Food that undergoes excessive dehydration may become ____________ on its surface.

Excessive dehydration of food can lead to a phenomenon known as case hardening. This occurs when the surface of the food dries out quickly, forming a hard outer layer. As moisture continues to escape from the interior, the hard outer layer can act as a barrier, trapping moisture inside. This can prevent the food from dehydrating uniformly and can cause it to retain an undesirable texture or even spoilage within the sealed interior.

Case hardening is especially problematic because it makes it difficult for moisture to evaporate completely from the food, impacting the quality and safety of the dried product. The outer surface looks dry and hard, while the inner parts may remain soft and moist, leading to inconsistent drying results that can affect flavor, longevity, and food safety.

The other options refer to different processes not directly related to the consequences of excessive surface dehydration. For instance, blanching is a pre-cooking process involving brief heat treatment to inactivate enzymes and preserve color and texture, while lyophilization (freeze-drying) is a controlled method of dehydration that prevents case hardening by removing water under low temperature and pressure. Mushy texture typically results from overcooking or improper handling, not from dehydration-related surface issues.