USE OF AMINO-ACID PROFILES OF PRETERM AND TERM HUMAN MILKS IN EVALUATING SCORING PATTERNS FOR ROUTINE PROTEIN-QUALITY ASSESSMENT OF INFANT FORMULAS

Reports on the amino acid composition of human milk vary considerably with respect to concentrations of sulfur amino acids. Often, analyses forego tryptophan determination, A complete analysis of protein and am ino acid concentrations was performed on human milk samples (5-10 days postpartum) collected from mothers of preterm (gestations of 25-32 we eks) and term (gestations of >36 weeks) infants. Careful attention was given to quantitate amino acids such as cysteine and tryptophan, whic h are vulnerable to acidic hydrolysis conditions. Differences in conce ntrations of total amino acids (expressed on protein basis) between pr eterm and term milks were small, despite the higher true protein conte nt of preterm milk versus term milk (19.20 versus 12.60 g/L). The meth ionine + cyst(e)ine contents of term and preterm milks (3.72-3.84 g/10 0 g protein) were comparable with those reported in 1991 by the Food a nd Agricultural Organization/World Health Organization (FAO/WHO) for m ature human milk (4.20 g/100 g protein) but higher than those reported in 1991 by the European Commission (2.9 g/100 g protein). The amino a cid pattern of human milk obtained in this study confirms that the 199 1 FAO/WHO amino acid scoring pattern for predicting protein quality of infant formulas is representative of the amino acid quality of both p reterm and term human milks.