AU2013101214A4 - Dairy product and process - Google Patents

Abstract

Denatured whey protein compositions for increasing the blood serum concentration of free leucine in a subject, preferably to substantially the same level as native whey protein.

Description

DAIRY PRODUCT AND PROCESS FIELD OF THE INVENTION [0001] The present invention relates to a denatured whey protein composition for increasing the blood serum concentration of free leucine in a subject to substantially the same level as native whey protein. The increased blood serum leucine concentration may result in any one or more of maintained or increased muscle protein synthesis, maintained or increased muscle mass, prevention or reduction of loss of muscle mass, preventing or decreasing muscle catabolism, prevention or treatment of cachexia, prevention or treatment of sarcopenia, increased rate of glycogen resynthesis, modulation of blood sugar levels, increased insulin response, increased satiety, reduced food intake, reduced calorie intake, improved glucose metabolism, increased rate of recovery following surgery, increased rate of recovery following injury, increased rate of recovery following exercise, or increased sports performance. BACKGROUND OF THE INVENTION [0002] Skeletal muscle contains 50-75% of all protein in the human body. Substantial depletion of skeletal muscle, associated with ageing (for example, age-related sarcopenia), various disease states (for example, cachexia and anorexia) or following surgery or sports, can increase both morbidity and mortality. Age-related sarcopenia is a condition characterised by progressive and generalised loss of skeletal muscle mass and strength. This carries increased risk of adverse outcomes such as physical disability, poor quality of life and death. Cachexia is defined as severe muscle wasting and is a complex metabolic syndrome associated with underlying illness. It is characterised by a loss of muscle mass, with or without loss of fat (Cruz-Jentoft AJ, Baeyen JP, Bauer JM et al. Sarcopenia: European consensus on definition and diagnosis. Age and ageing 2010; 39:412-423). [0003] The elderly or those suffering from disease require increased protein in their diet at a level greater than what is need for younger healthy individuals. Various studies report that additional protein intake can improve muscle mass, strength and function in the elderly. Additionally, other factors, including immune status, wound healing, blood pressure and bone health may be improved by increasing protein intake. (Wolf RR et al. Optimal protein intake in the elderly. Clin Nutr. 2008; 5:675-684). [0004] The essential amino acids (EAAs) are primarily responsible for the regulation of muscle protein synthesis, and of the EAAs, leucine is recognised as having a particular role in the stimulation of muscle protein synthesis (Garlick PJ). The role of leucine in the regulation of protein metabolism. J Nutr 2005; 135:1553S-1556S). [0005] Sources of leucine include meat, nuts, beans, brown rice, wheat and dairy. Dairy casein contains high levels of leucine, isoleucine and valine although whey protein contains higher levels of 1 leucine and of total essential amino acids (Fox PF, McSweeney PLH (eds), Advanced Dairy Chemistry, Volume 1 - Proteins, 3rd Ed, Kluwer Academic/Plenum Publishers, NY, 2003). [0006] It is therefore an object of the present invention to provide an improved or alternative method for increasing the serum leucine concentration in a subject, or to at least provide the public with a useful choice. SUMMARY OF THE INVENTION [0007] Accordingly, in one aspect the present invention relates to a denatured whey protein composition for increasing the blood serum concentration of free leucine in a subject, preferably to substantially the same level as native whey protein, wherein the denatured whey composition comprises non-hydrolysed whey protein that has been heated to at least about 70 0 C, or wherein at least 55% of the heat denaturable protein is denatured. [0008] In another aspect the invention relates to a method of increasing the blood serum concentration of free leucine in a subject, the method comprising administering to a subject in need thereof an effective amount of a denatured whey protein composition to increase the blood serum concentration of free leucine in a subject, preferably to substantially the same level as native whey protein. [0009] In another aspect the invention relates to use of a denatured whey protein composition in the manufacture of a formulation for increasing the blood serum concentration of free leucine in a subject, preferably to substantially the same level as native whey protein. [0010] Any of the following embodiments, alone or in any combination of any two or more of the following embodiments, may relate to any of the above aspects. [0011] In various embodiments the denatured whey protein composition is or comprises a whey protein concentrate (WPC) or whey protein isolate (WPI). In one embodiment the protein is a WPC or a WPI prepared by a method comprising a) providing an aqueous WPC or WPI solution having a protein concentration of 15-50% (w/v), at a pH of 4.7-8.5; b) heat treating the solution to more than 70'C, for a time that allows protein denaturation to occur; the heat treating comprising heating the solution while under conditions of turbulent flow, for example with a Reynolds number of at least 500; c) recovering the heat treated WPC or WPI. 2 [0012] In another embodiment the protein is a WPC or a WPI prepared by a method comprising a) providing an aqueous WPC or WPI solution having a protein concentration of 15-50% (w/v), at a pH of 4.7-8.5; b) heat treating the solution to more than 70'C, for a time that allows protein denaturation to occur; the heat treating comprising heating the solution while under conditions of turbulent flow, for example with a Reynolds number of at least 500; c) directly transferring the heat treated WPC or WPI either to a drier to be dried or to a mixer to be mixed with other ingredients. wherein the heat-treated WPC or WPI is not subjected to a mechanical shear process prior to drying other than where liquid is converted into droplets to facilitate drying, or wherein the heat treated WPC or WPI is not subjected to particle size reduction prior to step (c), or both. [0013] In one embodiment, the denatured whey protein composition is or comprises a whey protein concentrate (WPC) or whey protein isolate (WPI) prepared by a method comprising providing an aqueous WPC or WPI solution having a protein concentration of 15-50% (w/v), at a pH of 4.7-8.5; heat treating the solution to more than 70'C, for a time that allows protein denaturation to occur; the heat treating comprising heating the solution while under conditions of turbulent flow; and recovering the heat treated WPC or WPI, or directly transferring the heat treated WPC or WPI either to a drier to be dried or to a mixer to be mixed with other ingredients, wherein the transferred heat-treated WPC or WPI is not subjected to (a) a mechanical shear process prior to drying other than where liquid is converted into droplets to facilitate drying, or (b) particle size reduction prior to drying or mixing, or (c) both (a) and (b). [0014] In certain embodiments, for example of the liquid nutritional composition, the composition has after heating, and optionally after blending or homogenisation, a mean particle size of from about 0.3 pim to about 2 pim, or from about 0.5 pim to about 1.5 pim. For example, the composition has a mean particle size of about 1 pm. [0015] In certain embodiments, for example of the liquid nutritional composition, the composition has after heating, and optionally after blending or homogenisation, a particle size distribution wherein greater than about 95% of the particles are below about 10 pm. For example, the composition has a 3 particle size distribution wherein greater than about 95% of the particles are below about 5 pam, below about 4 ptm, below about 3 ptm, below about 2 ptm, or below about 1 ptm. [0016] In various exemplary embodiments, the liquid composition has a mean particle size that does not substantially increase when heated, for example, when heated with a heat treatment with an Fo value of at least equivalent to 80'C for 15s, for example when heated at greater than 1 00 0 C for 15 min. For example, the composition has a mean particle size that does not increase by more than 10-fold when heated at greater than 100 0 C for 15 min, in certain examples does not increase by more than 7-fold, by more than 5-fold, or by more than 3-fold, when heated with a heat treatment with an Fo-value of at least equivalent to 80'C for 15s, for example when heated at greater than 100 C for 15 min. [0017] In one exemplary embodiment, the liquid composition has a mean particle size that does not increase by more than 2-fold when heated at greater than 100 C for 15 min. [0018] In another embodiment, for example in certain embodiments of the liquid composition, the composition has a particle size distribution wherein greater than about 95% of the particles are below about 10 pam when heated at greater than 100 0 C for 15 min. For example, the composition has a particle size distribution wherein greater than about 95% of the particles are below about 5 pam, below about 4 pim, below about 3 pim, below about 2 pim, or below about 1 pim, when heated at greater than 100 C for 15 min. [0019] In another embodiment, for example in certain embodiments of the liquid composition, the composition has a particle size distribution wherein greater than about 95% of the particles are below about 10 pm when heated at greater than 100 0 C for 15 min at d) a pH of between about 4 to about 6, or e) a pH within about 0.5 of the average pI of the protein present in the composition. [0020] For example, the composition has a particle size distribution wherein greater than about 95% of the particles are below about 5 pim, below about 4 pim, below about 3 pim, below about 2 pim, or below about 1 pam, when heated at greater than 100 C for 15 min. [0021] In various embodiments, the whey protein comprises or is provided by an ingredient that comprises at least about 55% of the heat-denaturable protein present in a denatured state. In certain embodiments the whey protein comprises, consists essentially of, of consists of at least about 65% of the heat-denaturable protein present in a denatured state, at least about 70% of the heat-denaturable protein present in a denatured state, at least about 75% of the heat-denaturable protein present in a denatured 4 state, at least about 80% of the heat-denaturable protein present in a denatured state, at least about 85% of the heat-denaturable protein present in a denatured state, at least about 90% of the heat-denaturable protein present in a denatured state, at least about 95% of the heat-denaturable protein present in a denatured state, or at least about 99% of the heat-denaturable protein present in a denatured state. [0022] In various embodiments, the denatured whey protein composition is a liquid nutritional composition comprising a) from about 2% to about 25% by weight of protein that has been heated to at least 70'C or wherein at least about 55% of the heat-denaturable protein is denatured; b) from 0 to about 30% by weight fat; c) from about 0% to about 45% by weight carbohydrate; and wherein the nutritional composition has a pH of between about 4 to about 6, and a viscosity of less than 200 cP at a temperature of 20'C and a shear rate of 100 s-1. In another aspect, the denatured whey protein composition is a liquid nutritional composition comprising a) from about 2% to about 25% by weight of non-hydrolysed whey protein b) from 0 to about 30% by weight fat c) from about 0% to about 45% by weight carbohydrate and wherein the nutritional composition has a pH of between 4 and 6, and d) a viscosity of less than 200 cP when measured at 20'C and shear rate of 100 s-1, and e) had a heat treatment with an F 0 -value of at least equivalent to 80'C for 15s. In a further aspect, the denatured whey protein composition is a liquid nutritional composition comprising a) from about 2% to about 25% by weight of non-hydrolysed whey protein b) from 0 to about 30% by weight fat c) from about 0% to about 45% by weight carbohydrate and wherein the liquid nutritional composition has undergone when at a pH of between 4 and 6 a heat treatment with an F 0 -value of at least equivalent to 80'C for 15s, and wherein the liquid nutritional composition has a viscosity of less than 200 cP when measured at 20'C and shear rate of 100 s-1. In one embodiment, the denatured whey protein composition is a liquid nutritional composition comprising 5 a) from about 2% to about 25% by weight of non-hydrolysed whey protein wherein at least 55% of the heat-denaturable whey protein is denatured b) from 0 to about 30% by weight fat c) from about 0% to about 45% by weight carbohydrate and wherein the liquid nutritional composition has undergone when at a pH of between 4 and 6 a heat treatment with an F.-value of at least equivalent to 80'C for 15s, and wherein the liquid nutritional composition has a viscosity of less than 200 cP when measured at 20'C and shear rate of 100 /s. [0023] In one embodiment the denatured whey protein composition increases the blood serum concentration of free leucine in a subject, preferably to substantially the same level as native whey protein, within about 15, 30, 45 or 60 minutes of administration, including within about 15 to about 60, about 30 to about 60 or about 45 to about 60 minutes. In this and related embodiments, the native whey protein is an native whey protein concentrate (WPC), preferably a whey protein concentrate comprising about 80% or about 85% protein by weight. [0024] In one embodiment, the denatured whey protein composition is able to increase the concentration of free leucine in blood serum to at least about 205, 210, 215, 220, 225, 230, 235, 240, 245, 250 or 255 imol/L or more, and useful ranges may be selected between any of these values (for example about 205 to about 255, about 210 to about 255, about 215 to about 255, about 220 to about 255, about 225 to about 255, about 230 to about 255, about 235 to about 255, and about 240 to about 255 imol/L). [0025] In another embodiment, the denatured whey protein composition is able to increase the concentration of free leucine in blood serum to at least about 205 imol/L, as described above, for at least about 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 minutes or more following administration, and useful ranges may be selected between any of these values (for example about 5 to about 50, about 10 to about 50, about 15 to about 50, about 20 to about 50, about 25 to about 50, and about 30 to about 50 minutes). [0026] In one embodiment, the denatured whey protein composition is able to increase the concentration of free leucine in blood serum by at least about 205, 210, 215, 220, 225, 230, 235, 240, 245, 250 or 255% or more, and useful ranges may be selected between any of these values (for example about 205 to about 255, about 210 to about 255, about 215 to about 255, about 220 to about 255, about 225 to about 255, about 230 to about 255, about 235 to about 255, and about 240 to about 255%). [0027] In another embodiment, the denatured whey protein composition is able to increase the concentration of free leucine in blood serum by at least about 205%, as described above, for at least 6 about 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 minutes or more following administration, and useful ranges may be selected between any of these values (for example about 5 to about 50, about 10 to about 50, about 15 to about 50, about 20 to about 50, about 25 to about 50, and about 30 to about 50 minutes). [0028] In one embodiment, the increased blood serum leucine concentration results in any one or more of the following: a) maintained or increased muscle protein synthesis, b) maintained or increased muscle mass, c) prevention or reduction of loss of muscle mass, d) preventing or decreasing muscle catabolism, e) prevention or treatment of cachexia, f) prevention or treatment of sarcopenia, g) increased rate of glycogen resynthesis, h) modulation of blood sugar levels, i) increased insulin response to raised blood glucose concentration, j) increased satiety, k) reduced food intake, 1) reduced calorie intake, m) improved glucose metabolism, n) increased rate of recovery following surgery, o) increased rate of recovery following injury, p) increased rate of recovery following exercise, or q) increased sports performance. [0029] In various embodiments the composition or formulation comprises at least about 0.01, 0.1, 0.5, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 99% by weight protein and useful ranges may be selected between any of these values (for example, about 0.01 to about 10, about 0.01 to about 20, about 0.01 to about 30, about 0.01 to about 40, about 0.01 to about 50, about 0.01 to about 60, about 0.01 to about 70, about 0.01 to about 80, or about 0.01 to about 99%). [0030] In one embodiment the composition or formulation comprises additional protein from an animal or vegetable source or a combination thereof. In one embodiment the composition or formulation comprises whey protein and an additional protein source, such as animal protein or vegetable protein or a combination thereof. 7 [0031] In certain embodiments, the WPC or WPI comprises at least about 35% protein, at least about 50% protein, at least about 65% protein, at least about 70% protein, at least about 75% protein, or at least about 80% protein. In certain embodiments, higher protein content compositions are utilised, for example the WPC or WPI comprises at least about 85% protein, at least about 90% protein, or at least about 95% protein. [0032] In certain embodiments the protein present in the whey protein composition, for example a whey protein concentrate (WPC), a whey protein isolate (WPI), or a blend of whey protein sources including a blend of WPCs or WPIs or both, comprises, consists essentially of, of consists of non hydrolysed whey protein. In one exemplary embodiment, the protein present in the WPC or WPI comprises at least about 65% non-hydrolysed protein, at least about 70% non-hydrolysed protein, at least about 75% non-hydrolysed protein, at least about 80% non-hydrolysed protein, at least about 85% non-hydrolysed protein, at least about 90% non-hydrolysed protein, at least about 95% non-hydrolysed protein, or at least about 99% non-hydrolysed protein. In one embodiment, the WPC or WPI is essentially free of hydrolysed protein. [0033] In certain embodiments, less than about 10% of the protein is hydrolysed. In one example, less than about 8% of the protein is hydrolysed, less than about 5% of the protein is hydrolysed, less than about 2.5% of the protein is hydrolysed, or less than about 1% of the protein is hydrolysed. For example, in certain embodiments of the liquid nutritional composition of the invention, less than about 10%, less than about 8%, less than about 5%, less than about 2.5%, or less than about 1% of the protein present in the liquid nutritional composition is hydrolysed. [0034] In certain embodiments, more than about 60% of the heat-denaturable protein present in the composition or formulation is denatured, or more than about 65% of the heat-denaturable protein present in liquid nutritional composition is denatured. In one example, more than about 70% of the heat-denaturable protein present in liquid nutritional composition is denatured, or more than about 75% of the heat-denaturable protein present in liquid nutritional composition is denatured. For example, in certain embodiments of the liquid nutritional composition of the invention, more than about 65%, more than about 70%, more than about 75%, more than about 80%, more than about 85%, more than about 90%, more than about 95%, or more than about 99% of the heat-denaturable protein present in the composition is denatured. [0035] In various embodiments the composition or formulation comprises at least about 0.01, 0.1, 0.5, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 79, 81, 85, 90, 95 or 99% by weight denatured whey protein composition and useful ranges may be selected between any of these values (for example, 8 about 0.01 to about 10, about 0.01 to about 20, about 0.01 to about 30, about 0.01 to about 40, about 0.01 to about 50, about 0.01 to about 60, about 0.01 to about 70, about 0.01 to about 80, or about 0.01 to about 99%). [0036] In one embodiment the composition may additionally comprise a source of amino acids, amino acid precursors or amino acid metabolites or any combination of any two or more thereof, preferably free amino acids, amino acid precursors or amino acid metabolites, such as those selected from the group comprising alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, essential amino acids, non-essential amino acids, branched chain amino acids, amino acid precursors such as N-acetyl-L-tyrosine, amino acid metabolites such as alpha ketoglutaric acid and non-standard amino acids, and any combination of any two or more thereof. In one embodiment the composition or formulation comprises at least about 0.01, 0.1, 0.5, 1, 5, 10 or 15% by weight or more of free amino acids amino acid, precursors or amino acid metabolites and useful ranges may be selected between any of these values (for example, about 0.01 to about 1, about 0.01 to about 5, about 0.01 to about 10, or about 0.01 to about 15%). [0037] In one embodiment the composition or formulation comprises at least about 0.01, 0.1, 0.5, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50% by weight lipid and useful ranges may be selected between any of these values (for example, about 0.01 to about 10, about 0.01 to about 20, about 0.01 to about 30, about 0.01 to about 40, or about 0.01 to about 50%). [0038] In one embodiment the lipid is from an animal or vegetable source. [0039] In one embodiment the composition or formulation comprises at least about 0.01, 0.1, 0.5, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60 or 70% by weight carbohydrate and useful ranges may be selected between any of these values (for example, about 0.01 to about 10, about 0.01 to about 20, about 0.01 to about 30, about 0.01 to about 40, about 0.01 to about 50, about 0.01 to about 60, or about 0.01 to about 70%). [0040] In one embodiment the carbohydrate is selected from monosaccharides, disaccharides, oligosaccharides, or polysaccharides, and any combination of any two or more thereof. [0041] In one embodiment the composition or formulation comprises at least about 0.01, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10% by weight minerals or vitamins and useful ranges may be selected between any of these values (for example, about 0.01 to about 2, about 0.01 to about 4, about 0.01 to about 6, about 0.01 to about 8, or about 0.01 to about 10%). 9 [0042] In one embodiment the composition or formulation comprises from about 0.01 % to about 95% protein, from about 0.01% to about 50% lipid, from about 0.01% to about 70% carbohydrate, and from about 0.01% to about 10% minerals and vitamins. In one embodiment the composition or formulation comprises from about 0.01 % to about 50% protein, from about 0.01% to about 30% lipid, from about 0.01% to about 50% carbohydrate, and from about 0.01% to about 5% minerals and vitamins. In one embodiment the composition or formulation comprises from about 0.5% to about 15% protein, from about 0.10% to about 10% lipid, from about 0.10% to about 30% carbohydrate, and from about 0.1% to about 1% minerals and vitamins. [0043] In one embodiment the composition or formulation has an energy content from about 1 cal per 1OOmL to about 300 cal per 100 ml. [0044] In one embodiment, the protein provides from about 10% to about 40% of the total energy content of the composition or formulation. In a further embodiment of the composition or formulation, protein provides from about 10% to about 30% of the total energy content of the composition. [0045] In various embodiments the pH of the composition of formulation is about 1 to about 14, about 1 to about 5, about 6 to about 8, about 9 to 14, about 1 to about 9 or about 5 to about 9. [0046] In one embodiment the composition or formulation further comprises any one or more of fruit juice, juice concentrates, natural or artificial flavours, natural or artificial sweeteners, natural or artificial colours, fibres, probiotics, prebiotics, herbs, caffeine, guarana, glucosamine, free amino acids (as described above), organic acids, amino acid precursors, amino acid metabolites, taurine, alpha ketoglutaric acid, N-acetyl-L-tyrosine, creatine, creatine esters, creatine ethyl ester, creatine salts, creatine hydrochloride, beta-alanine, beta-hydroxy beta-methylbutyric acid and beta-hydroxy beta methylbuterate, or any combination of any two or more thereof. [0047] In various embodiments, the composition or formulation has a viscosity of less than 200 cP when measured at 20'C and shear rate of 100 s-1 after having undergone a heat treatment with an F.

value of at least equivalent to 80'C for 15s, or at least equivalent to 90'C for 15s, or at least equivalent to 100 C for 15s. In one example, the composition or formulation has a viscosity of less than 200 cP when measured at 20'C and shear rate of 100 s-1 after having undergone a heat treatment with an F.-value of at least equivalent to 121'C for 4s. [0048] In various embodiments, the composition or formulation has a viscosity of less than 200 cP when measured at 20'C and shear rate of 100 s-1 after having undergone a heat treatment of at least 10 equivalent to 121 C for 10 minutes. In one example, the liquid nutritional composition has a viscosity of less than 200 cP when measured at 20'C and shear rate of 100 s-1 after having undergone an ultra heat treatment (UHT) with an F 0 -value of at least equivalent to 140'C for 5s. [0049] In various embodiments, the composition or formulation has a viscosity of less than 150 cP, or less than 100 cP, or less than 50 cP when measured at 20'C and shear rate of 100 s-1 after having undergone a heat treatment with an F 0 -value of at least equivalent to 80'C for 15s. [0050] In one embodiment the composition or formulation is a consumer beverage that comprises from about 0.1 % to about 10% protein, from about 0.01% to about 5% lipid, from about 0.1% to about 15% carbohydrate, and from about 0.1% to about 2% minerals and vitamins and has an energy content of at least 1 cal per 100 ml. [0051] In one embodiment the composition or formulation is a recovery beverage additionally comprising any one or more of natural or artificial flavours, natural or artificial sweeteners, natural or artificial colours, or glucosamine, or any combination of any two or more thereof. In one embodiment the recovery beverage comprises from about 0.1% to about 10% protein, from about 0.01% to about 4% lipid, from about 0.10% to about 20% carbohydrate, and from about 0.10% to about 2% minerals and vitamins and has an energy content of at least 1 cal per 100 ml. [0052] In one embodiment the composition or formulation is a medical food additionally comprising any one or more of natural or artificial flavours, natural or artificial sweeteners or natural or artificial colours, or any combination of any two or more thereof. In one embodiment the medical food comprises from about 1% to about 20% protein, from about 1% to about 20% lipid, from about 1% to about 40% carbohydrate, and from about 0. 1% to about 5% minerals or vitamins and has an energy content of at least 50 cal per 100 ml. In various embodiments the medical food is acidic or neutral. [0053] In various embodiments the composition or formulation is an ingredient used in the preparation of a food. In one embodiment the composition or formulation is formulated for separate, simultaneous or sequential administration with a food. In various embodiments the food is confectionary, a bar, a dairy product, milk, a milk product, a milk powder, reconstituted milk, cultured milk, yoghurt, drinking yoghurt, set yoghurt, a beverage, a food additive, a drink additive, a dietary supplement, a nutritional product, a dietetic product or a medical food. [0054] In another embodiment the composition is or is formulated as a food, drink, food additive, drink additive, dietary supplement, nutritional product, dietetic product, medical food, enteral feeding product, parenteral feeding product, meal replacement, nutraceutical, medicament, or pharmaceutical. 11 [0055] In one embodiment the whey protein is a whey protein concentrate or a whey protein isolate. In another embodiment the whey protein is a whey protein concentrate or a whey protein isolate comprising about 50, 60, 70, 80 or 90% protein by weight. [0056] It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner. [0057] In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. [0058] The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. BRIEF DESCRIPTION OF THE DRAWINGS [0059] Figure 1 is a graph showing the change in absolute blood serum concentration of leucine (vmol/L) up to 180 minutes after consumption of a denatured whey protein composition (blue) and an native whey protein composition (green). DETAILED DESCRIPTION OF THE INVENTION [0060] The present inventors have surprisingly determined that denatured whey protein compositions may be used to effectively deliver leucine to the bloodstream at levels equivalent to native whey. Thus the present invention relates to use of denatured whey protein compositions for increasing blood serum leucine concentration, and in particular the present invention relates to use of a denatured whey protein composition for increasing the blood serum concentration of free leucine in a subject to substantially the same level as native whey protein. The increased blood serum leucine concentration 12 may result in any one or more of maintained or increased muscle protein synthesis, maintained or increased muscle mass, prevention or reduction of loss of muscle mass, preventing or decreasing muscle catabolism, prevention or treatment of cachexia, prevention or treatment of sarcopenia, increased rate of glycogen resynthesis, modulation of blood sugar levels, increased insulin response, increased satiety, reduced food intake, reduced calorie intake, improved glucose metabolism, increased rate of recovery following surgery, increased rate of recovery following injury, increased rate of recovery following exercise, or increased sports performance. 1. Definitions [0061] The term "comprising" as used in this specification means "consisting at least in part of". When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement or claim, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner. [0062] The term "dietetic product" means a product specially processed or formulated to satisfy particular dietary requirements which exist because of a particular physical or physiological condition and/or specific diseases and disorders and which are presented as such. [0063] An "effective amount" is the amount required to confer therapeutic effect. The interrelationship of dosages for animals and humans (based on milligrams per meter squared of body surface) is described by Freireich, et al., 1966. (see Freireich EJ, Gehan EA, Rall DP, Schmidt LH, Skipper HE (1966) Quantitative comparison of toxicity to anticancer agents in mouse, rat, hamster, dog, monkey and man. Cancer Chemother Rep 50: 219-244). Body surface area can be approximately determined from height and weight of the subject. See, e.g., Scientific Tables, Geigy Pharmaceuticals, Ardley, New York, 1970, 537. Effective doses also vary, as recognized by those skilled in the art, dependent on route of administration, carrier usage, and the like. [0064] The phrase "heat-denaturable protein" is measured as X(bovine serum albumin + a lactoalbumin + B-lactoglobulin + lactoferrin + immunoglobulins). [0065] The phrase "increasing the blood serum concentration of leucine" and its grammatical equivalents and derivates, refers to maintaining and increasing blood serum leucine concentrations, preferably to adequate physiological concentrations to maximally stimulate muscle protein synthesis in the post-prandial period. For the purposes of determining leucine levels in the blood, references to "blood", "blood serum" and "blood plasma" are interchangeable. 13 [0066] The term "milk protein concentrate" (or MPC) is a milk protein product in which greater than 55%, preferably greater than 75% of the dry matter is milk protein and the ratio of casein to whey proteins is approximately that of milk. Such concentrates are known in the art. [0067] The phrase "maintaining or increasing muscle mass" and its grammatical equivalents and derivatives, refers to an increase in muscle protein synthesis and/or a decrease in muscle protein breakdown which results in a gain or maintained muscle mass. [0068] The term "non-hydrolysed" when used with reference to a protein-containing compositions, such as a liquid nutritional composition, powder, WPC, WPI or the like, means less than 2% of the protein present in the composition has undergone hydrolysis, and in certain embodiments less than 1% of the protein present in the composition has undergone hydrolysis. [0069] The phrase "preventing or reducing loss of muscle mass" and its grammatical equivalents and derivatives, refers to prevention or decrease in muscle protein breakdown resulting in maintained muscle mass or decreased rate of muscle loss. [0070] A "subject" is an animal, preferably a mammal, more preferably a mammalian companion animal or human. Preferred companion animals include cats, dogs and horses. In one embodiment the subject is a human. Preferably the human is an adult, a child, or an infant. [0071] The term "treat" and its derivatives should be interpreted in their broadest possible context. The term should not be taken to imply that a subject is treated until total recovery. Accordingly, "treat" broadly includes amelioration and/or prevention of the onset of the symptoms or severity of a particular condition. [0072] A "whey protein concentrate" (WPC) is a fraction of whey from which lactose has been at least partially removed to increase the protein content to at least about 20, 25, 50, 55, 60, 65, 70, 75, 80 or 85% by weight, and useful ranges may be selected between any of these values (for example, about 25 to about 85). Generally the proportions of the whey proteins are substantially unaltered relative to the whey from which the WPC is derived. Whey protein concentrates are generally whey protein retentates resulting from a filtration process, such as ultrafiltration or ultrafiltration with diafiltration. Whey protein processing is discussed by Fox & McSweeney, 2003 (Fox PF, McSweeney PLH (eds), Advanced Dairy Chemistry, Volume 1 - Proteins, 3rd Ed, KIuwer Academic/Plenum Publishers, NY, 2003) and in the Dairy Processing Handbook, 2003 (Dairy Processing Handbook, Second Edition, Tetra Pak Processing Systems AB, Sweden, 2003) both incorporated by reference herein in their entirety. For the purposes of this specification, the term "WPC" includes WPIs when the context allows. 14 [0073] A "whey protein isolate" (WPI) is a fraction of whey from which lactose has been at least partially removed to increase the protein content to at least about 90% by weight, generally by microfiltration and ultrafiltration or ion exchange chromatography. See Fox & McSweeney, 2003 and the Dairy Processing Handbook, 2003. 2. Whey [0074] Whey protein or whey protein fractions without suitable processing will typically form a gel when heated under appropriate conditions (> 75 0 C, ~ pH 6 to 8, > 6 g TS/ 100 g) (Havea, P., Singh, H., Creamer, L. K. & Campanella, 0. H., Electrophoretic characterization of the protein products formed during heat treatment of whey protein concentrate solutions. Journal of Dairy Research, 65, 79 91, 1998) and formation of a gel is disadvantageous to formulation of consumer products. [0075] Whey protein comprises high levels of globular proteins that are sensitive to aggregation in the denatured state. The denaturation temperature of s-lactoglobulin is pH-dependent and at pH 6.7, irreversible denaturation occurs when the protein is heated above 65 0 C. This denaturation is believed to expose a free thiol group, which is reported to initiate inter -protein disulfide bond formation leading to polymerization resulting in aggregate formation. Other disulfide bridges and cysteine residues are thought to play a role in the polymerization reaction. oc-lactalbumin also has a denaturation temperature of about 65 0 C. Denatured P-lactoglobulin and oc-lactalbumin are both sensitive to calcium; this is particularly the case in the pH range of about 5 to about 8 where the protein carries a neutral to net negative charge. At pH outside this range, the protein carries a net positive or negative charge and is less sensitive to aggregation, including calcium-induced aggregation. [0076] WPC is rich in whey proteins, but also contains other components such as fat, lactose, and, in the case of cheese whey-based WPCs, glycomacroprotein (GMP), a casein-related non-globular protein. Typical methods of production of whey protein concentrate utilise membrane filtration. [0077] Accordingly, a WPC is a fraction of whey from which lactose has been at least partially removed to increase the protein content to at least 20% by weight. Particularly contemplated WPI include WPIs and WPCs having at least 90% of the TS of whey protein. [0078] WPI consists primarily of whey proteins with negligible fat and lactose content. Accordingly, the preparation of WPI typically requires a more rigorous separation process such as a combination of microfiltration and ultrafiltration or ion exchange chromatography. It is generally recognised that a WPI refers to a composition in which at least 90 weight % of the solids are whey proteins. 15 [0079] Whey proteins may originate from any mammalian animal species, such as, for instance cows, sheep, goats, horses, buffalo's, and camels. Preferably, the whey protein is bovine. [0080] Exemplary methods for preparing WPCs suitable for use in the present invention are provided in PCT International Applications PCT/NZ2007/000059 (published as WO 2007/108709) and PCT/NZ2010/000072 (published as WO 2010/120199), incorporated by reference herein in their entirety. 3. Compositions [0081] A composition useful herein may be formulated as a food, drink, food additive, drink additive, dietary supplement, nutritional product, dietetic product, medical food, enteral feeding product, parenteral feeding product, meal replacement, nutraceutical, medicament, or pharmaceutical. Appropriate formulations may be prepared by an art skilled worker with regard to that skill and the teaching of this specification. [0082] In one embodiment the composition is acidic. In another embodiment the composition is neutral. In various embodiments the composition is formulated for oral administration. [0083] In various embodiments the composition is any edible consumer product which is able to carry protein. Examples of suitable edible consumer products include liquids, confectionary products including, gels, ice creams, reconstituted fruit products, snack bars, food bars, muesli bars, spreads, sauces, dips, dairy products including yoghurts and cheeses, mayonnaise /salad dressings, drinks including dairy and non-dairy based drinks (such as milk drinks and yogurt drinks), sports supplements including dairy and non-dairy based sports supplements, food additives, and dietary supplement products. [0084] In one embodiment the food is selected from confectionery, a bar, a dairy product, milk, a milk product, a milk powder, reconstituted milk, cultured milk, yoghurt, drinking yoghurt, set yoghurt, a beverage, a food additive, a drink additive, a dietary supplement, a nutritional product, a dietetic product or a medical food. [0085] In one embodiment the composition is in the form of a cachet, a powder, a dispensable powder, granules, a suspension, an elixir, a liquid, or any other form that can be added to food or drink, including for example water, milk or fruit juice. [0086] In one embodiment the composition is formulated as a beverage. In one embodiment the beverage is acidic. In another embodiment the beverage is neutral. In another embodiment the 16 beverage is alkaline. In one embodiment the pH of the composition is from about 1 to about 4.6. Preferably the pH of the composition if from about 2 to about 3.7. In another embodiment the pH of the composition is about 1 to about 14, about 1 to about 5, about 6 to about 8, about 9 to 14, about 1 to about 9 or about 5 to about 9. [0087] In one embodiment the composition is in the form of a medical food, further comprising a source of lipid, a source of carbohydrate, optionally an additional source of protein, and optionally a source of vitamins and minerals. [0088] The lipid used may be vegetable lipid or animal lipid, including dairy lipid and fish oils. Vegetable oils are often exemplary because of their ease of formulation and lower saturated fatty acid content. Exemplary vegetable oils include canola (rapeseed) oil, corn oil, sunflower oil, olive or soybean oil. [0089] The carbohydrate used typically comprises digestible carbohydrate as 75-100% of the carbohydrate. The carbohydrate may comprise monosaccharides, disaccharides, oligosaccharides and polysaccharides and mixtures thereof. Oligosaccharides of glucose are typically used. A number of these are commercially available as maltodextrin (3-20 DE) or corn syrup for the longer chain carbohydrates (>20 DE). Non-digestible carbohydrates may also be included, for example, fructooligosaccharides, inulin, and galactooligosaccharides. These are typically present in amounts of 0.2-5% of the composition. [0090] In exemplary embodiments the liquid nutritional composition is a nutritionally complete composition or a high energy liquid or powder for breakfast or other times of the day. [0091] In exemplary embodiments the liquid nutritional composition contains nutrients that include vitamins and minerals. The recommended daily requirements of vitamins and minerals can be specified for various population subgroups. See for instance, Dietary Reference Intakes: RDA and Al for vitamins and elements, United States National Academy of Sciences, Institute of Medicine, Food and Nutrition Board (2010) tables recommended intakes for infants 0-6 , 6-12 months, children 1-3, and 4-8 years, adults males (6 age classes), females (6 age classes), pregnant (3 age classes) and lactating (3 age classes). Concentrations of essential nutrients in the liquid nutritional composition can be tailored in the exemplary serve size for a particular subgroup or medical condition or application so that the nutrition and ease of delivery requirements can be met simultaneously. [0092] In one embodiment the composition is in the form of pharmaceutical composition comprising an appropriate pharmaceutically acceptable carrier (including excipients, diluents, auxiliaries, 17 and combinations thereof) selected with regard to the intended route of administration and standard pharmaceutical practice. See for example, Remington's Pharmaceutical Sciences, 16th edition, Osol, A. Ed., Mack Publishing Co., 1980. [0093] Accordingly, the invention also is directed to doses, dosage forms, formulations, compositions comprising whey, including those disclosed herein, useful for the therapy of diseases, disorders, and/or conditions in humans and other mammals and other disorders as disclosed herein. The use of these dosage forms or formulations comprising one or more compositions of the invention enables effective treatment of these conditions. The dosage forms, formulations or compositions of the invention may be formulated to optimize bioavailability, or to return or maintain plasma, blood, or tissue concentrations within the normal therapeutic range, including for extended periods. [0094] The dosage forms, formulations or compositions of the invention may be formulated for periodic administration, for example to provide continued exposure to the one or more compositions of the invention. [0095] Examples of dosage forms suitable for oral administration include, but are not limited to tablets, capsules, lozenges, or like forms, or any liquid forms such as syrups, aqueous solutions, emulsions and the like, capable of providing a therapeutically effective amount of whey protein. [0096] Further examples of dosage forms of the invention include, but are not limited to modified release (MR) dosage forms including delayed-release (DR) forms; prolonged-action (PA) forms; controlled-release (CR) forms; extended-release (ER) forms; timed-release (TR) forms; and long-acting (LA) forms. For the most part, these terms are used to describe orally administered dosage forms, however these terms may be applicable to any of the dosage forms, formulations or compositions described herein. These formulations effect delayed total drug release for some time after drug administration, and/or drug release in small aliquots intermittently after administration, and/or drug release slowly at a controlled rate governed by the delivery system, and/or drug release at a constant rate that does not vary, and/or drug release for a significantly longer period than usual formulations. [0097] The compositions useful herein may be used alone or in combination with one or more additional agents. The additional agent may be a food, drink, food additive, drink additive, dietary supplement, nutritional product, dietetic product, medical food, enteral feeding product, parenteral feeding product, meal replacement, nutraceutical, medicament, or pharmaceutical. The additional agent may increase the efficacy at which whey protein is broken down or leucine is delivered to the bloodstream. 18 [0098] When used in combination with an additional agent, the administration of a composition useful herein and the other agent may be simultaneous or sequential. Simultaneous administration includes the administration of a single dosage form that comprises all components or the administration of separate dosage forms at substantially the same time. Sequential administration includes administration according to different schedules, preferably so that there is an overlap in the periods during which the composition useful herein and other therapeutic agent are provided. [0099] Additionally, it is contemplated that a composition in accordance with the invention may be formulated with additional active ingredients which may be of benefit to a subject in particular instances. For example, agents, such as therapeutic agents that target the same or different facets of the condition or disease process or interest may be used. Suitable agents are described above. [00100] In one embodiment the additional active ingredients may include lipids, carbohydrates, other proteins, minerals or vitamins, or flavouring agents. [00101] In one embodiment the composition may additionally comprise a source of amino acids, such as free amino acids, as described above. [00102] In one embodiment the composition may be supplemented with minerals, including, but not limited to chloride, sodium, calcium, iron, chromium, copper, iodine, zinc, magnesium, manganese, molybdenum, phosphorus, potassium, and selenium. Suitable forms of any of the foregoing minerals include soluble mineral salts, slightly soluble mineral salts, insoluble mineral salts, chelated minerals, mineral complexes, non-reactive minerals such as carbonyl minerals, and reduced minerals, and combinations thereof. [00103] The compositions may also optionally comprise vitamins. The vitamins may be fat-soluble or water soluble vitamins. Suitable vitamins include but are not limited to vitamin C, vitamin A, vitamin E, vitamin B12, vitamin K, riboflavin, niacin, vitamin D, vitamin B6, folic acid, pyridoxine, thiamine, pantothenic acid, and biotin. The form of the vitamin may include salts of the vitamin, derivatives of the vitamin, compounds having the same or similar activity of a vitamin, and metabolites of a vitamin. [00104] It should be understood that the additional agents may also be employed in a method according to the invention where they are administered separately, simultaneously or sequentially with a composition useful herein. The proportions of each component in the composition are tailored to optimise the efficacy of the composition for delivering leucine to or increasing muscle mass in a subject in need thereof. 19 [00105] As will be appreciated, the dose of the composition administered, the period of administration, and the general administration regime may differ between subjects depending on such variables as the severity of symptoms of a subject, the type of disorder to be treated, the mode of administration chosen, and the age, sex and/or general health of a subject. However, by way of general example, the inventors contemplate administration of from about 1 mg to about 2500 mg per kg body weight of a denatured whey composition described herein. [00106] It should be appreciated that administration may include a single daily dose or administration of a number of discrete divided doses as may be appropriate. It should be understood that a person of ordinary skill in the art will be able without undue experimentation, having regard to that skill and this disclosure, to determine an effective dosage regime (including daily dose and timing of administration) for a given condition. [00107] Compositions useful according to the invention may be prepared using methods known in the art. 4. Therapeutic outcomes and methods of assessing therapeutic outcomes [00108] Consumption of a composition of the invention by a subject may result in any one or more of the following: a) maintained or increased muscle protein synthesis, b) maintained or increased muscle mass, c) prevention or reduction of loss of muscle mass, d) preventing or decreasing muscle catabolism, e) prevention or treatment of cachexia, f) prevention or treatment of sarcopenia, g) increased rate of glycogen resynthesis, h) modulation of blood sugar levels, i) increased insulin response to raised blood glucose concentration, j) increased satiety, k) reduced food intake, 1) reduced calorie intake, m) improved glucose metabolism, n) increased rate of recovery following surgery, o) increased rate of recovery following injury, p) increased rate of recovery following exercise, or 20 q) increased sports performance. [00109] The method of achieving the above effects comprises the step of administering to a subject in need thereof an effective amount of a whey composition, as described herein, according to methods as described herein. It should be understood that in some embodiments consumption of a composition of the invention by a subject may result in at least maintenance of one of the above effects. For example, maintaining muscle mass, or maintaining the blood serum concentration of leucine. [00110] The efficacy of a composition useful according to the invention can be evaluated both in vitro and in vo. Briefly, in one embodiment a candidate composition can be tested for its ability, to for example, normalise or restore leucine levels or muscle mass. For in vo studies, a composition can be fed to or administered to an animal (e.g., a mouse) and its effects on restoring leucine delivery then assessed. Based on the results, an appropriate dosage range and administration route can be determined. 4.1 Increased delivery of leucine [00111] Assessment of blood serum leucine concentration following a meal is an important factor for assessing the ability of a protein-rich meal to stimulate muscle protein metabolism. Assessment of blood serum leucine following a meal is achieved by taking and assaying baseline blood samples, and serially collecting samples in the post-prandial period (up to 3 hours post prandial). [00112] Blood serum leucine concentration may be assessed according to the methods of the examples below, or as follows. Blood samples are collected in heparinised vacutainers. A 100lpL of whole blood is added to cold perchloric acid, and chilled for 10 minutes to allow the proteins to precipitate. Following centrifugation at 4 0 00 g for 2 minutes, 250 pL of KHC0 3 is added to neutralise the solution. The supernatant is stored -80 0 C until further analysis. Analysis of amino acids is achieved by high performance liquid chromatography (HPLC) complete with suitable standards. 4.2 Increased and decreased muscle protein synthesis [00113] Muscle protein synthesis is assessed by the changes in protein balance within a muscle. Various methods are available to assess changes in protein balance. Typically, methods involve measuring the fractional rate of muscle protein synthesis within a set time period (i.e. 2-3 hours post prandially). Briefly, participants have a baseline muscle biopsy taken from the vastus lateralis using standard protocols, and the muscle sample is blotted dry, visible fat and connective tissue is removed and the sample frozen in liquid nitrogen and stored at -80 0 C until further analysis. [00114] After refraining from any strenuous physical activity for three days, subjects have a catheter inserted into their antecubital vein for blood sampling. Following baseline blood samples, a second 21 catheter is inserted into their collateral arm for administration of a primed, constant, infusion of L-[ring 3 C]phenylalanine. Three hours following the start of the infusion, the subject undergoes a muscle biopsy from the collateral limb (from baseline measure) to measure the fasting rates of protein synthesis. Blood samples are drawn, and the subjects consume a protein beverage (enriched with 6% of the L [ring- 3 C]phenylalanine, to minimize disturbances in the isotopic equilibrium) to stimulate muscle protein synthesis in the post prandial period. Three hours after administration of the protein product, a final muscle biopsy is taken to assess the protein synthesis response that has occurred in the post prandial period. [0100] Analysis of samples occurs by isolating intracellular proteins from a piece of wet muscle. The sample is spun for 10 minutes to separate myofibrillar and collagen proteins. Removal of the sarcoplasmic proteins is achieved by precipitation with perchloric acid. The myofibrillar proteins are solubilised by adding NaOH and mixing every 10 minutes. Centrifugation at 4 00 0 g creates a supernatant containing the myofibrillar proteins, which is precipitated out using perchloric acid, washed and lyophilised. The amino acids are liberated using HCl and the sample is heated at 110 'C for 24 hours. Free amino acids are purified using cation exchange chromatography, and converted to their N Acetyl-n-propyl ester derivatives for analysis by gas chromatography combustion-isolate ratio mass spectrometry. [0101] The fractional synthetic rate is calculated using the formulae: [0102] FSR (% h-1) - Ep/Em X 1/t x 100 [0103] Where 'Ep' is the change in bound protein enrichment between the two biopsy samples, 'Em' is the average enrichment of the intracellular phenylalanine across the two samples and 'T is the time between the biopsies. 4.3 Reduction of loss of muscle mass [0104] Changes in muscle mass are assessed by utilising repeated measures of body composition with a suitable multi-compartment body composition analysis technique, such as Dual Energy X-ray Absorpitrometry, or a multi compartment model derived from hydrodensitometry or total body density. [0105] Various aspects of the invention will now be illustrated in non-limiting ways by reference to the following examples. EXAMPLES [0106] A description of each of the ingredients used in Example 1 is provided below. 22 [0107] Native whey protein concentrate (about 80% protein by dry weight, Fonterra Co-operative Group Limited, New Zealand). This is produced by ultrafiltration and diafiltration of cheese whey (see Fox & McSweeney, 2003). This powder is characterised in Table 1. [0108] The denatured whey protein powder used in the following examples is characterised in Table 1. This powder is produced according to the method described previously in PCT/NZ2010/000072 (published as WO 2010/120199). [0109] Table 1: Whey protein powders Protein Residual Denatured Primary Aggregate Name Content' Denaturable protein % Aggregate Size after Description Protein Size 3 Heating 4 Fonterra commercial Native 80.3 61 0-4 Gel WPC made by WPC ultrafiltration of cheese whey Powder produced Powder according to A 79.1 15 75 1.70 1.72 PCT/NZ2010/00007 2; published as W02010/120199 I % (TN x 6.38) 2 % Total/TN x6.38 3 of a 10%TS Solution D[4,3], pm 4 10% TS Solution D[4,3], pm Example 1: Comparison of various protein ingredients for delivering leucine to the bloodstream. [0110] Each of the protein ingredients were prepared as described above. [0111] Fifteen subjects aged 18-49 were selected to participate in the trial. Exclusion criteria for the trial included a regular use of protein supplements, a BMI of greater than 30kg/m 2 , a history of diabetes mellitus - Type I or II, or heart disease, chronic disease of the gastrointestinal tract (for example, inflammatory bowel disease), previous gastrointestinal surgery, pregnancy, allergies to any dietary protein (such as dairy or soy), serious co-morbidity that could, in the opinion of the investigator, prevent the subject from successfully completing the trial, and participation in any clinical trial within the last three months. [0112] An intravenous line was administered into each subject and a baseline blood sample obtained. The subjects were fasted for 10 hours prior to consuming a 250 ml solution comprising one of the whey protein ingredients, balanced for leucine content at 2.5 g leucine per 250 ml of solution by 23 adjusting the amount of the protein ingredients added. Consumption of the ingredient was restricted to a 5 minute period. [0113] Following consumption, additional blood samples were obtained at 15, 30, 45, 60, 90, 120 and 180 minute time points. [0114] The plasma was separated and stored at -80'C until analysis. Plasma samples were deproteinised through 100kD filters, and an aliquot of the deproteinised sample transferred into a small tube and vacuum dried. The dried sample was derivatised with Phenyllisothiocyanate (PITC), re-dried under vacuum and reconstituted in a dissolution buffer. [0115] Leucine concentration was measured using reverse phase liquid chromatography with detection at 254nm. [0116] The results depicted in Figure 1 show that levels of leucine in subjects who were administered the denatured whey protein concentrate (Denatured powder A) were comparable to those achieved in subjects who consumed the standard whey protein concentrate (native WPC). The maximum concentration of plasma leucine was achieved 45 minutes after consumption of both the denatured and native whey protein concentrates. [0117] This example shows that the denatured whey protein composition of the invention increases the plasma leucine concentration of a subject to substantially the same level as that achieved with a native whey protein composition. Example 2: The efficacy of whey compositions for delivering leucine to the bloodstream and for increasing muscle mass This example describes a randomised clinical trial for assessing the efficacy of whey compositions for delivering leucine to a subject. The efficacy of the composition for increasing muscle mass in a subject will also be described. [0118] Participants for the trial will be selected according to the inclusion and exclusion criteria detailed in Example 1. All participants will be randomly placed into groups and fed a single dose of a treatment composition. [0119] Treatment compositions may include denatured whey compositions with native whey or milk protein concentrates as positive controls. 24 [0120] The primary outcome of the trial will be to assess plasma leucine concentration following consumption of the various protein compositions. Secondary outcomes include assessment of isoleucine and valine plasma concentrations, gastric emptying rate (measured with ultrasonography) and acute gastrointestinal affects following consumption of the protein compositions. Serum amino acid concentrations will be determined by the method of Bloomfield, F.H. et al, (Effects of Intrauterine Growth Restriction and Intraamniotic Insulin-like Growth Factor-I Treatment on Blood and Amniotic Fluid Concentrations and on Fetal Gut Uptake of Amino Acids in Late-Gestation Ovine Fetuses, J. Ped. Gast. Nutr. (2002) 35:287-297), incorporated herein by reference. [0121] Data will show increased plasma leucine concentration and improved gastric emptying in subjects fed the test compositions. The plasma leucine concentrations achieved are comparable to the positive control and better than the negative control compositions. INDUSTRIAL APPLICABILITY [0122] The denatured whey compositions described herein may be used for increasing the blood serum concentration of free leucine in a subject, preferably to substantially the same level as native whey compositions. The increased blood serum leucine concentration results in any one or more of maintained or increased muscle protein synthesis, maintained or increased muscle mass, prevention or reduction of loss of muscle mass, preventing or decreasing muscle catabolism, prevention or treatment of cachexia, prevention or treatment of sarcopenia, increased rate of glycogen resynthesis, modulation of blood sugar levels, increased insulin response, increased satiety, reduced food intake, reduced calorie intake, improved glucose metabolism, increased rate of recovery following surgery, increased rate of recovery following injury, increased rate of recovery following exercise, or increased sports performance. [0123] Those persons skilled in the art will understand that the above description is provided by way of illustration only and that the invention is not limited thereto. 25

Claims (5)

1. A denatured whey protein composition for increasing the blood serum concentration of free leucine in a subject, wherein the denatured whey protein composition increases the blood serum concentration of free leucine in a subject within about 15, 30, 45 or 60 minutes of administration.

2. The composition as claimed in claim 1 wherein the denatured whey protein composition is able to increase the concentration of free leucine in blood serum to at least about 205, 210, 215, 220, 225, 230, 235, 240, 245, 250 or 255 vmol/L.

3. The composition as claimed in claim 1 or claim 2 wherein the denatured whey protein composition is able to increase the concentration of free leucine in blood serum to at least about 205 vmol/L for at least about 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 minutes.

4. The composition of any one of the preceding claims wherein the denatured whey protein composition is able to increase the concentration of free leucine in blood serum by at least about 205% for at least about 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50 minutes following administration.

5. The composition of any one of the preceding claims wherein the denatured whey protein composition is or comprises a whey protein concentrate (WPC) or whey protein isolate (WPI) prepared by a method comprising providing an aqueous WPC or WPI solution having a protein concentration of 15-50% (w/v), at a pH of 4.7-8.5; heat treating the solution to more than 70'C, for a time that allows protein denaturation to occur; the heat treating comprising heating the solution while under conditions of turbulent flow; and recovering the heat treated WPC or WPI, or directly transferring the heat treated WPC or WPI either to a drier to be dried or to a mixer to be mixed with other ingredients, wherein the transferred heat-treated WPC or WPI is not subjected to (a) a mechanical shear process prior to drying other than where liquid is converted into droplets to facilitate drying, or (b) particle size reduction prior to drying or mixing, or (c) both (a) and (b).