129 Method for the Determination of the Vitreousness of Durum Wheat

Methods Type: Generic Methods
Key data
Number: 129
Analyte: Vitreousness
Matrix: Durum Wheat
Year of Approval: 1980
Scope: This method is applicable to the determination of the proportions of vitreous and not fully vitreous kernels in durum wheat (Triticum durum L.).
Principle: The fractions defined under section 3 are separated by hand after external inspection of each individual kernel with the naked eye. A light-screening device is not to be used. All kernels, which are not, beyond doubt, recognizable form the outside as fully vitreous, have to be cut transversally with a scalpel and evaluated according to the appearance of the sectional areas of the endosperm. This is particularly important in the case of "washed" kernels (grains lavés) with less transparent envelops.

Definition

The term vitreousness applies to the proportion by weight of vitreous durum wheat kernels in 100 g of a sample as prepared for "Besatz"-analysis according to ICC Standard No. 102/1 (see section 8).

  • As (fully) vitreous pass only durum wheat kernels, which do not disclose the least trace of farinaceous endosperm under the described procedural conditions.
  • All the other durum wheat kernels count as not fully vitreous.
  • So-called "washed" durum wheat kernels (grains lavés) have, caused by the effect of moisture on the grain envelops, acquired a paler, dull, less-transparent external appearance. Outwardly they thus resemble farinaceous kernels. However, the vitreousness of the endosperm is not necessarily impaired. Kernels of this sort have therefore to be cut for evaluation.
  • Broken, insect-damaged, frost-damaged or sprouted durum wheat kernels are also separated into "vitreous" and "not fully vitreous" fractions. The vitreous portions are then put together and registered as the new fraction of "damaged vitreous durum wheat kernels". The not fully vitreous portions are put together with the fraction of undamaged, not fully vitreous durum wheat kernels.
  • Kernels of aestivum wheat (vulgare wheat, soft wheat, Triticum aestivum) of every quality are put together in one fraction.

 

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