Physical properties of kernels from modern maize hybrids used in Croatia

Abstract

The physical properties of maize are a result of kernel structure, they indicate chemical properties of the kernel, and hence, its nutritive value. This research aimed to explore the physical traits of kernels of 80 commercial maize hybrids from nine seed companies. The grain from investigated hybrids was produced during the same season on the same field under the same agricultural conditions. Moisture content, bulk and real density, Stenvert hardness (time to grind 17mL of grits, height of freshly ground grain, and coarse-to-fine particles ratio, C/F), flotation index, breakage susceptibility, kernel dimensions, and sphericity were determined in maize samples. Test weight was in a range from 70.2 to 82.1 kg/hL. Density ranged from 1.159 to 1.301 kg/L and similarly as test weight increased with increasing hardness (C/F; r=0.52 and 0.68, respectively; P<0.001); a trait that is related to breakage and insect resistance, and to decreased starch digestibility. Flotation index was from 8 to 100%, and its value decreased with increasing hardness (r=-0.65; P<0.001). A wide range of values in physical traits of investigated hybrids implies different behavior of grain during postharvest handling and processing and thus variable nutritive value.

Caracterização de sementes de uma variedade crioula de milho pipoca (Zea mays L. subsp. mays) cultivada em sistema orgânico pela Agricultura Familiar

“…A large part of the corn grain is constituted by empty space in the endosperm; therefore, the TKW becomes a more accurate measure than the HW (Kljak et al, 2020). The mean TKW of LP was 164.711 g, which is higher than that obtained for popcorn crop in an organic system by Cihangir and Oktem (2019); higher than that values found by Ertas et al (2009) in three yellow popcorn cultivars; and higher than the results presented by Karababa (2006), whose values ranged from 122.…”

“…Higher HW values are associated with lower ash, fiber, and protein content and higher vitreous endosperm content, providing better quality and yield to the grains and defining a higher market price (Agama-Acevedo et al, 2011;Mutlu et al, 2018;Pineda-Hidalgo et al, 2015;Čuklić et al, 2015 as cited in Kljak et al, 2020, p. 544). In contrast, low values indicate lower levels of starch, fat, and vitreous endosperm (Kljak et al, 2020). Stress factors during the grain growth stage, damage (physical, insect, and microbiological), adverse weather events such as frost, rain-induced field germination, presence of foreign materials, and defective grains (wrinkled or immature); moisture content; and drying methods negatively affect HW, reducing its value, which can also vary due to genetic differences, structure, and chemical composition of the grains.…”

“…The drying process reduces the moisture content and empty space in the grain endosperm and consequently, increases the HW and grain density. In this sense, ASG is considered a more suitable index for determining the moisture content and establishing the market price of the grain (Kljak et al, 2020;Okuyama et al, 2020;Sweley et al 2012;Vázquez-Carrillo, 2019).…”

“…The high protein content (14.58%) presented by LP compared to those obtained by other researchers with unmodified varieties and some hybrids (between 8.56% and 13.46%) (Agama-Acevedo et al, 2011;Paraginski et al, 2016b;Prasanthi et al, 2017;Ranathunga et al, 2016;Sweley et al, 2012;Vázquez-Carrillo et al, 2019) may justify the higher TKW obtained in this study. Another justification for the value obtained is the positive correlation between the TKW and the hardness of the grain, implying a greater vitreous endosperm (Coelho et al, 2018;Delcour & Hoseney, 2010;Kljak et al, 2020). The value of this index is influenced by genetic and environmental factors, cultivation conditions, and grain storage (Agama-Acevedo et al, 2011;Mutlu et al, 2018).…”

“…Paraginski et al (2015) reported that the lower TKW values observed in their study were due to the reduction in humidity and the increase in the respiratory and metabolic processes of the grains, which reduced the germination percentage and increased the electrical conductivity of the grains, particularly at a temperature of 35 °C, even with reductions in water content that caused a reduction in grain weight. Some grain dimensions can affect HW and TKW (Dubal et al, 2020;Kljak et al, 2020;Okuyama et al, 2020;Sweley et al 2012;Vázquez-Carrillo, 2019). Vàzquez-Carrillo et al (2019) observed a positive correlation between HW and sphericity.…”