Question

1. which test would show positive results for orange juice?

benedict test
lugol test
biuret test
sudan red test

1. which foods would have the following nutrient test results?

beef, peanut butter, tuna
apple juice, honey, orange juice
candy, table sugar, cake frosting
pasta, bread, crackers

1. which of the following would test positive in the biuret test, and negative in the sudan red test?

skim milk
wheat bread
meatloaf
vegetable oil

Explanation:

• Question 3: Orange juice contains reducing sugars. The Benedict test is used to detect reducing sugars. The Lugol test detects starch, the Biuret test detects proteins, and the Sudan Red test detects lipids.
• Question 4: The Lugol test (positive for starch) is shown. Pasta, bread, and crackers are high in starch. Beef, peanut butter, tuna are high in protein and fat; apple juice, honey, orange juice are high in sugars; candy, table sugar, cake frosting are high in sugars.
• Question 5: Skim milk has protein (positive Biuret) and low - fat (negative Sudan Red). Wheat bread has starch (Lugol test relevant), meatloaf has fat (could be positive Sudan Red in some cases), vegetable oil has fat (positive Sudan Red).

Answer:

1. Benedict test
2. pasta, bread, crackers
3. skim milk