oven method.
Water to 1 000,O ml
ISO 1743, Glucose syrup and dextrose - Determination of dry
Refractive index method.
matter content -
5.1.2 Stock Solution B
ISO 1773, Laboratory glassware - Boiling flasks (narrow-
necked).
Potassium sodium tartrate tetrahydrate
3460 g
(KNaC4H406-4H20)
l SO 5809, Starch, including derivatives and b y-products -
Sodium hydroxide (NaOH) 100,o g
Determination o f sulpha ted asb. 2)
Water to
1 000,O ml
Before use, decant the clear Solution from any Sediment that
3 Definitions
may form.
3.1 reducing power : The content of reducing sugars, ex-
pressed as the number of grams of anhydrous D-glucose per
5.1.3 Mixed Fehling’s Solution
100 g of the Sample, when determined by the method specified
in this International Standard.
Transfer into a dry stock glass bottle, in the following Order,
100 ml of Solution A (5.1 .l) and 100 ml of Solution B (5.1.2).
Mix weil.
3.2 dextrose equivalent : The content of reducing sugars,
expressed as the number of grams of anhydrous D-glucose per
100 g of the dry matter in the Sample, when determined by the
NOTE - DO not keep Fehling’s Solution. Prepare this mixed Solution
method specified in this International Standard. just before use and standardize it as specified in 7.1.
1) At present at the Stage of draft. (Revision, in Part, of ISO/R 385.)
2) At present at the Stage of draft.
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SIST EN ISO 5377:1998
5. AKRhydaous -g&ucsse, complying with the following pcsent sb d-Ie titratisn 40 be observed withcsu t the flask having to
be removed hm the h eating device.
requirements :
a so!ution containing 480 g/! sha!! be free from haze and
a)
sediment and sha!! show no more colour than the water
used in its preparatisn when examined downwards in 50 m!
Ness%er tubes (6.5) fil!ed to the marks;
b) the sulphated ash content sha!! be not greater than
MBTES
8,Ol % (&Hz) when determined by the method specified in
89 amended as fo!!ows :
1 A boiling aid (Tor example glass beads) may be added, if desired, to
ensure freedom from super-heating.
the mass of the test Portion sha!! be increased
11
2 Shield the burette from the Source of heat (6.6) at all times.
to 20 g,
sn!y a platinum dish sha!! be used fsr incineration,
3) the platinum d ish shall be weighed to the nearest
incineration;
0,3 sng before an d after the
.l.l Using a pipette 6.3), piace 25,O m! of the Fehling’s solu-
c) the maltose and/or isomaltsse content sha!! not exceed
tkm (5. i .3B in the clean, dry boiling flask (6.1!,
8,l % (mlm) and no sugar sf greater re!ative molecular
mass sha!! be detected.
7.12 Fi !! the burette (6.2) to the
zero mark with the D-g!u tose
standard reference so!utisn (5.3).
5.3 %ucose, Standard reference Solution.
7.‘M Run into the boiling flask from the burette, 18,O m! uf
5.31 DetermG7e the dry matter content of the anhydrsus
the Q-glucose sslution (5.3). Svviri the flask to mix the con-
D-glucose by the method specified in !SC L4l.
lE?MS.
5.32 VVeigh, to the nearest O,l mg, a mass sf the anhydrous
7.1. Place the boi!ing f!ask W-I the heating device (6.6),
D-glucose (5.2) containing 0,6OO g of ss!ids, disso!ve it in
previous!y adjusted so that the boiling commences in
water, transfer the Solution quantitively into a ‘800 m! one-mark
‘!20 L- i5 s as timed by the stop-watch (6.7).
volumetric f!ask NS), dilute to the mark with water and mix.
DO not adjust the heating device subsequently. Chis ensures
Prepare this ss!ution freshly on each day of use.
that once boiling has commenced the evolution of steam BS
brisk and continuous throughout the who!e of the titration pro-
cess, thus preventing to the maximum possible extent the en-
ethy8ene bI~e (CIGH18C!N~S.2H~O), indicator, 1 g/!
trance of air ta the titration f!ask vwifh csnsequent re-Oxidation
aqueesus solution.
of its csntents.
7.1.5 Bring the contents of the flask to the boi! and continue
boi!ing for 120 s (timed by the stop-watchi. Add 1 m! sf the
Ordinary Iaboratory apparatus and in particular methylene biue sslution (5.4) towards the end of this period.
After expiry of the 120 s period, commence adding the
D-g!ucose so!ution to the f!ask from the burette in 0,s m! in-
arrow-neeked boiBSng Ha&, of capacity 250 m!, com-
.a
crements unti! the cs!sur of the methy!ene b!ue is discharged,
plying with the requirements of !SO 1773.
boiling being csntinued during the whole titration.
6.2 Burette, of capacity 25 m!, graduated in subdivisions 0%
Note the total volume 0 f the D-glucose ss!ution I V na!),
O,O5 m!, complying with the requirements of ISO 385/2,
up to and including the penultimate 8,s m! increment.
class A.
NOTE - The disappearance of the colour of the methylene blue is best
seen by Booking at the upper layers and the meniscus of the contents of
ne-r-nar pipettes, of capacity 1 mE and 25 m!, com-
the titration flask, as these will be relatively free from the precipitated,
c!ass A.
plying with the requirements o f EO 648,
red topper(I) oxide. The colour disappearance is more easily seen
when indirect lighting is used. A white Screen behind the titration flask
is helpful.
Orte-maak wohmetric flasks, of capacity lMI m!,
QXXI m! and 1 808 m!, complying with the requirements of
7.1.6 Repeat 7.1.1 and 7.1.2.
ISO 1M2, class A.
7.1.7 From the burette run into the boiling flask a volume of
essler tubes, of capacity XI m!.
the D-giucose solutisn equa! to (iV - 0,3) m!.
.6 Heating dewice, suitab! e for . maintaining b oiling as re-
quired in 7.1.4 whi!st e nabling the cslour Change at the end- 7.1. Wepeat 7.1.4.
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SIST EN ISO 5377:1998
ISO5377=1981(E)
7.1.9 Bring the contents of the flask to the boil and continue b) After 7.1.4
boiling for 120 s (timed by the stop-watch). Add 1 ml of the
methylene blue Solution towards the end of this period. After 1) Immediately boiling Starts, add 1 ml of the
expiry of the 120 s period, commence adding the D-glucose methylene blue Solution and commence adding the test
Solution to the flask from the burette, initially in 0,2 ml in- Solution to the flask from the burette in 1,0 ml in-
crements and finally drop by drop, until the colour of the crements at intervals of approximately 10 s until the blue
colour of the methylene blue is discharged. If the blue
methylene blue (5.4) is just discharged, boiling being continued
colour is discharged before the addition of any 1,O ml in-
during the whole titration.
crements of test Solution, decrease the concentration of
Towards the end of this action, add the successive increments the test Solution and repeat the titration.
of the D-glucose Solution at intervals of 10 to 15 s. Complete
these additions within 60 s to give a total time of boiling not
Note the total volume of test Solution (V’ ml), add-
2)
longer than 180 s.
ed up to and including the penultimate increment.
A third titration with a slightly larger, appropriately adjusted, in-
V’ shall not be greater than 50 ml. If it is, increase the
itial addition of the D-glucose Solution may be necessary to
concentration sf the test Solution and repeat the titra-
achieve this.
tion.
3) The approximate reducing power (sec 3.1) (ARP) of
of the D-glu
7.1.10 Note the volume tose Solution up to
the test Sample is given by the formula
titration.
the end- Point of the final
7.1.11 lt is essential that the titre is between 19,0 and 21,0 ml
Fx100x500
of the D-glucose solution. If it is outside these limits, adjust the
ARP =
v’ x mg
concentration of the Fe
...
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