Wheat Germs and their Protein Quality for Human Nutrition

Abstract

The wheat germs are by-product originating from milling industry. But there is a little information about protein quality of wheat germ as nutritional protein source in human nutrition. Therefore, this paper reveals the protein quality of this by-product. Wheat germs are rich in protein content which is about 36.5 %. Wheat germs are characterized by high standardized ileal digestibility of protein and amino acids. A digestible indispensable ileal amino acid score (DIAAS), as the lowest ratio between the content of standardized ileal digestible amino acid in the protein source and amino acid requirements for people, is 82 %. It is limited by leucine. Content of other amino acids, with exception of isoleucine, is in surplus. The DIAAS reference ratio for isoleucine is 0.93 and for the other amino acids is in a range from 1.01 (tryptophan) to 1.28 (threonine). The DIAAS reference ratio for sulfur amino acids is 1.11. In conclusion, wheat germs are a rich source of a high-quality protein, with a high ileal digestible amino acids content. Protein quality based on DIAAS is limited by leucine followed by isoleucine, but other amino acids are in surplus. By an inclusion of wheat germs in nutrition we can obtain new protein source while