Food cooked in copper utensils lose ascorbic acid quickly because it?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Applied Nutrition & Dietetics

Medium

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Explanation

Ascorbic acid (Vitamin C) is highly susceptible to oxidation, a chemical reaction that degrades it.
Metal ions, particularly copper (Cu2+) and iron (Fe3+), act as powerful catalysts that dramatically accelerate this oxidation process.
When food is cooked in copper utensils, copper ions leach into the food and speed up the destruction of Vitamin C. Iron, often naturally present in food, also contributes to this degradation.
This catalytic oxidation is the specific reason for the rapid loss of Vitamin C when using copper cookware.

Option B: While copper is a potent catalyst for Vitamin C oxidation, aluminum is significantly less reactive and does not catalyze the reaction to the same extent as copper or iron.
Option C: This statement is true; Vitamin C is destroyed in alkaline conditions. However, it does not explain the specific role of copper utensils, which is the focus of the question. The primary mechanism related to copper is catalytic oxidation.
Option D: This statement is also true; Vitamin C is more stable in acidic environments. However, it describes a condition that preserves the vitamin, which is the opposite of what the question asks (why it is lost).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Chemical stability of Ascorbic Acid (Vitamin C) during food preparation as background academic context rather than a clinical decision trigger.
Nurses providing nutritional counseling should advise patients on proper food preparation techniques to preserve vitamin content, especially for labile vitamins like Vitamin C.
It is important to recommend the use of non-reactive cookware such as stainless steel, glass, or enamel-coated pots to minimize the catalytic destruction of Vitamin C.
Patients should be educated to consume Vitamin C-rich foods like fruits and vegetables fresh and raw when possible, or to use cooking methods like steaming or microwaving for short durations to retain nutrients.

How to Approach the Question

First, identify the key components of the question: 'copper utensils' and 'lose ascorbic acid'. This points to a specific chemical interaction.
Recall or deduce the properties of ascorbic acid (Vitamin C). It is known to be an unstable vitamin, sensitive to heat, light, and oxidation.
Consider the role of metals in chemical reactions. Many metals, including copper and iron, can act as catalysts, speeding up reactions.
Evaluate the options. Option A correctly identifies both copper and iron as catalysts for oxidation. Option B is less accurate because aluminum is not a significant catalyst. Options C and D describe general properties of Vitamin C but do not specifically address the role of the copper utensil.
Conclude that the catalytic oxidation by copper, often in conjunction with iron present in the food, is the most direct and accurate explanation for the rapid loss of Vitamin C.

Concept Tested & Keywords

Concept Tested: Chemical stability of Ascorbic Acid (Vitamin C) during food preparation.
Stem keywords: Food cooked, copper utensils, ascorbic acid, lose quickly
Lead-in keywords: because
Negative lead-in flag: false

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