Question 10
Sudan III reagent is added to a little sesame oil and shaken well. What is observed?
The right answer is the one marked above.
The oil layer turns red. The conclusion: that food contains lipids.
Keep the four tests apart by their endings — Sudan III gives a red oil layer for lipids, Benedict's a brick red precipitate for sugars, Biuret a dark purple for proteins, and iodine a blue-black for starch.