UNITED

NATIONS
E
Economic and Distr.
GENERAL
Social
Council TRADE/WP.7/GE.2/2003/15/Add.7
6 October 2003

Original: ENGLISH AND FRENCH

ECONOMIC COMMISSION FOR EUROPE

COMMITTEE FOR TRADE, INDUSTRY AND

Working Party on Agricultural Quality Standards

Specialized Section on Standardization of

REPORT OF THE FIFTIETH SESSION

Addendum 7

REVISED ANNEX I TO THE STANDARD LAYOUT

Note by the Secretariat: The Specialized Section agreed the text at its 50 th session and recommends to
the Working Party to adopt it as the revised Annex I to the UNECE Standard Layout for Dry and Dried
Produce (Fruit).
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ANNEX I

DETERMINATION OF THE MOISTURE CONTENT FOR DRIED FRUITS

METHOD 1 - LABORATORY REFERENCE METHOD

1. Scope and application

This reference method serves to determine the moisture for dried fruits, as dried or desiccated apricots,
figs, prunes, dates, grapes, apples, pears, etc.

2. Reference

This method is based on the method prescribed by AOAC: AOAC Official Method 934.06 - Moisture in
Dried Fruits

3. Definition

Moisture content for dried fruits: conventionally, loss in mass measured under the operating conditions
specified in AOAC Official Method 934.06. The moisture content is expressed as percentage by mass
(grams per 100 grams).

4. Principle

Determination of the moisture content of a test portion by drying in an oven 6 h at 70 ± 1º C under

5. Apparatus (see AOAC Official Method 934.06)

5.1 Analytical balance sensitive to 1 mg or better.

5.2 Mechanical mill or food chopper

5.3 Non-corrosive metal dish, provided with well-fitting lid, about 8.5 cm of diameter,
allowing the test portion to be spread to about 0.2 g/cm 2 or less.

5.4 Electric vacuum oven with thermostatic control capable of being regulated in normal
operation at 70 ± 1º C under pressure < 100 mm Hg (13.3 kPa.).

5.6 Desiccator containing an effective desiccant.

5.7 Steam-bath

6. Procedure

Follow the operating conditions as specified in AOAC Official Method 934.06 for Moisture in Dried
Fruits, with the following additional specifications, concerning the preparation of the test sample:

Homogenize the laboratory sample and take a minimum of 100 g of dried fruits as a test sample.
With non-pitted stone fruits (apricots, prunes, peaches, dates, etc), remove the stones using the
rest as a test sample.
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Grind or chop the test sample to obtain small particles, using either a mechanical mill or food
chopper, without overheating the product, or cut and grind by hand if necessary, using knife,
scissors, mortar and pestle or similar.

Use 5.0 to 10 g of the ground or chopped product as a test portion. Mix the test portion with circa
2 g of finely divided glass fiber filter or of washed sand, with the help of a spatula, and weigh to
the nearest 0,001 g.

When necessary, moisten the test portion and the glass fiber filter or the washed sand with a few
milliliters of water, mix thoroughly with the help of the spatula, and heat the open dish on the
steam-bath to near dryness, before complete the drying in the vacuum oven.

Carry out two determinations on the same test sample.

7. Expression of results and test report

The moisture content, W, as percentage by mass of the sample (grams per 100 grams), is equal to:

where
M0 is the mass, in grams, of the dish and lid. 1, 2, 3
M1 is the mass, in grams, of the dish and lid, and the test portion before drying. 1, 2
M2 is the mass, in grams, of the dish and lid, and the test portion after drying. 1, 2

Take as a result the arithmetic mean of the results of the two determinations, if the difference between the
results is smaller than 0.2%. The result has to be reported to one decimal place.

The test report shall show the method used and the results obtained. It shall mention any operating details
not specified or optional, and incidents, likely to have influenced the results. It shall also include all the
information necessary for the complete identification of the sample.

8. Repeatability

The difference between the results of two determinations carried out simultaneously or in rapid
succession by the same analyst, using the same apparatus and in the same laboratory, should not be
greater than 0.2 g of moisture per 100 g of sample.

1
Weigh to the nearest 0.001 g
2
In case, plus the glass fibre or washed sand, and spatula
3
After heating on the oven for 2 hours and cooling in the desiccator
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METHOD 2: RAPID METHOD

1. Scope and application

This rapid method serves to determine the moisture for dried fruits. 4

2. Reference

This method is based on the method prescribed by AOAC: AOAC Official Method 972.20 - Moisture in
Prunes and Raisins (Moisture Meter Method). This method is also commonly used as unofficial method
for the determination of moisture content in other kinds of dried fruits.

3. Definition

Moisture content for dried fruits: conventionally, correlation between moisture content and conductance-
temperature measured under the operating conditions specified in AOAC Official Method 972.20. The
moisture content is expressed as percentage by mass (grams per 100 grams).

4. Principle

Determination of the conductance and temperature of a test portion by the moisture tester meter and under
the operating conditions specified in AOAC Official Method 972.20. The moisture tester meter has to be
calibrated according to the laboratory method, for each kind of dried fruit, taken into account the variety
or commercial type and the type of presentation (whole, pitted, slabs, dices, etc) and, when necessary, the
crop year and/or the origin.

5. Apparatus (see AOAC Official Method 972.20)

5.1 Moisture tester meter type A series

5.2 Thermometer (if not incorporated to the moisture tester meter)

5.3 Mechanical mill or food chopper

6. Procedure

Follow the operating conditions as specified in AOAC Official Method 972.20 - Moisture in Prunes and
Raisins (Moisture Meter Method).

Carry out the determination on two test portions

7. Expression of results and test report

7.1 Result

The result should be the arithmetic mean of the two determinations. Report the result to one
decimal place.

7.2 Test report

The test report must state the method used and the results obtained. The report must contain all
the information necessary for the complete identification of the sample.

4
It is also possible to employ other rapid methods based on different conductance methods, or on the
principle of loss of mass by heating with apparatus including an halogen or infra-red lamp and a built-in
analytical balance, always at condition that the method and the apparatus has to be calibrated according the
laboratory method.