Question

The characteristics of 100% barrier to water vapor or oxygen transmission rate is occurred in __________.

• A. Polyethylene film
• B. PVC film
• C. PVDC film
• D. Aluminium foil

Hint:

Solid metal sheets like Aluminium foil (above critical thickness) provide a perfect, absolute 100% barrier against light, oxygen, moisture, and odors.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Food packaging materials are selected based on their barrier properties against environmental gases, water vapor, light, and aroma compounds to prevent oxidation, moisture gain/loss, and quality deterioration.

Step 2: Detailed Explanation:
Let us compare the barrier properties of the listed packaging materials:
1. Aluminium foil (D): Made from refined metallic aluminum rolled into thin sheets. At standard packaging thicknesses (typically greater than \(15\text{--}20\text{ }\mu\text{m}\)), aluminum foil possesses a continuous, crystalline metallic lattice that is completely impermeable to gases and liquids.
It provides an absolute 100% barrier to water vapor transmission rate (WVTR) and oxygen transmission rate (OTR), as well as a complete barrier to light and aroma compounds.
2. Polyethylene (PE) (A), PVC (B), and PVDC (C) films: These are polymeric plastics. Because polymers have amorphous and crystalline regions with microscopic intermolecular spaces, gases and water vapor can diffuse through them slowly over time. Although PVDC has excellent barrier properties compared to other plastics, none of these plastic films can achieve an absolute 100% barrier (zero transmission rate) like solid metal foil.

Step 3: Final Answer:
Therefore, the characteristics of a 100% barrier to water vapor or oxygen transmission rate occur in Aluminium foil.