Heating experiments under anoxic conditions on varieties of wheat
Archaeometry , Volume 47 p. 103- 114
Species of wheat were used to study the effects of formation processes on carbonized grains. For this purpose, grains of recent wheat were heated under controlled anoxic conditions. These experiments have revealed that the grains of the various varieties of wheat are not homogeneous in physical and chemical properties. Seven varieties of emmer wheat, two varieties of bread wheat and one variety of macaroni wheat were used for the experiments. The grains, both mealy and vitreous ones, were heated to 270Â°C for 60 min under anoxic conditions. Bulk elemental data shows that the C content is similar for all of the untreated varieties, but that the N content varies. The results of DTMS-EI experiments show that the molecular composition of the various untreated grains are similar, which is also true for the heated counterparts. The morphology of the heated grains shows a wide variation between the grains of the tested varieties. The grains become swollen and show protrusions or open creases, or remain intact. The reasons for this variation are the mechanical properties of the pericarp and the proteinaceous matrix of the endosperm. On the basis of the results, a variety of emmer wheat was used for further experiments.