Research On Technology Of Preparation Of Food-grade Calcium Lactate From Eggshell

At present, Eggshell has a low utilization ratio and pollutes environment at home. And the absorption of calcium lactate for people is better than any other calcium supplements. Therefore, this paper researched the technology of the preparation of food-grade calcium lactate from eggshell.This paper introduced a direct method technology of the preparation of food-grade calcium lactate from eggshell under normal temperature and pressure. That is to say the eggshell powder react with lactic acid directly after separating the membrane from eggshell. The single factor and orthogonal experiments were carried out. And the influence of every factor on yield and content of calcium lactate was discussed in-depth. The optimized process conditions were obtained. The results are as follows: 130% of eggshell powder batch weight, 3h of reaction time under normal temperature and pressure, twice of separation membrane from eggshell, 10min of stirring time and on standing for 15min, 20:1 of liquid to solid ratio, 3.0g of calcium hydroxide batch weight, 93℃ of removing magnesium temperature and 15min of removing magnesium time.Secondly, the quality of calcium lactate was analyzed. During the analysis, in order to overcome the difficulty of judging mutation point of chemical method, this paper brought forward firstly that content of calcium lactate was determined indirectly with refractometry. The feasibility was deduced theoretically and was verified through the experiments. Magnesium, arsenic and heavy metal lead were determined with atomic absorption spectrometry. The analysis results showed that the products accorded with the GB (GB 6226-86) level of food-grade calcium lactate.Finally, the yield of calcium lactate reached up 98.95%, that is to say the conversion rate of eggshell reached 92.02% and 17% was beyond literature report.And the content of calcium lactate is 99.18% and 1.18% higher than GB. Compared with the direct method reported, this preparation technology has some characters. They are as follows: First, the water was used as a separation agent in shell and membrane separation stage to reduce eggshell losses;Secondly, the neutralization reaction is under normal temperature and pressure;Thirdly, the removing magnesium technology was carried out after neutralization reaction.The research has not a new pollution with dealing with pollution of eggshell. This technology is under normal temperature and pressure. And the activity of eggshell is not destroyed. Due to the low energy consumption, simple equipments and higher profit, the technology has bright prospects of industrial practice.