Sensory comparison of low-protein recipes with glycomacropeptide-containing BetterMilk and liquid non-dairy coffee creamer among adults with phenylketonuria

Abstract

Phenylketonuria (PKU) results from deficiency of phenylalanine hydroxylase enzyme which is responsible for converting the essential amino acid phenylalanine to the non-essential amino acid tyrosine. PKU is treated with a low-protein diet and medical food/ formula providing supplemental protein without excess phenylalanine. Naturally phenylalanine-free, Glycomacropeptide (GMP) used in PKU medical foods/ formulas contains four essential amino acids and is fortified with methionine, leucine, histidine, tryptophan, and tyrosine to provide a near complete protein. Although sensory research has been conducted on GMP-based foods, sensory evaluation of commonly utilized low-protein recipes substituted with GMP-based formulas is undocumented. Such research is critical to development of appealing means for formula consumption. Study objectives were to compare sensory attributes (taste, aroma, texture, and overall acceptability) and preferences for low-protein cream of tomato soup, lemon pudding, and vanilla ice cream containing either a GMP-based formula or unflavored liquid non-dairy coffee creamer as the primary liquid ingredient and to solicit medical formula/food procurement information among adults with PKU. Data were subjected to paired t-tests with the Bonferroni correction (p< 0.0125) and analysis of variance. Thirty-one adults (80% female, 93% white) completed the study. Significantly higher scores (p<0.01) were reported for aroma, taste, and overall acceptability of the control soup and for all four sensory attributes of the control pudding. Control ice cream was ranked significantly higher (p<0.01) in taste and overall acceptability. No significant differences existed among scores of the four sensory attributes within each control or experimental recipe. Control samples were preferred over experimental samples for all recipes. Experimental samples for each recipe were on average scored in the "like" range. Only 23% of the sample reported they frequently consume medical foods, while equal numbers of participants reported they were/were not interested in using a medical food in preparation of low-protein recipes. These data may partially explain why control samples were preferred. Additionally, lower sensory scores for taste and aroma of the experimental soup, pudding, and ice cream may be attributed to the probiotics and docosahexaenoic acid within the GMP-based formula as both of these functional ingredients are capable of imparting strong flavors and aromas to foods. Additional research is needed to investigate the use of GMP-based formulas without added functional ingredients and isolated GMP, not GMP-based formulas, in low-protein recipes in order to expand dietary offerings for individuals with PKU.