Impact of Deficit Irrigation on Maize Physical and Chemical Properties and Ethanol Yield

Abstract

Cereal Chem. 90(5):453-462The objective of this research was to study the effect of irrigation levels (five levels from 102 to 457 mm of water) on the physical and chemical properties and ethanol fermentation performance of maize. Twenty maize samples with two crop rotation systems, grain sorghum-maize and maize-maize, were harvested in 2011 and evaluated at the Kansas State University Southwest Research-Extension Center near Garden City, Kansas, under a semiarid climate. Results showed that maize kernel weight, density, and breakage susceptibility decreased as irrigation level decreased. Starch contents of maize samples grown under a low irrigation level were approximately 3.0% lower than those under a high irrigation level. Protein contents ranged from 9.24 to 11.30% and increased as irrigation level decreased. Maize flour thermal and rheological properties were analyzed by differential scanning calorimetry and the Micro ViscoAmylo-Graph-U device. Starch gelatinization temperature increased significantly as irrigation level decreased, whereas starch pasting viscosity decreased as irrigation level decreased. Free amino nitrogen (FAN) was significantly affected by irrigation level: it increased as irrigation decreased. Ethanol fermentation efficiency ranged from 90.96 to 92.48% and was positively correlated with FAN during the first 32 h of fermentation (r 2 = 0.645). Deficit irrigation had a negative impact on ethanol yield. The maize with lower irrigation yielded about 4.0% less ethanol (44.14 mL/100 g of maize) than maize with high irrigation (45.92 mL/100 g of maize). Residual starch contents in the distillers dried grains with solubles were in a range of 0.80-1.02%. In conclusion, deficit irrigation had a significant effect on physical properties, chemical composition, ethanol yield, and fermentation efficiency of maize.

Effects of water deficit during grain filling on the physicochemical properties of waxy maize starch

“…The low viscosities under drought treatment are probably due to the decreased granule size, crystallinity, and swelling power , given that the large granules possess a loose packing ability, occupy a relatively larger volume, and are less stable toward shearing compared with the small granules at similar concentrations. Some studies also observed that drought decreased the pasting characteristics of cassava starch , sorghum starch , normal, and waxy maize flour . By contrast, Singh et al observed that the wheat starch peak viscosity was increased by water stress when the percentage of large granules was increased.…”

“…The vol% of the starch granules with diameters lower than 5 mm was slightly affected, whereas that for large granules (with the peak point as the boundary) was evidently reduced by water deficit in both varieties. Previous studies showed that drought reduces granule size in cassava [29], wheat [30], barley [31], and normal maize [11]. The small starch granule size is probably due to the fact that drought suppresses the development of starch granules, decreases the grain filling rate, and shortens the grain filling duration [32].…”

How Irrigation Water Affects the Yield and Nutritional Quality of Maize (Zea mays L.) in a Temperate Climate

“…Other authors have reported different results. For example, Liu et al [22] did not note any significant difference in the grain oil content of maize grown with different levels of irrigation. Considering the effect of drought stress on the grain oil content of summer maize, Ge et al [3] stated that moderate drought increased and that strong drought decreased the oil content.…”

“…Research conducted by Lu et al [21] in China showed that water deficit had no effect on the starch content of fresh waxy maize. Liu et al [22] reported that the starch content of the grain samples of maize grown with less irrigation was 3.0% smaller than with high irrigation levels.…”

Effects of waterlogging after pollination on the physicochemical properties of starch from waxy maize

“…Oktem (2008) observed that water deficit decreases some mineral element (Fe, Cu, and Zn) contents but increases the protein content in sweet maize grains. Liu et al (2013) observed that maize starch granule size and viscosities decrease and gelatinization temperatures increase under low irrigation levels. Our previous studies showed that high temperature, weak light, and drought after pollination significantly deteriorated the quality of waxy maize starch (Lu, Cai, Zhao, Shen, & Lu, 2015;Lu, Sun, Wang, Yan, & Lu, 2013;Lu et al, 2014).…”