Which of the following nutritional, chemical, and milling changes occur as a direct consequence of parboiling paddy?
Options:
(A) Water-soluble B-vitamins (thiamine, riboflavin, niacin) diffuse inward from the aleurone and germ into the starchy endosperm.
(B) Rice bran obtained from milling parboiled paddy contains a higher concentration of oil ($20\%\text{--}28\%$) compared to raw rice bran ($14\%\text{--}18\%$).
(C) Parboiled milled rice exhibits increased resistance to insect infestation during storage due to a harder endosperm texture.
(D) Parboiled rice requires less cooking time than raw milled rice.
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
Analysis of changes in parboiled rice:
- Option A is CORRECT: During soaking and steaming, water-soluble vitamins dissolve and migrate through concentration gradients into the central endosperm, preventing their total loss during bran scouring.
- Option B is CORRECT: Endosperm starch gelatinization seals cell walls, while heat breaks down lipid-protein complexes, facilitating easier oil recovery and higher oil percentage in the bran layer.
- Option C is CORRECT: The hard, compact, vitreous structure of parboiled grains resists penetration by storage insects such as *Sitophilus oryzae*.
- Option D is INCORRECT: Gelatinized and retrograded starch forms a tightly packed crystalline matrix that impedes hot water penetration, so parboiled rice requires *longer* cooking time ($25\text{--}35\text{ min}$) than raw rice ($15\text{--}20\text{ min}$).