Water absorption kinetics of blue maize (Zea mays L.) and influence on wet-milling properties

Abstract

The hydration behaviours of 15 blue maize accessions (Elotero de Sinaloa) were investigated, revealing the typical Downward Concave Shape. The Peleg model, a noted water absorption equation, suitably (r > 0.99, MRDM <4, SUMSQ <13) described the hydration kinetics. The Peleg constants K1 [(0.034–0.286 h (g/100 g solids)−1], a measure of the hydration rate, and K2 [(0.026–0.041 g/100 g solids)−1] that measures maximum absorbability, as well as predicted equilibrium moisture content, ME (39.55–50.13 g/100 g solids) were sample dependent. Multivariate analyses, Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC), that associated the water absorption kinetic parameters, physicochemical, and wet-milling characteristics of the kernels revealed significant (P ≤ 0.05) differences. Five PCs covered 90% of the variations, and AHC grouped the accessions into 3 clusters according to their dissimilarities. A further AHC analysis that included published data from 42 Mexican commercial white and yellow maize samples to solidly understand water absorption kinetics of maize generally, grouped the 57 samples into clusters that revealed important color-dependent and color-independent differences. The blue maize accessions presented particularities in their kernels, suggesting the prevalence of a soft or floury endosperm that enhanced water absorption, thereby favoring their processing (e.g., wet-milling) properties.