Lab: Sweetness in Carbs

          My partner and I began this experiment by writing down the structures and functions of 8 different carbohydrates- sucrose, glucose, fructose, galactose, maltose, lactose, starch, and cellulose. After we recorded the information regarding these carbs, we began the taste test. 
           Our hypothesis was that sucrose, glucose, fructose, galactose, and maltose would all taste sweet, while lactose, starch, and cellulose would not taste sweet. 
         From the small containers we were given, we used a spoon to dish out every carb into different locations on a paper towel with labels for our reference. When every carbohydrate was on the matting, we used the tips of our fingers to catch a small amount of each substance and taste it. The data we recorded included their names, their degree of sweetness from 0-200, their color, and their texture. 
         Sucrose, glucose, and fructose were granular and generally sweeter than the rest. Galactose, maltose, lactose, starch, and cellulose could be best described as powder in physical texture. The monosaccharides seemed to be sweeter, excluding galactose, and the disaccharides and polysaccharides were not very sweet at all, excluding sucrose. In general, the less rings in the structure of the carbohydrate, the sweeter it was. 
         This made a lot of sense because I find table sugar and fruits and juices to be sweeter than cornstarch and vegetables and other staple food items like potatoes.
         The tongue and the nose play key roles in allowing us to taste food. On the tongue, there are a lot of bumps called pappilae, and most of them have taste buds. These taste buds have sensitive microscopic hairs called microvilli. Every hair sends a message to the brain like a neuron when it tastes different tastes. The average person has around 10,000 taste buds, and although they are supposed to be replaced every 2 weeks, sometimes, they aren't. As people age, they lose taste buds, so that is one reason why people in our class could have had varying opinions on the sweetness levels of the samples in this lab. In our class, there are probably people with ages ranging from 15 to 18. In addition, the nose has olfactory receptors which are similar to the microvilli. When we eat, chemicals travel up our nose to contribute to our determination of each taste. However, if you are sick and your nose is plugged, the chemicals don't reach these receptors and that can also affect how you distinguish taste. Therefore, if there were people sick on the day of the lab, they could have also had different results on the sweetness levels. 

http://kidshealth.org/kid/talk/qa/taste_buds.html