Free Amino Acid Stability in Reducing Sugar Systems

Solutions of free amino acids were sterilized in different carbohydrate mixtures, at different pH values, and both browning and free amino acid content monitored at different storage temperatures. Results showed the expected behavior of a Maillard process, (e.g., increasing reaction rate with increases in pH, temperature and reducing sugar content). However, only three (tryptophan, histidine and lysine) of the amino acids tested (nine essential + taurine) were notably affected, even under stringent conditions (50°C storage, glucose containing solution at pH 7.5). Thus many free amino acids could probably be added to most food matrices without Maillard reactions affecting overall protein quality.