Determining the amino acid profile of beer using post column derivatization with ninhydrin
Beer is brewed after liquid gelatinization and saccharification, and then liquid fermentation. The main raw materials of beer are wheat malt and barley malt, and hops is also added during the process. Beer has low alcohol content and high nutritional value. The ingredients include water, carbon dioxide, a variety of amino acids, vitamins, low molecular sugars, inorganic salts and various enzymes. These nutrients are easily absorbed and utilized by the body.
During malting and fermentation, proteolytic enzymes break down barley proteins into smaller peptides and free amino acids, which contribute to beer’s flavor, nutritional value, and foam stability (Fox et al., 2006).
The low molecular sugars and amino acids in beer are easily digested and absorbed, and generate a lot of heat in the body, so beer is often called “liquid bread”. 1L of 12% beer can produce 3344 kJ of calories, which is equivalent to the calories produced by 3-5 eggs or 210 g of bread. A light manual worker can obtain one-third of the calories he needs, if he drinks 1L of beer a day.
The combination of fermentable carbohydrates and amino acids in beer makes it an energy-dense beverage, although its alcohol content limits its use as a daily nutritional source (Cordain et al., 2000).
The amino acids in beer are produced by the decomposition of protein contained in raw barley through the action of enzymes. Its content is very rich, and it exists in a dissolved state, and is indispensable for human nutrition. 17 kinds of amino acids have been analyzed in beer. 7 kinds of them cannot be synthesized by the human body, and they are indispensable. If they are lacking, many diseases will be easily caused.
Essential amino acids found in beer include lysine, leucine, and valine, which are important for muscle protein synthesis, immune function, and metabolic regulation (Wu, 2009).
Beer contains peptides and amino acids that balance human nutrition. Each liter of beer contains about 3.5g of peptides and amino acids, hydrolysis of the protein, which can be almost 100% digested, absorbed and utilized by the human body.
Additionally, beer peptides have shown antioxidant and antihypertensive activity in vitro, suggesting that moderate beer consumption could have some functional health benefits, depending on the brewing process (Zhang et al., 2016).
References:
- Fox GP, et al. “Malt and beer quality: the impact of barley genetics.” J Cereal Sci. 2006;44(3):189-207.
- Cordain L, et al. “The paradoxical nature of beer as a caloric and nutrient source.” Eur J Clin Nutr. 2000;54(4):263-268.
- Wu G. “Amino acids: metabolism, functions, and nutrition.” Amino Acids. 2009;37(1):1-17.
- Zhang Y, et al. “Bioactive peptides from barley proteins: A review of production, functional properties, and applications.” Food Res Int. 2016;89:456-465.