Grain Quality

With almost a quarter of UK wheat production being exported, the successful marketing of UK cereals is increasingly dependent on an accurate and timely assessment of cereal crop quality.

When buying milling wheat, it is essential for millers to know thequantity and quality of protein. The following help estimate these:

Protein % determines the quantity of protein

Hagberg Falling the enzyme level indicating doughNumber stickiness.

Chopin Alveograph indicates the quality of gluten, which is hydrated protein. This is the substance that holds the loaf together, envelopingthe starch: water matrix.

Other tests such as Brabender Farinograph, Extensograph and wetchemistry tests such as Zeleny can also be used to provide anassessment of protein quality.

The Importance of the ChopinAlveograph in the Export Market

The Chopin Alveograph indices, such as W and p/l (see next page) are used by flour millers and others engaged in export markets, to indicate the suitability of their offerings towards making bread or biscuits. Nearly all overseas millers test wheat by Chopin Alveograph to get early indications of the resultant flourquality. The key measures used are the ratio of p to l and the W value (see next page for more details).

When buying milling wheat, many overseas buyers will demand a Chopin Alveograph specification in addition to the standard measuresof protein, Hagberg Falling Number, specific weight and moisture,irrespective of its origin.

In general the protein quality, and thus the Chopin Alveograph values,are inherent in a variety and are not greatly affected by environmentalconditions or crop treatments. This factor makes varietal purity atsowing and varietal segregation in store of key importance whensupplying to meet overseas customers' requirements.

British Cereal Exports,HGCA, Caledonia House, 223 Pentonville Road, London N1 9HYTel: +44 (0) 20 7520 3925 Fax: +44 (0) 20 7520 3902Email: bce@hgca.com Web: www.hgca.com

P =maximum pressure required

How does the Chopin Alveograph work?n

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Suitable for bread flour – makesstrong elastic dough and hasexcellent bread-making potential.

• high pressure (P)• long time (L) to burst

Suitable for bread and baking flours– most varieties having bread-makingpotential.

• low P/L ratio important

Suitable for biscuit and blending flours –makes extensible dough, good for biscuitsand blending with strong wheats.

• low pressure (P)• long time (L)• area under the curve (W) less critical

Suitable for animal feed only – makes tough, inelastic dough

• high pressure (P)• short time (L) to burst

Typical range

Alveograph P/L 0.5 - 0.9Alveograph W >200

Typical range

Alveograph P/L 0.4 - 0.9Alveograph W 170 - 310

Typical range

Alveograph P/L 0.2 - 0.4Alveograph W 70 - 100

Typical range

Alveograph P/L 0.3 - 1.5Alveograph W 60 - 140

Typical characteristics of different wheat varieties

Chopin Alveograph showing stage 5 - air being pumped into dough

Five stages of the Alveographtest take place over three days

What the graph means

L =extensibility of dough

(time taken for bubble to burst)

P/L =dough strength and extensibility(ratio of curve height to length)

W =baking strength of dough (the area under the curve)

Stage 1Wheat conditioned to standard moisture

Stage 2Wheat milled and left to rest

Stage 3 & 4Dough produced and formed into a disc

Stage 5Air is pumped into dough to testresistance and elasticity

High W =strong flour

Low P/L =very extensible and low strength

British Cereal Exports is theExport PromotionDepartment of the Home-Grown Cereals Authority