Wheat conduction heating

Fig. 34.—Time-temperature curves for wheat starch-water systems heated by conduction (from Ref. 286).

Further studies on the decomposition of starch at various temperatures were conducted by Picon. He characterized the composition of gases evolved from pea, wheat, rice, and potato starch, as well as potato amylopec-tin and soluble starch from potatoes, when heated at temperatures fix)m 300 to 1000° (see Table XXIII). It may be seen that there are quite remarkable differences in the pyrolysis of various starches. However, these differences cannot be ascribed solely to the kind, but also to the variety, of plant that produced the starch. The thermal properties of the starch from two different varieties of a given plant differ more than those of starches from two kinds of starch (see Table XXIV). ... 

The recommended method [29] for the determination of the thermal diffusivity of individual kernels is to calculate it from experimentally measured values of the thermal conductivity of kernel material, specific heat, and kernel (particle) density—the so-called indirect method. The method may lead to approximate results with a relative error, which is difficult to estimate in respect to a true (real) value, which can only be determined by direct measurements. The results of thermal properties for wheat and corn [44] and for single soybeans [59] confirm the above. 

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