Week 2: Research

The librarian called me to the library to finally collect the books I reserved. I read briefly through each of the books and made notes on information that would further help me with my assessment task. I then combined these notes with my previous internet research to produce my research paper below. I have also incorporated in videos which also helped me with my understanding of my SRP topic. I have also acknowledged all the suppliers of each photo in my paper as well as referenced my videos.

RESEARCH PAPER:

What is Popcorn ?

Popcorn a type of special corn grain. Unlike white or yellow corn on the cob , it is usually not edible. Popcorn is the only corn out of the five types that pops. The Kernels of the popcorn range in colour from red,black,gold, off-white and many more. Popcorn  can be hulless and also come in a number of sizes, But they only have two basic shapes which are mushroom and round. As for flavour also varies.  The most common would be the yellow Popcorn which also pops the largest.   Popcorn is generally stripped from the cob and then heated into a pan instead of eaten off a cob. When the corn is heated the inside literally breaks through the tough hull , then forming the fluffy, crunchy kernels. Popcorn also have health benefits as it is a wholesome food thats aids in digestion through it’s supplement of necessary roughage.  Not only that, Popcorn is regarded as an excellent mealtime complement as stated by Health and medical groups. Not to mention this is because they are sugar-free , fat-free and low in calories and they are literally “light”- one gallon of unbuttered popcorn weighing only three and a half ounces and only carrying around 390 calories. Popcorn is so light as it is mostly air and on top of that has no artificial colour, preservative or sugars weighing it down.  Popcorn is also an inexpensive way to add fibre into your diet , making the grain economical. It is also a great source of high fibre , protein and other nutrients and is deemed one of the most healthiest snacks to have. Popcorn dates back to 1948 and we have the Native Americans to thank for that.

 

Popcorn Structure

The Popcorn kernel is composed of a majority  of starch , along with 13% of protein, fat and water all together. The hull, or pericarp is known as the harder coating under which is a dense and opaque starch layer as well as an inner starch layer which is composed of irregular polygon transulent grains which are approximately around 10 micrometers across. This popcorn characteristic is unique and is caused by the fact that it has in it’s interior a higher content of this transulent starch than any of the other corn grains. This unique characteristic means that the grain has the power to rise and expand from 20 to 40 times it’s original volume, unlike other grains which only expand 2 to 3 times it’s current size when heated.

Image supplied by:http://physicspoppingcorn.wikispaces.com/Task+1_+READ 

Image supplied by:http://physicspoppingcorn.wikispaces.com/Task+1_+READ 

What makes popcorn pop ?

Hoseney Zeleznak and Abdelrahman proposed a detailed mechanism for popping corn in the year 1983.  The model clearly suggested pericarp, the outer covering of the corn takes role in being a pressure vessel. Once the popcorn is exposed to heat of popping temperature , being 175oC, the kernel will then get heated and expanded due to the inside gases. The vaporising of the water in the transulent starch takes place to a small extent, but due to maintained pressure in the pericarp, majority of it stays as a superheated liquid water.

Image supplied by::http://physicspoppingcorn.wikispaces.com/Task+1_+READ
 

Image supplied by:http://physicspoppingcorn.wikispaces.com/Task+1_+READ 

The pericarp experiences major failure at the 8tm (8.1x10^5Pa) or higher pressure level. A “jelly-like” consistency is then produced. Steam then forms from the superheated water within the starch granules because of the failure of the pericarp. This steam goes on to expand around 1500 times it’s current volume when it was water. This then leads to expansion of the starch granules which blow up to 40 up to 100 micrometer sized particles.

Sufficient cooling then takes place thanks to the vaporising water in hand with the expanding gases which solidifies the starch forming the “white, fluffy, spongy” part of the popcorn.

Gif. supplied by:http://www.dailygifblog.com/2011/01/popcorn-popping-slow-motion.html 

What is the role of steam and water in Popcorn ?

Held in the transulent starch granules is the 13% of water composed in popcorn. Amazingly this water will remain as a liquid even at up to 175oC.  This happens because of superheating which is also referred to as boiling delay.  This allows the popcorn to be heated above boiling point of water without water the water boiling. Superheating works by surface tension in the liquid, leading to the suppressing of the growing bubbles.

Methods for cooking popcorn

Cooking popcorn can be carried out in 3 ways using heat transfer:

Conduction:

You will need a pan. You will have to cover this pan with oil and then with popcorn kernels. Place this pan on top of a stove and turn on the medium heat of the burner.    Then place a lid on top of the pan and in time shake the pan, moving the kernels around in the oil.  It is said that 1/4 cup which is around 0.0544kg of popcorn will take an extent of 4 minutes when using a 85kW stove.

Image supplied by:
http://www.recipetips.com/kitchen/images/refimages/grains/Cooking/popcorn/add_popcorn.jpg

Convection:

Popcorn Poppers are another way of creating popcorn. To use this device, you will have to place the popcorn kernels inside the popcorn popper. Following this, plug in the popper’s electrical cord and switch on. Heat will then be transferred to the kernels from the hot air, causing them to soon pop and expand in size.

Image supplied by: http://s1.hubimg.com/u/3068464_f260.jpg

Radiation:

Using a Microwavable popcorn bag that can be purchased from local stores, you simply place the popcorn bag flat onto the microwave plate and set given time on bag which is most commonly 3 minutes (using a 87kW microwave) and wait for it pop.

Image supplied by:http://heatherlconrad.com/wp-content/uploads/2011/03/microwave-popcorn.jpg

Best Popcorn “Pop-ability”

The best “pop-ability” of Popcorn, are composed of a stronger ‘more highly ordered crystalline’ arrangement of the cellulose molecules’, than the pericarp of poorer performing varieties. Identifying the key crystalline structure in popcorn has proven to determine the popcorn’s popping quality as Researchers at Purdue University in the US have found.

This current finding could lead on to improved microwave popcorn with fewer or even no un-popped kernels as they are predicting. Manufacturers have attempted in the decrease in the ‘old maids’ known as the un-popped kernels as  they can not only cause choking, destroy filling and break teeth they also represent unnecessary costs on wastage. However the problem still lives on, most commonly in microwave popcorn.

Because of problems with un-popped kernels retail sales in the US have had a major drop recently following 20 years of steady increase. Un-popped popcorn was recorded to have reached up to 1.5 billion pounds in the US, 1993. Sales have now dropped to 980 million pounds as stated by the Popcorn Board.

Although, $1.3 billion action has been taken, as a new study is said to bring cost-savings, which are to lead to new gains in the dropping $1.3 billion microwave popcorn market in the US.

“We believe that the amount and location of the cellulose component of the kernel are critical for crystallinity and think that this property can be transferred to corn kernels to improve their popping performance. We’re not sure yet exactly how this will be achieved, but we’re optimistic that enterprising researchers will be able to do this in the near future”, says food chemist Bruce Hamaker, Ph.D., of Purdue University in West Lafayette. (Hamaker,2005)


BUBBL.US UPDATE:

BIBLIOGRAPHY:

Stein,S. (Unknown) What is popcorn anyways ? [Internet]. Unknown. Available from: <http://www.tooter4kids.com/Popcorn/what_is_popcorn.htm>[accessed 11th March,2011].

Ellis-Christensen,T.( 2003) What is Popcorn? [Internet]. Sparks, NV,U.S.A. Available from: <http://www.wisegeek.com/what-is-popcorn.htm>[ accessed 11th March,2011].

Ablett,E.( 2011) Physics of Popping Corn [Internet]. 67 Langton Street

San Francisco, CA. Available from:< http://physicspoppingcorn.wikispaces.com/Task+1_+READ>[accessed 10th March, 2011].

Reed,W. (2005) Food chemists identify organic structure for maximum 'pop' in popcorn [Internet]. 34 000 Montpellier ,France. Available from:< http://www.foodnavigator.com/Science-Nutrition/Food-chemists-identify-organic-structure-for-maximum-pop-in-popcorn>[accessed 10th March,2011].

Hogan,D, (2005) The Chemistry Of Popcorn: It's All About 'Pop-Ability' [Internet]. 1 Research Court Suite 450 ,Rockville. Available from: <http://www.sciencedaily.com/releases/2005/04/050415112829.htm> [accessed 10th March,2011].


Landua,E.(2003) Popcorn! . Charlesbridge Publishing, USA.


Hureston,C. (2007) Anatomy of a Popcorn Kernel . AuthourHouse,USA.


Lunis.N.,&White,N. (1942) Popcorn Science. Newbridge,USA.


Brainiacs: Popcorn Popping in Slow Motion. 2008,Youtube, Unknown, 11th March,[Video]


Friday Afternoon Physics: Explosions of Vapour. 2009,Youtube,Unknown, 10th March,[Video]


Unknown: Superheating. 2007,Youtube, Unknown,10th March,[Video]