Nutritional composition for infants

Abstract

To provide a nutritive composition for infants having an amino acid composition more similar to breast milk, making it possible to ensure sufficient amino acid nutrition without excessive ingestion of protein.SOLUTION: The present disclosure provides a nutritive composition for infants containing protein. In the composition, the total content of phenylalanine and tyrosine is 7.6 wt.% or more in terms of total amino acid content, and 90 wt.% or more of the total protein content is derived from milk.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a nutritional composition for infants.

Background Art

[0002] For human infants, human milk (breast milk) is the ideal nutrition. However, when breast milk cannot be given for some reason, nutritional compositions such as prepared powdered milk and prepared liquid milk are generally used as nutrition to be given to infants as a substitute for breast milk. Such nutritional compositions are mainly made from cow's milk, and the nutritional components are adjusted to make the composition closer to breast milk. In particular, certain legal standards are defined for prepared milk for infants (Non-Patent Document 1).

[0003] Nutritional compositions for infants usually contain protein, which is an essential nutrient for infants. Generally, when manufacturing nutritional compositions for infants, casein and whey proteins derived from cow's milk are blended as protein sources. In nutritional compositions such as prepared milk for infants, there is a demand to make the composition closer to breast milk in order to further improve the health and development of infants. The ratio of casein to whey protein in cow's milk is 8:2 (weight ratio), while the same ratio in breast milk is 4:6 (weight ratio). Therefore, in the manufacture of nutritional compositions for infants, the ratio of casein to whey protein is designed to be closer to that of breast milk.

[0004] The nutritional value of protein varies depending on the amino acids that make it up. Furthermore, essential amino acids, which humans cannot synthesize, must be obtained through diet, but the amount required by infants differs for each essential amino acid. Conventionally, infant nutritional compositions manufactured using casein and whey protein derived from milk have been criticized for sometimes lacking essential amino acids compared to breast milk, depending on the type. This is because, even if the fractions are called casein and whey protein, the protein composition of each fraction differs between breast milk and cow's milk, resulting in different amino acid compositions for each fraction. Therefore, it has been proposed to adjust the amino acid composition by adding crystalline amino acids or by removing certain proteins from the whey protein fraction in cow's milk (Patent Documents 1-3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-214775 [Patent Document 2] Special Publication No. 2011-504365 [Patent Document 3] Special Publication No. 2014-520549 [Non-patent literature]

[0006] [Non-Patent Document 1] Ingestion Table No. 296 (September 9, 2019) Attachment 1 Labeling permission standards for foods for special dietary uses [Overview of the project] [Problems that the invention aims to solve]

[0007] In addition to the differences in amino acid composition mentioned above, milk-derived proteins and breast milk proteins are thought to have different bioavailability in the body. Therefore, when manufacturing infant nutritional compositions using milk-derived proteins, larger amounts of protein have been added than in breast milk. On the other hand, excessive intake of protein or specific amino acids during infancy has been pointed out as having adverse effects on infants, such as burdening their digestion and metabolism. However, simply reducing the protein content in infant nutritional compositions may lead to a deviation from the composition of breast milk, raising concerns that infants may not receive the necessary amino acid nutrition. In this context, the present invention aims to provide an infant nutritional composition with an amino acid composition closer to that of breast milk, which can ensure sufficient amino acid nutrition without excessive protein intake. [Means for solving the problem]

[0008] The inventors conducted intensive research to solve the above problems and found that, among the essential amino acids contained in conventional infant nutritional compositions, phenylalanine and tyrosine tend to be the most deficient compared to the composition of breast milk. As shown in Table 1, in 2007, the WHO committee presented the amino acid composition of breast milk when determining the age-specific essential amino acid requirements (WHO / FAO / UNU (2007), WHO technical report series no. 935), and the breast milk composition shown therein In terms of amino acid composition, the combined content of phenylalanine and tyrosine relative to the total amino acids was 9.7% by weight, compared to a lower value of 7.2-7.5% by weight in conventional infant formula. Based on this analysis, the inventors conceived the idea of ​​increasing the content of phenylalanine and tyrosine in the amino acid composition of infant nutritional composition. Focusing on the fact that casein and whey protein, both milk-derived proteins, have different amino acid compositions, and on the high bioavailability of casein, the inventors conceived the idea that by adjusting the blending ratio in the composition, it is possible to reduce excess amino acids while increasing the content of phenylalanine and tyrosine, thereby ensuring sufficient amino acid nutrition and achieving an amino acid composition closer to that of breast milk, thus completing the present invention.

[0009] [Table 1]

[0010] In other words, the present invention relates to an infant nutritional composition containing protein, wherein the total content of phenylalanine and tyrosine per total amino acid is 7.6% by weight or more, and 90% by weight or more of the total protein is derived from milk. In a preferred embodiment of the present invention, 33 to 70% by weight of the total protein is casein. In a preferred embodiment of the present invention, the tyrosine content per total amino acid is 3.6% by weight or more. In a preferred embodiment of the present invention, the phenylalanine content per total amino acid is 3.8% by weight or more. In a preferred embodiment of the present invention, the total protein content is less than 2.15 g per 100 kcal of composition. In a preferred embodiment of the present invention, the ratio of tryptophan content to the total content of phenylalanine and tyrosine is 21% by weight or less. In a preferred embodiment of the present invention, the nutritional composition is prepared milk. In this specification, when a numerical range is indicated with "~", the numbers at both ends of the range are also included. For example, 33~70% by weight means 33% by weight or more and 70% by weight or less. [Effects of the Invention]

[0011] According to the present invention, there is provided an infant nutritional composition having an amino acid composition closer to breast milk, which can sufficiently secure amino acid nutrition. More specifically, in the conventional infant composition, phenylalanine and tyrosine, which tend to be insufficient compared to breast milk, are secured in sufficient amounts. Further, in the conventional infant composition, the content of threonine, which tends to be excessively blended compared to breast milk, becomes an appropriate amount. According to the present invention, since the total protein mass contained in the composition can be reduced, a nutritional composition more useful for the health and development of infants can be realized.

Brief Description of the Drawings

[0012] [Figure 1] Electrophoresis image showing the casein content in prepared powdered milk 1 to 3.

Mode for Carrying Out the Invention

[0013] Next, the present invention will be described in detail. However, the present invention is not limited to the following embodiments and can be freely changed within the scope of the present invention.

[0014] The infant nutritional composition of the present invention contains protein. 90% by weight or more of the total protein of the infant nutritional composition is derived from milk, preferably 95% by weight or more, more preferably 98% by weight or more is protein derived from milk. Here, the total protein refers to the total amount of protein obtained by multiplying the nitrogen content contained in the nutritional composition by 6.25, which is the nitrogen-protein conversion coefficient. The nitrogen content can be quantified based on, for example, the "Analysis Methods for Nutritional Components, etc. (Appendix to the Food Labeling Standards (March 30, 2015, Shokushoku No. 139))" (hereinafter, the analysis method in the food labeling standards), that is, the Kjeldahl method or a combustion method including the improved Dumas method. Based on the "Analysis Methods for Nutritional Components, etc. (Appendix to the Food Labeling Standards (March 30, 2015, Shokushoku No. 139))" (hereinafter, the analysis method in the food labeling standards), that is, it can be quantified using the Kjeldahl method or a combustion method including the improved Dumas method.

[0015] The composition of the present invention typically contains whey protein as a milk-derived protein. The whey protein may be purified, high-purity whey protein, or it may be low-purity whey protein containing components other than whey protein. The dairy raw materials used to produce whey protein raw materials can also be used as a substitute for whey protein. In this case, the dairy raw materials can be called whey protein raw materials. As whey protein raw materials, ordinary dairy products containing whey protein such as raw milk, skim milk, whole milk powder, and skim milk powder can be used.

[0016] Methods for purifying whey protein include adding rennet, inorganic acids, or organic acids to milk or skim milk powder to remove casein and milk fat, or further processing the whey from the above process, or from milk or skim milk, using gel filtration, ultrafiltration, ion exchange, etc. Whey protein concentrates and whey protein isolates obtained by these methods can be used. Commercially available whey protein raw materials such as whey protein concentrate (WPC) and whey protein isolate (WPI) can also be used.

[0017] Generally, whey protein contains β-lactoglobulin, α-lactalbumin, serum albumin, immunoglobulin, lactoferrin, proteospeptone, etc., and the whey protein described herein may also contain these components. Furthermore, only one type of whey protein raw material may be used as the whey protein, or two or more types may be mixed and used.

[0018] The composition of the present invention typically contains a protein other than the whey protein as a milk-derived protein. Such a protein may be any protein commonly used in oral intake compositions, and may include skim milk powder, whole milk powder, casein, or soy protein. Casein is further classified into α-casein, β-casein, κ-casein, etc., but this In this invention, casein refers to the sum of these caseins. Furthermore, the casein used in this invention is The β-casein content can be the same as that of milk (approximately 38%).

[0019] The protein in this invention may include the milk-derived protein mentioned above, and peptide / amino acid fractions obtained by hydrolyzing other proteins. Alternatively, free amino acids may be used as the protein source in the nutritional composition.

[0020] In the composition of the present invention, the content of casein protein in the total protein is usually 33% by weight or more, preferably 41% by weight or more, and more preferably 44% by weight or more. Furthermore, the upper limit of the casein protein content in the total protein is usually 70% by weight or less, preferably 60% by weight or less, and more preferably 59% by weight or less. That is, the casein protein content in the total protein can be 33-70% by weight, 33-60% by weight, 33-59% by weight, 41-70% by weight, 41-60% by weight, 41-59% by weight, 44-70% by weight, 44-60% by weight, or 44-59% by weight. As mentioned above, the majority of the milk proteins typically included in the composition of the present invention consist of casein and whey protein. By adjusting the proportion of casein protein in this way, it becomes easier to achieve a predetermined range for the phenylalanine and tyrosine content in the infant nutritional composition described later. This is because casein contains a large amount of phenylalanine and tyrosine, and also because casein has high bioavailability.

[0021] The casein content of a nutritional composition can be quantified, for example, by SDS-PAGE. Specifically, the nutritional composition and casein standards of multiple concentrations are applied to the same volume of the same polyacrylamide gel, electrophoresis is performed, and the intensity (concentration) of the bands obtained by staining the gel with Coomassie blue is compared using analysis software to determine the casein content.

[0022] In the composition of the present invention, the total content of phenylalanine and tyrosine per total amino acids is 7.6% by weight or more, preferably 7.7% by weight or more, and more preferably 7.8% by weight or more. Furthermore, the upper limit of the total content of phenylalanine and tyrosine per total amino acids is usually 12% by weight or less, preferably 10% by weight or less, and more preferably 9.8% by weight or less. For example, the total content of phenylalanine and tyrosine per total amino acids can be 7.6-12% by weight, 7.6-10% by weight, 7.6-9.8% by weight, 7.7-12% by weight, 7.7-10% by weight, 7.7-9.8% by weight, 7.8-12% by weight, 7.8-10% by weight, or 7.8-9.8% by weight. By setting the content in this way, the amino acid composition of the nutritional composition becomes closer to that of breast milk. Furthermore, in the composition of the present invention, the total content of phenylalanine and tyrosine per 100 kcal of composition is usually 0.15 g or more, preferably 0.16 g or more. The upper limit is usually 0.22 g or less, preferably 0.19 g or less. For example, the total content of phenylalanine and tyrosine per 100 kcal of composition can be 0.15 to 0.22 g, 0.15 to 0.19 g, 0.16 to 0.22 g, or 0.16 to 0.19 g.

[0023] Here, total amino acids usually refer to the total amount of amino acids that make up proteins contained in a nutritional composition, namely histidine, isoleucine, leucine, lysine, phenylalanine, tyrosine, threonine, valine, aspartic acid, asparagine, serine, glutamic acid, glutamine, glycine, alanine, arginine, proline, methionine, cysteine ​​(cystine), and tryptophan. However, if substances added in forms other than proteins, such as free amino acids or peptides, are included, the total amount also includes the amino acids that make up those substances.

[0024] The content of these amino acids can be quantified, for example, by subjecting a nutritional composition hydrolyzed with an acid or base to a high-performance amino acid analyzer or high-performance liquid chromatography. Since glutamine and asparagine are converted to glutamic acid and aspartic acid, respectively, during hydrolysis, glutamic acid is quantified as the sum of glutamine and glutamic acid, and aspartic acid is quantified as the sum of asparagine and aspartic acid. Furthermore, the content of a predetermined amino acid per total amino acid refers to the ratio obtained by dividing the content of the predetermined amino acid quantified by the above method by the total amino acid content.

[0025] In the composition of the present invention, the tyrosine content per total amino acid is usually 3.6% by weight or more, preferably 3.7% by weight or more, and more preferably 3.8% by weight or more. Furthermore, the upper limit of the tyrosine content per total amino acid is usually 10% by weight or less, preferably 8% by weight or less, and more preferably 6% by weight or less. For example, the tyrosine content per total amino acid can be 3.6-10% by weight, 3.6-8% by weight, 3.6-6% by weight, 3.7-10% by weight, 3.7-8% by weight, 3.7-6% by weight, 3.8-10% by weight, 3.8-8% by weight, or 3.8-6% by weight. Furthermore, in the composition of the present invention, the tyrosine content per 100 kcal of composition is usually 0.05 g or more, preferably 0.07 g or more. The upper limit is usually 0.18 g or less, preferably 0.15 g or less, and more preferably 0.095 g or less. For example, the tyrosine content per 100 kcal of composition can be 0.05 to 0.18 g, 0.05 to 0.15 g, 0.05 to 0.095 g, 0.07 to 0.18 g, 0.07 to 0.15 g, or 0.07 to 0.095 g.

[0026] In the composition of the present invention, the phenylalanine content per total amino acid is usually 3.8% by weight or more, preferably 3.9% by weight or more, and more preferably 4% by weight or more. Furthermore, the upper limit of the phenylalanine content per total amino acid is usually 6% by weight or less, preferably 5% by weight or less, and more preferably 4.4% by weight or less. For example, the phenylalanine content per total amino acid can be 3.8-6% by weight, 3.8-5% by weight, 3.8-4.4% by weight, 3.9-6% by weight, 3.9-5% by weight, 3.9-4.4% by weight, 4-6% by weight, 4-5% by weight, or 4-4.4% by weight. Furthermore, in the composition of the present invention, the phenylalanine content per 100 kcal of composition is usually 0.05 g or more, preferably 0.07 g or more. The upper limit is usually 0.15 g or less, preferably 0.12 g or less. For example, the tyrosine content per 100 kcal of composition can be 0.05 to 0.15 g, 0.05 to 0.12 g, 0.07 to 0.15 g, or 0.07 to 0.12 g.

[0027] In the composition of the present invention, the ratio of tryptophan content to the total content of phenylalanine and tyrosine is 22% by weight or less, preferably 21% by weight or less, and more preferably 20% by weight or less. Furthermore, the lower limit of the ratio of tryptophan content to the total content of phenylalanine and tyrosine is usually 14% by weight or more, preferably 15% or more, and more preferably 17% by weight or more. For example, the ratio of tryptophan content to the total content of phenylalanine and tyrosine can be 14-22% by weight, 14-21% by weight, 14-20% by weight, 15-22% by weight, 15-21% by weight, 15-20% by weight, 17-22% by weight, 17-21% by weight, or 17-20% by weight.

[0028] In the composition of the present invention, the histidine content per total amino acid is usually 2.8% by weight or less, preferably 2.6% by weight or less, and more preferably 2.4% by weight or less. Furthermore, the lower limit of the histidine content per total amino acid is usually 1.5% or more, preferably 1.8% by weight or more, and more preferably 2% by weight or more. For example, the histidine content per total amino acid may be 1.5-2.8% by weight, 1.5-2.6% by weight, 1.5-2.4% by weight, 1.8-2.8% by weight, 1.8-2.6% by weight, 1.8-2.4% by weight, 2-2.8% by weight, 2-2.6% by weight, or 2-2.4% by weight. It is possible. In the composition of the present invention, the cysteine ​​content per total amino acid is usually 2.2% or less, preferably 2.0% by weight or less, and more preferably 1.7% by weight or less. Furthermore, the lower limit of the cysteine ​​content per total amino acid is usually 1.0% or more, preferably 1.2% by weight or more, and more preferably 1.4% by weight or more. For example, the cysteine ​​content per total amino acid can be 1-2.2% by weight, 1-2% by weight, 1-1.7% by weight, 1.2-2.2% by weight, 1.2-2% by weight, 1.2-1.7% by weight, 1.4-2.2% by weight, 1.4-2% by weight, or 1.4-1.7% by weight.

[0029] The nutritional composition of the present invention, having such a composition, is close to the amino acid composition of breast milk and is well digested, absorbed, and utilized by infants who ingest it. Therefore, even if the total protein content contained in the composition is reduced compared to conventional compositions, sufficient amino acid nutrition is ensured.

[0030] In other words, the total protein content in the composition of the present invention may be less than 2.15 g per 100 kcal of composition, more preferably 2.05 g or less, and even more preferably 1.95 g or less. Furthermore, the lower limit of the total protein content is usually 1.5 g or more per 100 kcal of composition, preferably 1.6 g or more, and more preferably 1.8 g or more. For example, the total protein content in the composition of the present invention can be 1.5 g or more but less than 2.15 g, 1.5 to 2.05 g, 1.5 to 1.95 g, 1.6 g or more but less than 2.15 g, 1.6 to 2.05 g, 1.6 to 1.95 g, 1.8 g or more but less than 2.15 g, 1.8 to 2.05 g, or 1.8 to 1.95 g per 100 kcal of composition. Alternatively, the total protein content in the composition of the present invention may be less than 11% by weight of the total dry weight of the composition, more preferably 10.5% by weight or less, and even more preferably 10% by weight or less. Furthermore, the lower limit of the total protein content may usually be 7.7% by weight or more of the total dry weight, preferably 8.2% by weight or more, and more preferably 9.2% by weight or more. For example, the total protein content in the composition of the present invention can be 7.7% by weight or more and less than 11% by weight, 7.7 to 10.5% by weight, 7.7 to 10% by weight, 8.2% by weight or more and less than 11% by weight, 8.2 to 10.5% by weight, 8.2 to 10% by weight, 9.2% by weight or more and less than 11% by weight, 9.2 to 10.5% by weight, or 9.2 to 10% by weight of the total dry weight of the composition.

[0031] Traditionally, in order to ensure the amino acid composition and content found in human breast milk, the total protein content in infant nutritional compositions tended to be excessive. However, as mentioned above, by reducing the total protein content, the burden on the infant's digestion and metabolism is reduced, and nutritional intake that is neither excessive nor insufficient can be achieved.

[0032] In the present invention, "infant nutritional composition" refers to food and beverages taken orally and is not particularly limited, but is preferably prepared milk, liquid food, etc., and more preferably prepared milk. The target of consumption is infants, toddlers, children, or adults, but is preferably infants. In the Ministerial Ordinance Concerning Standards for Ingredients of Milk and Dairy Products (Milk and Dairy Products Ordinance), prepared milk powder is defined as "a product made by processing raw milk, cow's milk, special milk, or food products manufactured using these as raw materials, or by using these as the main raw materials, with added nutrients necessary for infants and young children, and then putting it into a powder form." Prepared liquid milk is defined in the aforementioned ministerial ordinance as "a product made by processing raw milk, cow's milk, special milk, or food products made from these as raw materials, or by using these as the main raw materials, and adding nutrients necessary for infants and young children to make it liquid." Furthermore, prepared milk contains various nutrients such as proteins, oils and fats, carbohydrates, minerals, and vitamins, and includes products that have been processed into powder or liquid form. Furthermore, prepared milk also includes "infant formula," "infant liquid milk," and "infant formula for pregnant and lactating women," which are special dietary foods as defined by the Health Promotion Act, and infant formula This also includes forms such as nutritional powders for adults and nutritional powders for the elderly. In the present invention, the "infant nutritional composition" is more preferably infant formula and infant liquid milk.

[0033] The compositions of the present invention typically contain oils and fats in addition to the aforementioned proteins. Oils and fats can include animal fats such as milk fat obtained from the milk of mammals such as cattle, buffalo, goats, and donkeys, fish oil, and egg yolk oil; vegetable oils such as soybean oil, corn oil, sesame oil, perilla oil, rapeseed oil, palm oil, and sunflower oil; and oils and fats obtained by culturing microorganisms. In particular, it may contain unsaturated fatty acids that are normally found in breast milk, such as docosahexaenoic acid (DHA), arachidonic acid (ARA), eicosapentaenoic acid (EPA), linoleic acid, gamma-linolenic acid (GLA), alpha-linolenic acid, dihomo-gamma-linolenic acid (DHGLA), and stearidonic acid.

[0034] The compositions of the present invention typically contain carbohydrates. In terms of carbohydrates, it can include sugars such as lactose, dextrin, starch, raffinose, and lactulose, as well as dietary fiber such as indigestible dextrin and inulin.

[0035] The compositions of the present invention typically contain vitamins. Vitamins may include water-soluble vitamins such as B vitamins and vitamin C, as well as fat-soluble vitamins such as vitamin A, vitamin D, and vitamin E.

[0036] The compositions of the present invention typically contain minerals. The minerals of the present invention can be sodium, potassium, calcium, iron, zinc, manganese, and copper salts, and preferably can be formulated in the form of sodium chloride, potassium chloride, calcium carbonate, ferric pyrophosphate, zinc sulfate, manganese sulfate, copper sulfate, etc.

[0037] The infant nutritional composition of the present invention can be manufactured by conventional methods. The method for producing the composition of the present invention will be described below, using the case where the composition is prepared milk as an example. A predetermined amount of milk preparation ingredients containing whey protein, casein, peptides, free amino acids, oils and fats, carbohydrates, vitamins, minerals, etc., is added to water, raw milk, skim milk, whey, etc., mixed and dissolved by heating as appropriate, and then heat-sterilized to prepare liquid milk preparation. Some of the raw materials, such as oils and fats, are preheated and melted before being added to the raw material solution for the prepared milk prepared as described above. It is preferable that the raw material solution for the prepared milk to which the oils and fats have been added is homogenized using a homogenizer. The oils and fats can be mixed with a solution containing some of the raw materials for the prepared milk, homogenized, and then the remaining raw materials for the prepared milk can be added to complete the raw material solution for the prepared milk.

[0038] As described above, the prepared liquid milk is heat-sterilized at 75-150°C. Heat sterilization methods include plate sterilization, injection sterilization, and infusion sterilization. Following the heat sterilization process, a homogenization step may be added to standardize the size of the fat globules in the liquid and achieve a good emulsified state. The heat-sterilized liquid prepared milk is an intermediate product that can be used to produce the powdered prepared milk described later, but it can also be the final product itself. That is, the heat-sterilized liquid prepared milk can be hygienically transferred to a filling machine and filled directly into containers made of paper, plastic, aluminum, etc., to become the final product. In addition, the raw material solution for the prepared milk (prepared milk raw material) can be heat-sterilized before being mixed with the iron-bound whey protein solution.

[0039] As described above, the heat-sterilized liquid milk is further dried to produce powdered milk. This can be done. Furthermore, the liquid milk preparation can be concentrated before drying by conventional methods such as vacuum drying. Heat sterilization and drying may be performed in a single step. In the drying process, spray drying with hot air or freeze-drying can be used. Spray drying with hot air is preferable because it involves heating, thus providing a certain level of sterilization. The resulting powder can be filled into a product without adding any new components, or it can be filled into a product after mixing in hygienically controlled components, such as lactoferrin, which may denature during sterilization. [Examples]

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0041] <Example 1> (1) Preparation of powdered milk According to the formulations shown in Table 2, desalted milk whey protein powder (60% total protein by weight, manufactured by Mirai Co., Ltd.), sodium caseinate powder (90% total protein by weight, manufactured by Fonterra Co., Ltd.), lactose (manufactured by Mirai Co., Ltd.), mineral mixture (manufactured by Tomita Pharmaceutical Co., Ltd.), vitamin mixture (manufactured by Tanabe Seiyaku Co., Ltd.), lactulose (manufactured by Morinaga Milk Industry Co., Ltd.), raffinose (manufactured by Nippon Beet Sugar Manufacturing Co., Ltd.), and galactooligosaccharide liquid sugar (manufactured by Yakult Pharmaceutical Industry Co., Ltd.) were dissolved in 300 kg of warm water, and then heated and dissolved at 90°C for 10 minutes. Adjusted fat (manufactured by Taiyo Yushi Co., Ltd.) was added and homogenized. After that, sterilization and concentration processes were carried out and spray-dried to prepare approximately 95 kg each of Prepared Milk Powder 1 to 3.

[0042] [Table 2]

[0043] (2) Determination of amino acid content The amino acid content of the prepared milk powders 1-3 was quantified according to the following method. Table 3 shows the amino acid content of formula milk 1-3, along with that of breast milk.

[0044] (i) Method for quantifying histidine, isoleucine, leucine, lysine, phenylalanine, tyrosine, threonine, valine, aspartic acid + asparagine, serine, glutamic acid + glutamine, glycine, alanine, arginine, and proline. 30 mg of the prepared milk powder sample was weighed into a glass container, and 3 mL of 6 M hydrochloric acid (containing 0.1% phenol by volume) (manufactured by Kokusan Kagaku Co., Ltd.) was added. The glass container was then degassed and sealed. After heating at 110°C for 24 hours to hydrolyze all the proteins in the sample to amino acids, the filtrate was filtered with a cotton plug and subjected to an evaporator to remove the hydrochloric acid, and 5 mL of 0.02 M salt was added. The sample was redissolved with acid. The redissolved sample and an amino acid standard (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were subjected to a high-speed amino acid analyzer "L-8900" (manufactured by Hitachi High-Technologies Corporation) to quantify the content of each amino acid in the sample.

[0045] (ii) Method for determining methionine and cysteine A performic acid solution was prepared by mixing 30% hydrogen peroxide (manufactured by Kokusan Kagaku Co., Ltd.) and 99% formic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in a ratio of 1:9 (by volume). 30 mg of the prepared powdered milk sample was weighed into a glass container, 3 mL of performic acid was added, and the container was sealed with Parafilm. The container was then allowed to stand at 4°C for 18 hours to convert cysteine ​​(cystine) to cysteic acid and methionine to methionine sulfone. The glass container was heated to 65°C using a heat block, and the performic acid was removed by nitrogen blowing. 3 mL of 6 M hydrochloric acid (containing 0.1% phenol by volume) was added, and the glass container was degassed and sealed. After hydrolysis at 110°C for 18 hours, the filtrate filtered with a cotton plug was subjected to an evaporator to remove the hydrochloric acid, and the sample was redissolved in 5 mL of 0.02 M hydrochloric acid. The redissolved samples, methionine sulfone standard (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and cysteic acid standard (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were subjected to a high-speed amino acid analyzer "L-8900" (manufactured by Hitachi High-Technologies Corporation) to quantify the methionine and cysteine ​​content in the samples.

[0046] (iii) Method for quantifying tryptophan Thiodiethylene glycol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and ultrapure water were mixed in a 6:4 ratio (by volume) to obtain a 60% thiodiethylene glycol solution. 20 mg of the prepared powdered milk sample was weighed into a glass container, and 1.56 g of barium hydroxide pentahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 0.9 ml of ultrapure water, and 0.1 mL of 60% thiodiethylene glycol were added. The glass container was then degassed and sealed. After hydrolysis at 110°C for 12 hours, the solution was neutralized and diluted with 6M hydrochloric acid (manufactured by Kokusan Kagaku Co., Ltd.) to a pH of 7-9, and then made up to 50 mL with ultrapure water. The made-up sample and tryptophan standard (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were subjected to high-performance liquid chromatography (manufactured by Shimadzu Corporation) equipped with a fluorescence detector (Ex. 285 nm, Em. 348 nm) to quantify the tryptophan content in the sample.

[0047] [Table 3]

[0048] (3) Determination of casein content Casein standard (Sigma-Aldrich, catalog number: C7078) Prepared milk powders 1-3 were dissolved in an 8M urea aqueous solution to achieve protein concentrations of 0.27, 0.67, and 1.07 mg / mL, and a total protein concentration of 1.33 mg / mL. 1 / 4 equivalent of 4 x Laemmli sample buffer (Bio-Rad, catalog number: 1610747) with 10% volume of 2-mercaptoethanol (Bio-Rad) added was added, and the mixture was heat-denatured at 95°C for 5 minutes. Then, 10 μL of the mixture was added to each well of an SDS-PAGE gel (Bio-Rad, catalog number: 456-9036) in electrophoresis buffer (Bio-Rad, catalog number: 1610377). The total protein amounts added were 2 and 5 for casein standards. , and 8 μg, and 10 μg for prepared milk powders 1-3. The gels, subjected to electrophoresis at 150V for 45 minutes, were stained with Coomassie Blue stain (Bio-Rad, catalog number 456-9034), and converted to electrophoretic images using the ChemiDoc XRS+ imaging system (Bio-Rad). Image Lab software (Bio-Rad) Using the Volume Tools function of the company's software, the band corresponding to casein in each lane of the image was selected, and the intensity of the band was calculated (Figure 1). The total protein mass of the three casein standards and their Based on a calibration curve created from band intensities corresponding to protein content, the casein content per 10 μg of total protein in formula milk 1-3 was calculated. The selected band is near the center of the image, 20 Contains all α-casein, β-casein, and γ-casein molecules located in the ~37kDaa range. The selected area of ​​the bands in each lane was kept the same. As a result, the casein content per 10 μg of total amino acids in the prepared milk powders 1-3 was 3.2, 4.4, and 5.9 μg, respectively. This indicates that the casein content per total protein of the prepared milk powders 1-3 is 32% by weight, 44% by weight, and 59% by weight, respectively.

[0049] (4) Administration study in rats Six-week-old male SD rats were purchased from Charles River Japan. After acclimatizing them on a normal diet for 12 days, they were divided into three groups to ensure weight distribution was consistent (n=5). Subsequently, the diets of each group were adjusted. Switch to one of the prepared milk powders 1-3 and continue feeding for one week, then collect blood samples and plasma samples on the last day. A sample was prepared. The rats' food intake and body weight were recorded daily, and it was confirmed that there were no differences in either between the groups. An equal volume of 10% trichloroacetic acid solution was added to the plasma sample, and the supernatant was obtained by centrifugation at 21,500 g for 15 minutes. The supernatant sample and amino acid standards (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were subjected to a high-speed amino acid analyzer "L-8900" (manufactured by Hitachi High-Technologies Corporation) to quantify the free amino acid concentration in the plasma. Table 4 shows the plasma free amino acid concentrations in rats that ingested prepared milk powders 1-3.

[0050] [Table 4]

[0051] It is widely known that in the body, a deficiency of a particular essential amino acid leads to a decrease in the plasma free amino acid concentration of that amino acid, and that excessive intake of a particular essential amino acid leads to an increase in the plasma free amino acid concentration of that amino acid (Physiological reviews 50). P428 (1970). In other words, the plasma free amino acid concentration of essential amino acids can be said to be an indicator that reflects the excess or deficiency of amino acid nutrition in the body.

[0052] The total protein content of the prepared milk powder 2 and prepared milk powder 3 in this invention was lower than that of prepared milk powder 1, but as shown in Table 3, the essential amino acids in the prepared milk powder group 2 and the prepared milk powder group 3 The plasma free amino acid concentrations of ano acids, excluding threonine, were as follows: Plasma free amino acid concentrations in Group 1 of the prepared milk powder The amino acid concentration was equal to or higher than that of the amino acid concentration. The plasma free threonine concentration in Group 2 of the infant formula was significantly lower than that in Group 1 of the infant formula. However, as mentioned earlier, it has been pointed out that conventional infant formulas contain excessive amounts of threonine compared to breast milk (Table 1). Therefore, infant formula 2 is considered to provide more desirable amino acid nutrition for human infants. Furthermore, while the plasma free tyrosine concentration in Group 3 of the infant formula was significantly higher than that in Group 1, as mentioned earlier, conventional infant formulas have been criticized for having insufficient total tyrosine and phenylalanine content compared to breast milk (Table 1). Therefore, it is considered that Infant Formula 3 provides more desirable amino acid nutrition for human infants.

[0053] In other words, the present invention provides an infant nutritional composition with an amino acid composition closer to breast milk, which ensures sufficient amino acid nutrition without excessive protein intake by reducing the total protein content.

Claims

1. A nutritional composition for infants containing protein, The total content of phenylalanine and tyrosine per total amino acid is 7.6% by weight or more. The total protein content is less than 2.15 g per 100 kcal of composition. More than 90% of the total protein is derived from milk. Casein accounts for 33-70% by weight of the total protein. The ratio of tryptophan content to the total content of phenylalanine and tyrosine is 21% by weight or less. An infant nutritional composition (excluding breast milk) having a total content of phenylalanine and tyrosine of 0.15 g or more per 100 kcal of composition.

2. The composition according to claim 1, wherein the tyrosine content per total amino acid is 3.6% by weight or more.

3. The composition according to claim 1 or 2, wherein the phenylalanine content per total amino acid is 3.8% by weight or more.

4. The composition according to claim 3, wherein the ratio of the tryptophan content to the total content of phenylalanine and tyrosine is 14% by weight or more.

5. The composition according to claim 3, wherein the cysteine ​​content per total amino acid is 1.37% by weight or more.

6. The composition according to claim 3, wherein the proportion of the total threonine content per total amino acid is 5.56% by weight or less.

7. The composition according to claim 4, wherein 41 to 70% by weight of the total protein is casein.

8. The composition according to claim 4, which is a prepared milk.

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