GB 5009.3-2016National food safety standard - Determination of Moisture Content in Foods (English PDF)

Foreword

This Standard replaces GB/T 5009.3-2010 National food safety standard

Determination of moisture in foods, GB/T 12087-2008 Starch - Determination

of moisture content - Oven-drying method, GB/T 18798.3-2008 Instant tea in

solid form - Part 3.Determination of moisture content, GB/T 21305-2007

Cereals and cereal products - Determination of moisture content - Routine

reference method, GB/T 5497-1985 Inspection of grain and oilseeds;

Methods for determination of moisture content, GB/T 8304-2013 Tea -

Determination of Moisture Content, GB/T 12729.6-2008 Spices and

condiments - Determination of moisture content(entrainment method), GB/T

9695.15-2008 Meat and meat products - Determination of moisture content,

GB/T 8858-1988 Method for determination of dry matter and water content in

fruit and vegetable products, SN/T 0919-2000 Method for the determination of

moisture of tea for import and export.

Compared with GB 5009.3-2010, the main modifications in this Standard are

as follows.

- modified the scopes of Method 1 - Direct drying method, Method 2 -

Decompression drying method, Method 3 - Distillation method and

Method 4 - Karl Fischer volumetric method;

- modified the reagents, precision, annotation and analysis steps of

Method 1 - Direct drying method;

- modified the analysis steps of Method 3 - Distillation method;

- deleted the description of the Karl Fischer coulomb method of Method 4

- Karl Fischer volumetric method.

National Food Safety Standard

Determination of Moisture Content in Foods

1 Scope

This Standard specifies the determination method for moisture content in

foods.

Method 1 (Direct drying method) of this Standard is applicable to the

determinations of moisture content in foods such as vegetables, cereals and

their products, aquatic products, soy products, dairy products, meat products,

braised food products, grain (moisture content of less than 18%), oil (moisture

content of less than 13%), starch and tea at 101°C ~ 105°C; not applicable to

the sample of which the moisture content is less than 0.5g/100g. Method 2

(Decompression drying method) is applicable to the determination of moisture

content in high temperature easily decomposed sample and more moisture

samples (such as sugar, monosodium glutamate and other food); not

applicable to the determination of moisture in sugars added with other raw

materials (such as cream candy, soft sweets); not applicable to the sample of

which the moisture content is less than 0.5g/100g (excluding sugar and

monosodium glutamate). Method 3 (Distillation method) is applicable to the

determination of moisture in fruit of more water and more volatile ingredients,

spices and condiments, meat and meat products; not applicable to the

sample of which the moisture content is less than 1g/100g. Method 4 (Karl

Fischer volumetric method) is applicable to the determination of trace

moisture in foods; not applicable to the determination of moisture in foods

containing oxidizing agents, reducing agents, basic oxides, hydroxides,

carbonates, boric acid. Karl Fischer volumetric method is applicable to the

sample of which the moisture content is greater than 1.0 x 10-3g/100g.

Method 1 -- Direct drying method

2 Principle

Using the physical properties of water in food, at 101.3kPa (one atmospheric

pressure), the temperature of 101°C ~ 105°C, it shall use volatile method to

determine the dry weight loss in sample, including absorbent water, partially

crystallized water and substances that are volatile under these conditions.

Calculate the moisture content by the weighing values before and after

drying.

3 Reagents and materials

Unless otherwise stated, the reagents used in this method are of analytical

grade and water is Grade 3 water specified in GB/T 6682.

4 Instruments and equipment

5 Analysis steps

6 Expression of results

The moisture content in sample shall be calculated according to equation (1).

7 Precision

The absolute difference between the two independent determinations

obtained under repeatability shall not exceed 10% of the arithmetic mean.

8 Principle

Using the physical properties of moisture in food, after reaching to 40 kPa ~

53 kPa pressure, heat to 60°C ± 5°C. Use the decompression drying method

to remove moisture from the sample.

9 Instruments and equipment

10 Analysis steps

11 Expression of analysis results

Same with Clause 6.

12 Precision

The absolute difference between the two independent determinations

obtained under repeatability shall not exceed 10% of the arithmetic mean.

13 Principle

Using the physical properties of moisture in food, distill the moisture in food

and toluene or xylene by moisture tester. Calculate the moisture in sample

according to the volume of water received. This method is applicable to foods

containing more other volatile substances, such as spices.

14 Reagents and materials