Characterization of Polymeric Proteins from Vitreous and Floury Sorghum Endosperm

Ioerger, Brian P.; Bean, Scott R.; Tuinstra, Mitchell R.; Pedersen, Jeffrey F.; Erpelding, John E.; Lee, K. M.; Herrman, Timothy J.

doi:10.1021/jf0716883

Cited by 32 publications

(33 citation statements)

References 19 publications

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“…Protein in maize comprises around 8-12% of the total composition. Protein content has been correlated to hardness, and the variation in zein classes has been linked to differences in hardness (32,(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51). For most of these traits, the best correlations have been shown in samples gathered from larger sample sets grown over multiple sites and years.…”

Section: Hardness In Maize and Related Biochemical Factorsmentioning

confidence: 99%

Hardness Methods for Testing Maize Kernels

Fox

Manley

2009

J. Agric. Food Chem.

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Maize is a highly important crop to many countries around the world, through the sale of the maize crop to domestic processors and subsequent production of maize products and also provides a staple food to subsistance farms in undeveloped countries. In many countries, there have been long-term research efforts to develop a suitable hardness method that could assist the maize industry in improving efficiency in processing as well as possibly providing a quality specification for maize growers, which could attract a premium. This paper focuses specifically on hardness and reviews a number of methodologies as well as important biochemical aspects of maize that contribute to maize hardness used internationally. Numerous foods are produced from maize, and hardness has been described as having an impact on food quality. However, the basis of hardness and measurement of hardness are very general and would apply to any use of maize from any country. From the published literature, it would appear that one of the simpler methods used to measure hardness is a grinding step followed by a sieving step, using multiple sieve sizes. This would allow the range in hardness within a sample as well as average particle size and/or coarse/fine ratio to be calculated. Any of these parameters could easily be used as reference values for the development of near-infrared (NIR) spectroscopy calibrations. The development of precise NIR calibrations will provide an excellent tool for breeders, handlers, and processors to deliver specific cultivars in the case of growers and bulk loads in the case of handlers, thereby ensuring the most efficient use of maize by domestic and international processors. This paper also considers previous research describing the biochemical aspects of maize that have been related to maize hardness. Both starch and protein affect hardness, with most research focusing on the storage proteins (zeins). Both the content and composition of the zein fractions affect hardness. Genotypes and growing environment influence the final protein and starch content and, to a lesser extent, composition. However, hardness is a highly heritable trait and, hence, when a desirable level of hardness is finally agreed upon, the breeders will quickly be able to produce material with the hardness levels required by the industry.

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Section: Hardness In Maize and Related Biochemical Factorsmentioning

confidence: 99%

Hardness Methods for Testing Maize Kernels

Fox

Manley

2009

J. Agric. Food Chem.

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“…Polymeric proteins were characterized using a multi-extraction procedure described by Ioerger et al (2007). Soluble proteins (SP) were first extracted from 100 mg of ground sample using 0.5 mL of a 12.5 mM sodium borate buffer at pH 10.0 containing 2% sodium dodecyl sulfate (SDS) (w/v), with continual vortexing for 30 min.…”

Section: Protein Solubilitymentioning

confidence: 99%

“…Sorghum polymeric proteins were fractionated based on their solubility in different reagents based on the procedure by Ioerger et al (2007). Proteins soluble in SDS without sonication (SP) correspond to the albumin, globulin and kafirin-1 fraction of the Landry-Moureaux (L-M) fractionation procedure (Hamaker et al, 1986) and are composed primarily of monomeric kafirins; proteins extractable in SDS only after sonication (IP) correspond primarily to the L-M kafirin-2 fraction (crosslinked kafirins) and contain some glutelin; and, the remaining residue protein fraction (RP) is composed of the L-M glutelin-like, true glutelin and unextractable proteins (non-kafirins).…”

Section: Protein Solubilitymentioning

confidence: 99%

A Computationally Efficient Design Technique for Electric-Vehicle Traction Machines

Lazari

Wang

Chen

2014

IEEE Trans. on Ind. Applicat.

115

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a b s t r a c tA novel method was developed for concentrating proteins from sorghum flour utilizing a combination of extrusion and a-amylase treatment for starch liquefaction. A central composite design was used to optimize in-barrel moisture content (MC), enzyme concentration during extrusion (E1) and post-extrusion enzyme concentration (E2) in order to produce sorghum protein concentrates with high protein content (PC) and in vitro protein digestibility (D). Extrusion-enzyme liquefaction yielded concentrates with higher protein yield (82 db%) and digestibility (66%) than batch liquefaction alone because extrusion promoted starch and protein degradation. The optimum conditions for developing a sorghum protein concentrate with both high yield and digestibility were 32% MC, no E1, and 2.5% E2. The sorghum protein concentrate developed in this study can augment the nutritional value of gluten-free foods for individuals suffering from celiac disease and other forms of gluten and wheat intolerance.

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“…Protein body composition varies according to endosperm type, with vitreous (hard) endosperm types containing a higher proportion of kafirins, while corneous (soft) endosperm (high lysine) varieties contain higher levels of albumins, globulins and glutelins (78,79). Vitreous endosperm also contains a greater proportion of cross-linked proteins, which are present across a wider size range compared to floury varieties (80).…”

Section: Protein Bodiesmentioning

confidence: 99%

“…Vitreous endosperm contains a high degree of crosslinked storage proteins with a greater percentage of disulphide bonds. In both maize and sorghum, floury endosperm contains higher levels of non-kafirins, such as albumins and globulins, while vitreous endosperm contains a higher proportion of β-and γ-kafirin (80,154). Sorghum high digestibility (HD) lines, which exhibit increased lysine content, retain a vitreous endosperm (60).…”

Section: Grain Protein Compositionmentioning

confidence: 99%

Grain Proteomics of Sorghum: Improving Digestibility, Nutritional Quality and Starch Conversion to Ethanol

Cremer¹

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Sorghum is an important food staple in rural Asia, India and Africa and a major feedstock in developed countries. Originating in the semi-arid African savannah, sorghum is well adapted to drought prone environments and produces more biomass per unit water than maize. Extensive variability exists within the sorghum gene pool creating a diversity of plant forms with many commercial and industrial applications. Sorghum, provides an alternative to grain crops with greater irrigation and fertiliser requirements, such as maize, however, the grain is generally less digestible, especially upon cooking, due to extensive disulphide cross-linking among sulphur-rich storage proteins in the protein-starch matrix. This reduces the accessibility of proteolytic enzymes to starch, decreasing palatability and nutritional value, and resulting in the need for increased processing.The commercial value of cereals is largely determined by the chemistry of the protein-starch matrix.Located on the periphery of storage protein bodies, cysteine-rich β-and γ-kafirins prevent enzymatic access to internally positioned α-kafirins and to starch. The development of mutants is an efficient approach for studying genetic regulation of protein biosynthesis and compartmentalisation and shows how changes in protein profile affect the physical characteristics of the seed. An integrated proteomic approach was employed to characterise 28 sorghum lines with allelic variation at the kafirin loci, including three β-kafirin null mutants, in order to determine the effects of kafirin genetic diversity on the expression of storage proteins.High performance liquid chromatography (HPLC) and capillary electrophoresis were employed to profile water/salt-and alcohol-soluble protein fractions, revealing a wide range of diversity in protein content across the genotypes. Peak profiles were similar among β-kafirin null lines but different to normal lines, with a significant reduction in alcohol-soluble protein and the disappearance of a major set of protein peaks. The relative content of sequentially extracted soluble, insoluble and residual proteins was measured using RP-HPLC to evaluate the degree of crosslinking among storage proteins in the seed. High levels of insoluble and residual protein were associated with reduced digestibility.Gel-based separation of seed proteins and subsequent identification with tandem mass spectrometry identified a range of redox-active proteins affecting storage protein biochemistry. Multiple protein fractions were analysed across the β-kafirin null line QL12 and wild-type line 296B. The redox states of endosperm proteins, of which kafirins are a subset, have been shown to impact on quality traits in addition to the expression of proteins. Thioredoxin, active in the processing of storage v proteins at germination, has reported impacts on grain digestibility and was differentially expressed across the genotypes. A range of putative uncharacterised sorghum proteins regulating the folding and disulphide pairing of storage proteins ...

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Characterization of Polymeric Proteins from Vitreous and Floury Sorghum Endosperm

Cited by 32 publications

References 19 publications

Hardness Methods for Testing Maize Kernels

Hardness Methods for Testing Maize Kernels

A Computationally Efficient Design Technique for Electric-Vehicle Traction Machines

Grain Proteomics of Sorghum: Improving Digestibility, Nutritional Quality and Starch Conversion to Ethanol

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