Benedicts Test for Reducing Sugars:

Tube Solution/food Color reaction to Benedicts solution Presence of reducing sugar (green/reddish orange color)
1 1ml distilled water
2 good pinch glucose powder
3 good pinch table sugar (sucrose)
4 2 drops honey
5 finely chopped onion
6 finely chopped fruit
7 1ml milk
8
9
10

Which of the above solutions was included as your negative control? [1 pt]





Which of the above solutions was included as your positive control? [1 pt]






Which of the above foods/solutions tested positive for sugars? [4 pts]









Explain why sucrose (table sugar) yielded the result above. [2 pts]








What does this tell you about the way sugars are stored, for example in onions? [2 pts]

Sugar is actually a common name for glucose. Glucose is stored as starch in onions as it is a bulb present in plants.


Would you use the Benedicts test to investigate if a cake mix were sugar free? Explain your answer [2 pts]

The benedicts test cannot be used to determine if a cake mix is sugar free or not. This is because benedicts test is used to determine the presence of reducing sugars like maltose and lactose. Fructose also gives a positive test. We use sucrose in food so we cannot detect the presence or absence of sucrose in the cake mix



Iodine Test for Starch:


Depression Number Solution/food Color reaction to iodine solution Presence of starch (bluish-black color)
1 ½ ml distilled water
2 pinch glucose powder
3 pinch cornstarch
4 ½ ml egg white
5 finely chopped onion
6 Finely chopped potato
7 1 drop honey
8
9
10

Which of the above solutions was included as your negative control? [1 pt]



Which of the above solutions was included as your positive control? [1 pt]





Which of the above foods/solutions tested positive for starch? [4 pts]











Did any of the animal sources contain starch? Explain your answer. [2 pts]













Did any of the same foods test positive for both reducing sugars (Benedicts Test) and starch (Iodine Test)? Explain your answer. [4 pts]












Proteins:
Tube Solution/food Color reaction to Biuret Reagent Presence of protein (violet color)
1 2ml distilled water
2 2ml milk
3 2ml egg white
4 2ml egg yolk
5 2ml honey
6
7
8
9
10

Which of the above foods/solutions tested positive for protein? [4 pts]


Did any of the foods/solutions that tested positive for protein also test positive for reducing sugars (Benedicts Test) or starch (Iodine test)? Explain your answer. [2 pts]









How is the structure of proteins in plants and animals similar? [3 pts]










How are proteins in plants and animals different? [3 pts]











Lipids:

Test Solution/food Grease spot indicating the presence of lipid
1 1ml distilled water
2 Oil-vinegar salad dressing
3 walnut
4 Egg white (wipe away excess)
5 Egg yolk (wipe away excess)
6
7
8
9
10

Which of the foods tested were positive for the presence of lipid? [4 pts]




Part 2 – Tracking Macromolecules in Your Diet

Include a copy of your “nutrient intake” and record the following nutrient intakes in the space below. NOTE: Nutrient Intake is the name of the report generated at www.MyPyramid.gov [10 pts]


Kilocalories Percent Total Recommended
Energy Intake Intake

Carbohydrate ___________ ______________ 45-65%

Protein ________________ ______________ 10-35%

Total Fat _______________ _______________ 20-35%


Show your calculations in the space below



How did your consumption of macronutrients compare to the recommended intake?

Answer rating: 100% (QA)

Benedict Test 1distill water included negative control 2Glucose included as positive controlwhich is simple sugar reducing sugar shows positive result ... View the full answer