Paneer crumbles after freezing because the water content within the paneer expands into ice crystals, disrupting its protein structure and causing it to become brittle. This results in a crumbly texture upon thawing.
Paneer, being a fresh cheese, has a high moisture content. When you freeze paneer, the water inside it turns into ice crystals. These ice crystals are larger than the water molecules they replace, causing them to expand. This expansion puts pressure on the protein matrix of the paneer, essentially tearing it apart at a microscopic level.
Upon thawing, the ice crystals melt, leaving behind empty spaces where the ice once was. The protein structure, already weakened by the freezing process, is unable to hold its shape, leading to a crumbly and less cohesive texture. The paneer loses its characteristic firmness and becomes more prone to breaking apart. The extent of crumbling depends on the freezing rate, the initial moisture content of the paneer, and the thawing method. Slower freezing and thawing generally result in larger ice crystals and more damage.
To minimize crumbling, press the paneer to remove excess water before freezing. Wrap it tightly in plastic wrap and then place it in an airtight container. When thawing, do so slowly in the refrigerator to help minimize ice crystal damage. Soaking the thawed paneer in warm water for a few minutes can also help restore some of its softness.