Nutritional fortification products and foods containing them

Abstract

We provide nutritionally fortified products that allow for easy and consistent protein intake with every meal. [Solution] A product added to food for nutritional fortification, characterized in that: the product contains 95% by weight or more of whey protein isolate (WPI) powder with a protein content of 90% by weight or more; the proportion of low molecular weight protein components in the total protein content of the WPI powder is less than 1%; the low molecular weight protein components are the protein components that pass through the filter when an aqueous solution of the WPI powder is centrifuged using a centrifugal ultrafiltration filter with a nominal fractionation molecular weight of 10 kDa, and which exhibit coloration by the bicinchonic acid (BCA) method; and the proportion is a value obtained by determining the absorbance of the aqueous solution of the WPI powder before centrifugal filtration (A) and the absorbance of the filtrate after centrifugal filtration (B) using the BCA method, dividing B by A and expressing it as a percentage.

Description

Technical Field

[0001] The present invention relates to a nutritional enhancement product for use by adding to food, and more specifically, to a whey protein product suitable for adding to food and eating, and food containing the same.

Background Art

[0002] As people age, generally the amount of food intake decreases, and the protein intake per meal and per day decreases. The decrease in protein intake promotes the decline in muscle strength or muscle mass associated with aging (so-called sarcopenia), and sarcopenia leads to frailty.

[0003] Epidemiological studies have shown that preventing frailty by protein intake is effective for maintaining the healthy life span of the elderly. It has also been reported that a high intake of animal-derived protein may be associated with a reduced risk of future high-order functions (the risk of falling into outcomes such as functional impairment in daily life, the need for care, and death). Therefore, increasing the intake of animal protein is desirable for the elderly.

[0004] Since protein is an essential nutrient for the human body, it is important to maintain health by ingesting an appropriate amount daily, not only for the elderly. To ingest an appropriate amount of protein, it has been conventionally practiced to ingest a protein supplement in addition to or instead of a meal. Examples of protein supplements include whey protein, casein protein, and soy protein. Among these, whey protein is a high-quality protein source that contains essential amino acids in a balanced manner, contains a large amount of BCAA (branched-chain amino acid) that promotes the synthesis of muscle protein and controls its decomposition, and has good digestion and absorption, and is considered effective for muscle protein synthesis.

[0005] Whey protein products are sold in powder form and consumed by dissolving or suspending them in water or other liquids. While such products are convenient for people who want to increase muscle mass or replace meals with protein powder, consuming protein powder drinks daily can be a burden for elderly people with reduced appetites. If increasing protein intake becomes a burden or the enjoyment of each meal is lost, it becomes difficult to continue, so there is a need for a way to consume protein without stress.

[0006] Attempts have already been made to increase protein intake without causing any burden by adding protein to food. For example, Patent Documents 1 to 3 disclose inventions related to protein products for addition to food and foods with added protein. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 5377202 [Patent Document 2] Patent No. 5377203 [Patent Document 3] Japanese Patent Publication No. 2020-150805

[0008] However, there is still a demand for products that can fully meet multiple needs, such as being easy to incorporate into daily meals, being able to be consumed without increasing food intake, and being delicious and easy to eat without any unpleasant taste. [Overview of the project] [Problems that the invention aims to solve]

[0009] In view of the current situation, the present invention aims to provide a product that can supplement protein without impairing the taste or flavor of food (especially soups such as miso soup) so that elderly people can easily consume it every day. [Means for solving the problem]

[0010] To solve the aforementioned problem, the inventors hypothesized that if whey protein could be added to miso soup and other dishes frequently consumed by the elderly, they could increase their protein intake without feeling burdened. However, when whey protein was actually added to miso soup, the flavor of the soup clearly changed. Even if muscle strengthening could be expected from the addition of protein, it would be difficult to continue consuming it if the meal did not taste good. Therefore, after further research, it was found that even among WPIs containing high concentrations of protein, WPI with a reduced content of low molecular weight protein components does not impair the flavor of miso soup when added.

[0011] The present invention, which can solve the above problems, has the following configuration. [1] Products added to food for nutritional fortification, It must contain 95% or more by weight of whey protein isolate (WPI) powder with a protein content of 90% or more by weight. The proportion of low molecular weight protein components in the total protein content of the WPI powder is less than 1%. The low molecular weight protein component is the protein component that passes through a centrifugal ultrafiltration filter with a nominal molecular weight cutoff of 10 kDa when an aqueous solution of the WPI powder is centrifuged using the said filter, and which exhibits coloration by the bicinchonic acid (BCA) method. The aforementioned ratio is a value obtained by determining the absorbance of the aqueous solution of the WPI powder before centrifugal filtration (A) and the absorbance of the filtrate after centrifugal filtration (B) using the BCA method, and then dividing B by A and expressing it as a percentage. Nutritionally fortified products characterized by [specific features]. [2] A nutritional fortified product as described in [1], intended for consumption as an addition to soups. [3] The nutritional fortified product according to [2], wherein the soup is miso soup. [4] Foods containing any one of the nutritional fortification products listed in [1] to [3]. [5] The instant food for soup, as described in [4]. [6] The food according to claim 5, wherein the soup is miso soup. [Effects of the Invention]

[0012] The nutritional fortification products according to the present invention are not only suitable for efficient protein intake, but also have little impact on the taste when added to foods such as miso soup. Therefore, according to the present invention, it is possible to provide nutritional fortification products and foods that can be incorporated into daily meals without any discomfort. [Modes for carrying out the invention]

[0013] The residue left over after cheese production from milk is called cheese whey, and the residue left after casein is removed from milk is called acid whey. Products made by processing these wheys to increase their protein concentration are called whey protein.

[0014] There are three types of whey protein known: WPC (Whey Protein Concentrate), WPI (Whey Protein Isolate), and WPH (Whey Protein Hydrolysate). WPC is a type of whey protein with a protein content of approximately 70-85% by weight. It is produced by a membrane filtration method, where whey is filtered through a membrane (filter), and the protein components that do not pass through the membrane are concentrated and dried. For example, WPC can be produced by concentrating whey through an ultrafiltration (UF) membrane, or by concentrating whey through a microfiltration (MF) membrane followed by a UF membrane. WPC has a low protein purity and does not completely remove lipids and carbohydrates, but it is characterized by its sweet taste, ease of consumption, and low price. WPI is a whey protein with a higher protein purity than WPC, and its protein content is about 90% by weight or more. WPI is usually manufactured by removing impurities by an ion exchange method to concentrate the protein component, followed by concentration through a UF membrane and then drying. WPI has less carbohydrates and lipids, so it has lower calories than WPC and is characterized by being drinkable even for people with lactose intolerance. WPH is a product obtained by hydrolyzing whey protein into peptides with an enzyme and is characterized by a fast absorption rate.

[0015] Among the commercially available whey protein powders, WPC powder is the most common in the market. However, when WPC powder is added to miso soup, the flavor of the miso soup deteriorates. Also, when WPI powder manufactured by an ion exchange method or a milk protein hydrolyzate is added to miso soup, the flavor of the miso soup deteriorates.

[0016] On the other hand, WPI powder with the proportion of low molecular weight protein components in the total protein amount reduced to less than 1% could be eaten without a sense of discomfort without impairing the flavor of the miso soup even when added to the miso soup.

[0017] Although not wishing to be bound by theory, whey protein contains not only proteins with a large molecular weight but also relatively low molecular weight peptides, free amino acids, etc. Such low molecular weight protein components have a taste property. Therefore, it is considered that by using WPI powder with these reduced to less than 1%, the influence on the taste of food is suppressed.

[0018] The method for measuring the protein content in WPI is well-known in the art. Specifically, according to the semi-micro Kjeldahl method, after measuring the total nitrogen in the sample, the total protein amount can be calculated by multiplying by a conversion factor (6.38). In the present invention, WPI with a protein content of 90% by weight or more is used.

[0019] In this specification, low molecular weight protein components refer to protein components that pass through a centrifugal ultrafiltration filter with a nominal molecular weight cutoff of 10 kDa when an aqueous solution prepared by completely dissolving WPI powder in phosphate buffer is centrifuged, and that can be measured by the BCA (bicinchoninic acid) method. Detailed measurement methods are as described in the examples. In this specification, protein components are intended to include not only proteins but also amino acids and peptides.

[0020] The WPI powder contained in the nutritional fortification product of the present invention can be produced, for example, by concentrating whey by treating it with a UF membrane (also called an ultrafiltration membrane), then with an MF membrane (also called a microfiltration membrane), and then with an NF membrane (nanofiltration membrane), spray-drying the resulting concentrate to make a powder, and coating it with lecithin as needed. In the above method, the order of the UF membrane treatment and the MF membrane treatment may be reversed. Alternatively, the proportion of low molecular weight protein components may be reduced to less than 1% by performing ion exchange treatment before NF treatment instead of UF membrane treatment and / or MF membrane treatment. Alternatively, the protein purity may be further increased by using the above three-stage membrane concentration process in combination with the ion exchange method.

[0021] As mentioned above, WPI powder is generally manufactured via ion exchange, but WPI is not limited to products manufactured by ion exchange; it refers to products with a higher protein content than WPC (generally those with a protein content of 90% by weight or more). Therefore, whey protein with a protein content of 90% by weight or more, achieved by using a more advanced membrane concentration method than that typically used in the WPC manufacturing process, is also included in the category of WPI.

[0022] The nutritional fortification product of the present invention preferably contains 95% by weight or more of the WPI powder, may contain 97% by weight or more, 98% by weight or more, or 99% by weight or more, or may consist only of WPI powder.

[0023] The WPI powder of the present invention may be coated with lecithin to enhance its solubility. Lecithin-coated WPI powder is also included in the WPI powder of the present invention. Examples of lecithin used for lecithin coating include soy lecithin, sunflower lecithin, rapeseed lecithin, and egg yolk lecithin. Methods for lecithin coating are well known in the art; for example, WPI powder can be coated by spraying a lecithin solution onto it during a further drying step of WPI powder produced by spray drying.

[0024] The particle size of the WPI powder of the present invention is not particularly limited, but the median diameter (D) measured by laser diffraction scattering is not particularly limited. 50 The particle size is preferably 30 to 500 μm, more preferably 50 to 300 μm, and particularly preferably 70 to 200 μm.

[0025] The WPI powder of the present invention is suitable for consumption as an additive to food because it contains few flavor components such as amino acids and peptides. In particular, it is suitable for consumption as an additive to soups such as miso soup, clear soup, potage soup, and consommé soup. Adding it to miso soup is preferable because it is easy for the elderly to incorporate it into their daily meals.

[0026] The nutritional fortification product of the present invention may be added directly to cooked food, or it may be added to food in advance by a food processing manufacturer or the like. For example, it may be included in frozen food that can be eaten simply by heating it in a microwave oven, or in instant food that can be eaten simply by adding hot water.

[0027] A preferred example of a food containing the nutritional fortified product of the present invention is instant soup, such as instant miso soup. Such instant soups may be solid (e.g., in block, granular, or powder form) produced by methods such as freeze-drying or spray-drying. Some instant soups contain a paste-like soup base (e.g., fresh miso paste) and dried ingredients (e.g., green onions, okra, wakame seaweed, tofu, etc.) packaged separately. In this case, it is preferable that the nutritional fortified product of the present invention be packaged together with the dried ingredients.

[0028] The preferred daily intake of WPI powder according to the present invention varies depending on the age, sex, weight, etc. of the person taking it, but for the elderly, it is preferable to take 5g or more per day, for example, about 10g to 30g. The daily intake may be taken all at once, but since WPI is absorbed quickly, it is more preferable to take it in multiple doses (for example, 2 to 3 times).

[0029] The food of the present invention preferably contains 2 to 20 g, 3 to 15 g, 4 to 10 g, or 4.5 to 7 g of the WPI powder per serving. A preferred example is an instant soup individually packaged for each serving containing 4 to 20 g of the WPI powder of the present invention (for example, a block-shaped instant soup manufactured by freeze-drying). In particular, it is ideal to consume 10 g to 30 g of WPI powder by eating an instant food (for example, instant miso soup) containing about 4 to 10 g (for example, 4.5 to 6 g) of the WPI powder of the present invention once or multiple times a day.

[0030] Miso soup is a particularly suitable food to which the nutritional fortification product of the present invention is added. In this case, the miso may be red miso, white miso, rice miso, soybean miso, or blended miso, and the origin of the miso's raw materials or place of origin is not limited. Furthermore, the miso soup may be made from powdered miso, fresh miso, or freeze-dried products.

[0031] The nutritional fortified product of the present invention may contain additives such as vitamin components and / or mineral components in addition to the WPI powder described above. The nutritional fortified product of the present invention does not necessarily have to contain vitamin B6 and / or zinc.

[0032] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. [Examples]

[0033] The protein sources used were all powdered whey proteins: Daiichi Lacto Q (Daiichi Kasei Co., Ltd., WPI, manufactured using membrane processing only, with lecithin coating), Daiichi Lacto D-24 (Daiichi Kasei Co., Ltd., WPI, manufactured using membrane processing only), Daiichi Lacto EM-90 (Daiichi Kasei Co., Ltd., WPI, manufactured using ion exchange method), Daiichi Lacto EM-80D (Daiichi Kasei Co., Ltd., WPC), Daiichi Lacto EM-G (Daiichi Kasei Co., Ltd., WPC), Rich Pro W800 (Daiichi Kasei Co., Ltd., hydrolyzed milk protein), and May Protein (Meiji Co., Ltd., protein supplement). Only Daiichi Lacto Q was lecithin coated. Table 1 shows the protein, ash, carbohydrate, and lipid content per 100g of each protein source.

[0034] [Confirmation Test 1] Measurement of low molecular weight protein components (BCA method) The proportion of low molecular weight protein components in the total protein content of each protein material was measured. The measurement results are shown in Table 1. The measurement method is as follows. A 0.2 w / v% aqueous solution of approximately 50 mL was prepared (stock solution) by adding the protein material to 20 mmol / L pH 7.5 phosphate buffer and completely dissolving the protein material using vibrations from an ultrasonic cleaner. Next, a centrifuge test tube equipped with an ultracentrifuge filter with a nominal molecular weight cutoff of 10 kDa (Amicon) was used. [登録商標]10 g of the stock solution was placed in an Ultra-15 centrifugal filter device (10,000 NMWL, Merck Millipore) and centrifuged at 20°C and 4000 × g for 50 minutes. The filtrate containing the components (low molecular weight protein components) that passed through the filter was then collected. 50 μL each of the stock solution and filtrate were mixed with 250 μL of the phosphate buffer and 3 mL of BCA reagent (Protein Assay BCA Kit, Fujifilm Wako Pure Chemical Industries, Ltd.) and reacted at 37°C for 30 minutes. After the reaction, the mixture was cooled to room temperature with running water and measured at OD562 nm (Shimadzu UV-2600i). The phosphate buffer was used as the blank sample. The value obtained by subtracting the absorbance of the blank sample from the absorbance of the stock solution was defined as "A," and the value obtained by subtracting the absorbance of the blank sample from the absorbance of the filtrate was defined as "B." The ratio of low molecular weight protein components to the total protein amount was calculated by dividing B by A and multiplying by 100 (B / A(%)). The results are shown in Table 1.

[0035] [Table 1]

[0036] WPI produced solely by membrane processing has a protein content of 90% by weight or more, similar to WPI produced via ion exchange. Daiichilacto Q is a powder made by coating Daiichilacto D-24 with lecithin, and compared to Daiichilacto D-24, it has a higher amount of carbohydrates and lipids due to the lecithin coating.

[0037] [Confirmation Test 2] Measurement of particle size distribution and solubility The particle size distribution of each protein material (in powder form) was measured using laser diffraction scattering. Measuring instruments: SALD-2200, SALD-DS21 (Shimadzu Corporation) Suction method: Turntable method Average number of measurements: 16 Refractive index: 1.60-0.10i

[0038] The solubility in water was measured using the following procedure. A 200 mL glass beaker (outer diameter x height: 68 x 91 mm) was used, 100 mL of deionized water was added, and the stirrer bar was rotated to adjust the vortex height to 2.5 cm. Then, 1.0 g of the protein material was added. The time until complete dissolution was measured and used as an indicator of solubility.

[0039] The measurement results are shown in Table 2. [Table 2]

[0040] WPI produced solely by the membrane treatment method showed a larger particle size than WPI produced by the ion exchange method. However, this difference in particle size is thought to be due to differences in manufacturing methods, such as the spray drying process, rather than differences in raw material composition. Daiichilacto Q exhibited a larger particle size than Daiichilacto D-24 due to its lecithin coating, and dissolved more easily than other protein materials after lecithin treatment.

[0041] [Evaluation Test 1] Dispersion and solubility in powdered instant miso soup Each protein source (3.5g) was pre-mixed with 4.6g of commercially available powdered miso (instant miso). The entire mixture was placed in a cup, and 91.9g of 70°C hot water was poured over it (total volume 100g). Ten panelists visually evaluated the dispersion and solubility after lightly stirring with a stirrer. Solubility was evaluated on a three-point scale as shown below, and the average score was calculated. Note that the powdered miso itself disperses and dissolves easily simply by adding hot water. Also, one serving of miso soup (150g) contains 5.25g of protein source. 5 points: Dispersed and dissolved by stirring. 3 points: Even after stirring, there were still some lumps and undissolved particles. 1 point: Even after stirring, there were many lumps and undissolved particles.

[0042] [Evaluation Test 2] Sensory evaluation when added to powdered instant miso soup Ten panelists tasted the miso soup prepared in Evaluation Test 1 and evaluated its flavor through sensory perception. They evaluated the flavor on the following five-point scale, and the average score was calculated. 5 points: It had almost no protein flavor and was delicious to drink. 4 points: It didn't have much of a protein flavor and was drinkable. 3 points: Neither agree nor disagree. 2 points: It had a slight protein flavor, which made it difficult to drink. 1 point: It had a protein-like flavor and I couldn't drink it.

[0043] The results of evaluation tests 1 and 2 are shown in Table 3. [Table 3]

[0044] Regarding solubility, since miso soup itself is originally in a suspended state, none of the products significantly affected the appearance of the miso soup. However, Daiichi Lacto Q, a lecithin-coated WPI powder, exhibited the best dispersion and solubility, resulting in a miso soup appearance that was completely indistinguishable from the original.

[0045] Regarding taste, both WPIs produced solely by the membrane processing method (Examples 1 and 2) did not impair the natural flavor of the miso soup and could be consumed without any discomfort. No change in flavor due to lecithin coating was observed. In contrast, WPI, WPC, hydrolyzed milk protein, and protein supplements (Comparative Examples 1-4) produced by the ion exchange method all, to varying degrees, impaired the flavor of the miso soup.

[0046] As shown in Table 1, WPC, hydrolyzed milk protein, and protein supplements have a low protein content and therefore contain a large amount of impurities (carbohydrates and lipids). It is possible that these whey proteins affect the flavor of food due to these impurities. However, both Daiichi Lacto Q and Daiichi Lacto EM-90 are WPIs with a protein content of 90% by weight or more and are low in carbohydrates and lipids. Despite this, there was a significant difference in their impact on the flavor of miso soup.

[0047] Daiichilact EM-90 is manufactured using a common method for WPI production, namely, by increasing the protein concentration using ion exchange and then treating it with a UF membrane. In contrast, Daiichilact Q is produced by repeatedly concentrating the protein using MF, UF, and NF membranes, thereby eliminating low-molecular-weight components that pass through the membrane and increasing the protein concentration. Therefore, Daiichilact Q should contain very few relatively low-molecular-weight peptides or free amino acids (components that pass through the membrane). Peptides and amino acids have taste-enhancing properties depending on their type and combination, so differences in the amount of low-molecular-weight protein components may be contributing to differences in taste when added to food. In the next test, we examined the difference in taste of WPI itself before it was added to food.

[0048] [Evaluation Test 3] Evaluation test using a taste recognition device for protein materials A taste recognition device was used to investigate the difference in taste between WPI produced solely by the membrane processing method and WPI produced via the ion exchange method. The test procedure was as follows:

[0049] A protein material was added to 10 mmol / L potassium chloride and dissolved by stirring with a magnetic stirrer to prepare a 3.28 w / w% test solution. The taste characteristics of the test solution were measured using a taste recognition device SA402B (Intelligent Sensor Technology Co., Ltd.). Five types of lipid membrane sensors (AAE, CT0, CA0, C00, and AE1) were used, and measurements were repeated four times. The first measurement was discarded, and the values ​​analyzed from the average were converted into taste parameters. Samples with insignificant inter-sample discrimination and those with no taste were excluded from evaluation according to the manual. According to the user manual for this device, a difference in taste that a person can perceive is defined as a measurement difference greater than "±1," and a difference greater than "±0.5" is considered to be recognizable by trained individuals such as analytical sensory testers or those with a keen sense of taste.

[0050] The results are shown in Table 4. [Table 4]

[0051] WPI produced solely by the membrane processing method showed significantly lower values ​​(a difference of 2 or more) in the bitterness and off-flavor categories compared to WPI produced via the ion exchange method, demonstrating a significant difference in taste.

[0052] [Confirmation Test 3] Size Exclusion Chromatography As is clear from the above tests, there was a significant difference in the taste of WPI itself between WPI produced solely by membrane processing and WPI produced via ion exchange, and there was also a large difference in their impact on the taste of food. The reason for this is thought to be that WPI produced solely by membrane processing has a lower content of low-molecular-weight peptides (dipeptides, tripeptides, etc.) and amino acids, which are presumed to be involved in taste.

[0053] The BCA method used in confirmation test 1 involves adding a reagent containing bicinchoninic acid (BCA) and copper sulfate to a sample containing protein components under alkaline conditions, resulting in peptides of three or more amino acids being converted into divalent copper ions (Cu2+ ) forms a chelate complex with (biuret reaction), and then this divalent copper ion is converted to a monovalent copper ion (Cu) by the protein. + The BCA method utilizes the principle that the copper ion is reduced to a monovalent copper ion, and this monovalent copper ion then coordinates with two molecules of BCA, resulting in a purple color. For this reason, the BCA method does not react with components that do not form complexes with copper ions, or with amino acids that number only one or two.

[0054] To complement the BCA method, each WPI was analyzed by size exclusion chromatography to confirm the presence of low molecular weight protein components, including amino acids and dipeptides, which are presumed to be involved in the taste.

[0055] Analysis conditions HPLC system: Nexera (Shimadzu Corporation) Column: Tosoh TSKgel-G2000SWXL, inner diameter 7.8 mm x length 300 mm, silica packing particle size 5 μm (fractionation range: globular proteins 5,000~150,000) Mobile phase: 0.5mol / L Na2SO4, 0.02mol / L NaPi (pH7.0) Flow rate: 1.0 mL / min, Column temperature: 22°C, Injection volume: 50 μL, Sample cooler: 15°C Detector: SPD-M40 (210nm)

[0056] While 210nm or 280nm wavelengths are typically used for protein measurement by absorbance, 210nm was chosen for this study. The reasons for this choice are that 280nm measurement fails to detect amino acids and peptides that do not contain aromatic compounds, 210nm also detects components other than protein (such as organic acids), but can measure amino acids that 280nm cannot, and WPI is composed of over 90% protein by weight, resulting in fewer impurities such as organic acids. As a test solution, a 0.2 w / v solution of the protein material was prepared using the mobile phase solution.

[0057] Under the above analytical conditions, β-lactoglobulin (β-Lg: 18.4 kDa) is excluded, and substances smaller than α-lactalbumin (α-La: 14 kDa) are detected as the main component. It is expected that some of the substances smaller than α-La are involved in taste. The total area of ​​the chromatogram was defined as "Ta," and the area of ​​the low-molecular-weight substances retained after α-La was defined as "a." The percentage of the low-molecular-weight area was calculated by dividing a by Ta and multiplying by 100 (a / Ta (%)).

[0058] When Daiichilacto Q and Daiichilacto EM-90 were measured using the method described above, the proportion of low molecular weight area was 18.1% for Daiichilacto Q and 20.1% for Daiichilacto EM-90, showing a significant difference between the two (p<0.05). Therefore, the conclusion that WPI (Daiichilacto Q) produced solely by the membrane processing method has a lower content of taste-enhancing amino acids and dipeptides than WPI (Daiichilacto EM-90) produced via the ion exchange method, and thus is less likely to affect the taste of food, was supported.

[0059] [Evaluation Test 4] Sensory evaluation when added to fresh miso soup Two types of commercially available raw miso were weighed out in 7.5g portions to make a total of 15g. This was dissolved in 150g of 70°C hot water, and 5.6g of protein material was added to prepare miso soup at a concentration suitable for actual consumption. Subsequently, the taste of the miso soup was measured using a taste recognition device, as in Evaluation Test 3. The raw miso used was Ryotei no Aji (with dashi) (Marukome Co., Ltd.) and Fumi Ichiban (with dashi) (Hanamaruki Co., Ltd.). Each serving (150g) of miso soup contains 4.92g of protein.

[0060] The results are shown in Table 5. [Table 5]

[0061] Compared to miso soup without added protein material (control), the miso soup of Example 3 fell within the ±1 range for all measured items. Since the taste recognition device used in the experiment considers a relative value within ±1 to be negligible to human taste, this result is consistent with the sensory test results indicating that the miso soup could be consumed without any discomfort even after adding Daiichi Lacto Q. Furthermore, the slight positive values ​​for each item suggest that Daiichi Lacto Q also enhanced the overall flavor of the miso soup. In contrast, the miso soups in Comparative Examples 5-8 all had bitterness and off-flavor values ​​that were 2 or more points higher than the control, confirming that these whey proteins impair the flavor of the miso soup, similar to the results of the sensory evaluation.

[0062] [Evaluation Test 5] Evaluation test of the difference in odor when added to fresh miso soup. Of the miso soups prepared in Evaluation Test 4, Example 3 and Comparative Example 5 were evaluated using the odor identification device FF-2020S (Shimadzu Corporation). The odor identification device is characterized by its ability to evaluate the overall strength and quality of odors by creating a reference axis using 10 gas sensors and 9 types of standard gases, and by measuring and analyzing odor components without separation. The measurement procedure is as follows.

[0063] 0.5 mL of miso soup was placed in a 3 L simple sample bag, and 2 L of dry pure nitrogen gas was added. The bag was then left to stand in a 50°C constant temperature bath for 30 minutes. After that, the generated gas was transferred to another sample bag, and the odor was analyzed using absolute value expression analysis Asmell.

[0064] The results are shown in Table 6. [Table 6]

[0065] The odor index values ​​shown in Table 6 represent the intensity of the odor. A difference of 3 or more in these values ​​indicates a difference that can be perceived by the human sense of smell. The inter-sample similarity is expressed as a percentage of the similarity between samples. A value of 90% or higher indicates a difference that cannot be judged by the human sense of smell and is considered to be within the margin of error. The measurement results showed that neither WPI (Whey Protein Ion) affected the aroma of the miso soup when added to it.

[0066] [Evaluation Test 6] Solubility and Sensory Evaluation Test of Freeze-Dried Miso Soup 11.1g of WPI was mixed with 30g of commercially available raw miso and 150g of deionized water. 10g of this mixture was frozen and then dried using a freeze dryer to prepare freeze-dried miso soup. For control, freeze-dried miso soup was prepared using the same method, but without WPI, and with the amount of deionized water increased accordingly (161.1g). The raw miso used was Ryotei no Aji (with dashi) (Marukome Co., Ltd.) and Fumi Ichiban (with dashi) (Hanamaruki Co., Ltd.), with 15g of each used. It is assumed that twice the amount of hot water added before drying (300g) will be added when consuming the miso soup, resulting in 4.88g of protein per serving (150g) of miso soup.

[0067] 20 mL of 70°C hot water was poured over these freeze-dried products, and their solubility was visually evaluated. Their flavor was then evaluated through a sensory test (six panelists for each test). The scores are as shown in Evaluation Tests 1 and 2.

[0068] The results are shown in Table 7. [Table 7]

[0069] As shown in Table 7, freeze-drying miso soup with added WPI improved its dispersibility and solubility. The sensory evaluation results for taste were almost the same as those for powdered miso soup. Freeze-dried miso soup containing WPI produced solely by the membrane processing method had a natural flavor that was almost indistinguishable from regular miso soup. However, freeze-dried miso soup containing WPI produced by the ion exchange method had a significant impact on the miso soup's flavor and exhibited an unnatural taste. [Industrial applicability]

[0070] The nutritional fortification products of the present invention can be added to meals simply by adding them, thus increasing protein intake without adding an extra dish or increasing the amount of food consumed. Furthermore, they do not impair the flavor of the food, so they can be enjoyed without any sacrifices. For this reason, the nutritional fortification products and foods of the present invention are suitable for people who want to increase their protein intake without feeling burdened, and are particularly suitable for elderly people who are at risk of sarcopenia and frailty due to reduced food intake. Because the nutritional fortification products and foods of the present invention are useful in maintaining the quality of life of the elderly, they can be used not only at home but also in various facilities such as hospitals and nursing homes.

Claims

1. Products added to food for nutritional fortification, It must contain 95% or more by weight of whey protein isolate (WPI) powder with a protein content of 90% or more by weight. The proportion of low molecular weight protein components in the total protein content of the WPI powder is less than 1%. The low molecular weight protein component is the protein component that passes through the filter when an aqueous solution of the WPI powder is centrifuged using a centrifugal ultrafiltration filter with a nominal fractionation molecular weight of 10 kDa, and which exhibits coloration by the bicinchonic acid (BCA) method. The aforementioned ratio is a value obtained by determining the absorbance (A) of the aqueous solution of the WPI powder before centrifugal filtration and the absorbance (B) of the filtrate after centrifugal filtration using the BCA method, and then dividing B by A to express it as a percentage. Nutritionally fortified products characterized by [specific features].

2. A nutritional fortified product according to claim 1, for consumption by adding it to soup.

3. The nutritional fortified product according to claim 2, wherein the soup is miso soup.

4. A food containing the nutritional fortified product according to any one of claims 1 to 3.

5. The food according to claim 4, which is an instant food for soup.

6. The food according to claim 5, wherein the soup is miso soup.

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