Infant formulas, designed to provide similar nutritional composition and performance to human milk, are recommended when breastfeeding is not enough to provide for the nutritional needs of children under 12 months of age. In this context, the present study aimed to assess the protein quality and essential amino acid content of both starting (phase 1) and follow-up (phase 2) formulas from different manufacturers. The chemical amino acid score and protein digestibility corrected by the amino acid score were calculated. The determined protein contents in most formulas were above the maximum limit recommended by FAO and WHO guidelines and at odds with the protein contents declared in the label. All infant formulas contained lactoferrin (0.06 to 0.44 g·100 g-1) and α-lactalbumin (0.02 to 1.34 g·100 g-1) below recommended concentrations, whereas ĸ-casein (8.28 to 12.91 g·100 g-1), α-casein (0.70 to 2.28 g·100 g-1) and β-lactoglobulin (1.32 to 4.19 g·100 g-1) were detected above recommended concentrations. Essential amino acid quantification indicated that threonine, leucine and phenylalanine were the most abundant amino acids found in the investigated infant formulas. In conclusion, infant formulas are still unconforming to nutritional breast milk quality and must be improved in order to follow current global health authority guidelines.
Keywords: HPLC; amino acid score; amino acid score corrected protein digestibility; breastfeeding; caseins; infant formulas; protein quality; whey proteins.