dietary compliance is the primary issue for pku patients on amino acid formula , particularly those emerging from childhood . schuett , v . e . ; 1990 ; ( dhhs publication no hrs - mch - 89 - 5 ), reported that more & gt ; 40 % of pku patients in the us , eight years or older , are not compliant with their diet . the high osmolality , bitterness of amino acids and metallic taste contributed by other components discourage formula consumption . there have been many attempts to improve acceptance of foods and beverages for those with pku , such as making dry formulae that include caseino glycomacropeptide in combination with amino acids encapsulated to reduce their unpleasant flavor . ( ballevre et al . 2003 ). although it might have a pleasant flavor , a powdered formula may not be convenient for a person on the go . ready - to - drink , shelf - stable formulae , such as beverages , pose particular challenges , at least in part because the components essential for complete sustenance components must be incorporated into or combined to produce the nutritional formula in such a way that they remain dissolved , suspended or otherwise retained in the formula ( beverage ). this is a challenge because each ingredient in the nutritional formula has unique requirements for making it stable . particularly difficult to incorporate is the caseino - glycomacro - peptide , which contains sialic acid attached to an amino acid residue on the chain . this sialic acid reduces the isoelectric point of the peptide as a function of the fraction of sites occupied by sialic acid . thus , the isoelectric point can change as the peptide is being processed . peptides are not soluble at or near their isoelectric ph and tend to precipitate or gel . described herein is a method by which nutritional formulas described are made , with the result that the formula is ready - to - drink and shelf - stable . nutritional formula preparation can be carried out using the method represented schematically in the figure . kitting of ingredients is carried out as indicated : kitting of dry ingredients , to produce a dry ingredient mixture is prepared by kitting together dry ingredients without sodium hexametaphosphate ( shmp ) or mineral blend ; kitting together of shmp , cuso 4 , feso 4 and , as needed , other minerals ; and kitting of ingredients for oil incorporation . the shmp and minerals are mixed in water separately . ingredients for oil incorporation are heated and incorporated together . these include tyrosine , oss , ssl , cocoa butter , vegetable oil and other oil - soluble ingredients . they are subject to high shear and homogenization to produce an emulsion . the resulting three combinations ( see the figure ) are combined with water , as shown in the figure and subjected to the conditions shown , beginning with the step sequentially add to high shear blender . as represented , ( 1 ) water , gmp , amino acids , vitamins and other dry ingredients are added or introduced into a metered volume of water to produce a first mixture ; ( 2 ) shmp , minerals and water are kitted together and added to the result of ( 1 ); ( 3 ) the emulsion produced as shown in the figure is incorporated into the result of ( 1 ) and ( 2 ) and vitamin c is added to the resulting product , which is subjected to uht process at about 140 ° c . for a short time ( e . g ., 5 - 6 seconds ). the resulting formula is stored in an aseptic tank and packaged , such as aseptically . alternatively , the nutritional formula is packaged by canning . in some embodiments , the dry ingredients include caseino glycomacropeptides ( gmp ), amino acids , and vitamins . shmp is combined with minerals , such as a metal fortification mixture , which comprises at least one type of metallic ions to produce a shmp - minerals in water ( shmp - metal mixture ). in some embodiments , metal fortification mixture comprises two or more types of metallic ions . in some embodiments , the metallic ions is copper ( e . g ., cu 2 ± ) and / or iron ( e . g ., fe 2 + ). in some embodiments , the metallic ions are from sources such as cuso 4 and / or feso 4 . an emulsion is prepared by combining and heating oil ingredients , which includes tyrosine , modified starch , sodium stearoyl lactylate ( ssl ), oils such as cocoa butter and vegetable oil , and other oil soluble ingredients . the modified starch used herein is an amphiphilic starch , which is hydrophilic and hydrophobic in nature . the modified starch is used to bind to fat to prevent the fat from interacting with the proteins by steric hindrance . for example , a normally hydrophilic starch is modified to incorporate hydrophobic moieties such as octenyl groups which binds to fats . the resulting modified starch has an amphiphilic nature and thus surface active properties which are useful in stabilizing oil / water emulsions . in some embodiments , the modified starch is octenyl succinate starch ( oss ) or another amphiphilic starch . the hydrophobic octenyl moiety binds the fats in the emulsion assuring that the starch remains attached to the fat globule , preventing the fats from interacting with the proteins by steric hindrance . the heated and combined oil ingredients are then added to a mixer , such as a high shear mixer , with water and are homogenized to form an emulsion . in some embodiments , the oil ingredients are homogenized with water at about 60 - 80 ° c . and about 400 psi to about 3000 psi . in one embodiment , the oil ingredient are homogenized at about 70 ° c . and about 500 psi to about 2000 psi . as shown , the mixtures are sequentially added to a blender such as a high shear blender : the dry ingredient mixture is mixed into metered volume of water , the fortified shmp mixture is added , the emulsion is incorporated , and vitamin c is added last . in some embodiments , the vitamin c is sodium ascorbate and / or ascorbic acid . the combined mixture is subjected to ultra - high temperature processing ( uht ) at about 130 - 150 ° c . for about 4 to about 10 seconds . in one embodiment , the uht process occurs at 140 ° c . for about 5 to about 6 seconds . the resulting formula is subsequently placed / stored in aseptic tank and then aseptically packaged . dry ingredient mixture was prepared by kitting together the dry ingredients without sodium hexametaphosphate ( shmp ), vitamins , or mineral . table 1 below provides the weight of dry ingredients used . the dry ingredients are caseino glycomacropeptides ( gmp ), amino acids , vitamins , sugar , dextrin , natural flavoring products , natural food coloring , sodium chloride , cellulose gum , carrageenan , and sweeteners . in another step , shmp is combined with a copper and iron fortification mixture . in another step , vitamins and minerals are mixed together in water to provide a vitamin and mineral fortification mixture . subsequently , the shmp with the copper and iron fortification mixture is mixed with the vitamin and mineral fortification mixture , thereby forming a metal / mineral fortified shmp mixture . in a separate step , an emulsion is prepared by combining and heating oil ingredients , which includes l - tyrosine , octenyl succinate modified starch ( oss ), sodium stearoyl lactylate ( ssl ), cocoa butter , vegetable oil . the heated and combined oil ingredients are then added to a high shear mixer with water and are homogenized to form an emulsion at about 70 ° c . and about 500 psi to about 2000 psi . the foregoing mixtures are then sequentially added to a blender such as a high shear blender in the following order : the dry ingredient mixture is mixed into metered volume of water , the fortified shmp mixture is added , the emulsion is incorporated , and vitamin c ( sodium ascorbate and ascorbic acid ) is added last . table 1 below provides the amounts of each ingredient used to prepare the formula . the combined mixture is subjected to ultra - high temperature processing ( uht ) at about 140 ° c . for about 5 to about 6 seconds the resulting formula is subsequently stored in aseptic tank and then aseptically packaged using prisma packages .
this is a process to make a shelf - stable , liquid , ready - to - drink , aseptic nutritional formula for the treatment of pku , tyrosinemia or other errors of metabolism . the liquid nutritional formula has caseino - glyco - macropeptide as the primary protein source and complementary essential amino acids to complete the requirement profile . the beverage also includes vitamins and minerals sufficient to meet daily requirements . when used as a complete diet , the nutritional formula includes a carbohydrate source and a fat source . the nutritional formula has a pleasant taste .