Biochemical Basis of Kernel Milling Characteristics and Endosperm Vitreousness of Maize (original) (raw)
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Altered starch structure is associated with endosperm modification in Quality Protein Maize
Proceedings of the National Academy of Sciences, 2003
The biochemical basis of modified kernel texture in Quality Protein Maize (QPM) is poorly understood. Proteomic analysis of several QPM lines indicated increased levels of granule-bound starch synthase I in the soluble nonzein protein fraction of these genotypes. Increased extraction of this enzyme reflected a change in starch structure, which was manifested as shorter amylopectin branches and increased starch-granule swelling. In mature kernels, these alterations in starch structure were associated with interconnections between starch granules that resulted in a vitreous kernel phenotype. Understanding the molecular basis for this previously uncharacterized starch structure will accelerate the development of QPM.
Nutritionally Induced Changes in Endosperm of shrunken‐1 and brittle‐2 Maize Kernels Grown In Vitro
Crop Science, 1996
Although mineral nutrition affects maize (Zea mays L.) yield by controlling starch deposition in kernels, the mechanisms involved are largely unknown. Our objectives were to examine this relationship by nutritionally and genetically altering starch production in the endosperm. Kernels of W64A and two starch‐deficient mutants, shrunken‐1 and brittle‐2, were grown in vitro with varying supplies of N (0–50 mM) or P (0–6 mM) to produce different degrees of endosperm starch production, and the levels of enzyme activities and metabolites associated with carbohydrate and N metabolism were examined. In vitro grown kernels exhibited the expected starch phenotypes, and a minimum level of media N (25 mM) and P (2 mM) was required optimal growth. However, increasing the availability of N or P could not overcome the genetically induced decrease in starch deposition of the mutants. Nitrogen deficiency enhanced sugar accumulation, but decreased amino acid levels, soluble protein, enzyme activity, ...
Contribution of zein content and starch characteristics to vitreousness of commercial maize hybrids
Journal of Cereal Science, 2018
Fast, simple laboratory methods were used to analyze 22 maize samples varying in kernel vitreousness from 50.23% to 76.41%. Samples were analyzed in terms of zein content (53.86e86.37 g/kg endosperm DM), amylose content (190.76e259.77 g/kg endosperm DM), amylose to amylopectin ratio in starch (0.28 e0.43), as well as starch granule size (10.95e14.89 mm in equivalent diameter) and starch granule shape (circularity, 0.85e0.94). More vitreous samples had higher zein and amylose content, as well as smaller and less circular starch granules. Nearly all grain traits on their own significantly affected vitreousness, and a multiple regression model to account for their combined effects was able to explain 61.8% of variability in kernel vitreousness. Zein content contributed most to the model, followed by starch granule projected area and circularity. In contrast, the amylose content contributed only 5.1% to the model. These results suggest that starch-protein interactions influence maize kernel vitreousness more strongly than starch molecular properties do.
European Journal of Agronomy, 2017
Starch composition of maize grains is of great importance when used in animal feed and many processing industries. Maize production involves hybrids with different kernel composition and hardness, sown at areas that range from subtropical to temperate cold climates. Therefore, it is relevant to understand how the environment influences starch composition. The objective of this work was to analyze the effect of location and sowing date on starch composition of maize grains. Field experiments were carried out at five locations across the argentinean maize-production area during two growing seasons. At each location, two sowing dates and three hybrids differing in endosperm hardness (i.e. semi-dent, a semi-flint and flint) were evaluated. Late sowing dates reduced amylose percentage and amylose/starch ratio. This last variable increased as latitude decreased. Minimum temperature during effective grain filling period explained those latitude and sowing date effects. This finding would be helpful to estimate starch composition of maize kernels to be expected in order to satisfy specific end uses.
Agronomy
Maize’s (Zea mays L.) nutrient content can be modified through selection. The objective of this study was to assess the nutritive value of 13 maize hybrids from four endosperm types, and the relationship between nutrient concentration, agronomic and rheological value. The hybrids were evaluated in two locations of Northwestern Spain over two years. There was genetic diversity among endosperm types and genotypes for all nutrients, with significant environmental effects, but few genotype × environment interactions. Flint hybrids had the highest protein and lipid content. The mutant wx1 significantly increased protein and reduced lipid, and both wx1 and o2 reduced ash and starch content and increased total fiber. Variability among hybrids within the wx1 endosperm was significant for most nutrients. Correlations between nutrients were rarely significant, implying that protein and lipid can be improved independently. Protein and lipid were negatively correlated with grain yield and plant...
Zein Compositions of Mechanically Separated Coarse and Fine Portions of Maize Kernels
Cereal Chemistry Journal, 1997
Cereal Chem. 74(1):75-78 Coarse and fine kernel portions from 24 maize inbreds (six grown in two years) and four hybrids were separated by grinding and sifting. Zeins from both portions of all genotypes were analyzed by reversed-phase high-performance liquid chromatography (RP-HPLC) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Results agreed, in general, with those of a previous study in which endosperm separation was done manually, suggesting that endosperm fractionation can be done by mechanical means. Compositions of zeins, as revealed by RP-HPLC and SDS-PAGE, support the hypothesis that zeins help determine maize endosperm hardness. Publication no. C-1997-0110-02R. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American Association of Cereal Chemists, Inc., 1997.
Grain properties of yellow and red kernel maize hybrids from Serbia
Selekcija i semenarstvo, 2020
Physical traits, kernel structure and chemical composition of five yellow and five red kernel maize hybrids were the subjects of this study. The 1000-kernel weight, a physical indicator of grain quality, ranged from 325.76±7.47 g (ZP 555 red) to 375.63±4.18 g (ZP 606). The hard endosperm fraction content varied between 57.66±0.93% (ZP 4007) and 67.08±0.42% (ZP 366 red). Regarding chemical composition, starch was predominant constituent ranging from 66.80±0.18 (ZP 4007 red) to 72.96±0.37 (ZP 606). The highest protein content was detected in ZP 606 (10.72±0.11) and the lowest in ZP 7007 red hybrid (8.63±0.04%). Milling response was highly influenced by hard endosperm fraction content (0.81**), and starch content was strongly correlated to 1000-kernel weight (0.77**). Whole-grain maize flours produced from yellow and red kernels without removing the germ are naturally gluten-free and can be used as functional food ingredients. All yellow and red kernel maize hybrids investigated in thi...
Food Chemistry, 2019
The present study aims to evaluate the physicochemical, rheological, and safety properties of starches isolated from maize kernels with different types of defects. Starch isolation showed to be a valuable alternative to defective yellow maize kernels, since the presence of the evaluated kernel defects (broken, fermented, rotten, moldy, germinated, insect-damaged, and shrunken and immature kernels) did not provide significant changes on starch purity and colour. Only starch isolated from shrunken and immature kernels exhibited reduced extractability. Starch obtained from germinated kernels exhibited the greatest solubility. While flour from moldy kernels showed 7.5 ppb of aflatoxin A1, 25.0 ppb of aflatoxin A2, and 1229.4 ppb of fumonisin B1, any of these mycotoxins were detected in isolated starch. In sum, minor changes in pasting, thermal, crystallinity, and morphological properties of the isolated starches from defective kernels were determined, which does not impair its use in industrial processes.