Eggshells Calcium Extraction and the Application in Food Fortifications

Eggshells are the hard, outer covering of eggs. It is known that eggshells are discarded as waste materials, although they contain a significant amount of calcium. The study was aimed to extract and quantify calcium from the eggshells and fortification on the biscuit and yogurt products. The extraction of calcium was done using calcium chloride with HCL solution at different propositions (1:1, 1:5, 1:10, 1:15, and 1:20). After extraction, the sample was dried at 50 °C temperature for 3 hours to obtain dry calcium chloride. Calcium was fortified at a concentration of 100 ppm, 1000 ppm, and 2000 ppm in both the biscuits and yogurt, respectively. The calcium-fortified samples were analyzed for sensory properties and chemical composition. The ash content of calcium-fortified yogurt (0.47) was slightly higher than normal yogurt (0.44), while the other chemical components remains similar to the control. For the sensory evaluation result, the biscuit with 2000 ppm calcium-fortified biscuit and 1000 ppm calcium-fortified yogurt was found to be highly acceptable among the calcium-fortified samples. The extraction of calcium chloride from eggshells was obtained the highest for eggshells on HCl ratio 1:20 (w/v) where calcium chloride was found 32.92%, 26.95%, and 23.63% for duck, layer chicken, and local chicken eggshells, respectively. The extraction rate of calcium chloride of duck eggshells was higher than the local and layer chicken’s eggshells. Therefore, it may be opined that the fortified products (2000 ppm Ca) contained a considerably higher amount of calcium content than the control sample.