“Grain” analyses cover both technological standards and health standards.
Further analyses, e.g. physical and chemical components or “commercial analyses”, are also covered here.
Technological Quality Standards
Technological parameters are assessed in relation to the end use in industry (starch or milling). The “Promatest” is a test originally devised for the starch industry but can now be used for a number of applications. It was devised in 1990 and is based on the analysis of the denaturing of heat-sensitive proteins in the kernel. It is useful in the post-harvest and drying stages to assess treatment conditions and detect any alterations that may have affected the kernel. New! Working on the same basis, assessments can be made testing moist samples in the laboratory to determine the behaviour of maize hybrids and their resistance to heat shock during drying.
The sedimentation test is specifically for the starch industry and the laboratory technique is very similar to the industrial process. The measurement of the difference in density between the proteins and starch, i.e. the degree of separation of the two elements, shows the level of compliance with the original agronomic qualities.
The key elements for optimal yield in the starch industry are the vitreousness of the albumen together with the absence of any cracks.
The yield as cornmeal is estimated by: - infra-red measurement expressing the hardness of the albumen with the gross yield as cornmeal. - using a pilot press to express the gross yield as hominy.
A flotation test is used to categorise grains according to density and there is a strong correlation between the hardness and vitreousness of the albumen.
Health Quality
Health quality is basically defined according to the levels of various mycotoxins and of ergosterol. Regulations have set maximum levels for aflatoxin and ochratoxin. Regulations are currently being drawn up setting thresholds for other substances such as zearalenon, DON and fumonisins.
Two Techniques for Two Purposes: Qualitative descriptions and quantitative measurements can be given for mycotoxins by using the technique known as ELISA, or by chromatography. Not all of these methods are included in the AFNOR or ISO reference lists, but chromatography is used as a reference. ELISA is a less costly technique and is used for screening purposes only. The laboratory is actively involved in work that will help standardise these methods.
ELISA techniques used in the laboratory give quantitative measurements of target mycotoxins and are checked and validated on a regular basis against references from internal analyses or the “ring test” used by BIPEA and IRTAC.
Four chromatographic analysis facilities (gas and liquid) are a reference tool recognised by the different players in the sector and in the context of strict requirements on a number of procedures — HACCP, traceability and regulatory thresholds.
Technological Quality Standards
