Study on the process of calcium citrate recovery for chitin clean production

In this study,chitin was extracted from Solenocera melantho shell,and the protein was removed by alkaline protease and decalcified by citric acid. Combined with ultrasonic-assisted method,the process conditions for the recovery of calcium citrate were optimized. The main quality indicators of chitin and calcium citrate were tested. On the basis of single-factor test,the concentration of citric acid(%),liquid-solid ratio,the ultrasonic time were analyzed and optimized by the Box-Behnken design. The optimized parameters of the extraction technology were obtained as follows:The concentration of citric acid 10%,liquid-solid ratio 12∶1 mL/g,the ultrasonic time 50 min. Under these conditions,the yield of calcium citrate was 93.49%±0.07%,the yield of chitin was 18.93%±0.06%. The quality of chitin product reached the standard of food grade. The quality of calcium citrate was in accordance with the criterions of Chinese regulations for calcium citrate additives. This study provided a scientific theoretical basis for the process of calcium citrate recovery in chitin clean production.