The measurement of wet gluten colour

Abstract

The aims of this investigation were to devise an instrumental method of measuring wet gluten colour to replace the subjective methods in current use, and to investigate the relationship between flour colour (GCF) and wet gluten colour. A number of sample preparation methods and colour measuring instruments were investigated.

The preferred method involved grinding 150g of wheat on a Glen Creston disc mill, washing out the gluten using a Glutomatic semi-automatic gluten washer, and measuring its colour on the L* scale on a Dr Lange tristimulus colour instrument. This method gave rapid and acceptably reproducible results. Correlations between wet gluten colours measured in this way and the GCF of flours milled from the same wheats on a laboratory Buhler mill showed that although gluten colour was one of the factors affecting flour GCF the relationship was not sufficiently strong to be useful for predictive purposes. A similar correlation exercise in which dry flour colour measured by a tristimulus instrument replaced GCF was more encouraging, and the developed method of measurement of wet gluten colour may be of more use if and when the milling industry moves towards dry flour colour measurement.