Which of the following chemicals is used in blanching water to retain green colour in vegetables before dehydration?

Correct option is D

• Sodium bicarbonate is sometimes added in small amounts to blanching water to help preserve the bright green colour of vegetables by reducing the conversion of chlorophyll to pheophytin.
• It raises the pH slightly, which helps the pigment stay greener during heating.
• However, excessive amounts may soften tissues, so only minimal quantities are used.
• Potassium metabisulphite (KMS) is used mainly for preventing enzymatic browning and sulphitation but is not the primary agent for retaining green colour in blanching.
• Aluminium chloride is not used in food blanching.
• Copper sulphate can fix green pigments but is not permitted due to toxicity concerns.