Some methodological aspects of determining wet gluten quality by the glutomatic method (a laboratory note)
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Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, P.O. Box 201, 20-290 Lublin 27, Poland
Acceptance date: 2000-01-03
Int. Agrophys. 2000, 14(2): 263–267
One of the weak sides of the glutomatic method for testing wet gluten quality (ICC Standard No. 155) is a variable amount of wet gluten subjected to the action of the centrifugal force as various amounts of gluten are washed out from various wheats. The present study on the influence of such conditions as: storage (from 0 to 50 min), fragmentation (from 1 to 6 equal parts) and a weighed amount of wet gluten (from 0.5 to 3.5 g) on the gluten index (GI) value were conducted. The results showed that the physical properties of wet gluten formed at the end of its washing out and expressed by the gluten index are liable to considerable changes in the course of its storage at invariable moisture. The fragmentation degree of a wet gluten piece during centrifuging had not significant influence on value of the determined gluten index. An increasing quantity of gluten from 0.5 to 2.5 g during centrifugation causes a proportional decrease of the GI value. However, a further rise of the weighed amount of wet gluten above 2.5 g results in slow-down and then slow -lift of the gluten index value. The range of decrease in the GI depends, first of all, on the wheat cultivar and, most frequently, it is inversely proportional to the gluten quality. The results obtained indicate the necessity to consider the constant weighed amount of the wet gluten piece when it is subjected to centrifugal force test by the Glutomatic method.