Abstract:

In order to make full use of calcium resources in eggshells, a three-factor orthogonal polynomial regression design model was established to extract calcium citrate from eggshells through ultrasonic technology. The optimal extraction parameters were 180-mesh in granule size of eggshell powder, 700 W of ultrasonic power, 25 min of ultrasonic treatment, 2:1 of critic acid and eggshell powder ratio. The extraction rate of calcium citrate was 90.83% under this optimal condition. Compared with traditional extraction methods, ultrasonic technology not only increased extraction rate of calcium citrate, but also overcame coagulation precipitation during preparation of calcium citrate.

Key words: egg shell, calcium citrate, ultrasonic technology, orthogonal polynomial regression