EP4326091A1

EP4326091A1 - High protein liquid nutritional compositions

Info

Publication number: EP4326091A1
Application number: EP22720235.5A
Authority: EP
Inventors: Necla Mine EREN; Rachel BLUMBERG; Kelley LOWE; Stephen Pearson
Original assignee: Abbott Laboratories
Current assignee: Abbott Laboratories
Priority date: 2021-04-19
Filing date: 2022-04-13
Publication date: 2024-02-28
Also published as: WO2022225770A1

Abstract

Liquid nutritional compositions comprise at least about 125 mg/ml of a protein system comprising, based on the weight of the protein system, less than 40 wt % micellar casein, greater than 15 wt % non-micellar casein, whey protein, whey protein hydrolysate, and partially hydrolyzed collagen. The liquid nutritional compositions further comprise at least about 5 mg/ml of β-hydroxy β-methylbutyrate (HMB), fat, and carbohydrate. The liquid nutritional compositions have a zero shear rate viscosity greater than 100 cp, an infinite shear rate viscosity of less than 200 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of greater than about 1.5.

Description

HIGH PROTEIN LIQUID NUTRITIONAL COMPOSITIONS

FIELD OF THE INVENTION

[0001] The present invention relates to liquid nutritional compositions which contain a high protein content. The liquid nutritional compositions have a novel protein system and exhibit stability to withstand sterilization temperatures, a desirable viscosity profile, and desirable sensory attributes.

BACKGROUND OF THE INVENTION

[0002] Muscle is the most abundant tissue in the body. The mass and functionality of muscle are key determinants of strength, endurance and physical performance throughout a lifespan. Muscle is a plastic tissue that shows variations in muscle mass and muscle fiber size according to physiological and pathological conditions. Muscle mass is maintained by a delicate balance between protein synthesis and protein degradation. The muscle is a highly adaptive tissue that responds rapidly to anabolic stimuli, such as physical activity or food intake. Conversely, prolonged fasting, immobilization, and malnutrition are known to cause rapid muscle loss. Muscle atrophy occurs when protein degradation rates exceed protein synthesis. This phenomenon happens in a wide variety of conditions and, most commonly, upon aging.

[0003] From the age of 35-40 years in adult humans, muscle mass typically starts to decline progressively by 0.4-1.0% per year. The age-related loss of muscle mass and strength in otherwise healthy, aging individuals is referred to as sarcopenia. The resulting decline in muscle mass and strength may increase the risk of developing metabolic diseases and/or physical disabilities and can result in the inability to maintain daily functioning. There is a general consensus among the scientific community that muscle atrophy is associated with a variety of undesirable outcomes, including delayed recovery from illness, poorer quality of life, physical disability, reduced resting metabolic rate, decreased insulin sensitivity, slowed wound healing, and higher health care costs. [0004] Muscle tissue responds to anabolic stimuli, i.e., dietary protein intake and physical activity, for protein synthesis. Nevertheless, for subjects encountering injury, illness, and/or aging, implementation of sufficient physical activity for protein synthesis to maintain or increase muscle mass is not always possible, convenient, an/or sufficient for protein synthesis to exceed protein degradation. Therefore, it is often desirable to employ nutritional intervention strategies which provide higher protein intake in order to resist or reduce the loss of muscle mass and strength and/or to promote muscle regeneration. Liquid nutritional compositions which contain protein and may be used as meal substitutes and/or meal supplements provide a convenient means for increasing protein intake in order to resist or reduce the loss of muscle mass and strength and/or to promote muscle regeneration. However, as a practical matter, there is a limit to the amount of protein which may be included in such liquid nutritional compositions as higher protein contents typically result in compositions which are not sufficiently stable to heat treatments for sterilization employed during manufacturing, compositions which exhibit unacceptably high viscosity, and can result in fouling of processing equipment and/or an excessively thick liquid product which is undesirable for oral consumption, and/or compositions which do not exhibit sensory attributes necessary for good consumer acceptance.

[0005] Beta-hydroxy-beta-methylbutyrate (HMB) has been disclosed as useful in building or maintaining muscle mass and strength in selected individuals and has been employed in both liquid and powdered nutritional compositions. However, HMB, typically added as the calcium salt, calcium HMB monohydrate, has a tendency to complex with proteins and/or minerals to cause undesirable gelation and/or particle sedimentation in liquid nutritional compositions. This tendency can be accelerated when the liquid composition contains relatively high levels of protein, especially when the composition is subjected to thermal treatment in the form of pasteurization and/or sterilization.

[0006] Accordingly, a need exists for improved liquid nutritional compositions having high protein content and exhibiting an advantageous combination of properties which provide stability to withstand heat sterilization, a desirable viscosity profile, and desirable sensory attributes. Such a need also exists for liquid nutritional compositions which are not cost prohibitive for regular, such as daily, use by consumers.

SUMMARY OF THE INVENTION

[0007] It is therefore an object of the invention to provide liquid nutritional compositions having high protein content and exhibiting an advantageous combination of properties which provide heat stability and desirable sensory attributes.

[0008] In one embodiment, the invention is directed to a liquid nutritional composition which comprises at least about 125 mg/ml of a protein system comprising, based on the weight of the protein system, less than 40 wt % micellar casein, greater than 15 wt % non-micellar casein, whey protein, whey protein hydrolysate, and partially hydrolyzed collagen. The liquid nutritional composition further comprises at least about 5 mg/ml of b-hydroxy b-methylbutyrate (HMB), fat, and carbohydrate. The nutritional composition has a zero shear rate viscosity greater than 100 cp, an infinite shear rate viscosity of less than 200 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of greater than about 1.5.

[0009] The inventive liquid nutritional compositions are advantageous in providing a high source of protein in a product exhibiting heat treatment stability, acceptable viscosity, and desirable sensory attributes. These and additional advantages will be more fully apparent in view of the detailed description herein.

BRIEF DESCRIPTION OF THE DRAWING

[00010] The drawing may facilitate understanding of certain aspects or embodiments of the invention, wherein

[00011] Fig. 1 shows a non-Newtonian model of viscosity as a function of shear rate in an exemplary composition according to the invention. DETAILED DESCRIPTION

[00012] While the general inventive concepts are susceptible of embodiment in many different forms, described herein in detail are specific embodiments of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the general inventive concepts. Accordingly, the general inventive concepts are not intended to be limited to the specific embodiments illustrated and described herein.

[00013] The invention is directed to liquid nutritional compositions. The term “liquid nutritional composition” as used herein encompasses all forms of liquid nutritional compositions, including emulsified liquids, and ready-to-drink liquids. The liquid nutritional compositions are suitable for oral consumption (i.e. , by mouth) or gastric consumption (i.e. , via a feeding tube) by a human. In a specific embodiment, the liquid nutritional compositions are ready-to-drink liquids intended for oral consumption by a human. In another specific embodiment, the liquid nutritional compositions are ready to use liquids for administration via a feeding tube.

[00014] All percentages, parts and ratios as used herein, are by weight of the total composition, unless otherwise specified. All such weights as they pertain to listed ingredients are based on the active level and, therefore, do not include solvents or byproducts that may be included in commercially available materials, unless otherwise specified.

[00015] The terminology as set forth herein is for description of the embodiments only and should not be construed as limiting the disclosure as a whole. Unless otherwise specified, “a,” “an,” “the,” and “at least one” are used interchangeably. Furthermore, as used in the description and the appended claims, the singular forms “a,” “an,” and “the” are inclusive of their plural forms, unless the context clearly indicates otherwise.

[00016] Throughout this specification, when a range of values is defined with respect to a particular characteristic of the present invention, the present invention relates to and explicitly incorporates every specific subrange therein. Additionally, throughout this specification, when a group of substances is defined with respect to a particular characteristic of the present invention, the present invention relates to and explicitly incorporates every specific subgroup therein. Any specified range or group is to be understood as a shorthand way of referring to every member of a range or group individually as well as every possible subrange or subgroup encompassed therein.

[00017] The various embodiments of the liquid nutritional compositions of the present disclosure may also be substantially free of any optional or selected ingredient or feature described herein, provided that the remaining liquid nutritional composition still contains all of the required ingredients or features as described herein. In this context, and unless otherwise specified, the term “substantially free” means that the selected nutritional composition contains less than a functional amount of the optional ingredient, typically less than 1%, including less than 0.5%, including less than 0.1%, and also including zero percent, by weight, of such optional or selected essential ingredient.

[00018] The liquid nutritional compositions described herein may comprise, consist of, or consist essentially of the essential steps and elements, respectively, as described herein, as well as any additional or optional steps and elements, respectively, described herein.

[00019] Unless otherwise indicated herein, all exemplary embodiments, sub-embodiments, specific embodiments and optional embodiments are respective exemplary embodiments, sub embodiments, specific embodiments and optional embodiments to all embodiments described herein.

[00020] The liquid nutritional compositions of the present invention employ a novel protein system comprising a combination of protein components which allow the compositions to have a high protein content while avoiding the disadvantages often encountered in conventional high protein liquid nutritional compositions. More specifically, the protein system comprises, based on the weight of the protein system, less than 40 wt % micellar casein, greater than 15 wt % non-micellar casein, whey protein, whey protein hydrolysate, and partially hydrolyzed collagen.

In more specific embodiments, the protein system comprises from about 30 wt % to less than 40 wt % micellar casein, from about 15 wt % to about 35 wt % non-micellar casein, from about 10 wt % to about 20 wt % whey protein, from about 10 wt % to about 20 wt % whey protein hydrolysate, and from about 10 wt % to about 20 wt % partially hydrolyzed collagen. In a more specific embodiment, the protein system comprises from about 35 wt % to less than 40 wt % micellar casein, from about 15 wt % to about 25 wt % non-micellar casein, from about 10 wt % to about 20 wt % whey protein, from about 10 wt % to about 20 wt % whey protein hydrolysate, and from about 10 wt % to about 20 wt % partially hydrolyzed collagen. In another more specific embodiment, the protein system comprises from about 30 wt % to about 35 wt % micellar casein, from about 20 wt % to about 30 wt % non-micellar casein, from about 10 wt % to about 20 wt % whey protein, from about 10 wt % to about 20 wt % whey protein hydrolysate, and from about 10 wt % to about 20 wt % partially hydrolyzed collagen.

[00021] Casein is the major protein in cow’s milk and contains all 20 of the essential and nonessential amino acids necessary for synthesizing body proteins, including those that make up muscle tissue. Micellar casein comprises colloidal particles that allow the casein protein and its associated calcium-phosphate complexes to be soluble in the liquid phase. However, availability and sustainability of micellar casein as a major protein component may be limited. Additionally, because micellar casein contains a relatively high inherent calcium content, the amount of micellar casein added to compositions also containing calcium HMB is limited to avoid excessive calcium content which, as noted above, can cause instability, gelation and/or sedimentation in liquid compositions. Therefore the amount of micellar casein in the nutritional compositions is desirably limited to less than 40 wt % of the protein system. Non-micellar casein, for example caseinates such as sodium caseinate and calcium caseinate, are less expensive sources of casein that can be employed to provide the non-micellar casein in the protein system.

[00022] Micellar casein and non-micellar casein may be added to the compositions as individual ingredients. Alternatively, milk protein concentrate is a source of both micellar casein and non-micellar casein and may be used as a source for both in the liquid nutritional compositions of the invention. Partially hydrolyzed milk protein is also a source of micellar casein and can be suitably employed in the liquid nutritional compositions of the invention. Both milk protein concentrate and partially hydrolyzed milk protein typically also include whey protein, and the partially hydrolyzed milk protein typically includes hydrolyzed whey protein (whey protein hydrolysate). In another specific embodiment, the whey protein hydrolysate has a degree of hydrolysis of from about 5 to about 30, or more specifically, from about 10 to about 30. The relative amounts of the required proteins, i.e., micellar casein, non-micellar casein, whey protein, and hydrolyzed whey protein, in these ingredients can be used to determine the amounts of milk protein concentrate and/or partially hydrolyzed milk protein to include in the liquid nutritional compositions.

[00023] If necessary, based on the relative amounts of the required proteins in milk protein concentrate and/or partially hydrolyzed milk protein, additional whey protein and/or whey protein hydrolysate may also be included as an ingredient in the liquid nutritional compositions. In another specific embodiment, separate whey protein, i.e., other than that contained in an ingredient such as milk protein concentrate, is not added to the nutritional compositions.

[00024] The partially hydrolyzed collagen may comprise bovine, porcine or other collagen source and may be derived from hide, skin, bone, or other collagen-containing material. In a specific embodiment, the partially hydrolyzed collagen comprises bovine or porcine collagen. In additional embodiments, the hydrolyzed collagen has a degree of hydrolysis of from about 5 to about 30, or more specifically, from about 10 to about 30. In additional specific embodiments, the collagen has a median molecular weight in a range of from about 600 to about 4000 Da. [00025] In a specific embodiment, the protein system of the liquid nutritional compositions of the invention is formed from milk protein concentrate, partially hydrolyzed milk protein, partially hydrolyzed whey protein, and partially hydrolyzed collagen. [00026] The protein systems allow incorporation of a high level of protein in the nutritional compositions having a desirable viscosity profile, good stability to withstand sterilization temperatures, and desirable sensory attributes such as palatability, mouth feel, taste, and/or aroma, without the expense of a higher micellar content system. The hydrolyzed proteins contribute to the desirable viscosity profile, avoiding unacceptably high viscosity that interferes with manufacturing, heat stability and/or consumption of the compositions. Diversification of the hydrolyzed proteins (whey and collagen) in the protein system is advantageous in preventing unacceptable bitterness and maintaining a high-quality protein blend which has a protein digestibility corrected amino acid score (PDCAAS) of greater than 100 %. PDCAAS can be calculated from the amino acid content according to the 1991 Food and Agriculture Organization (FAO)/World Health Organization (WHO) preschool child guidance, the 2007 FAO/WHO/ United Nations University (UNU) 1-2 yr guidance, or the 2007 FAO/WHO/UNU adult guidance, summarized as follows:

Amino Acid 1991 FAO/WHO 2007 FAO/WHO/UNU 2007 FAO/WHO/UNU preschool child 1-2 yr Adult lsoleucine^A* 28 31 30

Leucine^A* 66 63 59

Lysine* 58 52 45

Methionine*+

Cystine

Methionine*† + Cysteine† 25 26 22

Phenylalanine*'

Tyrosine

Phenylalanine*' + Tyrosine' 63 46 38

Tryptophan 11 7.4 6

Threonine* 34 27 23

Valine^A* 35 42 39

Histidine*' 19 18 15

Branched chain amino acids

Arginine

Glutamine

Aspartic Acid

Proline

^ABranched Chain Amino Acid, ‘Essential amino acid, +Sulfur amino acids, 'Aromatic amino acids Glutamine is measured as glutamine+glutamic acid. Cysteine is calculated from cystine by multiplying with factor of 1 .008. [00027] In specific embodiments, the protein systems of the invention exhibit scores of greater than 100% according to each of these PDCAAS. In more specific embodiments, the protein systems of the invention exhibit scores of greater than 110% according to each of these PDCAAS. Using only hydrolyzed whey to achieve a low viscosity profile yields compositions with bitter taste, while using only hydrolyzed collagen to achieve a low viscosity profile yields a low quality protein blend having a PDCAAS of less than 100. While not intending to be limited by theory, it is believed that the components of the protein system exhibit an optimized thermodynamic compatibility and, optionally along with minerals and stabilizer, drive polymer chain dynamics to yield a palatable, structured fluid with a relatively higher zero shear rate viscosity and a lower infinite rate viscosity, even after heat treatment. The proteins are not so thermodynamically compatible so as to exhibit gelation (for example, as the result of strong interactions among components that are capable of spanning a 3-D structure that entraps water), but at the same time are not so thermodynamically incompatible so as to result in phase separation.

[00028] The liquid nutritional compositions exhibit a unique rheological behavior as defined by the viscosity profile that provides significant advantages. The higher zero shear rate viscosity is advantageous to suspend insoluble nutrients, including those formed by HMB and/or minerals, and to prevent physical stability defects like sediment and/or phase separation. The lower infinite rate viscosity is advantageous during processing and consumption. For example, transport of the composition through processing equipment renders a lower viscosity composition which enables heating and mass transport through pipes and heat exchangers. Further, prior to consumption, mild shaking of the composition renders a lower composition viscosity providing good palatability and mouth feel, resulting in good consumer acceptance. [00029] Specifically, the liquid nutritional compositions have a zero shear rate viscosity greater than 100 cp, an infinite shear rate viscosity of less than 200 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of greater than about 1.5. In a more specific embodiment, the liquid nutritional compositions have a zero shear rate viscosity of from 101 to about 850 cp, an infinite shear rate viscosity of from about 10 to about 150 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of from about 1.55 to about 20. In more specific embodiments, the liquid nutritional compositions have a zero shear rate viscosity of from 101 to about 600 cp, an infinite shear rate viscosity of from about 25 to about 130 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of from about 1.55 to about 10. In yet more specific embodiments, the liquid nutritional compositions have a zero shear rate viscosity of from 101 to about 500 cp, an infinite shear rate viscosity of from about 10 to about 135 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of from about 1.55 to about 5. Viscosity is measured with a rotational rheometer (ARES G2, TA Instrument) equipped with temperature control (advanced peltier system), at 20°C or 25°C, using a recessed concentric cylinder (bob and cup) geometry. In such measurements, shear rate is ramped from 0.5 to 500 sec^-1 logarithmically by collecting at least 5 points per decade with steady state sensing. Theory of shear rheometry is described, inter alia, by Macosko, Rheology: Principles , Measurements and Applications, Wiley-VCH (1994).

[00030] The rheological behavior of the liquid nutritional compositions of the invention may be described with advanced non-Newtonian models such as Cross or Carreau-Yasuda. Fig. 1 shows a representative curve for a non-Newtonian fluid and Cross model parameters. In a specific embodiment, Trios software is used for non-Newtonian model fitting (non-linear least squares regression) according to the model equation:

(n-n-)/(n -no)=1/ (1+(k*Y)ⁿ) wherein h is viscosity as a function of shear rate (Pa s), h is zero shear (rate) viscosity (Newtonian viscosity) (Pas), ho is infinite (rate) viscosity (Pas), k is consistency (characteristic time) (sec), g is shear rate (sec-1), and n is rate index.

[00031] The protein system may therefore be included in the liquid nutritional compositions in an amount to provide a high protein content product. More specifically, the liquid nutritional compositions comprise at least about 125 mg/ml of the defined protein system. In specific embodiments, the liquid nutritional compositions comprise at least about 135 mg/ml, or at least about 145 mg/ml, of the defined protein system. The high protein content is advantageous in proving a protein-based caloric density. In specific embodiments, the liquid nutritional compositions have a caloric density of at least about 2.0 kcal/ml, or at least about 2.2 kcal/ml, or at least about 2.4 kcal/ml.

[00032] The liquid nutritional compositions also comprise HMB. As noted above, HMB refers to beta-hydroxy-beta-methylbutyrate (also referred to as beta-hydroxyl-3-methyl butyric acid, beta-hydroxy isovaleric acid). All weights, percentages, and concentrations as used herein to characterize HMB are based on the weight of HMB, regardless of the source, unless otherwise specified. Any source of HMB is suitable for use in the liquid nutritional compositions of the invention. Examples include HMB as the free acid, a salt, including an anhydrous salt, an ester, a lactone, or other product forms that otherwise provide a bioavailable form of HMB. In specific embodiments of the liquid nutritional compositions of the invention, the source of HMB is selected from the group consisting of alkali metal HMB, alkaline earth metal HMB, HMB free acid, HMB lactone and combinations of two or more thereof, or the HMB is selected from the group consisting of sodium HMB, potassium HMB, magnesium HMB, chromium HMB, calcium HMB and combinations of two or more thereof. In a specific embodiment, the HMB source is calcium HMB monohydrate. The liquid nutritional compositions comprise at least about 5 mg/ml, or, more specifically, comprise about 5 mg/ml to about 15 mg/ml HMB.

[00033] The liquid nutritional compositions also comprise fat and carbohydrate. While the fat and carbohydrate may result solely from the protein sources employed in the compositions, in specific embodiments, the liquid nutritional compositions comprise additional sources of fat and carbohydrate. The term “fat” as used herein, unless otherwise specified, refers to lipids, fats, oils, and combinations thereof. In specific embodiments of the liquid nutritional compositions of the invention, the fat comprises algal oil, canola oil, flaxseed oil, borage oil, safflower oil, high oleic safflower oil, high gamma-linolenic acid (GLA) safflower oil, corn oil, soy oil, sunflower oil, high oleic sunflower oil, cottonseed oil, coconut oil, fractionated coconut oil, medium chain triglycerides (MCT) oil, palm oil, palm kernel oil, palm olein, long chain polyunsaturated fatty acid, or combinations of two or more thereof. In a more specific embodiment, the fat comprises corn oil, canola oil, sunflower oil, or a combination of two or more thereof. The amount of an additional source of fat in the nutritional compositions can vary considerably depending upon, for example, the specific dietary needs of the intended user. In specific embodiments, the nutritional compositions comprise from 0.5 wt% to 20 wt%, about 0.5 to about 15 wt%, about 0.5 to about 10 wt%, about 0.5 to about 5 wt%, or about 5 to about 15 wt% fat, based on the weight of the nutritional composition.

[00034] In specific embodiments of the liquid nutritional compositions of the invention, the carbohydrate may be any one or more sources of carbohydrate known for use in nutritional compositions. In specific embodiments, the carbohydrate comprises maltodextrin, hydrolyzed starch, modified starch, hydrolyzed cornstarch, modified cornstarch, polydextrose, dextrins, corn syrup, corn syrup solids, rice maltodextrin, brown rice mild powder, brown rice syrup, sucrose, glucose, fructose, lactose, high fructose corn syrup, honey, sugar alcohol such as maltitol, erythritol, or sorbitol, isomaltulose, sucromalt, pullulan, potato starch, corn starch, fructooligosaccharides, galactooligosaccharides, oat fiber, soy fiber, gum arabic, sodium carboxymethylcellulose, methylcellulose, guar gum, gellan gum, locust bean gum, konjac flour, hydroxypropyl methylcellulose, tragacanth gum, karaya gum, gum acacia, chitosan, arabinoglactins, glucomannan, xanthan gum, alginate, pectin, low methoxy pectin, high methoxy pectin, cereal beta-glucans, carrageenan, psyllium, fiber, fruit puree, vegetable puree, isomalto- oligosaccharides, monosaccharides, disaccharides, tapioca-derived carbohydrates, inulin, and artificial sweetener, or combinations of two or more thereof. In a more specific embodiment, the carbohydrate comprises sucrose, corn syrup, maltodextrin, glucose, lactose, honey, sugar alcohol, isomaltulose, sucromalt, galactooligosaccharide, fructooligosaccharide, or a combination of two or more thereof. The amount of carbohydrate in the nutritional compositions can vary considerably depending upon, for example, the specific dietary needs of the intended user. In specific embodiments, the nutritional compositions comprise about 5 wt% to about 65 wt%, about 5 wt% to about 50 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 30 wt%, about 5 wt% to about 25 wt%, about 10 wt% to about 65 wt%, about 10 wt% to about 50 wt%, about 10 wt% to about 40 wt%, or about 10 wt% to about 30 wt% carbohydrate, based on the weight of the nutritional composition.

[00035] In further embodiments, the liquid nutritional compositions comprise minerals, or, more specifically, divalent metals comprising calcium and magnesium. The liquid nutritional compositions advantageously contain calcium to build and maintain strong bones and teeth, and magnesium to support energy creation, protein formation, gene maintenance, creation and repair of DNA and RNA, the contraction and relaxation of muscles, and nervous system regulation. A suitable source of calcium comprises HMB when the HMB is provided in the form of a calcium salt such as calcium HMB monohydrate, although other sources of calcium may also be employed. Suitable sources of magnesium include, but are not limited to, at least one of magnesium hydroxide, magnesium phosphate, magnesium carbonate, and magnesium chloride. In more specific embodiments, the liquid nutritional compositions comprise from about 0.1 to about 0.5 wt %, or from about 0.2 to about 0.4 wt %, divalent metals comprising calcium and magnesium.

[00036] As both calcium and magnesium have a tendency to compromise the composition stability, the liquid nutritional compositions, in specific embodiments, further comprise a chelation system to chelate with soluble calcium and magnesium. In a specific embodiment, the chelation system comprises citrate, for example, potassium citrate, and phosphate, for example, at least one of disodium phosphate dihydrate and potassium phosphate. In more specific embodiments, the liquid nutritional compositions comprise from about 0.2 to about 0.7 wt %, or from about 0.3 to about 0.6 wt %, of a chelation system comprising citrate and phosphate. In additional embodiments, the weight ratio of citrate and phosphate to calcium and magnesium is from about 1 : 1 to about 3: 1 , or from about 1 : 1 to about 2: 1. The chelation of calcium and magnesium reduces the tendency of these divalent metals to interfere with the stability of the compositions. Additionally, the structured rheology of the compositions, including the higher zero shear rate viscosity, allows the chelates to remain suspended in the compositions and resist sedimentation.

[00037] In further embodiments, the liquid nutritional compositions comprise one or more stabilizers to assist in maintaining the desired structured rheology of the compositions. Suitable stabilizers include but are not limited to microcrystalline cellulose, carboxymethyl cellulose and/or gellan gum. In a specific embodiment, the liquid nutritional compositions comprise a stabilizer comprising microcrystalline cellulose and sodium carboxymethyl cellulose. In a more specific embodiment, the liquid nutritional compositions comprise from about 0.05 to about 0.2 wt % of a stabilizer comprising microcrystalline cellulose and sodium carboxymethyl cellulose. [00038] The liquid nutritional compositions may further comprise one or more additional components that may modify the physical, chemical, aesthetic, or processing characteristics of the nutritional composition, without departing from the described rheological characteristics of the compositions, or that serve as additional nutritional components. Non-limiting examples of additional components include preservatives, emulsifying agents (e.g., lecithin), buffers, sweeteners, including artificial sweeteners (e.g., saccharine, aspartame, acesulfame K, sucralose), colorants, flavorants, thickening agents, probiotics, and so forth.

[00039] Additionally, the liquid nutritional compositions may further include vitamins or related nutrients, non-limiting examples of which include vitamin A, vitamin B12, vitamin C, vitamin D, vitamin K, thiamine, riboflavin, pyridoxine, niacin, folic acid, pantothenic acid, biotin, choline, inositol, salts and derivatives thereof, and combinations thereof. Water soluble vitamins may be added in the form of a water-soluble vitamin (WSV) premix and/or oil-soluble vitamins may be added in one or more oil carriers as desired. [00040] In additional embodiments, the liquid nutritional compositions may further include one or more additional minerals, non-limiting examples of which include phosphorus, zinc, manganese, sodium, potassium, molybdenum, chromium, chloride, and combinations thereof, for example, as citrates, phosphates, carbonates, sulfates, chlorides, or the like, or in other forms as known in the art.

[00041] The components of the liquid nutritional compositions may be combined in any desired manner. In a specific embodiment of one suitable manufacturing process, the nutritional composition may be formed by combining an aqueous protein-in-water (PIW) slurry with a protein-in-fat (PIF) slurry and a carbohydrate-mineral (CHO-MN) slurry. The slurries are blended together with heat and agitation, for example by an emulsifier and/or homogenizer.

[00042] The liquid nutritional compositions are subjected to a heat treatment which provides sterilization sufficient to maintain microbiological stability of the liquid nutritional compositions over a desired shelf-life. In a specific embodiment, the heat treatment should provide sufficient sterilization to the composition in order to maintain microbiological stability of the liquid nutritional composition over a shelf-life of at least about 9 months. The specific heating conditions are not critical and various heating processes known in the art may be employed. In a specific embodiment, the heating temperature and time are sufficient to achieve a F₀ (lethality, the time necessary to achieve a minimum of a 12 log reduction in the microbial population of C. botulinum at 121.1 C) of 7.5 minutes (see Kumar et al, Food Processing: Principles and Applications, Second Edition, Clark et al, editors, 2014 John Wiley & Sons, Ltd.). In one embodiment, the composition may be heat treated, for example by high temperature, short time (HTST) heat treatment, for example at a temperature of from about 165° F to about 195° F (from about 70° C to about 90° C) for about 15 to 25 seconds. In another embodiment, the composition may be heat treated, for example, by ultra-high temperature (UHT) heat treatment, for example, at a temperature of from about 280° F to about 305° F (from about 138° C to about 152° C), for at least about 5 seconds. Advantageously, the liquid nutritional compositions of the invention are heat stable to withstand a UHT treatment with a minimum F₀ of 7.5 min, without significant physical change and without fouling processing equipment.

[00043] The liquid nutritional compositions have a pH of from about 6 to about 7.5, more specifically, from about 6.5 to about 7.5, from about 6.8 to about 7.4, or from about 7.1 to about 7.3. The pH may be adjusted in one or more steps throughout the process, or in final processing of the compositions, as desired.

[00044] The following Examples demonstrate various features and embodiments of the liquid nutritional compositions of the invention and are intended to be illustrative only and non-limiting in nature.

Example 1

[00045] This example shows an exemplary protein system for use in the inventive compositions, comprising milk protein concentrate (MPC), partially hydrolyzed milk protein (PHMP), hydrolyzed whey protein (whey protein hydrolysate, WPH) and hydrolyzed collagen (HC). Protein Systems 1A and 1B as described in Table 1 employ milk protein concentrates having, respectively, higher and lower micellar casein contents.

Table 1: Protein Systems

[00046] The described protein systems are combined with additional nutritional ingredients, including fat (for example, canola oil, high oleic sunflower oil and corn oil), carbohydrate (for example, corn syrup an d sucrose), calcium HMB monohydrate, minerals, vitamins and stabilizers, to form high protein content liquid nutritional Compositions 1A and 1B, respectively, containing 14.4 g/100 ml of the protein systems, as shown in Table 2.

Table 2: Protein Systems in Nutritional Composition (14.40 g/100 ml)

Example 2

[00047] In this Example, additional nutritional compositions 1-26 having a composition as described in Example 1, including 14.40 g/100 ml of the protein system of Composition 1A, were prepared. The compositions included a source of magnesium as indicated in Table 3, with total magnesium and calcium at a level of about 0.33 wt %, about 0.4-0.5 wt % of a citrate and phosphate chelation system, and about 0.075-0.2 wt % of a stabilizer comprising methyl cellulose and sodium carboxymethyl cellulose. The compositions were subjected to UHT heat treatment as previously described to provide sterilization sufficient to maintain microbiological stability of the liquid nutritional compositions over a shelf-life of at least about 9 months, and maintained their physical form without any significant stability issues or process equipment fouling. After heat treatment, the compositions were subjected to measurement of several properties. Total solids (TS, wt %) were measured according to Official Methods of Analysis of AOAC INTERNATIONAL, 18th Ed.”, Methods 925.09 and 926.08, AOAC INTERNATIONAL, Gaithersburg, MD, USA, (2005) (Modified), wherein moisture is determined and total solids are calculated as the difference. Sedimentation (S) was measured by hand shaking a sample in a 4 or 8 oz product container having a diameter of about 58.5 mm (+/- 0.5mm), back and forth for 3 seconds - keeping the distance and speed back and forth consistent for all samples. The shaken product was decanted into a glass beaker and any remaining sediment observed in the product container was measured using a mm ruler. Apparent viscosity was measured as a function of shear rate using the previously described procedure. The measured viscosities were used to obtain zero shear rate viscosity, infinite rate viscosity, consistency, k, and rate index, n, by fitting to the Cross model via non-linear least square regression. Finally, protein content was determine using the Kjeldahl method in which the conversion factor was 6.25 protein/N, per the American Oil Chemists' Society (AOCS) official Method Ac 4-91The results are set forth in Table 3. The quality of the fit to the Cross model, R², for each composition is also included in Table 3. These compositions exhibited the structured rheology described herein, with an advantageously high protein content. Additionally, in adult consumer testing of these compositions, a majority of subjects scored positive sensory attributes of aftertaste, texture, mouthfeel, and overall liking.

Table 3: Liquid Nutritional Compositions

[00048] While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, such descriptions are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative compositions and methods, or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the general inventive concept.

Claims

What is claimed is:

1. A liquid nutritional composition, comprising at least about 125 mg/ml of a protein system comprising, based on the weight of the protein system, less than 40 wt % micellar casein, greater than 15 wt % non-micellar casein, whey protein, whey protein hydrolysate, and partially hydrolyzed collagen; at least about 5 mg/ml of b-hydroxy b-methylbutyrate (HMB); fat; and carbohydrate, wherein the nutritional composition has a zero shear rate viscosity greater than 100 cp, an infinite shear rate viscosity of less than 200 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of greater than about 1.5.

2. The nutritional composition of claim 1, wherein the protein system comprises from about 30 wt % to less than 40 wt % micellar casein, from about 15 wt % to about 35 wt % non-micellar casein, from about 10 wt % to about 20 wt % whey protein, from about 10 wt % to about 20 wt % whey protein hydrolysate, and from about 10 wt % to about 20 wt % partially hydrolyzed collagen.

3. The nutritional composition of claim 1 or 2, wherein the protein system is formed from milk protein concentrate, partially hydrolyzed milk protein, partially hydrolyzed whey protein, and partially hydrolyzed collagen.

4. The nutritional composition of any one of claims 1-3, wherein the partially hydrolyzed whey protein has a degree of hydrolysis of from about 10 to about 30 and the partially hydrolyzed collagen has a degree of hydrolysis of from about 5 to about 30.

5. The nutritional composition of any one of claims 1-4, comprising at least about 135 mg/ml of the protein system.

6. The nutritional composition of any one of claims 1-5, having a caloric density of at least about 2.0 kcal/ml, or at least about 2.2 kcal/ml, or at least about 2.4 kcal/ml.

7. The nutritional composition of any one of claims 1-6, comprising about 5 mg/ml to about 15 mg/ml HMB.

8. The nutritional composition of any one of claims 1-7, wherein the HMB is provided as alkali metal HMB, alkaline earth metal HMB, HMB free acid, HMB lactone or a combination of two or more thereof, or, more specifically, the HMB is provided as calcium HMB monohydrate.

9. The nutritional composition of any one of claims 1-8, comprising from about 0.1 to about 0.5 wt % divalent metals comprising calcium and magnesium and from about 0.2 to about 0.7 wt % of a chelation system comprising citrate and phosphate.

10. The nutritional composition of claim 9, wherein the weight ratio of citrate and phosphate to calcium and magnesium is from about 1:1 to about 3:1.

11. The nutritional composition of claim 9, wherein the source of magnesium comprises at least one of magnesium hydroxide, magnesium phosphate, magnesium carbonate, and magnesium chloride, and the source of phosphate comprises at least one of disodium phosphate dihydrate and potassium phosphate.

12. The nutritional composition of any one of claims 1-11 , wherein the nutritional composition has a zero shear rate viscosity of from 101 to about 850 cp, an infinite shear rate viscosity of from about 10 to about 150 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of from about 1.55 to about 20.

13. The nutritional composition of any one of claims 1-11, wherein the nutritional composition has a zero shear rate viscosity of from 101 to about 600 cp, an infinite shear rate viscosity of from about 25 to about 130 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of from about 1.55 to about 10.

14. The nutritional composition of any one of claims 1-11, wherein the nutritional composition has a zero shear rate viscosity of from 101 to about 500 cp, an infinite shear rate viscosity of from about 10 to about 135 cp, and a ratio of zero shear rate viscosity to infinite shear rate viscosity of from about 1.55 to about 5.

15. The nutritional composition of any one of claims 1-14, wherein the nutritional composition further comprises a stabilizer comprising microcrystalline cellulose and carboxymethylcellulose sodium.

16. The nutritional composition of any one of claims 1-15, wherein the fat comprises corn oil, canola oil, sunflower oil, or a combination of two or more thereof.

17. The nutritional composition of any one of claims 1-16, wherein the carbohydrate comprises sucrose, corn syrup, maltodextrin, glucose, lactose, honey, sugar alcohol, isomaltulose, sucromalt, galactooligosaccharide, fructooligosaccharide, or a combination of two or more thereof.

18. The nutritional composition of any one of claims 1-17, exhibiting a protein digestibility corrected amino acid score (PDCAAS) of greater than 100.