Comparative between Ammonia Ion selective electrode and dye binding method to study effect of processing methods on protein content of plain Yogurt

In this study, two analytical methods were used to determinate the protein, the ammonia ion selective electrode method and dye binding method using orange G and the spectrophotometer at _max 478 nm by determining the linearity, accuracy, precision, limit of detection and limit of quantitation of each. In comparison, the dye binding method was chosen for its accuracy, repeatability, sensitivity (LOD, LOQ) and speed of performance. After that, it was applied to samples of prepared plain yogurt to study effect of different properties (source, heat treatment and type) of used milk on protein content of plain yogurt.