[Latent heat of vaporization in amaranth (Amaranthus hybridus)]

The vapor pressure at four temperatures and 10 moisture contents in a range between 26.8 and 3.6 g/100 dry matter, were determined by the manometric method in two samples of milled amaranth seeds, known as "ataco" or "sangoracha". For each humidity, the relationship between vapor pressure of the flour and vapor pressure of water at different temperatures is satisfactorily described by power equations, which are herein presented. The slope was used in the determination of latent heat of vaporization, according to Othmer's law. An exponential equation describing the relationship between the rate of latent heat and moisture content on a dry basis are established and discussed. This allows calculation with sufficient exactitude of the latent heat of vaporization values in amaranth, particularly at low moisture contents. The data are useful in calculations for drying or extrusion operations, largely applied in cereals.