03 - Sweet Laboratory: Exploring Food Science with Biotechnology
Introduction
In this experiment, students will investigate how gel electrophoresis unlocks the color code by investigating food dyes used to make colorful candies.
Background Information Color is an integral aspect of our culture. Companies have long been using color additives in a variety of products, including candies, shampoos, perfumes, drinks, etc. All the colors that we see are a mixture of the three primary colors: red, green, and blue. That these three simple colors can be combined to form the myriad of colors that we see everyday makes them a great example of how complex things, such as colors, can be broken down into their individual components. In the classroom, a great way to break down colors is by examining color additives in food. The color of food has always been important for us. The early Romans believed that people not only eat with their palate, but also “eat with their eyes”. For centuring, humans have used dyes from natural ingredients to add color to food, drink, clothing, and other products. These days, manufacturers add colors to food to offset color loss due to product exposure to various environmental conditions and to make them look more attractive to consumers. As the use of color additives to food continues to grow, concerns regarding the addition of food colors to products also emerge. The seven more commonly used food dyes in the United States are shown in Table 2-1. However, the FDA and independent scientists are looking into whether or not certain dyes, such as yellow 5 and red 40, are linked to hyperactivity or allergic reactions.
Figure 2-1: Example of Candy Ingredient Label
AGAROSE GEL ELECTROPHORESIS
Agarose gel electrophoresis is widely used to separate molecules based upon charge, size and shape. It is particularly useful in separating charged biomolecules such as DNA, RNA and pro- teins. Agarose gel electrophoresis possesses great resolving power, yet is relatively simple and straightforward to perform. The gel is made by dissolving agarose powder in the electropho- resis buffer. The solution is boiled to dissolve the agarose and then cooled to approximately 60º C and poured into a gel tray where it solidifies. The tray is submerged in a buffer-filled electrophoresis apparatus, which contains electrodes. Samples are prepared for electrophoresis by mixing them with glycerol or sucrose to give the mixture higher density. This makes the samples denser than the electrophoresis buffer. These
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