Determination of some physical and chemical properties of bread fortified in terms of mineral substances by using egg shell

In this study, considering recommended daily allowance (RDA) for adults, children, adolescent and pregnant women-breastfeeding mothers, the egg shell powders (ESP) of which are obtained from egg shells of chickens having four different feeding type and growth conditions ( industrial, organic, free range, village) are substituted with flour respectively corresponding to 800 mg, 1000 mg and 1300 mg/ 150 g bread,corresponding to S1, S2, S3, then occurring changes about physical, chemical, rheological and sensorial properties of prepared dough and bread samples are studied. The results obtained from control bread (S0) that do not contain egg shell powder and fortified bread samples, while amount of added egg shell powder increased bread volume and height also (p≤0.05) increased, density and specific volume did not change significantly (p≥0.05). About crumb L*, a*, b* colour values, L* -brightness value increased as ESP level increased (p≤0.05), while a*, b* values were similar with control (p≥0.05). Titratable acidity of bread is significant (p≤0.05) and decreased compared to control. Water activity, pH and ash values increased with increasement of ESP (p≤0.05). Ca, Fe, Zn, Mg and Cu contents changed significantly with ESP addition (p≤0.05) and the highest Ca content was found with bread that was fortified at S3 level of village egg shell. The effect of ESP addition on water absorbtion, stability, softening degree, maximum resistance, energy and resistance to extension decreased, extensibility value increased. The rheological and physical analysis results obtained from control and fortified bread samples showed that Ca that comes from egg shell powder strengthened flour structure, did not effect dough and bread making characteristics negatively almost at highest egg shell powder level. The effect of egg shell powder addition on instrumental hardness value of bread is significant (p≤0.05). Bread fortified with egg shell powder are fewer hard than control and besides decrease in hardenss value is not linear. According to sensory evaluation results; all the bread samples are found acceptable in terms of sensory with general hedonic scores changing between 3.77 – 4.46 / 5. Both containing high calcium content and having higher bread volume with improvement of bread making and quality characteristics, the best combination of egg shell powder- level is bread fortified with 23.5 g (S1) village egg shell powder . Besides the addition of egg shell powder at highest level (S3) did not effect physical and sensorial properties of bread negatively. Considering all analysis and sensory analysis, fortification of bread with egg shell powder has provided evaluation of an industrial waste as a functional product that is highly acceptale by consumers. Keywords; Egg shell, waste, mineral substance, fortification, Ca