A calorimetric procedure to measure arnylose content of various starchy raw materials has been developed. It is based on the measurement by Differential Scanning Calorimetry (DSC) of the enthalpy change of the formation of complexes between amylose and add phospholipid (L-a-lysophosphatidylcholine from egg yolk) observed during cooling.Contrasting to the colorimetric determination of amylose, the DSC procedure is not influenced by the presence of amylopectin or indigenous lipids. For rice and maize flours, the amylose content determinations are very similar for both colorimetric and DSC methodologies whether the starchy material was raw or pre-cooked. But the DSC methodology is more repeatable and time saving; in particular, the defatting and starch determination steps can be omitted. -~~ ~ Eine schnelle Methode zur Bestimmung des Amylosegehaltes unter Anwendung der Differential-Raster-Calorimetrie. Eln calorimetrisches Verfahren zur Bestimmung des Amylosegehaltes verschiedener starkehaltiger Rohrnaterialien wurde entwickelt. Es basiert auf der Messung durch Differential-Raster-Calorimetrie (DSC) der Enthalpieanderung durch die Bildung von Komplexen zwischen Amylose und den Zusatz von Phospholipid (L-a-lysophosphatidylcholin aus Eigelb), beobachtet wahrend der Abkiihlung. Im Gegensatz zur kolorimetrischen Amylosebestimmung wird das DSC-Verfahren nicht durch die Gegenwart von Amylopektin oder innewohnende Lipide beeinflu&. Bei Reis-und Maismehlen sind die Bestimmungen des Arnylosegehaltes einander sehr ahnlich sowohl fur die kolorirnetrischen als auch fur die DSC-Methodologien, gleichgiiltig ob das starkehaltige Material roh oder vorgekocht war. Jedoch ist die DSC-Methodologie reproduzierbarer und zeitsparend; insbesondere konnen die Entfettungs-und Starkebestimmungs-Stufen wegfallen.

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The physicochemical characteristics of eight samples of lifin, a traditional maize market flour of Benin, were determined. They had very similar proximate composition and a median particle size (PSm) under 200 μm; four, having a PSm under 180 μm, can be considered as fine or very fine and should be preferred by consumers. The grains of twenty-one maize cultivars of Benin including local ecotypes (5) and new cultivars (16) were physicochemically characterized and were tested for their ability to give fine whole grain flours. The five local ecotypes presented common traits such as high friability, low vitreousness, and dent kernel percentage giving relatively fine flours with low damaged starch content. On the contrary, most new cultivars had vitreous and hard grains and half gave very coarse flours with PSm over 200 μm. The more friable the grain was, the finer the whole grain flour it gave and the lower damaged starch it contained. Keywords: Maize; grain; hardness; physicochemical characteristics; milling; flour