Are food-based plastics a good idea?

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(...) Food-based plastics, made out of everything from corn to sugarcane, have rapidly grown in popularity over the past several years. Packaging materials, gift cards, cell phone casings -- all can be made from these eco-friendly materials. As the quality of food-based plastics improves, they will have broader and broader applications.

Proponents cite two main advantages of food-based plastics over their petroleum-based counterparts. _______, they’re made from a renewable resource.

_____________ farmers grow the crops these plastics are made out of, production can continue indefinitely. _________, food-based plastics are widely considered to be easier on the environment. ___________, they require much less energy to produce than traditional plastics and release fewer greenhouse gases in the process.

____________, they break down into harmless organic compounds -- in the right conditions.

Now for the drawbacks. One of the most glaring is their relatively low melting point. _______ popular plastics like polyethylene terephthalate (pet) may have melting points well beyond 400 degrees Fahrenheit (204 degrees Celsius), some plant-based plastics turn into puddles just from being left in a car on a sunny day. _________, polylactic acid (pla), a corn-based plastic used by retail giant Wal-Mart among other companies, can have a melting point of just 114 degrees Fahrenheit (46 degrees Celsius). _____________, food-based plastics are simply unsuitable for a wide range of applications.

___________, food-based plastics may not be as environmentally friendly as they appear. _________ they are biodegradable, most only break down under very specific conditions found in industrial composting plants. _____________ you can’t simply throw them on the compost pile in your backyard and expect them to

turn into soil, and if they do end up in a landfill, they break down just as slowly as conventional plastics. ________ food-based plastics can be recycled, they can’t simply be mixed in with other recyclable plastics. _________, the recycling industry considers food-based plastics a «contaminant» that takes time and money to process.

A final argument against food-based plastics is that generating them requires land and resources that could be going to producing actual food. Already, the U.S.

Department of Agriculture (uSda) estimates that, by 2014, nearly a quarter of all grain production will go toward making ethanol and other biofuels; if food-based plastics take off, that number could climb even higher. Environmentalists also worry about the harmful effects of the pesticides and genetically modified crop strains used to create some of these plastics.

But don’t give up on food-based plastics yet. ________ they still represent less than 1 percent of the plastics market, some very large companies have committed to both improving and using the plastics moving forward. ____________, electronics manufacturers Panasonic and NEC have both announced the development of food-based plastics with significantly improved durability, heat resistance and ease of production compared to products currently on the market. Metabolix, another bioplastics manufacturer, has developed a plastic called Mirel that biodegrades in normal compost piles. Production costs for food-based plastics are rapidly dropping as well, which, coupled with their widening range of applications, will make them a much stronger alternative to conventional plastics moving forward.

Perhaps the strongest argument for food-based plastics, however, is that after we’ve finally exhausted our supply of oil, they’ll still be waiting for us.

(Adapted from:



• Which of the transition signals above was more frequent in the text?

• Which is the typical sentence structure it appears in?

• What does it express, instantiation, additional information or contrast?

• How does the sentence structure help to express that meaning?

Will the caffeine in chocolate make me jittery? Probably not. Cacao does contain a number of stimulants, such as caffeine and theobromine, but in small amounts that are diluted even further when processed into chocolate. In fact, one ounce of milk chocolate contains about the same amount of caffeine as one cup of decaffeinated coffee. Interestingly, one study has shown that the smell of chocolate may actually relax you by increasing theta waves in the brain.

Can chocolate cause headaches? There is little evidence of this, although some studies suggest that chocolate may trigger headaches specifically in migraine sufferers.

Is chocolate an aphrodisiac? Not really. Chocolate contains small amounts of a chemical called phenylethylamine (pea) that is a mild mood elevator. It’s the same chemical that our brain produces when we feel happy or «in love.» The mild «rush» we get from this substance may be why some people say they’re

«addicted» to chocolate.

Will chocolate raise my cholesterol levels? Contrary to popular misconception, eating lots of chocolate does not raise blood cholesterol levels.

Chocolate contains stearic acid, which is a neutral fat that does not raise bad cholesterol (ldl). Also, the cocoa butter in chocolate contains oleic acid, a mono-unsaturated fat. This is the same type of fat found in olive oil that may actually raise good cholesterol (hdl).

Will eating chocolate make me fat? It can—if you eat enough of it. Chocolate, especially milk chocolate, is high in calories. In fact, it was once prescribed to help fatten up patients suffering from wasting diseases like tuberculosis.

However, some people claim that drinking a cup of hot chocolate before a meal actually diminishes their appetite. One researcher even experimented with helping patients lose weight by having them sniff a chocolate-scented patch whenever they were tempted to snack!

Does chocolate contain any nutrients? Yes, it does, in small amounts.

A 1.5-ounce milk chocolate bar contains recommended daily values of the following vitamins and minerals: 3 grams of protein; 15% of the Daily Value of riboflavin; 9% of the Daily Value for calcium; 7% of the Daily Value for iron. And if you add nuts like almonds or peanuts into the mix, you increase all READING COMPREHENSION

Read the following extract. Then, try to complete the gaps in the second part of the text:

Will I live longer if I eat chocolate? Perhaps. A Harvard University study

In document Working with Techincal and Scientific English (Page 84-87)

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