Liking of low-phenylalanine products in Phenyilketonuria patients: a case study comparing subjects from North and South of Italy

Background A low and controlled dietary phenylalanine intakes is the mainstay of phenylketonuria therapy. Even if many amino acid mixtures have been developed these products are really poor liked by phenylketonuria patients. In this context, casein Glycomacropeptide (GMP) could be an interesting alternative protein source to usual amino acid mixtures. The aim of the present study was to evaluate sensory properties and liking of L-amino acid and GMP samples comparing patients from North and South of Italy. Methods 67 phenylketonuria patients (age range: 14-40 years), 34 admitted to San Paolo Hospital (Milan) and 33 admitted to A.O.U. Federico II of Naples, were recruited. Patients evaluated 8 low protein samples: 4 L-amino acid base samples and 4 GMP base samples, flavored with the same aromas (neutral, chocolate, strawberry and tomato) and with an equivalent protein intake of 5g/100ml. For each sample, participants were asked to indicate which sensory attributes characterize the formulations and to score the overall liking. Results The mean blood phenylalanine (SD) was 675,2 (307) and mean Body Mass Index was 23,4 (4,5). Significant differences were found between samples regarding liking scores in both groups (Milan: F= 42.48; p <0.001; Naples: F=23.59, p <0.001). GMP samples were generally preferred than amino acid mixtures, especially for samples flavored with chocolate and strawberry, described as sweets, with a mild and natural taste and odor. Patients from South of Italy gave significant higher liking scores to the amino acid base samples compared to patients from North suggesting different attitude toward products. Discussion The results of this study demonstrated that GMP-based formulas showed a greater acceptability compared to amino acid mixtures. In this context, different products could be developed using this cheese whey derived protein in order to improve compliance with dietary treatment of phenylketonuria patients.