Abstract
If you developed a super-sour candy, drink, or dessert, to whom would you sell it? Do people of all ages love sour, or is there a difference between the sour preferences of kids and adults? Try this mouth-puckering science fair project to find out!Objective
Determine whether there is a difference between adults' and children's preferences for sour tastes.
Introduction
Do you know anyone who likes to eat lemons? Or loves really sour candies? Maybe you are one of those people! People have different definitions of what they find palatable (PAH-lih-tuh-bul), which means "good to eat." There are many different factors that go into deciding whether or not something is palatable. One of the biggest parts of that decision is how something tastes. Humans can sense five tastes: sour, salty, bitter, sweet, and umami (oo-MAH-mee), which is the non-salty part of how soy sauce tastes.
Taste is detected by the taste buds that line the tongue and other parts of the mouth. Figure 1 shows a diagram of a taste bud. Although there is some variation from person to person, the human tongue has an average of about 10,000 taste buds. Inside each taste bud are several receptor cells. These cells can sense the five different tastes, and they send that information to the brain.
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| Figure 1. Each taste bud contains many different taste receptor cells, which help to detect the five different tastes: sour, salty, bitter, sweet, and umami. (Adapted from Selbst Erstellt, 2008.) |
In addition to taste, people think about several other factors when deciding if something is acceptable to eat. These include other components of flavor, like how spicy a food is or how it smells, the texture and temperature of a food, and whether the food is something they like eating for cultural or personal reasons. Figure 2 shows a diagram of the different factors people consider when making their food choices.
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| Figure2. This diagram shows the different factors humans use to determine if a food is acceptable to eat or not. Taste, at the center of the diagram, is one of the most important factors; but other things, including what is typically considered "yummy" in a culture, are also part of the decision. |
One job food scientists can have is working at companies to help them design new foods. One of the things they have to do is conduct sensory analysis, which is the scientific process of determining how people react to different foods, and then make decisions about whether or not they like them. Food scientists already know a lot about people's food preferences. For example, they know that babies usually prefer sweet foods, like applesauce and sweet potatoes, over more bitter foods, like broccoli. They also know that Americans and Europeans like mint-flavored toothpastes, while people in China and Japan prefer their toothpastes to be fruit-flavored. But what about sour? There are a lot of sour candies and drinks advertised on TV, in magazines, and in other places that tempt kids, but not many of those advertisements make the foods sound appealing to adults. Is there a difference in the percentage of kids versus adults who like sour-tasting foods? You can find out in this mouth-puckering science fair project by conducting a taste test with four lemonades, each with a different concentration of citric acid. Citric acid is the natural chemical that gives citrus fruits, like limes, lemons, oranges, and grapefruit, their sour taste. Who do you think will like the sourest lemonade the best?
Terms, Concepts and Questions to Start Background Research
Bibliography
These websites have more information about taste and taste buds:
This website offers help with creating graphs:
Materials and Equipment
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Experimental Procedure
| Lemonade Batch # | Level of Sourness | Quantity of Citric Acid Stock Solution to Add to the Drink Mix | Quantity of Water to Add to the Drink Mix |
| 1 | None | None | 4 cups |
| 2 | Low; similar to 10% lemon juice | 3 Tbsp | 4 cups |
| 3 | Medium; similar to 50% lemon juice | 2/3 cup | 3 and 1/3 cups |
| 4 | High; similar to 100% lemon juice | 2 cups and 2 Tbsp | 2 cups |
| Volunteer # | Adult or Kid | Favorite Lemonade Batch # | Least Favorite Lemonade Batch # |
| 1 | |||
| 2 | |||
| 3 |
Variations
Credits
Tirza Thebert
Sandra Slutz, PhD, Science Buddies
Last edit date: 2008-10-06 00:00:00
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