Preparation Of Calcium Acetate With Eggshell

Eggshell is a bio-resource of calcium and the main composition is calcium carbonate. Calcium acetate is used wildly in the wield of food and pharmaceutical industry, the eggshell is transformed to calcium acetate to fully utilize the calcium carbonate in the research. The processing including separating membrane from eggshell、direct neutralization reaction using eggshell and acetate acid, the purification methods and comprehensive utilization of acetate acid are studied. Physicochemical properties and characterization of ECA(eggshell calcium acetate) and the effect of ECA to the structure characteristics and physicochemical indexes on Chinese sausage during preservation were also researched. The results shows as below:Taking acetate acid solution as separation agent, the optimal separationprocessing was:separation time 0.5h, temperature 50℃, the amount of acetate acid 1.0ml by single factor and orthogonal test. The optimal neutralization reaction parameter was obtained by quadratic general rotary unitized design, the result is:acetic acid concentration 6mol/L, temperature 79.38℃, time 5.98h, the ratio of eggshell to acetate 1:5, the real yield of calcium acetate is 98.48% and the purity of calcium acetate is 96.99%. The additional acetate acid was recycled by rotary evaporator, the production costs can be lower and the efficiency be higher, it can be refered for ECA industry.The crude ECA was purified by adding CaO according to the difference of calcium hydroxide and magnesium hydroxide. the optimal purification technology date is: temperature 65℃, time 15min, the amount of CaO 0.5g, the content of CA is 99.79%-101.6%. The magnesium ion was exchanged using cation exchange resin, and the result is:concentration of CECA is 13%, the time is 90min, the temperature is 40℃, the content of ECA is 99.37%. The concentrating and drying way ECA solution is dried by the rotary evaporator, bath drying and air drying as to produce dry ECA.The content of calcium, magnesium, Pb and As in ECA was determined, the result is CA 99.76%, Mg 0.42813%, Pb 1.354×10-6%; the Arsenic salts are in line with national standard requirement. The difference between ECA and CCA was studied by SEM. The CA was obtained for long trigonal system crystal sheet structure, and it was found that eggshell calcium acetate crystal particles was smaller than CCA crystal particles, the crystallinity of ECA is higher and better crystal arrangement than CCA. The diffraction date and spectrogram of ECA and CCA were studied by x-ray diffraction. it shows that the characteristic peaks of ECA were consistent with No.00-019-0199 Ca(C2H3O2)2·0.5(H2O) in JCPDS cards. But the matching degree of CCA is lower with Ca(C2H3O2)2·0.5(H2O), it is because that CCA is composed of kinds of crystal water and Calcium Acetate Acetic Acid Hydrate C6H10CaO6·H2O. IR was taken to research the molecule structure, the absorption spectrograms of ECA and CCA were obtained. The intensity of ECA characteristic absorption on 3000cm-1-4000cm-1,1610.55cm-1, 1540.38cm-1, and 1449.52cm-1 were different from CCA. The characteristic absorption of ECA is found consistent with Calcium acetate, monohydrate of NIST. The decomposition temperature and kinetic parameters of eggshell dehydration and thermal decomposition were obtained with different heating rate by DSC.The calcium was added into Chinese sausage in the form of ECA, and the experiments show that:10%-30% of calcium RDA adding amount can improve the color of Chinese sausage. The firmness and work of shear is reduced by adding ECA. There is no significant difference between treatments and control on springiness and Cohesiveness, but hardness, adhesiveness, gumminess, chewiness and resilience of treatments are significant different from the control. The indexes are good when adding amount is 10%-30%, and 30% batch can improve the adverse changes of sausage during preservation.