Which structure of the barley kernel protects the embryo and consists of cellulose, amino acids, and lignin?

The husk, which is the outer protective layer of the barley kernel, is primarily responsible for safeguarding the embryo inside it. This layer is composed of cellulose, amino acids, and lignin, which contribute to its structural integrity and protective function. The husk acts as a barrier against physical damage and microbial invasion while also playing a role in moisture retention during the initial stages of germination.

Understanding the composition of the husk helps clarify its purpose; cellulose provides rigidity, lignin adds to the toughness, and the amino acids are vital for the metabolic activities that occur during germination. In the context of brewing, the husk also plays a significant role in the mashing process, acting as a filter medium that helps separate solid grain materials from liquid wort.

While other parts of the barley kernel, such as the aleurone layer and the starchy endosperm, have their specific functions—like nutrient storage and enzyme production—the critical role of protecting the embryo is uniquely associated with the husk. The embryo itself is responsible for plant development, but it does not provide protection in the same manner that the husk does.