Effect of kernel type on hardness and interrelationship with endosperm chemical components of Malawian local maize (Zea mays L.) varieties during storage

Abstract

The aim of this study was to establish the attributes of kernel type based on kernel hardness and its interrelationship with maize endosperm chemical components, which are essential during storage. Three local varieties and one hybrid variety commonly grown by smallholder farmers in central Malawi were used. For storage experiment, the maize samples were infested with Prostephanus truncatus, larger grain borer (LGB) for eight weeks. Due to the high propensity of maize to cross-pollinate, the kernels were classified into flint and dent kernels to establish the physicochemical properties of the kernel type and variety independently. Local variety (L-3) exhibited the lowest number and weight of damaged grains and the highest adult LGB cadavers. Local variety, L-1 and L-3 had significantly the highest proportion of flint kernels type. Moreover, flint kernels of local varieties showed significantly the highest hardness, and the highest content of protein, total zein, α-zein and zinc (p < 0.05). Furthermore, hardness was significantly and positively correlated with total zein and 14 kDa β-zein content (p < 0.05). Zein in the endosperm, particularly 19 and 22 kDa α-zein mainly contributed to distinct hardness of the local varieties hence may contribute to physical barrier of the kernels against storage pests.

Variabilidade nutricional e física de variedades tradicionais de milho (Zea mays L.) cultivados no vale do Juruá, Acre, Brasil

“…This affinity for hard grains implies directly in less action of digestive enzymes, and consequently can reduce the degradability of starch causing a lower digestibility (27) . However, hard grains have higher protein content compared to grains with pharyngeal consistency, that is, those with lower VIT and DSD (28) . Observing the results of Table 2, it is noticed that in group 2 and 3 the varieties presented lower values of VIT and DSD in relation to those of group 1, which had higher digestibility, higher proportions of starch and available energy, but lower contents of CP.…”

Variabilidade nutricional e física de variedades tradicionais de milho (Zea mays L.) cultivados no vale do Juruá, Acre, Brasil

“…Essa afinidade por grãos duro implica diretamente em menor atuação das enzimas digestivas, e consequentemente podem reduzir a degradabilidade do amido ocasionando uma menor digestibilidade (27) . Entretanto, grãos do tipo duro apresentam maior teor de proteína em comparação aos grãos com consistência farinácea, ou seja, aqueles com menor VIT e DSD (28) .…”