Zein

Key takeaways

Zein belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Zein to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Zein from memory before moving on to harder problems.

Reference excerpt

Zein ( ZEE-in) is a class of prolamine protein found in maize. It is usually manufactured as a powder from corn gluten meal. Zein is one of the best understood plant proteins. Pure zein is clear, odorless, tasteless, hard, water-insoluble, and edible, and it has a variety of industrial and food uses.

Commercial uses Historically, zein has been used in the manufacture of a wide variety of commercial products, including coatings for paper cups, soda bottle cap linings, clothing fabric, buttons, adhesives, coatings and binders. The dominant historical use of zein was in the textile fibers market where it was produced under the name "Vicara". With the development of synthetic alternatives, the use of zein in this market eventually disappeared. By using electrospinning, zein fibers have again been produced in the lab, where additional research will be performed to re-enter the fiber market. It can be used as a water and grease resistant coating for paperboards and allows recyclability. Zein's properties make it valuable in processed foods and pharmaceuticals, in competition with insect shellac. It is now used as a coating for candy, nuts, fruit, pills, and other encapsulated foods and drugs. In the United States, it may be labeled as "confectioner's glaze" (which may also refer to shellac-based glazes) and used as a coating on bakery products or as "vegetable protein." It is classified as Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration. For pharmaceutical coating, zein is preferred over food shellac, since it is all natural and requires less testing per the USP monographs. Zein can be further processed into resins and other bioplastic polymers, which can be extruded or rolled into a variety of plastic products. With increasing environmental concerns about synthetic coatings and the current higher prices of hydrocarbon-based petrochemicals, there is increased focus on zein as a raw material for a variety of nontoxic and renewable polymer applications, particularly in the paper industry. Other reasons for a renewed interest in zein include concern about the landfill costs of plastics, and consumer interest in natural substances. There are also a number of potential new food industry applications. Researchers at the University of Illinois at Urbana-Champaign and at William Wrigley Jr. Company have recently been studying the possibility of using zein to replace some of the gum base in chewing gum. They are also studying medical applications such as using the zein molecule to "carry biocompounds to targeted sites in the human body". There are a number of potential food safety applications that may be possible for zein-based packaging according to several researchers. A military contractor is researching the use of zein to protect MRE food packages. Other packaging/food safety applications that have been researched include frozen foods, ready-to-eat chicken, and cheese and liquid eggs. Food researchers in Japan have noted the ability of the zein molecule to act as a water barrier. While there are numerous existing and potential uses for zein, the main barrier to greater commercial success has been its historic high cost until recently. Zein pricing is now very competitive with food shellac. Zein may be extracted as a byproduct in the manufacturing process for ethanol or in new off-shore manufacture.

Gene family Alpha-prolamins are the major seed storage proteins of species of the grass tribe Andropogoneae. They are unusually rich in glutamine, proline, alanine, and leucine residues and their sequences show a series of tandem repeats presumed to be the result of multiple intragenic duplication. In Zea mays (Maize), the 22 kDa and 19 kDa zeins are encoded by a large multigene family and are the major seed storage proteins accounting for 70% of the total zein fraction. Structurally the 22 kDa and 19 kDa zeins are composed of nine adjacent, topologically antiparallel helices clustered within a distorted cylinder. The 22 kDa alpha-zeins are encoded by 23 genes; twenty-two of the members are found in a roughly tandem array forming a dense gene cluster. The expressed genes in the cluster are interspersed with nonexpressed genes. Some of the expressed genes differ in their transcriptional regulation. Gene amplification appears to be in blocks of genes explaining the rapid and compact expansion of the cluster during the evolution of maize.

Other biodegradable polymers Cellophane Plastarch material Poly-3-hydroxybutyrate Polycaprolactone Polyglycolide Polylactic acid

References

External links

Worked examples

Example 1 — a first encounter with Zein

Start with the simplest possible case. Write down what Zein claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Zein before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Zein ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Zein

In research: Zein appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Zein in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Zein is common in secondary-school and first-year university syllabi. It links to neighbouring topics Biodegradable plastics, Food additives, Protein families, so understanding it makes those chapters shorter.
In everyday life: Look for Zein outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Zein in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Zein means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Zein out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Zein in simple terms?

Zein ( ZEE-in) is a class of prolamine protein found in maize. It is usually manufactured as a powder from corn gluten meal.

Why does Zein matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Zein?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Zein.