1. Lab – Identifying food nutrients WRITE THIS DOWN- MEMORIZE IT

2. Using indicators Indicators are chemicals that react in a certain way when they come into contact with another substance.

3. 1. STARCH Does your food contain starch? -Iodine is an indicator of starch. When it comes into contact with starch, the molecule will turn black. Iodine is orange, however. So if the substance turns orange or yellow, but not black, there is No starch = THERE MUST BE BLACK for starch.

4. Polysaccharides are starch! Which of the following items contain starch? Potato Corn starch Rice Firewood Water Milk How would you test it?

5. ??? Does iodine indicator show the presence of other saccharides? No – only polysachharides – they are the big chains of saccharides. Iodine attaches to the chains and wraps around them like hairs around a hair brush. You need another indicator to find glucose (monosaccharides)

6. 2. GLUCOSE (Is there glucose or sugar in your food?) Indicator to use is called BENEDICTS BENEDICTS solution turns green then orange, then red, then brown GREEN,ORANGE,RED, BROWN Green is a small amount of sugar, brown is a lot. Any of these colors means that there is sugar present

7. 3. PROTEIN Some foods contain protein. To test for protein you use the indicator called Biuret Solution – When the Biuret hits the protein in a food, the protein molecule will turn what color? VIOLET or PURPLE If it shows PINK, it has a little protein in it.

8. 4. Lipids Fats are lipids There are two tests Brown paper is one – just put it on the paper. If it gets greasy, it has fat in it. 2 nd test – Sudan Stain This is a red stain. It will form oily beads and float on top of the substance if fat is present. What color will the beads be?

9. Summary Benedicts = sugars (green,orange,red,brown) Biurets = Protein ( violet or pink) Iodine = Starch (black) Sudan = Lipids (pink oil floats on top)