The Role of Physicochemical Properties of Maize in Shaping the Amylolytic and Proteolytic Dynamics of Malts

abstract

Maize could serve as a raw material for malt production. However, the influence of its intrinsic characteristics on the development of enzyme activities remains unexplored. This study aims to evaluate the effect of the physicochemical features of different maize varieties on the malting process (soaking and germination) and enzyme activity (amylolytic and proteolytic) of malts. Five maize varieties were used: pepitilla (PLA), white (WTE), yellow (YLO), western blue (WBE), and cacahuazintle (CTE). The physical and chemical properties of raw materials were determined and related to their hydration kinetics, germination power, and enzyme activities. Maize varieties presented different physical properties and were classified by their flotation index as hard (PLA), intermediate (WTE and YLO), and soft (WBE and CTE) kernels. All maize varieties exhibited similar hydration kinetics, requiring 7 h of soaking to achieve 30% moisture. All maize varieties exhibited different enzyme activities during the germination period, with PLA showing the highest diastatic activity (up to 343.7 U/g) and WBE having the highest proteolytic activity (19.9 U/g). Germination power and diastatic activity were positively correlated with the protein (r ¿ 0.949) and fat (r ¿ 0.903) contents in raw materials, while the grain length was positively correlated with proteolytic activity (r ¿ 0.897). Flotation index and thickness were negatively correlated with diastatic activity (r ¿ ¿ 0.907). The ¿- and ß-amylase reached values up to 39 CU/g and < 0.8 U/g, respectively, depending on the maize variety. Thickness was also negatively correlated with ß-amylase activity (r = ¿ 0.892). Physicochemical features of maize varieties were proven relevant to producing malts with high enzyme activity. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.