LABELING WHEAT-FLOUR WITH C-13

C-13-enriched hour was obtained by the photosynthetic incorporation of (CO2)-C-13 during the grain filling period of wheat plants. The mean atom % excess of the pooled flour obtained on two consecutive years was 2.6% and 3.9% The C-13-labelled flour was used as a substrate to measure starch digestion and the effect of gelatinisation on (CO2)-C-13 recovery in a healthy adult volunteer. Only 400 mg of C-13 flour/adult were required in order to accurately measure the excretion of (CO2)-C-13. The starch load could be varied by the addition of flour with natural C-13 abundance. An increased rate of starch hydrolysis after gelatinisation was demonstrated after the ingestion of a 50 g starch load. Wheat starch can be successfully labelled with C-13 and used as a substrate for C-13 breath tests.