Formation of Lysinoalanine on Alkaline Treatment of Soybean Protein

Abstract

The formation of lysinoalanine, N⁶-(DL-2-amino-2-carboxyethyl)-L-lysine, on alkaline treatment was investigated. Changes of basic amino acids and cystine during alkaline treatment at different pH, times and temperature, were analyzed with an amino acid analyzer.
The results show:
1) Lysinoalanine was formed depending on pH, temperature and time on alkaline treatment. The higher pH, temperature and time, the higher amount of lysinoalanine was recognized.
2) The formation of lysinoalanine seemed to be related to cystine in proteins. In 11S protein having higher content of cystine than 7S protein, the higher amount of lysinoalanine was recognized.
3) The formation of lysinoalanine was slightly recognized in soybean products.