Measuring Protein in Frozen Dairy Desserts by Dye Binding

Area of Science:

• Food Science
• Analytical Chemistry

Background:

• Accurate protein quantification is crucial for food product quality control.
• Traditional methods like Kjeldahl analysis are time-consuming and require specialized equipment.

Purpose of the Study:

• To compare the accuracy and reliability of the Acid Orange 12 dye binding method against the Kjeldahl method for protein determination in frozen dairy desserts.
• To assess the suitability of the dye binding method for routine quality control in the dairy industry.

Main Methods:

• Protein content was analyzed in 24 frozen dairy dessert samples using both the Kjeldahl method (total nitrogen) and the Acid Orange 12 dye binding method.
• Statistical analysis, including correlation, was performed to compare the results from the two methods.
• Kjeldahl results were also analyzed after correction for non-protein nitrogen content.

Main Results:

• A highly significant statistical correlation was observed between the Kjeldahl and dye binding methods.
• The Kjeldahl method, based on total nitrogen, generally yielded higher protein values (+0.11% average difference) compared to the dye binding method.
• After correcting Kjeldahl results for non-protein nitrogen, the values were lower (-0.20% average difference) than those obtained by dye binding.

Conclusions:

• The Acid Orange 12 dye binding method demonstrates sufficient accuracy for monitoring protein concentration in vanilla ice cream, ice milk, and related frozen dairy desserts.
• The dye binding method presents a viable, potentially faster alternative to the Kjeldahl method for quality control in these products.