Comparative Analysis of Protein in Selected Infant Formula Using Dye-Binding and Formol Methods

Aim: The protein content of some infant milk formula was determined using Dye-binding and Formol methods in comparison to the manufacturer’s values as reference.

Study Design: The study was an experimental design.

Place and Duration of Study: This study was carried out at the laboratory of Chemistry department, Federal University of Agriculture, Makurdi, Nigeria between June, 2021 and December, 2021.

Methodology: Dye-binding Method was done by weighing about 5 g of the baby milk samples into beakers and 100 mL distilled water was added and mixed thoroughly. 20 mL of diluted 80% orange G dye solution was added to 2 mL of the milk solution and shaked vigorously. The sample was centrifuged at 820 rpm for 5 minutes and a clear filtrate obtained whose absorbance was then analyzed using spectrophotometer. For Formol Method I g of each of the milk samples was weighed into different beakers then 10 mL of distilled water and 0.7 mL saturated potassium oxalate was added along with 3 drops of phenolphthalein indicator into the mixture. Two drops of NaOH solution was titrated into the mixture and a pink colour appeared which diminished immediately. About 2 mL of formaldehyde was added and shaken for few seconds then titrated using sodium hydroxide (NaOH) until the mixture turned light pink.

Results: The mean and standard deviation of protein content using Dye-binding method are; Peak baby milk 2.49 ± 0.13 g, My boy milk 2.54 ± 0.06 g. For formol methods Peak baby milk has 0.13 ± 0.01 g and My boy milk 0.1 ± 0.01 g. The result showed that both infant formula under the Dye-binding method and formol method was significantly different (p<0.05) when compared to the reference value (1.7 Peak baby and 0.11 My boy). However, values obtained from Formol method for My boy milk was closest to the reference (factory value) only a slight difference of about 0.01 g.

Conclusion: In conclusion, Formol method is more closely related to the reference values (manufacturer’s values). Thus, the Formol titration may be used with confidence as a quick test for approximating the protein content of skim milk solids which is typical of baby milks.