Effect of different kilning schedules on qualitative characteristics of wheat malt

Abstract

Three different kilning schedules (low temperatures; medium temperatures; and high temperatures) were applied to eight varieties of different wheat species (three durum wheat, three soft wheat, one emmer variety, and one spelt variety) to evaluate the effects of kiln temperature on the main qualitative parameters of wheat malt, the difference among varieties and their interaction. For the most significant quality parameters of malt, including diastatic power, Kolbach index, FAN, and viscosity, KSA consistently yielded more favorable outcomes than medium temperature and high temperature, whose effects on malt parameters, although significant, were not particularly relevant. PCA analysis showed in Dim1, the main source of variability is the intrinsic varietal structure, and that in Dim2, a secondary but relevant source of variation, was due to kilning schedule intensity. Furthermore, the response to thermal treatment was genotype-specific rather than species-specific, and the principal technological shift occurred between low temperature and the most intense kilning schedules (medium temperature/high temperature). To gain insight into the suitability of varieties with malt quality closer to industry requirements, a non-statistical, multi-criteria deterministic tool called High Performance Index, but consistent with PCA analysis, being highly correlated with the PC1 score, was used to provide a useful decision-making tool by attempting to translate industrial requirements from analytical parameters of interest. The highest High Performance Index values were obtained from the Federico II and Antalis varieties using the kilning schedule low temperature. In the future, the study will be aimed at evaluating the same varietal set considering higher temperature levels with the prospect of reaching the production of beer.