Abstract:In order to increase utilization of waste eggshells and develop a new amino acid biocalcium, the preparation technology of calcium-lysine was studied, and the structure was characterized. In this paper, eggshells and L-lysine were taken as raw materials, and the chelate rate was used as the standard. The single factor test and response surface test were applied to screen and optimize 4 factors (reaction time, reaction temperature, pH, the molar ratio of L-lysine and CaCl2) for the calcium-lysine chelating capacity. The chelating process was determined as follows: the reaction time was 49 min, the reaction temperature was 70 ℃, the pH value was 8.7, the molar ratio of L-lysine and CaCl2 was 2:1. Under the optimum conditions, the chelate rate of calcium-lysine was 82.84%, and it had 3.55% and 1.72% higher chelation rates than calcium citrate and calcium glutamate, respectively. The structure of eggshells’ calcium-lysine was characterized by FT-IR and XRD, the results showed that -NH2 and -COOH chelate reaction occurred with calcium ions, and both the N atom and the O atom participated in the reaction. The research confirmed the chelating reaction between L-lysine and CaCl2.
