Generally, freezing food destroys anywhere from 30% to 66% of the enzymes in the food. Freezing is not as damaging as cooking. My own experiences and experiments have demonstrated that freezing alters the water and fiber in food and causes slow or constipated digestion if frozen food (even if defrosted) is eaten in excessive quantities. Water expands when frozen. The delicate fribrous structures inside all fruits and vegetables are damaged as water expands during the freezing process.