JP6139150B2 - Protein nutritional composition - Google Patents

Description

  The present invention relates to a composition for supplementing protein, and more particularly, to a protein nutrition supplement composition intended for patients with impaired renal function, particularly artificial dialysis patients. Artificial dialysis patients often fall into a chronic undernourishment, and in particular tend to lack protein nutrition. Many foods and protein preparations containing a large amount of protein contain a large amount of phosphorus and potassium. However, since phosphorus and potassium are excreted by the kidney, they accumulate in the body when the kidney function decreases. Therefore, in such patients, phosphorus intake, which increases with protein intake, causes arteriosclerosis and bone lesions, and excessive potassium intake causes increased risk of cardiac diseases such as arrhythmia and tachycardia. Each is a problem.

  The main components of protein contained in rice endosperm are easily digestible glutelin, globulin, albumin and indigestible prolamin. As a method of producing a protein composition extracted from rice endosperm, heat-resistant amylase is allowed to act on polished rice or rice flour, and the remaining protein is recovered as a precipitate (enzyme-treated rice protein), There is a known method (alkaline-extracted rice protein) for precipitating and recovering the protein extracted by adding an alkaline solution, and the protein utilization efficiency as a nutrient is significantly higher in the latter than in the former. Has been reported to be comparable to casein (Non-patent Document 1).

  Patients with kidney disease, especially those with dialysis, are chronically undernourished. In addition to the increase in protein catabolism associated with artificial dialysis, phosphorus and potassium taken at the same time as protein intake accumulates in the blood, which adversely affects the body. This is because the amount of protein intake is limited in order to limit intake.

  Milk protein and soybean protein are widely used as protein sources, but these are not preferable as protein nutrient sources for patients with renal diseases because of their high phosphorus and potassium contents. Although techniques for removing phosphorus and potassium from milk proteins by ion exchange resin treatment or aluminum hydroxide treatment are known (Patent Document 1 and Patent Document 2), they have undergone complicated processes such as ion exchange resin treatment. It is expensive and the burden on patients with kidney disease is large. On the other hand, gelatin, collagen, and collagen peptides are disclosed as proteins having low phosphorus and potassium contents (Patent Document 3). However, these are animal-derived proteins and are not preferred to be taken by patients with allergies.

  Against this background, there has been a strong demand for a safe protein nutrition source with low phosphorus and potassium contents, excellent protein utilization efficiency, and low risk of allergies.

Japanese Patent No. 3411035 Japanese Patent No. 3131691 JP 2008-247748 A

Kumagai et al., J Nutr Sci Vitamol 55, 170-177 (2009)

  The subject of the present invention is excellent in the protein utilization efficiency that can be safely ingested without increasing the risk of excessive intake of phosphorus and potassium in patients with renal diseases, particularly those with artificial dialysis, whose intake of phosphorus and potassium is restricted. It is to provide a protein nutritional composition.

  The inventors of the present invention have intensively conducted research on proteins derived from rice endosperm, and the content of phosphorus and potassium in the protein preparation extracted from rice endosperm is significantly lower than that of other protein preparations. When the extracted protein preparation was administered to animals, it was found that the amounts of phosphorus and potassium in urine or blood were suppressed, and the present invention was completed. Specifically, the present invention provides the following.

  (1) A protein nutritional composition comprising rice endosperm protein as an active ingredient and intended for patients with impaired renal function and artificial dialysis patients.

  (2) The protein nutrition composition according to (1), wherein the concentration of inorganic phosphorus in the rice endosperm protein is 300 mg or less with respect to 100 g of pure protein.

  (3) The protein nutrition composition according to (2), wherein the rice endosperm protein has an inorganic potassium concentration of 4.0 mg or less with respect to 100 g of pure protein.

  According to the present invention, the content of phosphorus and potassium is small compared to other food proteins, and by taking this, protein nutrition can be supplemented without excessive intake of phosphorus or potassium. The present invention is a protein nutritional supplement containing such rice endosperm protein as an active ingredient, and is suitable for protein nutritional supplementation for artificial dialysis patients, chronic renal failure patients with impaired renal function, and the elderly.

It is the graph which compared the amount of inorganic phosphorus excretion in urine at the time of ingesting the test meal which contained various proteins and loaded sucrose 20% to GK rat which is a non-obesity type diabetes model rat. The abbreviations mean C: casein diet group, RP: rice endosperm protein diet group, RBP: rice bran protein diet group, SP: soybean protein diet group. It is a graph which shows the result of having measured the urinary inorganic phosphorus excretion amount every 2 weeks when a test diet containing various proteins is ingested for 8 weeks in obese diabetes model rats. The abbreviations are the same as those in FIG.

  Hereinafter, the rice protein composition extracted with alkali is abbreviated as “rice endosperm protein” or “rice endosperm protein composition”. Rice endosperm protein can be extracted with alkali using rice endosperm such as polished rice or rice flour as a raw material. Since rice bran contains phosphorus-rich components such as phytic acid, it is desirable that the rice bran component is sufficiently removed by thoroughly polishing the rice bran and the skin wrinkle component is sufficiently removed by washing the rice. When using polished rice, a part of the protein is extracted by soaking in an alkaline solution, but it is recovered by extracting the protein contained in the rice tissue by grinding the soaked rice by wet grinding or the like. The rate can be increased. When using rice flour, protein is extracted with high efficiency by soaking in an alkaline solution for 1 hour to 1 day.

  The concentration of alkali used for extraction is preferably 0.1% to 2%, more preferably 0.15 to 0.25%. Since the protein solution to be extracted contains a large amount of alkali-soluble fiber, it is preferably removed using a sieve or a filter cloth having a fine mesh. By adding an acid such as hydrochloric acid to the protein solution and adjusting to pH 5-6, the aggregated protein can be recovered as a precipitate. If the protein solution is pre-heated to about 50 ° C and then neutralized, protein aggregates can be obtained even at pH 7, and if this is heated to 80 ° C or higher, the aggregates grow even larger. At least protein aggregates can be efficiently recovered by filtration using a sieve or filter press. A rice endosperm protein composition can be obtained by appropriately washing the recovered protein aggregate and drying it using airflow drying, fluidized bed drying, freeze drying, or the like. By performing heating at the time of neutralization, a swollen protein aggregate is obtained, and by drying this aggregate, a rice endosperm protein composition having excellent water retention and touch compared to the case without heating is obtained. It can be used for a wider range of applications.

  Rice endosperm protein obtained by the alkali extraction method is excellent as a protein supplement source for kidney disease patients because of its excellent digestibility and high utilization efficiency as protein nutrition. Moreover, in the rice endosperm protein composition, phosphorus and potassium in the rice endosperm tissue are efficiently removed, and their content is small, and phosphorus is 100 to 250 mg per 100 g of the sample (120 to 300 mg with respect to 100 g of pure protein). , Potassium is 1.0 to 5.0 mg per 100 g sample (2.0 to 4.0 mg per 100 g pure protein), and even if taken by a renal disease patient such as a dialysis patient, Protein intake is possible without worrying about an increase in blood concentration. The upper limit of phosphorus intake recommended for dialysis patients is approximately 600 mg / day per 50 kg of standard body weight, and potassium is 1,500 mg / day, and the range of additional intake as a protein supplement is set to 10% of each. In the case of the rice endosperm protein preparation A, which will be described later, it is calculated that it is possible to ingest up to 23 g as pure protein and in the case of the rice endosperm protein preparation B up to 50 g. These values correspond to 54% and 118% of the required protein intake of 42.5 g in an adult weighing 50 kg. These rice endosperm protein preparations are used for patients with renal diseases such as dialysis patients and those with impaired renal function. It turns out to be an excellent source of additional protein supplements. From the above, as a protein supply source for renal disease patients such as dialysis patients and those with impaired renal function, the content of phosphorus with respect to 100 g of pure protein is 300 mg or less, preferably 150 mg or less, and the content of potassium with respect to 100 g of pure protein is 4.0 mg or less. Preferably, a protein preparation of 3.0 mg or less is suitable, and the rice endosperm protein sufficiently satisfies these conditions. The phosphorus content in 100 g of pure protein is measured by ICP emission spectrometry, and the potassium content is measured by atomic absorption spectrometry.

  Processed foods containing rice endosperm protein composition can be used for beverages, baked goods, jelly-like foods, soups, porridges, etc., and processed into suitable food forms according to the pathology of patients with kidney disease Is also possible. Needless to say, a low content of phosphorus or potassium should be used as an auxiliary material used in processed foods.

<Example 1> Preparation and Mineral Content of Rice Endosperm Protein (for Animal) 25 kg of Koshihikari rice flour (purchased from Niigata Flour Milling Co., Ltd.) was suspended in 100 L of 0.2% sodium hydroxide solution and left overnight at 20 ° C. The suspension was supplied to a centrifuge “H-130I” manufactured by Kokusan Co., Ltd. at a flow rate of about 5 L / min. The rotation speed was 1,400 rpm. The centrifugal supernatant flowing out was collected and centrifuged again under the same conditions to obtain a protein extract from which the starch granules were removed. The protein that was aggregated by adjusting the pH of the protein extract to 5.5 was recovered using centrifugation as described above. The protein precipitate was suspended in about 50 L of water and then centrifuged again, and the recovered precipitate was lyophilized. By repeating the same operation 8 times, about 6 kg of rice endosperm protein preparation A was obtained.

  The nitrogen content of this sample is obtained by oxygen circulation combustion and TCD gas chromatographic detection method using Sumika NC-900 made by Sumika Chemical Analysis Co., Ltd., and this is multiplied by 5.95 which is the nitrogen coefficient of rice endosperm protein. Purity was determined. The protein purity of sample A was calculated to be 90%. The mineral content of sample A was analyzed by entrusting it to the Japan Food Analysis Center. The results are shown in Table 1. Moreover, it compared with the mineral content of casein (Nippon Shinyaku Co., Ltd. casein sodium CW) and soybean protein (Fuji Pro-F made from Fuji essential oil). As a result, it was found that the sample A had a significantly lower phosphorus and potassium content than casein and soy protein.

<Example 2> Preparation of rice endosperm protein for clinical test and test food production 25 kg of Koshihikari rice flour was treated with 100 L of 0.2% sodium hydroxide solution and centrifuged twice as in Example 1. A protein extract was obtained. The extract was passed through a 285 mesh (aperture 53 μm) sieve to remove the fibrous material. This solution was heated to 50 ° C., and 6N hydrochloric acid was added to adjust the pH to 7.0. The solution was incubated at 80 ° C. for 30 minutes to grow a large protein aggregate. After cooling this, the protein was recovered on a sieve using a 285 mesh sieve. The protein was suspended in about 50 L of water and subjected to the same sieving treatment, and this operation was repeated three times to wash the protein with water. The obtained wet protein was squeezed into a squeezed bag to remove moisture, and then freeze-dried. The same operation was repeated 20 times to obtain about 15 kg of rice endosperm protein preparation B. The protein purity of sample B was 92%. The mineral analysis results of the sample B are shown in Table 1. As with the sample A, the contents of phosphorus and potassium were low.

  A test meal for clinical trials was prepared using the preparation B (see Table 3). The formulation was determined so that 1 g of the test food contained 5 g of rice endosperm protein as a pure protein.

<Example 3>
A GK rat (male), a non-obese diabetic model animal, was purchased from Japan SLC at 7 weeks of age. After 7 days of acclimatization, the animals were reared under conventional conditions. A high sucrose diet (20% sucrose) according to AIN-93G is used as the feed, and the rice endosperm protein, rice bran protein, soybean protein, or casein prepared in Example 1 is used as the protein, and the protein content is 20%. Prepared in the same manner. Table 2 shows the component analysis results of each feed.

  A tray was placed under the metabolic cage, and urine was collected daily for 3 days. Three days of urine were combined, the urinary phosphorus concentration was determined by the vanadomolybdic acid absorptiometry, and the amount of inorganic phosphorus excreted in urine per day was calculated. The analysis of phosphorus concentration was entrusted to the Japan Food Analysis Center.

  As shown in FIG. 1, the amount of urinary inorganic phosphorus excreted per day was high in the casein diet and the minimum in the rice endosperm protein diet.

<Example 4>
ZDF rats (male), an obese diabetic model rat, were purchased at 6 weeks of age from Charles River Japan. After 10 days of preliminary breeding, the animals were raised with a standard feed (10% sucrose) according to AIN-93G. Urine was collected at intervals of 2 weeks from the start of breeding in the same manner as in Example 3, and the amount of inorganic phosphorus excreted in urine was measured. As shown in FIG. 2, even when this model animal was used, urinary inorganic phosphorus excretion was high in the casein diet group and low in the rice endosperm protein diet group.

<Example 5>
Under the approval of the Niigata University School of Medicine Ethics Committee, a clinical trial was conducted on maintenance dialysis patients. A test was conducted in which 10 patients on maintenance dialysis were recruited and a test meal containing rice endosperm protein was ingested for 2 weeks. Table 3 shows the composition of the test meal. Each 11 g of the test meal (5 g as a rice endosperm protein pure product) was filled in an aluminum wrapping material, and this was dissolved in a small amount of water or hot water once a day for drinking. Instructions were given to continue the normal diet during the test period, and the test meal was added to the foods normally consumed.

  As subjects, we recruited adult maintenance hemodialysis patients with stable general condition and tending to undernutrition. The selection criteria were those who showed a serum albumin level of 3.8 mg / dl or less, showed a tendency toward malnutrition, understood the gist of this clinical study, and obtained written consent (gender-independent). Excludes persons with serious diseases in the heart, liver, etc., severe infections, before and after surgery, persons with severe trauma, persons with food allergies, and other persons judged inappropriate by the attending physician. did. The 10 people recruited were 75.4 ± 7.8 years of age, 3 men and 7 women.

  Two weeks before the start of the test, one week before, just before the start, blood was collected 1 week and 2 weeks after the intake of the rice endosperm protein diet, and blood tests, blood biochemical tests, and blood mineral analysis were performed. Table 4 shows the analysis results of blood inorganic phosphorus and potassium before and after the rice endosperm protein food intake (immediately before and after 2 weeks). In addition, since the 2nd test subject did not ingest the rice endosperm protein food for 5 days due to the cold during the test period, it was excluded from the analysis target, and analysis was performed by 9 subjects.

  Even if maintenance dialysis patients ingested 5 g of rice endosperm protein every day for 2 weeks, the concentration of inorganic phosphorus and potassium in the blood did not increase, so intake of rice endosperm protein at this dose was problematic for maintenance dialysis patients Not confirmed. In addition, no adverse events were observed other than the common cold of No. 2 test subject, and it was judged that it was safe for maintenance dialysis patients to take rice endosperm protein at a dose of 5 g / day.

Claims (4)

A protein nutritional composition for patients with reduced renal function or artificial dialysis, comprising as an active ingredient a rice endosperm protein having an inorganic phosphorus concentration of 300 mg or less per 100 g of pure protein. A protein nutritional composition for patients with impaired renal function or artificial dialysis, comprising as an active ingredient rice endosperm protein having an inorganic potassium concentration of 4.0 mg or less per 100 g of pure protein. The protein nutrition composition according to claim 1, which suppresses an increase in blood inorganic phosphorus due to ingestion. The protein nutrition composition according to claim 2, which suppresses an increase in blood inorganic potassium due to ingestion.

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