Nutritive 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 have been established for prepared milk for infants (Non-Patent Document 1).

[0003] Nutritional compositions for infants usually contain proteins, which are essential nutrients 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 (by weight), while the same ratio in breast milk is 4:6 (by weight). 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 proteins varies depending on the amino acids that compose them. In addition, essential amino acids that humans cannot synthesize must be ingested from food, but the amounts required by infants differ for each essential amino acid. Conventionally, in infant nutritional compositions that have been manufactured using casein and whey protein derived from cow's milk, it has been pointed out that the amino acids necessary for infants may be insufficient depending on the type, compared to breast milk. This is because, even if they are fractions called the same casein and whey protein in breast milk and cow's milk, the protein compositions that make up each fraction are different, and the amino acid compositions of each fraction also differ between breast milk and cow's milk. Therefore, it has been proposed to adjust the amino acid composition by adding crystalline amino acids or removing some proteins from the whey protein fraction in cow's milk (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] It is considered that, in addition to the difference in the above amino acid composition, the availability in the living body of proteins derived from cow's milk and breast milk proteins is different. Therefore, when manufacturing an infant nutritional composition using proteins derived from cow's milk, a larger amount of protein has been blended than breast milk. On the other hand, excessive intake of proteins or specific amino acids during infancy has been pointed out to have adverse effects, such as becoming a burden on the digestion and metabolism of infants. However, simply reducing the protein content in the infant nutritional composition may deviate from the composition of breast milk, and there is a concern that the amino acid nutrition necessary for infants may be insufficient. Under such circumstances, an object of the present invention is to provide an infant nutritional composition having an amino acid composition closer to that of breast milk, which can sufficiently secure amino acid nutrition without excessive intake of protein.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have 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, the Committee of the WHO in 2007 presented the amino acid composition of breast milk when determining the age-specific requirements for essential amino acids (WHO / FAO / UNU (2007), WHO technical report series no. 935). In the amino acid composition of breast milk shown here, the total content rate of phenylalanine and tyrosine with respect to the total amino acids is 9.7% by weight, whereas in conventional powdered milk formulas, it was as low as 7.2 to 7.5% by weight. In the amino acid composition, the content rate of the total of phenylalanine and tyrosine with respect to the total amino acids is 9.7% by weight, whereas in conventional prepared powdered milk, it was a low value of 7.2 to 7.5% by weight. Based on such analysis, the inventors of the present invention came up with the idea of increasing the contents of phenylalanine and tyrosine in the amino acid composition of the nutritional composition for infants. Then, focusing on the fact that the constituent ratios of the amino acids contained in casein and whey protein, which are milk-derived proteins, are different, and the high bioavailability of casein, by adjusting the blending ratio in the composition, while reducing excessive amino acids, the contents of phenylalanine and tyrosine are increased, sufficient amino acid nutrition is ensured, and an amino acid composition closer to breast milk can be achieved, thus completing the present invention.

[0009]

Table 1

[0010] That is, the present invention is a nutritional composition for infants containing protein, wherein the total content ratio of phenylalanine and tyrosine per total amino acids 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 content ratio of tyrosine per total amino acids is 3.6% by weight or more. In a preferred embodiment of the present invention, the content of phenylalanine per total amino acids 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 the composition. In a preferred embodiment of the present invention, the ratio of the content of tryptophan 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 formula milk. In addition, when a numerical range is described as "~" in this specification, the numerical values at both ends are also included in the range. For example, 33 to 70% by weight represents 33% by weight or more and 70% by weight or less.

Advantages of the Invention

[0011] According to the present invention, there is provided an infant nutritional composition having an amino acid composition closer to that of 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. Also, 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

Embodiments 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, for example, based on the "Analysis Methods of 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, by using the Kjeldahl method or a combustion method including the modified Dumas method. Based on the "Analysis Methods of 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, by using the Kjeldahl method or a combustion method including the modified Dumas method.

[0015] The composition of the present invention usually contains whey protein as a protein derived from milk. As the whey protein, either purified high-purity whey protein or a low-purity one containing components other than whey protein may be used. The milk raw material used for producing the whey protein raw material can also be directly used as a substitute for whey protein. In this case, the milk raw material can be referred to as the whey protein raw material. As the whey protein raw material, ordinary dairy products containing whey protein such as raw milk, skim milk, whole milk powder, and skim milk powder can be used.

[0016] As a method for purifying whey protein, there are methods such as adding rennet, inorganic acid, or organic acid to milk or skim milk powder to remove casein and milk fat, or further treating the whey from the above-mentioned step, or milk or skim milk by gel filtration method, ultrafiltration method, ion exchange method, etc. Whey protein concentrates, whey protein isolates, etc. obtained by these methods can be used. In addition, 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, proteose peptone, etc. However, the whey protein in this specification may also contain these components. In addition, only one type of whey protein raw material used as whey protein may be used, or two or more types may be mixed and used.

[0018] The composition of the present invention usually contains proteins other than the above-mentioned whey protein as a protein derived from milk. Such proteins may be those commonly used in oral intake compositions, and skim milk powder, whole milk powder, casein, soy protein, etc. can be used. Casein is further classified into α-casein, β-casein, κ-casein, etc. However, this In the invention, casein means the sum total of these caseins. Further, the casein used in the present invention may have a β-casein content equivalent to that of milk (approximately 38%).

[0019] The protein in the present invention may contain the above-mentioned milk-derived protein and a peptide-amino acid fraction obtained by hydrolyzing other proteins. Further, free amino acids may be used as the protein source of 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, more preferably 44% by weight or more. Further, the upper limit of the content of casein protein in the total protein is usually 70% by weight or less, preferably 60% by weight or less, more preferably 59% by weight or less. That is, the content of casein protein in the total protein can be 33 to 70% by weight, 33 to 60% by weight, 33 to 59% by weight, 41 to 70% by weight, 41 to 60% by weight, 41 to 59% by weight, 44 to 70% by weight, 44 to 60% by weight, or 44 to 59% by weight. As described above, most of the milk proteins usually contained in the composition of the present invention are composed of casein and whey protein. By setting the ratio of casein protein in this way, it becomes easier to make the contents of phenylalanine and tyrosine in the nutritional composition for infants described later fall within a predetermined range. This is because casein contains a large amount of phenylalanine and tyrosine, and the bioavailability of casein is high.

[0021] The casein content of the nutritional composition can be quantified, for example, by SDS-PAGE. That is, the nutritional composition and casein standards of a plurality of concentrations are applied to the same volume of polyacrylamide gel, electrophoresed, and then the intensity (density) of the bands obtained by staining the gel with Coomassie Brilliant Blue is compared with analysis software to obtain the result.

[0022] In the composition of the present invention, the total content rate of phenylalanine and tyrosine per total amino acids is 7.6% by weight or more, preferably 7.7% by weight or more, more preferably 7.8% by weight or more. Also, the upper limit of the total content rate of phenylalanine and tyrosine per total amino acids is usually 12% by weight or less, preferably 10% by weight or less, more preferably 9.8% by weight or less. For example, the total content rate of phenylalanine and tyrosine per total amino acids can be 7.6 to 12% by weight, 7.6 to 10% by weight, 7.6 to 9.8% by weight, 7.7 to 12% by weight, 7.7 to 10% by weight, 7.7 to 9.8% by weight, 7.8 to 12% by weight, 7.8 to 10% by weight, or 7.8 to 9.8% by weight. By setting the content to such, the amino acid composition of the nutritional composition becomes closer to breast milk. Also, in the composition of the present invention, the total content of phenylalanine and tyrosine per 100 kcal of the 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 the 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, the total amino acids usually refer to the total amount of amino acids constituting the protein contained in the nutritional composition, that is, histidine, isoleucine, leucine, lysine, phenylalanine, tyrosine, threonine, valine, aspartic acid, asparagine, serine, glutamic acid, glutamine, glycine, alanine, arginine, proline, methionine, cysteine (cystine), tryptophan. However, when those added in forms other than protein, such as free amino acids and peptides, are included, the amount includes the amino acids constituting them.

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

[0025] In the composition of the present invention, the content ratio of tyrosine per total amino acids is usually 3.6% by weight or more, preferably 3.7% by weight or more, more preferably 3.8% by weight or more. The upper limit of the content ratio of tyrosine per total amino acids is usually 10% by weight or less, preferably 8% by weight or less, more preferably 6% by weight or less. For example, the content ratio of tyrosine per total amino acids can be 3.6 to 10% by weight, 3.6 to 8% by weight, 3.6 to 6% by weight, 3.7 to 10% by weight, 3.7 to 8% by weight, 3.7 to 6% by weight, 3.8 to 10% by weight, 3.8 to 8% by weight, or 3.8 to 6% by weight. In addition, in the composition of the present invention, the content of tyrosine per 100 kcal of the 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, more preferably 0.095 g or less. For example, the content of tyrosine per 100 kcal of the 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 content of phenylalanine per total amino acids is usually 3.8% by weight or more, preferably 3.9% by weight or more, more preferably 4% by weight or more. Also, the upper limit of the content of phenylalanine per total amino acids is usually 6% by weight or less, preferably 5% by weight or less, more preferably 4.4% by weight or less. For example, the content of phenylalanine per total amino acids can be 3.8 to 6% by weight, 3.8 to 5% by weight, 3.8 to 4.4% by weight, 3.9 to 6% by weight, 3.9 to 5% by weight, 3.9 to 4.4% by weight, 4 to 6% by weight, 4 to 5% by weight, or 4 to 4.4% by weight. Also, in the composition of the present invention, the content of phenylalanine per 100 kcal of the 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 content of tyrosine per 100 kcal of the 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 the content of tryptophan to the total content of phenylalanine and tyrosine is 22% by weight or less, preferably 21% by weight or less, more preferably 20% by weight or less. Also, the lower limit of the ratio of the content of tryptophan to the total content of phenylalanine and tyrosine is usually 14% by weight or more, preferably 15% or more, more preferably 17% by weight or more. For example, the ratio of the content of tryptophan to the total content of phenylalanine and tyrosine can be 14 to 22% by weight, 14 to 21% by weight, 14 to 20% by weight, 15 to 22% by weight, 15 to 21% by weight, 15 to 20% by weight, 17 to 22% by weight, 17 to 21% by weight, or 17 to 20% by weight.

[0028] In the composition of the present invention, the content of histidine per total amino acids is usually 2.8% by weight or less, preferably 2.6% by weight or less, more preferably 2.4% by weight or less. Also, the lower limit of the content of histidine per total amino acids is usually 1.5% or more, preferably 1.8% by weight or more, more preferably 2% by weight or more. For example, the content of histidine per total amino acids can be 1.5 to 2.8% by weight, 1.5 to 2.6% by weight, 1.5 to 2.4% by weight, 1.8 to 2.8% by weight, 1.8 to 2.6% by weight, 1.8 to 2.4% by weight, 2 to 2.8% by weight, 2 to 2.6% by weight, or 2 to 2.4% by weight. This can be achieved. In the composition of the present invention, the content of cysteine per total amino acids is usually 2.2% or less, preferably 2.0% by weight or less, more preferably 1.7% by weight or less. Also, the lower limit of the content of cysteine per total amino acids is usually 1.0% or more, preferably 1.2% by weight or more, more preferably 1.4% by weight or more. For example, the content of cysteine per total amino acids can be 1 to 2.2% by weight, 1 to 2% by weight, 1 to 1.7% by weight, 1.2 to 2.2% by weight, 1.2 to 2% by weight, 1.2 to 1.7% by weight, 1.4 to 2.2% by weight, 1.4 to 2% by weight, or 1.4 to 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 sufficiently digested and absorbed and utilized in the body in the infants who ingest it. Therefore, even if the total protein content contained in the composition is reduced compared to the conventional ones, amino acid nutrition is sufficiently ensured.

[0030] That is, the total protein content in the composition of the present invention may be less than 2.15 g per 100 kcal of the composition, more preferably 2.05 g or less, and even more preferably 1.95 g or less. Also, the lower limit of the total protein content is usually 1.5 g or more, preferably 1.6 g or more, and more preferably 1.8 g or more per 100 kcal of the composition. For example, the total protein content in the composition of the present invention may be 1.5 g or more and less than 2.15 g, 1.5 to 2.05 g, 1.5 to 1.95 g, 1.6 g or more and less than 2.15 g, 1.6 to 2.05 g, 1.6 to 1.95 g, 1.8 g or more and less than 2.15 g, 1.8 to 2.05 g, or 1.8 to 1.95 g per 100 kcal of the 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. Also, 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 may 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] Conventionally, in order to ensure the amino acid composition and content contained in human breast milk, the total protein mass in infant nutritional compositions has tended to be excessively blended. However, as described above, by reducing the total protein mass, the burden on the digestion and metabolism of infants is eliminated, and nutritional intake with alleviated excess and deficiency is achieved.

[0032] In the present invention, the "nutritional composition for infants" refers to food and drink taken orally and is not particularly limited, but is preferably prepared milk, liquid food, etc., and more preferably prepared milk. The ingestion target may be infants, toddlers, children, or adults, but is preferably infants. Prepared powdered milk is defined in the ordinance of the Ministry of Health, Labour and Welfare regarding the ingredient standards of milk and dairy products (Ordinance on Milk, etc.) as "raw milk, cow's milk, special milk, or food products manufactured from these as raw materials, processed, or made into powder form with the addition of nutrients necessary for infants as the main raw material". Prepared liquid milk is defined in the aforementioned ordinance as "raw milk, cow's milk, special milk, or food products manufactured from these as raw materials, processed, or made into liquid form with the addition of nutrients necessary for infants as the main raw material". In addition, prepared milk is a product in which nutritional components such as various proteins, fats and oils, carbohydrates, minerals, and vitamins are blended, and includes those processed into powder or liquid form. In addition, prepared milk further includes "prepared powdered milk for infants", "prepared liquid milk for infants", and "powdered milk for pregnant and lactating women" among the foods for special purposes defined by the Health Promotion Act, and also includes forms such as prepared powdered milk for toddlers , nutritional powder for adults, nutritional powder for the elderly, etc. In the present invention, the "nutritional composition for infants" is more preferably prepared powdered milk for infants and prepared liquid milk for infants.

[0033] The composition of the present invention usually contains fats and oils in addition to the aforementioned proteins. As the fats and oils, it can include milk fat obtained from the milk of mammals such as cows, water buffalo, goats, and camels, animal fats and oils such as fish oil and egg yolk oil, vegetable fats and oils such as soybean oil, corn oil, sesame oil, perilla oil, rapeseed oil, palm oil, and sunflower oil, as well as oils and fats obtained by culturing microorganisms. In particular, it may contain unsaturated fatty acids usually contained in breast milk. Examples of unsaturated fatty acids include docosahexaenoic acid (DHA), arachidonic acid (ARA), eicosapentaenoic acid (EPA), linoleic acid, γ-linolenic acid (GLA), α-linolenic acid, dihomo-γ-linolenic acid (DHGLA), stearidonic acid, etc.

[0034] The composition of the present invention usually contains carbohydrates. Examples of carbohydrates include saccharides such as lactose, dextrin, starch, raffinose, lactulose, etc., and dietary fibers such as indigestible dextrin and inulin can also be included.

[0035] The composition of the present invention usually contains vitamins. Examples of vitamins include water-soluble vitamins such as vitamin B group and vitamin C, and fat-soluble vitamins such as vitamin A, vitamin D, and vitamin E can also be included.

[0036] The composition of the present invention usually contains minerals. As the minerals of the present invention, salts of sodium, potassium, calcium, iron, zinc, manganese, and copper can be used, and preferably, they can be formulated in the form of sodium chloride, potassium chloride, calcium carbonate, ferric pyrophosphate, zinc sulfate, manganese sulfate, copper sulfate, etc.

[0037] The nutritional composition for infants of the present invention can be produced by conventional methods. Hereinafter, taking the case where the composition is prepared milk as an example, the production method of the composition of the present invention will be described. A prepared milk raw material containing a predetermined amount of whey protein, casein, peptides, free amino acids, oils and fats, carbohydrates, vitamins, minerals, etc. is added to water, raw milk, skim milk, whey, etc., appropriately heated and mixed and dissolved, and then heat sterilized to prepare a liquid prepared milk. Some of the raw materials, the oils and fats, are pre-heated and melted and added to the raw material solution of the prepared milk prepared above. The raw material solution of the prepared milk added with oils and fats is preferably homogenized by a homogenizer. The oils and fats can be mixed with a solution in which a part of the raw material of the prepared milk is dissolved, homogenized once, and then the remaining raw material of the prepared milk is added to complete the raw material solution of the prepared milk.

[0038] The liquid prepared milk mixed and prepared as described above is heat-sterilized at 75 to 150 °C. As the heat-sterilization method, plate sterilization, injection sterilization, infusion sterilization, etc. can be used. Following the heat-sterilization step, a homogenization step can also be added to make the fat globules in the liquid uniform in size and achieve a good emulsified state. The heat-sterilized and produced liquid prepared milk is an intermediate product that can be used to produce the powdered prepared milk described later, and at the same time, it can also be the final product itself. That is, the heat-sterilized and produced liquid prepared milk can be hygienically transferred to a filling machine and filled directly into containers such as paper, plastic, and aluminum to make a product. Also, the raw material solution (prepared milk raw material) of the prepared milk can be heat-sterilized before mixing with the iron-binding whey protein solution.

[0039] The liquid prepared milk heat-sterilized as described above is further dried to produce powdered prepared milk This can be done. Also, before drying, the liquid prepared milk can be concentrated by a conventional method such as vacuum drying. Heat-sterilization and drying may be carried out in one step. In the drying step, spray drying with hot air or freeze drying can be carried out. Spray drying with hot air is preferable in that a certain sterilizing effect is exerted because it involves heating. The obtained powder can be filled and made into a product without adding new components, or it can be filled and made into a product after mixing with hygienically managed components, such as lactoferrin which may be denatured during sterilization.

Example

[0040] The present invention will be described more specifically below using examples, but the present invention is not limited to these examples.

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

[0042]

Table 2

[0043] (2) Quantification of amino acid content The amino acid contents of prepared milk powders 1 to 3 were quantified according to the following method. Table 3 shows the amino acid contents of prepared milk powders 1 to 3 together with breast milk.

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

[0045] (ii) Quantification method for methionine and cysteine 30% hydrogen peroxide (manufactured by Kokusan Chemical Co., Ltd.) and 99% formic acid (manufactured by Fujifilm Wako Pure Chemical Corporation) were mixed at a ratio of 1:9 (volume ratio) to prepare a performic acid solution. 30 mg of the prepared milk powder sample was weighed into a glass container, 3 mL of performic acid was added, and after sealing with parafilm, it was allowed to stand at 4°C for 18 hours to convert cysteine (cystine) in the sample to cysteic acid and methionine to methionine sulfone. The glass container was heated to 65°C in a heat block, and performic acid was removed by nitrogen blowing. Then, 3 mL of 6M hydrochloric acid (containing 0.1% by volume of phenol) was added, and the glass container was subjected to suction degassing and sealing. After hydrolysis at 110°C for 18 hours, the filtrate filtered through a cotton plug was subjected to an evaporator to remove hydrochloric acid, and the sample was redissolved with 5 mL of 0.02M hydrochloric acid. The redissolved sample, methionine sulfone standard product (manufactured by Fujifilm Wako Pure Chemical Corporation), and cysteic acid standard product (manufactured by Fujifilm Wako Pure Chemical Corporation) were subjected to a high-speed amino acid analyzer "L-8900 type" (manufactured by Hitachi High-Technologies Corporation) to quantify the methionine and cysteine contents in the sample.

[0046] (iii) Method for quantifying tryptophan Thiodiethylene glycol (manufactured by Fujifilm Wako Pure Chemical Corporation) and ultrapure water were mixed at a ratio of 6:4 (volume ratio) to obtain a 60% thiodiethylene glycol solution. 20 mg of the prepared milk powder sample was weighed into a glass container, 1.56 g of barium hydroxide pentahydrate (manufactured by Fujifilm Wako Pure Chemical Corporation), 0.9 ml of ultrapure water, and 0.1 mL of 60% thiodiethylene glycol were added, and then the glass container was subjected to suction degassing and sealing. After hydrolysis at 110°C for 12 hours, it was neutralized and diluted with 6M hydrochloric acid (manufactured by Kokusan Chemical Co., Ltd.) to a pH of 7-9, and made up to 50 mL with ultrapure water. The made-up sample and tryptophan standard product (manufactured by Fujifilm Wako Pure Chemical Corporation) 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) Quantification of casein content Casein standard product (manufactured by Sigma-Aldrich, catalog number: C7078) was dissolved in 8M urea aqueous solution to a total protein concentration of 0.27, 0.67, 1.07 mg protein / mL, and prepared milk powder 1-3 was dissolved in 8M urea aqueous solution to a total protein concentration of 1.33 mg protein / mL. To this, 10% by volume of 2-mercaptoethanol (manufactured by Bio-Rad) was added, and 1 / 4 equivalent of 4x Laemmli sample buffer (manufactured by Bio-Rad, catalog number: 1610747) was added. After heat denaturation at 95°C for 5 minutes, 10 μL of each was applied to the wells of an SDS-PAGE gel (manufactured by Bio-Rad, catalog number: 456-9036) in electrophoresis buffer (manufactured by Bio-Rad, catalog number: 1610377). As for the total protein mass applied, the casein standard product was 2, 5, and 8 μg, and prepared milk powder 1-3 was 10 μg. The gel electrophoresed at 150 V for 45 minutes was stained with Coomassie Brilliant Blue staining solution (manufactured by Bio-Rad, catalog number 456-9034) and converted into an electrophoresis image using a ChemiDoc XRS+ imaging system (manufactured by Bio-Rad). Using the Volume Tools function of Image Lab software (manufactured by Bio-Rad ), the bands corresponding to casein in each lane in the image were selected, and the intensity of the bands was calculated (Figure 1). Based on the calibration curve created from the total protein masses of the three casein standard products and the band intensities corresponding to those protein masses, the casein content per 10 μg of total protein in prepared milk powder 1-3 was calculated. The bands to be selected included all of α-casein, β-casein, and γ-casein located in the range of 20 ~37 kDa near the center of the image, and the selected area of the bands in each lane was the same. As a result, the casein content per 10 μg of total amino acids in prepared milk powder 1-3 was 3.2, 4.4, and 5.9 μg in order. This indicates that the casein content per total protein of Prepared Milk Powders 1 to 3 is 32% by weight, 44% by weight, and 59% by weight, respectively.

[0049] (4) Administration Test on Rats Six-week-old male SD rats were purchased from Charles River Japan. After acclimation feeding with a normal diet for 12 days, they were divided into three groups (n = 5) so that there was no bias in body weight. Thereafter, the diet of each group was switched to any one of Prepared Milk Powders 1 to 3, and the breeding was continued for one week. Blood was collected on the last day to prepare plasma samples. The food intake and body weight of the rats were recorded daily, and it was confirmed that there was no difference among the groups. An equal amount of 10% trichloroacetic acid solution was added to the plasma samples, and after centrifuging at 21,500 g for 15 minutes to obtain the supernatant, the supernatant samples and amino acid standards (manufactured by FUJIFILM Wako Pure Chemical Corporation) were subjected to a high-speed amino acid analyzer "Model L-8900" (manufactured by Hitachi High-Technologies Corporation) to quantify the free amino acid concentration in the plasma. Table 4 shows the free amino acid concentrations in the plasma of rats that ingested Prepared Milk Powders 1 to 3.

[0050]

Table 4

[0051] In vivo, when a specific essential amino acid is deficient, the free amino acid concentration of the amino acid in the plasma decreases, and when a specific essential amino acid is ingested in excess, it is widely known that the free amino acid concentration of the amino acid in the plasma increases (Physiological reviews 50 P428 (1970)). That is, it can be said that the free amino acid concentration of essential amino acids in the plasma is an index reflecting the deficiency or excess of amino acid nutrition in the body.

[0052] The total protein contents of Prepared Milk Powder 2 and Prepared Milk Powder 3 according to the present invention were reduced compared to Prepared Milk Powder 1. However, as shown in Table 3, in the Prepared Milk Powder 2 group and the Prepared Milk Powder 3 group, the essential amino The plasma free amino acid concentration of amino acids, except for threonine, was equal to or higher than that of the plasma free amino acid concentration in Group 1 of the prepared milk powder. The plasma free threonine concentration in Group 2 of the prepared milk powder was significantly lower than that in Group 1 of the prepared milk powder. However, as described above, in conventional prepared milk powder, it has been pointed out that the content of threonine is excessive compared to breast milk (Table 1). Therefore, Prepared Milk Powder 2 is considered to supply more desirable amino acid nutrition for human infants. In addition, the plasma free tyrosine concentration in Group 3 of the prepared milk powder was significantly higher than that in Group 1 of the prepared milk powder. However, as described above, in conventional prepared milk powder, it has been pointed out that the total content of tyrosine and phenylalanine is insufficient compared to breast milk (Table 1). Therefore, Prepared Milk Powder 3 is considered to supply more desirable amino acid nutrition for human infants.

[0053] That is, the present invention provides an infant nutritional composition with an amino acid composition closer to breast milk, which can ensure sufficient amino acid nutrition without excessive protein intake by reducing the 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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