The Fat Content of Snack Food

       I.            Objective: In this experiment you will extract the fat from a snack food, calculate the amount of fat, and compare it to the amount of fat on the label.

    II.            Materials and Procedures:

A.    Materials:

-100 ml Beaker            -Balance          -Paper Towels             -Forceps          -Glass Funnel

-Snack Food                -Zip Lock Bag             -Stirring Rod               -Evaporating Dish

-Hexane           -Iron Ring       -Fume Hood                -Graduated Cylinder               -Goggles

-Filter Paper                -Ring Stand

B.     Procedures:

1.Place about 2g of a snack food in a zip lock bag and close the bag. Crush the food into extremely small pieces by smashing them with your hands.

2.Place an empty 100ml beaker on the balance pan and hit the tare button. Add the snack food to the beaker and record the mass in Table 1.

3.Measure approximately 15ml of hexane into a graduated cylinder. Add the hexane to the snack food in the beaker and stir for about 10 minutes. Use the stirring rod to ensure that all surfaces of then crumbs are wet with hexane. Leave the beaker in the fume hood.

4.Determine and record the mass of a piece of filter paper and evaporating dish.

5.Set up a filtration apparatus using the weighed filter paper, and evaporating dish and a funnel.

6.Gently swirl the mixture in the beaker and pour it into the filter paper. Add 5ml hexane to the beaker and swirl again to rinse the beaker. Pour this into the filter paper. Repeat the hexane rinsing a second time in order to get all of the mixture out of the beaker.

7.After all the liquid has passed through the filter paper, use forceps to carefully transfer the filter paper and its solid contents onto a layer of paper towels. Allow the paper to dry in the hood until all the hexane has evaporated. (This should take 20-30 minutes so we will wait over night.) Put name on towels.

8.Put name on the evaporating dish and place it in the fume hood until all of the hexane evaporates. This may take several days.

9.Determine and record the mass of the filter paper and its contents and the evaporating dish and its contents.

C.    Safety:

Do not eat or drink the lab materials. Do not set the beaker precariously on window sill or fume hood. Do not crush fingers instead of chips.

 III.            Analysis:

A.    Data- Type of snack food: Light Ruffles

Table 1: Mass Data

Object	Mass (g)
Mass snack food (initial)
Mass of filter paper
Mass of filter paper & snack food
Mass snack food (final)
Mass evaporating dish
Mass evaporating dish & fat
Mass fat

 

Table 2: % Fat in Snack Food

Group #	Snack Food	% Fat
1	Ruffles
2	Ruffles
3	Ruffles
4	Light
5	Light
6	Light
7	Light
8	Light

 

B.     Calculations:

1.A) Calculate the mass of the snack food after filtration.

B) and the mass of fat after evaporation.

2.Calculate the difference between the original mass of the snack food and the mass after of the snack food and the mass after filtration. (This difference is the mass of the extracted fat.)

3.Calculate the percent by mass of the fat in the snack food, using the following formula: % Fat= mass of fat (1 b) / original mass of food x100

Record in Table 2

4.Calculate the estimate of the number of dietary calories produced in the digestion of the fat in this snack food sample.

5.Convert the dietary calories (DC) for your sample size to DC based in your serving size. This is your DC from the digestion of fat.

6.Calculate the percentage of calories from fat.

% cal from fat = DC from digestion of fat / total DC (from package) x 100

7.RSD for each snack food.

C.    Graphs: % Fat in Ruffles: X-axis= types of Chips Y-axis= % Fat

D.    Questions

1.If you tested both “light” and regular snack foods, was there a significant difference in the fat content. Explain.

2.Discuss how did the amount fat calculated compared to the amount recovered by evaporation.

 IV.            Conclusion:

*Note: The snack food does not have to be the chips I used.