25 - Amino Acids in Beer

Abstract

Nitrogenous compounds are considered very important in beer playing a key role in determining the quality and stability of the finished product. They include amino acids, peptides, polypeptides, proteins, nucleic acids and their degradation products. These compounds affect flavor, foam stability, haze formation, color, yeast nutrition and biological stability. The nitrogenous compounds in beer are derived mainly from barley malt and its adjuncts. Moreover the brewing process may have an important role in determining complex profile of nitrogenous compounds present in the final beer. The content of nitrogen compounds in barley depends on variety and on environmental condition in cultivation. During malting the storage proteins are degraded to amino acids and other peptides. These amino acids are important in wort to promote a good fermentation and the yeast budding. During fermentation amino acids are used in different ways by yeasts and may have many effects on the final quality of beer: in particular the amino nitrogen content influences the flavor profile of beer. The amino acids present in final beer could influence negatively the stability of product promoting haze formation. Nitrogen compounds may also play an important role influencing the foam quality and stability.