Development of analysis methods and method validation for the qualitative and quantitative determination of carboxymethyl cellulose (CMC) in yogurt and ayran

Carboxymethyl cellulose (CMC) is a cellulose derivative obtained by chemical modification of natural cellulose. CMC is generally prepared by reaction of an alkali cellulose with monochloroacetate or its sodium salt in an organic medium. Carboxymethylcellulose or sodium carboxymethyl cellulose is a white, yellowish, fibrous structure additive which is generally added to foods as a thickener. Although it is widely used in food industry, using CMC is prohibited in dairy products yoghurt, ayran etc. However, CMC is used in order to increase the consistency in especially yoghurt and ayran by some producers. In this study, yoghurt and ayran products containing CMC were produced. First, cmc isolation works was made from this products. Precipitation wasper formed with CuSO4 by taking advantage of the interaction between CMC and casein proteins at pH 6.70. Precipitation of CMC with 𝐶𝑢++is a specific event. Phenol and H2SO4 were treated with spectrophotometer to obtain maximum absorbance at 490 nm. In addition, the spectra of blind and CMC supplemented samples were compared with FI-TR instrument. For qualitative analysis, positive and negative studies were performed at LOQ level. Qualitative and quantitative validation and measurement uncertainties of these methods were performed using spectrophotometric method and FTIR spectrophotometer for CMC detection. In the quantitative study, spectrophotometer device was used and LOD, LOQ, repeatability, reproducibility, recovery and accuracy studies were performed. The LOD value for the yogurt sample was 0.03%, the LOQ value was 0.10%, and the LOD value for the ayran sample was 0.03%, the LOQ value was 0.11%. In the study containing 0.50% CMC in the yogurt sample, the recovery rate was found to be an average of 99.72 ± 2.07. In the study containing 1.00 % CMC in the yogurt sample, the recovery rate was found to be an average of 100.71 ± 1.88. In the study which contains 0.50% CMC in the ayran sample, the rate of recovery was found to be 99.05% ± 2.11 and in the study containing 1.00% CMC, the average recovery rate was 99.57 ± 0.94%. Extended uncertainty in the 95% confidence interval (k = 2) was calculated as ± Ux 9.00% (0.09). In qualitative studies, analysis was performed on both spectrophotometer and FTIR spectrophotometer devices. Sensitivity, Accuracy, False Negative Rate, Specificity, False Positive Rate, LOD, Harmony of Observed and Expected Results, and Strength parameters were studied. For ayran and yogurt samples; sensitivity parameter 100%, accuracy parameter 100%, false negative rates 0%, specificity rate 100%, and false positive rate 0%. The data obtained as a result of all these studies will be evaluated and turned into a scientific text.