Food Chemistry — Chemistry

Home › PYQ › Chemistry › Food Chemistry

Food Chemistry

2 questions

All (2) Unattempted (2) Skipped (0) Correct (0) Wrong (0)

Q.1

WBCS Prelims 2016

In the manufacture of Vanaspati ghee from vegetable oils, which among the following gas is used?

A. Nitrogen

B. Carbon dioxide

C. Hydrogen

D. Neon

Explanation

Why Correct: Hydrogen gas catalyzes the hydrogenation of unsaturated vegetable oils, converting liquid oils into solid or semi-solid Vanaspati ghee.
Distractor Analysis: Nitrogen serves as an inert blanketing gas in food packaging to prevent oxidation. Carbon dioxide is a greenhouse gas and fire extinguishing agent. Neon is a noble gas used in lighting and advertising signs.
Takeaway: Nickel or palladium catalysts typically facilitate industrial hydrogenation reactions at high temperatures and pressures.

Answer or skip previous question to unlock.

Q.2

WBPSC Miscellaneous Prelims 2019

When a few drops of iodine solution is added to rice water, the solution turns blue-black in colour. This indicates that rice water contains

A. fats

B. complex proteins

C. starch

D. simple proteins

Explanation

Why Correct: Iodine forms a deep blue-black complex with starch (amylose component). This is a standard qualitative test for starch.
Distractor Analysis: Fats do not react with iodine to produce blue-black colour; iodine stains fats brownish. Complex proteins (e.g., proteins) give a yellow colour with iodine. Simple proteins (e.g., amino acids) do not produce blue-black colour with iodine.
Takeaway: The iodine test is specific for starch; remember blue-black colour = starch, no colour change = no starch.

Sign in to Papersetters