REVIEW: Zein Extraction from Corn, Corn Products, and Coproducts and Modifications for Various Applications: A Review

Abstract

Cereal Chem. 88(2):159-173Corn can be fractioned to produce starch, fiber, oil, and protein in relatively pure forms. The corn kernel contains 9-12% protein, but half of this is an industrially useful protein called zein. Dry milled corn (DMC), corn gluten meal (CGM), and distiller's dried grains with solubles (DDGS) are all coproducts from corn that contain zein and are used for zein extraction. Because it is insoluble in water, zein has found uses in many products such as coatings, plastics, textiles, and adhesives. Newer appli-cations are taking advantage of zein's biological properties for supporting growing cells, delivering drugs, producing degradable sutures, and producing biodegradable plastics. This review covers zein characteristics and nomenclature, past and current practices in processing and extraction of zein from corn products and coproducts, and the modifications of zein for various applications.

Zein-Based Nanoparticles Improve the Oral Bioavailability of Resveratrol and Its Anti-inflammatory Effects in a Mouse Model of Endotoxic Shock

“…Negligible levels of TNF-α were observed before LPS 452 administration. The oral administration of Rsv-NP-Z induced a decrease in the levels of 453 TNF-α with respect to mice pre-treated with resveratrol solution and the positive controlIn the past zein was proposed as material for the preparation of nanoparticles due to its 459 hydrophobic character, degradability, adherence properties and versatile processability 460 19,20 . However, as zein possesses abundant non-polar amino acids, the dispersability of 461 the resulting nanoparticles in an aqueous media (and, therefore, their potential 462 applications) is a challenge 30 .…”

“…Zein is the major 110 storage protein of maize and comprises aprox. 45-50% of the total protein content in 111 corn 19 . Since zein is a natural protein, it is actually a heterogeneous mixture of 112 different peptides than can be divided in four main fractions: i) α-zein (75-85% of total 113 protein) with two main MW of 21-25 kDa and 10kDa, ii) β-zein (10-15%) of a MW of 114 17-18 kDa, iii) δ-zein, a minor fraction of 10kDa and vi) γ-zein (5-10%) with a MW of 27 115 kDa 19,20 .…”

“…Since zein is a natural protein, it is actually a heterogeneous mixture of 112 different peptides than can be divided in four main fractions: i) α-zein (75-85% of total 113 protein) with two main MW of 21-25 kDa and 10kDa, ii) β-zein (10-15%) of a MW of 114 17-18 kDa, iii) δ-zein, a minor fraction of 10kDa and vi) γ-zein (5-10%) with a MW of 27 115 kDa 19,20 . Zein is an amphiphilic protein, possessing high percentages of hydrophobic 116 amino acids such as leucine (20%), proline (10%) and alanine (10%) 19,20 . Due to this 117 amino acid composition, zein is insoluble in water and, thus, the resulting devices (e.g.…”

Synthesis, characterization and antibacterial activity of biodegradable films prepared from Schiff bases of zein

“…These mechanical properties of Schiff bases of zein films can be explained on the basis that structure of zein consists of a meshwork composed of doughnut structures formed by asymmetric rods joined to each other via hydrophobic interactions that subsequently maintain film integrity, while intensive hydrophobic interactions can be also responsible for the brittleness and lack of flexibility in zein films (Guo et al 2005). On the other side, lutein (natural pigment) had an obvious role in maintaining the helical structure of zein polypeptides and subsequently affect formation of zein assemblies (Anderson and Lamsal 2011). Increase of the flexibility of zein films via its reaction with phenolic aldehydes by forming Schiff bases of zein can be attributed to form side phenolic and alkyl groups of aldehydes on zein polypeptide chains resulting to attenuate the hydrophobic interactions between these chains and subsequently increase of chain mobility and flexibility of the resultant film.…”

Formation and properties of aqueous compatible colloidal blends between pre-gelatinized maize starch and zein

“…Biomaterial application of starch due to its unique physicochemical and functional properties include: carrier for active materials (Kaur et al, 2007 and as biodegradable films (Weber et al, 2002). Zein can also be used for encapsulation to achieve controlled release of drugs (Mathiowitz et al, 1991), as coatings for cosmetic products (Avalle, 1998) and as biodegradable films and plastics (Anderson and Lamsal, 2011). However, materials from individual biopolymers (starch or zein alone) mostly have inferior properties compared to synthetic polymers.…”