Effects of Nitrogen Rates on the Physicochemical Properties of Waxy Maize Starch
2019
Wang, Jue | Wen, Zhangrong | Fu, Pengxiao | Lu, Weiping | Lu, Dalei
Appropriate nitrogen fertilization is essential for improving grain yield and starch quality, while reducing N fertilizer costs. The starch physicochemical properties of two waxy maize hybrids, namely, Suyunuo5 (SYN5) and Yunuo7 (YN7), under N rates of 0 (zero N application [N0]), 150 (low N rate [LN]), 225 (moderate N rate [MN]), and 300 (high N rate [HN]) kg ha–¹ are elucidated. Grain starch content initially increases, peaks at MN, and decreases as N rate is increased. N fertilization reduces the starch granule size of YN7. The starch granule size of SYN5 increases under MN. SYN5 exhibits high short/long amylopectin chain ratios under LN and MN. The short/long amylopectin chain ratio of YN7 is unaffected by MN but is increases by LN and HN. The swelling power of YN7 is similar among different N levels, whereas that of SYN5 increases under N fertilization. N fertilization changes starch pasting and thermal properties. Starch with large granules exhibit high trough, final, and setback viscosities and gelatinization temperatures. Starch with high long‐chain ratios is susceptible to retrogradation. In conclusion, appropriate N application (225 kg ha–¹ for SYN5 and 150 kg ha–¹ for YN7) favors starch accumulation, and starch has high viscosity and low retrogradation tendency.
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