GB/T 7416-2008 English PDF (GB/T7416-2008)

GB/T 7416-2008: Malting barley
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GB/T 7416-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.060
B 22
Replacing GB/T 7416-2000
Malting barley
ISSUED ON: JUNE 25, 2008
IMPLEMENTED ON: JUNE 01, 2009
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Product classification ... 7
5 Requirements ... 7
6 Analysis method ... 8
7 Inspection rules ... 16
8 Marking, packaging, transportation and storage ... 17
Appendix A (Informative) Analysis method of self-controlled technical indicators of
enterprises ... 19
Malting barley
1 Scope
This Standard specifies the terms and definitions, product classification, requirements,
analysis methods, inspection rules, marking, packaging, transportation and storage of
malting barley.
This Standard applies to the acquisition, inspection and sale of barley specially used for
beer brewing.
2 Normative references
The terms in the following documents become the terms of this Standard by reference
to this Standard. For dated references, all subsequent amendments (not including errata
content) or revisions do not apply to this standard. However, parties to agreements that
are based on this Standard are encouraged to study whether the latest versions of these
documents can be used. For undated references, the latest edition applies to this
Standard.
GB/T 191, Packaging - Pictorial marking for handling of goods
GB/T 601, Chemical reagent - Preparations of reference titration solutions
GB/T 603, Chemical reagent - Preparations of reagent solutions for use in test
methods (GB/T 603-2002, neq ISO 6353-1:1982)
GB 2715, Hygienic standard for grains
GB/T 5491, Inspection of grain and oilseeds - Methods for sampling and sample
reduction
GB/T 6682, Water for analytical laboratory use - Specification and test methods
(GB/T 6682-1992, neq ISO 3696:1987)
3 Terms and definitions
The following terms and definitions are applicable to this Standard.
3.1
malting barley
Express the results obtained to integers.
6.6.2.4 Precision
The absolute difference of two independent test results under repeatability cannot
exceed 2% of the arithmetic mean value.
6.7 Protein
6.7.1 Principle
Under the action of a catalyst, use sulfuric acid to decompose the sample, so that the
nitrogen in the organic compound is converted into ammonia, and the distilled ammonia
is absorbed by the boric acid solution; determine the nitrogen content by the acid-base
titration method.
6.7.2 Reagents and solutions
6.7.2.1 Ammonia-free water: prepared according to GB/T 603.
6.7.2.2 Concentrated sulfuric acid: 95% ~ 98%.
6.7.2.3 Sodium hydroxide solution (400 g/L): Weigh 400 g of sodium hydroxide and
dissolve it in 1 L of ammonia-free water; let stand. Pipette the supernatant into a bottle
with a rubber stopper.
6.7.2.4 Boric acid solution (20 g/L): Weigh 20 g of boric acid, dissolve it in water, and
dilute to 1 L.
6.7.2.5 Hydrochloric acid standard titration solution [c (HCl) = 0.1 mol/L]: prepared
and calibrated according to GB/T 601.
6.7.2.6 Mixed catalyst: Mix potassium sulfate (K2SO4) and copper sulfate
(CuSO4·5H2O) in a ratio of 10+1, and grind finely.
6.7.2.7 Bromocresol green indicator solution (1 g/L): prepared according to GB/T 603.
6.7.2.8 Methyl red indicator solution (1g/L): prepared according to GB/T 603.
6.7.2.9 Bromocresol green mixed indicator solution: Pipette bromocresol green ethanol
solution and methyl red ethanol solution in a ratio of 10+4, and mix them evenly.
6.7.3 Apparatus
6.7.3.1 Kjeldahl apparatus: self-assembled instrument or complete set of instruments.
6.7.3.2 Balance: sensitivity 0.1 mg.
6.7.3.3 Acid burette: 50 mL.
V2 – volume of hydrochloric acid standard titration solution consumed during titration
of test pieces, in milliliters (mL);
V1 – volume of hydrochloric acid standard titration solution consumed during blank
titration, in milliliters (mL);
c – concentration of the hydrochloric acid standard titration solution, in moles per liter
(mol/L);
14 – value of the molar mass of nitrogen, in grams per mole (g/mol) [M (N) = 14];
m – mass of the weighed test pieces, in grams (g);
X1 – mass fraction of water content of test pieces, %;
6.25 – conversion factor of nitrogen and protein.
Express the results obtained to one decimal place.
6.7.6 Precision
The absolute difference of two independent test results obtained under repeatability
cannot exceed 4% of the arithmetic mean value.
6.8 Plump grains and thin grains
6.8.1 Principle
The barley sample is sieved by kernel size in a vibrating three-layer sieve deck with
different hole sizes.
6.8.2 Apparatus
6.8.2.1 Balance: sensitivity 0.1 g.
6.8.2.2 Separator: Driven by the motor through the crankshaft, it is equipped with 3
layers of sieve plates with a vertical distance of 12 mm ~ 25 mm, and has a cover and
a chassis. The total height of the whole machine is 80 mm ~ 100 mm.
The separator shall meet the following requirements:
Sieve plate material: made of hard brass with a thickness of 1.3 mm ± 0.1 mm, with
strip holes on it, and a processing tolerance of 0.03 mm.
Sieve plate size: 43 cm in length, 15 cm in width.
Sieve hole size: The upper part is 25 mm in length, and the lower part is 22 mm in
length. Width: 2.8 mm for sieve I, 2.5 mm for sieve II, and 2.2 mm for sieve III.
7.3.1 During acceptance, the corresponding quality inspection department is
responsible for inspecting batch by batch according to the provisions of this Standard.
7.3.2 The acceptance inspection items include: net content, sensory requirements,
foreign materials, damage rate, water content, thousand kernels weight, 3-day
germination rate, 5-day germination rate, protein, plump grains, and thin grains.
7.4 Determination rules
7.4.1 Take specimens according to Table 4, and check the packaging and net content
first. Where the inspection result reaches the rejection number, judge the whole batch
of products as unqualified.
7.4.2 Among the physical and chemical indicators, water content and 5-day germination
rate are the main indicators of the quality grade. When other indicators are of the same
grade, but one of the indicators of water content or 5-day germination rate is not of this
grade, the grade of this indicator shall prevail.
7.4.3 Among the physical and chemical indicators, if all other indicators are of the same
grade, and only one indicator (except water content and 5-day germination rate) is lower
than this grade, it will not be degraded. But if the indicator is lower than the next grade,
it will be downgraded to the next one.
7.4.4 Among the physical and chemical indicators, when all other indicators are of the
same grade, but two indicators (except water content and 5-day germination rate) are
lower than this grade, it will be downgraded to the next one.
8 Marking, packaging, transportation and storage
8.1 Marking
8.1.1 When the malting barley is transported to the grain depot or a specified place, the
place of origin, variety name, harvest time, purchase date, category and grade shall be
marked.
8.1.2 The products sold shall have a quality certificate, and shall be indicated with the
name and address of the manufacturer, product name and variety, batch number, net
weight, and the implementation standard code.
8.1.3 The pictorial marking for storage and transportation shall comply with the relevant
provisions of GB/T 191.
8.2 Packaging
8.2.1 No matter which kind of packaging is used; different varieties and different origins
must not be mixed into the warehouse.
Appendix A
(Informative)
Analysis method of self-controlled technical indicators of enterprises
A.1 Determination of mold count in barley
A.1.1 Principle
By rinsing with sterile water, wash the microorganisms on the surface of the barley in
water; then, cultivate on the medium; judge the degree of mold contamination on the
surface of the barley according to the number of colonies.
A.1.2 Reagents and solutions
Rose Bengal medium (31.6 g/L): Weigh 31.6 g of rose Bengal medium; add 1 000 mL
of water to dissolve; aliquot; autoclave at 121 °C for 20 min for later use.
A.1.3 Apparatus
A.1.3.1 Shaker: Rotating speed 180 r/min ~ 200 r/min.
A.1.3.2 Erlenmeyer flask: 300 mL.
A.1.3.3 Petri dish: 10 cm in diameter.
A.1.3.4 Pipette: 0.2 mL.
A.1.4 Analysis steps
A.1.4.1 Weigh 10 g (accurate to 0.02 g) of kernel test pieces and pour them into a
triangular flask filled with 90 mL of sterile water; tighten the cotton plug; place it on
the shaker; shake at 30 °C at a speed of 180 r/min ~ 200 r/min for 30 min.
A.1.4.2 Melt the rose Bengal medium; pour it into a plate under aseptic conditions; cool
it to solid before use.
A.1.4.3 Under sterile conditions, use a sterilized pipette to draw 0.2 mL of solution in
A.1.4.1 and apply it on the plate (3 plates for each test piece in parallel); invert the plate;
incubate at 25 °C for 7 days.
A.1.4.4 Count the number of colonies on the plate.
A.2 Identification of barley varieties
A.2.1 Gel electrophoresis
A.2.1.1 Principle
Identify barley varieties by polyacrylamide gel electrophoresis (PAGE), and use slab
gel electrophoresis to separate the alcohol soluble protein of barley.
A.2.1.2 Reagents and solutions
A.2.1.2.1 Extract: Weigh 18 g of urea and 0.01 g of methyl green; dissolve in water;
then, add 1 mL of 2-sulfhydryl ethanol and 20 mL of 2-chloroethanol; then, use water
to dilute to 100 mL.
A.2.1.2.2 Ferrous sulfate solution (5 g/L): prepared according to GB/T 603.
A.2.1.2.3 Gel stock solution: Weigh 115.3 g of acrylamide, 4.6 g of
methylenebisacrylamide, 69.2 g of urea, 1.2 g of glycine, 1.2 g of ascorbic acid; dissolve
in water; add 3 mL of ferrous sulfate solution (newly prepared), 23 mL of glacial acetic
acid; mix well, and dilute to 1 L. After suction filtration, put it into a brown bottle; store
it at 4 °C; use it within the same month.
A.2.1.2.4 Hydrogen peroxide solution: Absorb 2 mL of 30% hydrogen peroxide; use
water to dilute to 100 mL.
A.2.1.2.5 Electrode buffer solution: Weigh 2 g of glycine; dissolve it in water; add 20
mL of glacial acetic acid; add water to 5 L.
A.2.1.2.6 Trichloroacetic acid solution (10 g/L): Weigh 10 g of trichloroacetic acid;
dissolve it in water; dilute to 100 mL.
A.2.1.2.7 Coomassie brilliant blue solution (10 g/L): Weigh 1 g of Coomassie brilliant
blue; dissolve it in 95% ethanol; dilute to 100 mL.
A.2.1.2.8 Staining solution: Take 20 mL of trichloroacetic acid solution; add 1 mL of
Coomassie blue solution; mix well and set aside.
A.2.1.3 Apparatus
A.2.1.3.1 Vertical plate gel electrophoresis apparatus.
A.2.1.3.2 Analytical balance: sensitivity 0.1 mg.
A.2.1.3.3 Centrifuge: rotating speed 5 000 r/min, centrifuge tube Φ9 mm × 35 mm;
A.2.1.4 Analysis steps
A.2.1.4.1 Number of samples: Take 100 kernels of barley for this determination.
A.2.1.4.2 Extraction of hordein: Grind each kernel of barley separately and put it into
a centrifuge tube; draw 0.4 mL of extract and mix; soak for at least 16 h; put the
A.2.2.2.2 EDTA solution (0.5 mol/L, pH = 8.0): Weigh 186.1 g of ethylene diamine
tetraacetic acid (EDTA, C10H14N2O8Na2·2H2O); add it to 800 mL of water; stir on a
magnetic stirrer; use sodium hydroxide to adjust the pH value of the solution to 8.0
(approximately 20 g of NaOH granules are needed); then, dilute to 1 L; autoclave after
aliquoting.
A.2.2.2.3 DNA extract: Weigh 46.75 g of sodium chloride and 20 g of
cetyltrimethylamine bromide (CTAB); add 800 mL of deionized water; shake the
container to dissolve the solute completely. Then, add 50 mL of Tris-hydrochloric acid
solution (A.2.2.2.2) and 20 mL of EDTA solution (A.2.2.2.2); use water to dilute to 1
L; autoclave after aliquoting.
A.2.2.2.4 Trichloromethane-isoamyl alcohol solution (24+1): Measure 240 mL of
trichloromethane and 10 mL of isoamyl alcohol and mix well.
A.2.2.2.5 Ribonuclease A (RNaseA, 10 mg/mL): purchased from a biochemical reagent
company.
A.2.2.2.6 PCR amplification reagents: purchased from biochemical reagent companies
[PCR amplification reagents include: Taq DNA polymerase, dNTP, magnesium
chloride (MgCl2), PCR buffer (containing MgCl2), primers].
A.2.2.2.7 Electrophoresis buffer I (10×TBE): Weigh 108 g of Tris base, 55 g of boric
acid and 7.44 g of EDTA and mix; use redistilled water to dissolve; then, dilute to 1 L.
A.2.2.2.8 Electrophoresis buffer II (50×TAE): Weigh 242 g of Tris base and 37.2 g of
EDTA and mix; add 57.1 mL of glacial acetic acid; use redistilled water to dissolve;
dilute to 1 L.
A.2.2.2.9 TE buffer solution: Add 10 mL of Tris-hydrochloric acid solution (A.2.2.2.1)
and 2 mL of EDTA solution (A.2.2.2.2) in 800 mL of water in turn; add water to fix
volume to 1 L; aliquot and autoclave.
A.2.2.2.10 Sterile water: Take 100 mL ~ 200 mL of redistilled water, and sterilize at
121 °C for 20 min.
A.2.2.2.11 Denaturing sample loading buffer: Weigh 10 g of sucrose, 20 mg of
bromophenol blue, 20 mg of xylene cyanol; dissolve in 90 mL of deionized formamide;
use redistilled water to dilute to 100 mL.
A.2.2.2.12 Stationary liquid (10%): Measure 100 mL of glacial acetic acid; add 900 mL
of redistilled water; mix well.
A.2.2.2.13 Sodium thiosulfate solution (10%): Weigh 10 g of sodium thiosulfate; add
100 mL redistilled water to dissolve.
A.2.2.2.14 Gel solution (6%): Weigh 60 g of acrylamide, 3.1 g of methylene
bisacrylamide, 420 g of urea and draw 50 mL of electrophoresis buffer I (A.2.2.2.7);
mix well; use redistilled water to dissolve; dilute to 1 L.
A.2.2.2.15 Gel staining solution: Weigh 1 g of silver nitrate; add 1 000 mL of redistilled
water; then, add 1.5 mL of formaldehyde; mix well.
A.2.2.2.16 Gel developer: Weigh 30 g of anhydrous sodium carbonate; add 1 000 mL
of redistilled water to dissolve; then, add...