Pulsed electric field (PEF) application on wheat malting process: Effect on hydration kinetics, germination and amylase expression

Abstract

Wheat malt has been widely used in food industry as an important source of endogenous enzymes, such as amylases. However, malting is a time-consuming process. Thus, this work proposed pulsed electric field (PEF) application to enhance wheat hydration, germination and amylase expression. Two-step hydration of Hendrix wheat variety was studied. PEF treatments (3 kV·cm−1; total energy applied of 9.9 and 19.8 kJ·kg−1) were applied with wheat in the water at the beginning or after the first hydration cycle. Hydration curves were accurately described by the Weibull exponential model (R2adj > 0.98). The more intense PEF treatments enhanced hydration rate (25%), water holding capacity (15%) and germination parameters when applied before the first hydration cycle. PEF enhanced α- and β-amylase activity by up to 104% and 25%, respectively, compared to control. Therefore, PEF can be used as a clean emerging technology to improve the malting process and malt quality. Industrial relevanceGrowing concerns have gained attention regarding the use of synthetic enzymes or higher amounts of natural resources to perform enzymatic process to food applications. Malting cereals represents a clean technology to provide natural enzymes from natural resources, even though it is still considered a time- and energy-consuming method. In this sense, the use of pulsed electric fields (PEF) demonstrated to be a green and efficient technique to enhance the overall wheat malting process. Besides improving the process kinetics, the enzymatic activity and, thus, the quality of the final malt can be also improved. Because of that, malting producers can process wheat more rapidly to obtain more efficient ingredients when incorporating PEF to their processes. On the other hand, brewery and baking sector can use wheat malt stimulated by PEF as raw material with comparable technological effects as conventional malts, but in lower amounts instead.