Zein: A history of processing and use
01 Jan 2002-Cereal Chemistry (The American Association of Cereal Chemists, Inc.)-Vol. 79, Iss: 1, pp 1-18
TL;DR: In this article, a review of the early literature on zein is presented, which reexamines the old literature and reconciles it with new zein research to illustrate some of the unique properties of and opportunities for zein.
Abstract: Corn is the largest and most important agricultural commodity in America. Zein, one of the components in corn, has long been investigated for uses other than food and feed. Zein is a unique and complex material, and it is one of the few cereal proteins extracted in a relatively pure form. Today, because of environmental concerns, interest in zein utilization is again growing. Some of the more important research on zein is more than 50 years old. Most of this work has been either forgotten, lost, or difficult to locate. Much of this work was done at the USDA laboratory in Peoria, IL. Since most early zein literature is still easily accessible at that laboratory, this review on zein has been prepared making use of this old literature. This review reexamines the old literature and reconciles it with new zein research to illustrate some of the unique properties of and opportunities for zein.
Citations
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TL;DR: This review is intended to summarize the applications of nanotechnology relevant to food and nutraceuticals together with identifying the outstanding challenges.
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TL;DR: The development of nanocomposites is a new strategy to improve physical properties of polymers, including mechanical strength, thermal stability, and gas barrier properties, including montmorillonite and kaolinite clays and graphite nanoplates.
Abstract: The development of nanocomposites is a new strategy to improve physical properties of polymers, including mechanical strength, thermal stability, and gas barrier properties. The most promising nanoscale size fillers are montmorillonite and kaolinite clays. Graphite nanoplates are currently under study. In food packaging, a major emphasis is on the development of high barrier properties against the migration of oxygen, carbon dioxide, flavor compounds, and water vapor. Decreasing water vapor permeability is a critical issue in the development of biopolymers as sustainable packaging materials. The nanoscale plate morphology of clays and other fillers promotes the development of gas barrier properties. Several examples are cited. Challenges remain in increasing the compatibility between clays and polymers and reaching complete dispersion of nanoplates. Nanocomposites may advance the utilization of biopolymers in food packaging.
589 citations
Cites background from "Zein: A history of processing and u..."
...Zein, a relatively hydrophobic protein found in corn kernels, is known to form films easily (Winters and Deardorff 1958; Shukla and Cheryan 2001; Lawton 2002)....
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TL;DR: The interpretation of the common fermentation end products, microbial populations, organoleptic properties, and changes in nutritive aspects of silage during storage of silages are discussed with emphasis on a North American perspective.
541 citations
TL;DR: This review aims to provide an overview of the major sources of plant proteins, their physiochemical functionalities and nutritional properties, with emphasis on the research needed to support technology innovation for more plant protein to meet world nutritional requirements and as food sources to feed the growing world population.
Abstract: Increasing utilisation of plant protein is required to support the production of protein-rich foods that can replace animal proteins in the human diet so as to reduce the strain that intensive animal husbandry poses to the environment. From a nutritional standpoint, with the right combination, plant proteins can supply sufficient amounts of essential amino acids for human health requirements. In addition to their role as a macronutrient, proteins play an integral role in structural formation of foods through processes such as emulsification, foaming, gelation and dough formation. This review aims to provide an overview of the major sources of plant proteins, their physiochemical functionalities and nutritional properties, with emphasis on the research needed to support technology innovation for more plant protein to meet world nutritional requirements and as food sources to feed the growing world population.
504 citations
Cites background from "Zein: A history of processing and u..."
...The major applications of zein are as a polymer material for film, coatings and plastics (Lawton, 2002)....
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TL;DR: An overview of Pickering emulsions is given, focusing on some kinds of solid particles commonly serving as emulsifiers, three main types of products from PickeringEmulsions, morphology ofSolid particles and as-prepared materials, as well as applications in different fields.
Abstract: Pickering emulsion, a kind of emulsion stabilized only by solid particles locating at oil-water interface, has been discovered a century ago, while being extensively studied in recent decades. Substituting solid particles for traditional surfactants, Pickering emulsions are more stable against coalescence and can obtain many useful properties. Besides, they are more biocompatible when solid particles employed are relatively safe in vivo. Pickering emulsions can be applied in a wide range of fields, such as biomedicine, food, fine chemical synthesis, cosmetics and so on, by properly tuning types and properties of solid emulsifiers. In this article, we give an overview of Pickering emulsions, focusing on some kinds of solid particles commonly serving as emulsifiers, three main types of products from Pickering emulsions, morphology of solid particles and as-prepared materials, as well as applications in different fields.
463 citations
Cites background from "Zein: A history of processing and u..."
...Zein is an abundant material extracted from corn, which has been extensively studied in many fields (Shukla and Cheryan, 2001; Lawton, 2002)....
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References
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TL;DR: In this paper, the authors tested the gas permeability of proteins and cellulose films made from corn-zein and wheat gluten, and found that hydrogenated cellulose (HPC) films increased gas permeabilities as the concentration of plasticizer increased.
291 citations
TL;DR: Transparent unplasticized zein films were prepared in aqueous ethanol or acetone as mentioned in this paper, showing that films prepared in acetone were stronger but less flexible than those prepared in ethanol.
Abstract: Transparent unplasticized zein films were prepared in aqueous ethanol or acetone. Tensile properties indicated that films prepared in acetone were stronger but less flexible than those prepared in ethanol. Both types of films, however, were too brittle for most applications. Films containing a glycerol:poly(propylene glycol) ratio of 1:3 exhibited elongation values almost fifty times greater than glycerol-plasticized films. Incorporation of cross-linking agents into zein films resulted in approximately a 2−3-fold increase in tensile strength values. Water vapor barrier properties were best for unplasticized zein films cross-linked with 20% polymeric dialdehyde starch. Incorporation of plasticizer into zein films resulted in an almost doubling in water vapor permeability values. Keywords: Hydrophilic; film; zein; tensile properties; plasticizer; cross-linking agents; water vapor permeability
287 citations
"Zein: A history of processing and u..." refers background in this paper
...Park and coworkers (1994) showed that polyethylene glycol was a more effective plasticizer for zein than glycerol; this was later corroborated by Parris and Coffin (1997)....
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...6% (Parris and Coffin 1997) to 213% (Herald 1996) for comparably plasticized films....
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...Film elongation ranges from 2.6% (Parris and Coffin 1997) to 213% (Herald 1996) for comparably plasticized films....
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...Parris and Coffin (1997) demonstrated that a 1:1 mixture of polypropylene glycol and glycerol was a more effective plasticizer than either alone....
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Journal Article•
TL;DR: In this article, a new method to separate maize proteins into zein (prolamin) and nonzein classes was used to quantitatively measure the prolamins (zein and kafirin), and nonprolamins in five maize and sorghum genotypes.
Abstract: A new method to separate maize proteins into zein (prolamin) and nonzein classes was used to quantitatively measure the prolamins (zein and kafirin) and nonprolamins in five maize and sorghum genotypes. Some 90-95% of protein was extracted using a pH 10 buffer containing 1% sodium dodecyl sulfate and 2% 2-mercaptoethanol. Ethanol or t-butanol was added to the maize and sorghum extracts at 70 or 60%, respectively, to precipitate nonprolamin proteins ; those remaining in solution were prolamins. The amount of protein in these fractions was compared to that obtained with the conventional Landry-Moureaux method which uses aqueous alcohol plus 0.6% 2-mercaptoethanol as the extraction solvent. Using this new method, zein contents of 50-60% of total protein were found for maize whole grain flours, with 62-74% zein for endosperm alone. Kafirin contents were 68-73% in sorghum whole grain flours, and 77-82% in sorghum endosperm. Prolamin and nonprolamin fractions were judged to be pure based on SDS-PAGE. Zein contents determined by the new method were between 5-12% higher than those obtained by the conventional procedure ; kafirin contents were 12-22% higher. This new method provides a highly reproducible, accurate procedure for determining the content of prolamin and nonprolamin proteins. Yet it is simpler and faster than the conventional fractionation method.
218 citations
"Zein: A history of processing and u..." refers methods in this paper
...Zein is the principle storage protein of corn and constitutes 44–79% of the endosperm protein, depending on the corn variety and separation method used (Larkins 1981; Hoseney 1994; Hamaker et al 1995; Landry et al 2000)....
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TL;DR: Water was removed from aqueous ethanol by using cellulosic materials, starch, corn, and other agents to reduce the combustion energy of the ethanol product.
Abstract: Water was removed from aqueous ethanol by using cellulosic materials, starch, corn, and other agents. The combustion energy of the ethanol product can exceed the energy needed to carry out the dehydration by a factor of 10.
213 citations
Additional excerpts
...Corn grits can be used to dehydrate ethanol (Ladisch and Dyck 1979; Ladisch et al 1984)....
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TL;DR: In this article, a method for preparation of zein films involving plasticization of vein with oleic acid to form an intermediate moldable resins was presented, where the resin was stretched over rigid frames to form thin membranes that were set in flexible films.
Abstract: A new method for preparation of zein films involving plasticization of zein with oleic acid to form an intermediate moldable resin was presented. The resin was stretched over rigid frames to form thin membranes that were set in flexible films. The objective of the study was to investigate the effect of film preparation method on film properties. Tensile properties, microstructure, and thermal behavior of zein films plasticized with oleic acid were investigated for films prepared by conventional casting from ethanol solutions and by stretching of plasticized resins. Cast films were stiff and brittle, whereas resin films showed more flexibility and toughness. Differential scanning calorimetry thermograms of cast films indicated phase separations were generated when heated that were not observed for resin films. Microstructure images showed a higher degree of structure development and orientation in resin than in cast films. Glass-transition temperatures of resin films were measured at -94 and 104.4...
194 citations
"Zein: A history of processing and u..." refers background in this paper
...Recently, researchers have begun to prepare zein films or sheets by a molding process (Lai and Padua 1997; Lai et al 1997)....
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...Padua and coworkers (Lai and Padua 1997; Lai et al 1997; Santosa and Padua 1999) showed that the tensile strength of zein sheet plasticized with fatty acids decreased as fatty acid content increased....
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