|
UDC 664.8 : 620.1
IS0
I NT ERN AT I ON A L O RG A N IZATl O N FOR S TA N DA RD I ZAT l ON
IS0 RECOMMENDATION
R 762
..-
FRUIT AND VEGETABLE PRODUCTS
DETERMINATION OF MINERAL IMPURITIES
1 st EDIT ION
June 1968
.--
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
---------------------- Page: 1 ----------------------
BRIEF HISTORY
The IS0 Recommendation R 762, Fruit and vegetable products ~ Determination of mineral
impurities, was drawn up by Technical Committee ISOlTC 34, Agricultural food products, the
Secretariat of which is held by the Magyar Szabvinyügyi Hivatal (MSZH).
Work on this question by the Technical Committee began in 1960 and led, in 1964, to the
adoption of a Draft IS0 Recommendation.
In October 1966, this Draft IS0 Recommendation (No. 1022) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by
the foliowing Member Bodies :
Australia Hungary Romania
Brazil India South Africa,
Bulgaria Iran Rep. of
Chile Ireland Thailand
Colombia Israel Turkey
Czechoslovakia Korea, Rep. of United Kingdom
France Netherlands U.S.S.R.
Germany
Poland Yugoslavia
Greece
Portugal
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in June 1968, to accept it as an IS0 RECOMMENDATION.
-2-
---------------------- Page: 2 ----------------------
ISO/R 762-1968 (E)
IS0 Recommendation R 762 June 1968
FRUIT AND VEGETABLE PRODUCTS
DETERMINATION OF MINERAL IMPURITIES
1. SCOPE
This IS0 Recommendation describes a procedure for the determination, by the flotation
1.1
method, of mineral impurities in fruit and vegetable products.
1.2 Field of application
This method serves for the determination of heavy impurities, generally originating from the
soil (sand) but which can also consist of metallic or mineral fragments of high density.
Siliceous impurities are determined by the method described in IS0 Recommendation R 763,
Products derived from fruits and vegetables - Determination of ash insoluble in hydrochloric
acid.
2. PRINCIPLE
Separation of organic matter by washing, incineration at 500 to 600 "C and weighing of the residue
obtained.
3. APPARATUS
3.1 Muffle furnace, regulated at 500 to 600 OC.
3.2 Analytical balance.
3.3 Blender.
3.4 Desiccator, containing an efficient desiccant.
3.5 Beakers, 250 and 600 ml.
3.6 Dish, of quartz, porcelain or platinum.
3.7 Filter paper, ashiess.
3.8
Separating funnel, 2 litres, provided with a wide-bore tap (see figure) for continuous separating, or
3.9 Conical glass vessel with foot, 1000 ml, for discontinuous separation.
-3-
---------------------- Page: 3 ----------------------
I.
ISO/R 762-1968 (E)
4. PROCEDURE
4.1 Preparation of sample
Thoroughly mix the laboratory sample*, using the blender (3.3) if necessary. Frozen products
should first be thawed.
4.2 Test portion
Weigh into the 250 ml beaker :
- from 50 to 100 g of the sample prepared as described in clause 4.1 for liquid products,
thick products or frozen products,
- 20 g of the sample prepared as described in clause 4.1 for dried products.
Transfer this test portion to the 600 ml beaker and add 200 to 250 ml of water; bring the
mixture to the boil, then leave it overnight at ambient temperature to allow the product to
rehydrate. To ensur
...