Characterization of a 19 kDa α-Zein of High Purity

Cabra, Vanessa; Arreguín-Espinosa, Roberto; Gálvez, Amanda; Quirasco, Maricarmen; Vázquez-Duhalt, Rafael; Farrés, Amelia

doi:10.1021/jf048530s

Cited by 87 publications

(81 citation statements)

References 32 publications

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“…In our case, this effect can also be responsible for the observed improvement in the separation of zein proteins. Zein proteins are known to interact with each other and to naturally form dimers, trimers and even more complex aggregates [17][18][19][20]. It is therefore supposed that at the beginning of the separation the concentration of NH 4 1 will either decrease (see Fig.…”

Section: Effect Of the Ammonium Concentrationmentioning

confidence: 99%

Reproducible and efficient separation of aggregatable zein proteins by CZE using a volatile background electrolyte

2007

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Zein proteins are a complex mixture of polypetides that belong to the alcohol-soluble storage proteins group (prolamines) in corn. These proteins constitute about 50-60% of the total endosperm protein and are classified in different groups on the basis of differences in their solubility and sequence. Among them, zein proteins are considered the majority group showing a high tendency to aggregate what makes their analysis by any analytical method very difficult. Thus, CZE of these proteins requires the use of very complex BGEs noncompatible with online ESI-MS analysis. The aim of this work was to find a new BGE for the CZE separation of zein protein fully compatible with ESI-MS while providing further light on the complex CZE separation of aggregatable proteins. Thus, it is demonstrated in this work that efficient and reproducible CZE separations of zein proteins can be achieved by using a BGE composed of water, ACN, formic acid and ammonium hydroxide. Besides, it is shown that zein analysis is significantly improved by including the effect of an ammonium gradient during their separation. It is experimentally verified that the ammonium gradient can easily be achieved in CZE by either working with a sample zone with a low concentration of ammonium and a BGE with a high concentration, or conversely, working with a sample zone with high ammonium concentration and a BGE with low concentration of ammonium, giving rise in both cases to a significant improvement in the CZE separation of these proteins. It is demonstrated that this procedure can give rise to efficiency improvements of up to 20-fold in the CZE separation of zein proteins. Under optimized conditions, 20 proteins could be separated with average efficiencies higher than 400 000 theoretical plates/m. Some possible explanations of this effect are discussed including stacking, protein-capillary wall adsorption, protein solubility and protein-salt interactions.

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Section: Effect Of the Ammonium Concentrationmentioning

confidence: 99%

Reproducible and efficient separation of aggregatable zein proteins by CZE using a volatile background electrolyte

2007

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“…Although there were 8 molecular weight fractions from the gel-permeation chromatography software analysed data, the focus was on the fraction with the average molecular weight greater than 10,000 Da. The choice of fraction >10, 000 Da was based on the fact this was the fraction with the highest molecular weight and this fraction covered the zein proteins although it is generally known that the molecular weight of zein protein can range as low as 19,000 Da to as high as ranging from 20,000-24, 000 Da or even above as reported by other authors (Dauzer and Rees 1976;Cabral et al 2005). Our assumption was also based on the fact that all the other components in the film forming solution which was analysed (95 % ethanol Mw = 46.07, gallic acid Mw = 170 and ethylene glycol MW = 62.07) had molecular weights less than 100 Da and therefore any component contributing to molecular weight above 10, 000 Da was coming from zein proteins.…”

Section: Molecular Weight Distributionmentioning

confidence: 99%

Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films

Masamba

Hategekimana

et al. 2016

J Food Sci Technol

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In this study, the effect of gallic acid on mechanical and water barrier properties of zein-oleic acid 0-4 % composite films was investigated. Molecular weight distribution analysis was carried out to confirm gallic acid induced cross linking through change in molecular weight in fraction containing zein proteins. Results revealed that gallic acid treatment increased tensile strength from 17.9 MPa to 26.0 MPa, decreased water vapour permeability from 0.60 (g mm m, increased solubility from 6.3 % to 10.2 % and marginally increased elongation at break from 3.7 % to 4.2 % in zein films only. However, gallic acid treatment in zein-oleic composite films did not significantly influence mechanical and water barrier properties and in most instances irrespective of oleic acid concentration, the properties were negatively affected. Results from scanning electron microscopy showed that both gallic acid treated and untreated zein films and composite films containing 3 % oleic acid had a compact and homogeneous structure while those containing 4 % oleic acid had inhomogeneous structure. The findings have demonstrated that gallic acid treatment can significantly improve mechanical and water barrier properties especially in zein films only as opposed to when used in composite films using zein and oleic acid.

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“…Although the analysis produced 8 molecular weight fractions based on the standards used, the focus was on the molecular weight fraction with molecular weight greater than 10,000 Da. This choice of fraction (>10,000 Da) was based on the fact this is the fraction where the zein proteins are supposed to be covered considering the fact that the molecular weight of zein has previously been reported to range from 20,000 to 24,000 Da or even above [19,20]. The assumption that cross-linking indeed took place in the zein proteins covered in the fraction with the molecular weight greater than 10,000 Da was further supported by the fact that irrespective of plasticizer type, all the other components in the film forming solution had molecular weights less than 200 Da.…”

Section: Molecular Weight Distribution Analysismentioning

confidence: 99%

Effect of Type of Plasticizers on Mechanical and Water Barrier Properties of Transglutaminase Cross-Linked Zein–Oleic Acid Composite Films

Masamba¹,

Hategekimana

et al. 2015

International Journal of Food Engineering

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The effect of using four plasticizers namely ethylene glycol, propylene glycol, glycerol and sorbitol on mechanical and water barrier properties of transglutaminase cross-linked zein-oleic acid composite films was investigated. Results revealed that both mechanical and water barrier properties of the films were significantly affected (p<0.05) by plasticizer type. Tensile strength (TS), water vapour permeability (WVP) and solubility (SB) values were all better in ethylene glycol control plasticized films compared to other plasticizers. Furthermore, irrespective of plasticizer type, transglutaminase treatment improved TS while when oleic acid was incorporated into the films in the range of 1-4% based on zein weight, the mechanical and water barrier properties of the composite film were diversely affected. Results from scanning electron microscopy for the 2% oleic acid-incorporated composite films revealed a rough and irregular surface morphology for the sorbitol plasticized films. Overall, ethylene glycol provided better mechanical and water barrier properties.

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Characterization of a 19 kDa α-Zein of High Purity

Cited by 87 publications

References 32 publications

Reproducible and efficient separation of aggregatable zein proteins by CZE using a volatile background electrolyte

Reproducible and efficient separation of aggregatable zein proteins by CZE using a volatile background electrolyte

Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films

Effect of Type of Plasticizers on Mechanical and Water Barrier Properties of Transglutaminase Cross-Linked Zein–Oleic Acid Composite Films

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