|Science Projects for Students|
Food contains various types of molecules. Those, which exist in food in the greatest amounts, are proteins, fats, and carbohydrates. After food is eaten by humans, carbohydrates are digested, or broken down, into a form that our bodies are able to use for energy. Just as a car today needs gasoline as its energy source, humans need carbohydrates as their source of energy. Carbohydrates contain a group of large molecules known as starch. Examples of foods which are largely made-up of starch are crops known as cereal grains such as rice (e.g. rice cakes), wheat (e.g. bread), and corn (e.g. corn flakes). Starch exists as two different types of molecules known as: amylose and amylopectin. The shape of amylose is similar to that of a spring. The quantity of amylose in rice kernels has a big impact on the properties of cooked rice kernels. That is, rice with little amylose will be sticky and soft. But rice with a large amount of amylose will be harder and not sticky. People in some areas of the world tend to prefer rice that is soft and sticks together (low in amylose) such as in Japan and Korea. While in other areas such as India and Pakistan, people generally prefer rice that is harder and not sticky (high in amylose). Consumers in the United States choose rice with various types of cooking properties because they have various ethnic backgrounds and have had the opportunity to try foods, which originated in other countries. However, the largest quantity of rice purchased in the United States is moderately firm and not sticky.
Being able to measure the quantity of amylose and amylopectin is a very valuable laboratory method considering the importance of those carbohydrates to rice quality. Most methods available today use iodine to measure amylose and amylopectin. When iodine is exposed to amylose a blue color is formed. Iodine with amylopectin produces a purple color. The greater the quantity of either carbohydrate the darker the color. If neither amylose nor amylopectin are present a solution of iodine will remain a yellow color.
Purpose of Experiment
The purpose of this experiment is to examine the amylose content of various types of rice and cereal grain fractions. Another purpose is to gain an awareness of the diversity in cereal grain eating and cooking properties, which are controlled by differences in their chemical make-up.
* Note: Sweet rice can be purchased in Asian or ethnic food stores. Wheat gluten can be found in the baking section of grocery stores. Grocery stores or pharmacies will generally carry iodine.
Record the Results
Record the Results
Conclusions Based on Experimental Results
Question: How many foods and beverages can you name which contain rice?
Answer: It is difficult to say how many foods and beverages in the world are made using rice. The reason being that the list is always changing as new products are created by food processing industries, restaurants and in people's homes all around the world everyday.
Some examples of foods which contain rice are as follows: canned chicken and rice soap, rice cakes, puffed rice cereal, Cream of Rice, Kellogg's Rice Krispies and Special K, multi-grain cereals, miso (fermented rice seasoning), kochujang (a fermented soybean and rice paste, which originated in Korea, is used like ketchup, sake (rice wine), pet foods, rice paper/wrappers, rice pilaf, rice milk, baby formulas, rice pudding, rice noodles, unleavened bread, rice bran oil, beer, bounden balls, rice cake (e.g. dosai from India), rice based casseroles, rice snack foods (e.g. kroepeck and lohuwa from the Philippines)and rice vinegar.