JPH04210577A - Cholesterol level rise-inhibitory food and production thereof - Google Patents

Abstract

PURPOSE:To obtain a food having marked cholesterol level rise-inhibitory effect by using, as active ingredient, a water-soluble protein derived from silk fibroin. CONSTITUTION:The objective food containing, as active ingredient, the partial hydrolyzate of a protein derived from silk fibroin, 150-50000 in average molecular weight, at such a level as to account for 10 or more wt.% of the whole protein of the final food. Said hydrolyzate can be obtained by hydrolysis of a protein derived from silk fibroin until the production rate for free amino acid comes to 1-70wt.%.

Description

[Detailed description of the invention]

[00011

[Industrial Field of Application] The present invention relates to a food that suppresses cholesterol rise. More specifically, the present invention relates to strepta fib [
■It relates to a food product characterized by containing water-soluble protein derived from inn and a method for producing the same. [0002] [Prior Art] Silk is composed of proteins whose main components are fibroin and sericin, and has been used as a fiber since Daigyo. However, the fibroin itself is different from normal proteins, and contains pepsin, sericin, etc. Since it is not easily affected by digestive enzymes such as helipsin, no attempt has been made to use it in foods. Therefore, the present inventor developed a technology to utilize leukemia white matter, mainly fibroin, in foods, as described in Japanese Unexamined Patent Application Publication No. 1256352.
Publication No. 2), or technology used in hangover prevention foods (
JP-A-1-256352). Furthermore, as mentioned above, fibroin is not easily affected by digestive enzymes, so it improves its digestibility and absorption through hydrolysis, and also discloses a technology that utilizes a unique amino acid composition to express an alcohol metabolism promoting effect ( JP-A-2-177864). [0003]However, it is still unclear what kind of action foods containing fibroin have in vivo. In particular, it has recently become known that various proteins express physiological effects in the ingested body that cannot be explained by their amino acid composition alone. It is expected that it will have effects other than those inferred from its amino acid composition. [0004]

[Problems to be Solved by the Invention] As a result of intensive studies on the physiological effects of foods containing silk fibroin, the present inventors found that protein derived from silk fibroin surprisingly has a remarkable effect on suppressing cholesterol rise. The present invention has been completed based on the finding that this phenomenon occurs. [0005]

[Means for Solving the Problems] According to one aspect of the present invention, there is provided a food product for inhibiting cholesterol elevation, which is characterized by containing a protein derived from the class fibroin. [0006] The otofibroin-derived protein is preferably adjusted to account for 80% by weight or more of the total protein in the food. [0007] The protein is preferably a partial hydrolyzate of silk fibroin-derived protein. [0008] The average molecular weight of the partial hydrolyzate is 15
It is preferable that it is 0-so, ooo. [0009] The present invention also provides a method of producing cholesterol, which is characterized by partially hydrolyzing a protein derived from silk fibroin until the production of free amino acids is 1 to 70%, and adding the obtained partially hydrolyzed protein. This shows a method for producing a food product that suppresses the rise in temperature. [00101 Hereinafter, the present invention will be described in detail. [0011] Silk is a fibrous protein secreted from the silk glands of silkworms, and is composed of fibroin fibers hardened with sericin. Fibroin can be obtained by removing sericin from sheath threads by smelting. Silk fibroin contains glycine (Gly) and alanine (A1
A protein that contains a very large amount of (G1 y3A1
It is said to have a composition represented by a2X2)n (X is an amino acid other than glycine or alanine). An example of the composition is shown in Table 1. [00121

[Table 1] [0013] Next, the process of obtaining protein from fibroin fibers will be explained. [00143 Fibroin fibers can be obtained from cocoons, silk threads, etc. by any known method, such as by dissolving, precipitation, extraction, purification, culturing, or the like. In the present invention, it is possible to use the fibroin fiber itself as a protein, but preferably,
Partial hydrolysis is carried out according to the following method. [0015] That is, the obtained fibroin fibers are heated and dissolved in a concentrated solution of mineral acids selected from hydrochloric acid, sulfuric acid, phosphoric acid, etc., partially hydrolyzed, and then neutralized and desalted to obtain an aqueous solution derived from silk fibroin. A solution containing the protein can be obtained.゛It is also possible to dissolve fibroin fibers, for example, in a 45% calcium chloride solution or in a solution in which the weight ratio of calcium chloride, ethanol, and water is 1:2:8, and then desalinate this solution to obtain silk fibroin-derived fibers. It is also possible to obtain a solution containing water-soluble proteins. If this solution is further hydrolyzed with a proteolytic enzyme selected from papain, samoase, elastase, vancreatin, etc., a partially hydrolyzed water-soluble protein that is reversibly soluble in water can be obtained. If such a water-soluble protein-containing liquid is dried and powdered by a method such as spray drying or freeze drying, a water-soluble protein powder derived from class fibroin can be obtained. [0016] The degree of hydrolysis is preferably such that the average molecular weight of the partially hydrolyzed protein is in the range of 150 to so, ooo, more preferably 200 to 20,000. If the average molecular weight of the partially hydrolyzed protein is 50.000 or more, it is difficult to process because of its gelling ability, and is particularly undesirable for application to beverage-type foods. Moreover, if the average molecular weight is 150 or less, taste characteristics such as bitterness and sweetness will be strong, making it undesirable for use in foods, and the effect of suppressing the increase in cholesterol will not be sufficiently expressed. In addition, the amount of free amino acids produced after hydrolysis is 1 to 70% of the raw material fibroin fiber.
Preferably, the patient is in serious condition. When the amount of amino acids produced is 70% by weight or more of the fibroin fiber, the taste will be strong,
The effect of suppressing cholesterol rise also decreased, and by 12%
If it is below, the water-soluble protein will not be reduced to a sufficiently low molecular weight, resulting in poor processability. [0017] The amount of free amino acids produced in a water-soluble protein solution derived from silk fibroin can be determined by treating the water-soluble protein solution with basic carbonate steel, making amino acids and peptides into copper complexes, and converting this into an anion exchange resin. Adsorb, 0.05
This was done by quantifying the free amino acids eluted with M borate buffer using an automatic amino acid analyzer. However, since acidic amino acids were not liberated by the boric acid buffer, the water-soluble protein solution was directly subjected to an amino acid analyzer for quantification. [00181 The food in the present invention does not have a particularly limited form, and includes, for example, beverages, jelly, bread,
Noodles, side dishes, frozen desserts, instant foods, canned foods, bottled foods, etc. can be mentioned. It may also contain various additives used in general foods (for example, fragrances, coloring agents, emulsifiers, swelling agents, preservatives, seasonings, etc.). [0019] The preferable range of the content of silk fibroin-derived protein in the cholesterol increase-suppressing food according to the present invention varies depending on the properties, composition, and use of the food.
- Boat fishing is not particularly limited as long as the protein content derived from rope fibroin is at a level that allows one person to orally ingest 500 mg to 5 g of protein at a time. That is, if the content of silk fibroin-derived protein is low, a large amount of the food must be ingested in order to exhibit a sufficient cholesterol rise suppressing effect, which is not preferable. Further, it is preferable that the protein derived from the class fibroin is adjusted to account for 10% by weight or more of the total protein in the food. In other words, if the occupancy of silk fibroin-derived protein in the total protein is 10% by weight or less, it will be greatly influenced by the properties and composition of other proteins, and it will be difficult to substantially exhibit the effect of suppressing cholesterol rise. become. [00201 The total protein content in a food is calculated by measuring the amount of N (nitrogen) in the food according to a conventional method such as the Kjeldahl method, and multiplying the obtained value by 6.25. . In addition, a protein-containing solution derived from silk fibroin (
Alternatively, the protein content in the powder) refers to the amount of N in the solution calculated according to the same method as for the total protein. [00211] Next, the present invention will be explained in more detail with reference to Examples. [0022] [Example] Example 1. 100g of silk thread (moisture 10%),
It was dissolved in a 45% calcium chloride aqueous solution and dialyzed to obtain a fibroin solution. 1 g of commercially available papain was added to this, and the mixture was stirred at 37°C for 20 minutes. Then, 90°C, 30
Heat for 1 minute and lyophilize. The powder obtained was 75 g.
The average molecular weight is approximately 20,000, and the amount of free amino acids produced is 2
．． 5%, indicating that it is easily soluble in water. [0023] Example 2. 100g of silk thread (10% moisture)
was dissolved in concentrated hydrochloric acid, water was added to make a total volume of about 2 liters, and hydrolysis was carried out at 50°C for 4 hours and 30 minutes while adjusting the hydrochloric acid concentration to 2N. Next, the mixture was neutralized with caustic soda, desalted by electrodialysis, concentrated to about 200 ml under reduced pressure aw1, and freeze-dried. The obtained powder was 82 g, average molecular weight was 300, free amino acid production amount was 28% by weight,
It had a slightly sweet taste, was easily soluble in water, and was easy to drink. [o o 24] Test example 1. Synthetic feed C shown in Table 1 was prepared using the powder obtained in Example 2, and male Wistar rats (5 weeks old) were raised using this feed for 33 days. After the breeding was completed, blood was collected from the tail vein, and serum cholesterol levels were measured according to a conventional method. As a control, Table 1
Synthetic feeds A and B shown in the following were prepared and reared in the same manner.
Serum cholesterol levels were measured. These results are shown in Table 3.
Shown below. The amino acid mixture in the table is a mixture of amino acids according to the fibroin composition shown in Table 1, and the basic feed is a protein-free and fiber-free feed (manufactured by Oriental Yeast Industry Co., Ltd.). [0025]

[Table 2] [0026]

[Table 3] [00271] As shown in Table 3, the increase in serum cholesterol was clearly suppressed in the group to which the feed containing the fibroin-derived protein according to the present invention was administered. [0028]

Effects of the Invention As detailed above, the food containing the water-soluble protein derived from the class fibroin according to the present invention has a remarkable effect of suppressing the increase in cholesterol, and therefore can be used to prevent high cholesterol, diabetes, obesity, etc. It is useful for treatment, etc.

Claims (5)

[Claims] 1. A food product for suppressing cholesterol rise, characterized by containing a protein derived from silk fibroin. 2. The cholesterol rise-suppressing food according to claim 1, wherein the silk fibroin-derived protein is adjusted to account for 10% by weight or more of the total protein in the food. 3. The cholesterol increase-suppressing food according to claim 1, wherein the protein is a partial hydrolyzate of silk fibroin-derived protein. 4. The average molecular weight of the partial hydrolyzate is 15
4. The cholesterol increase-inhibiting food according to claim 3, which has a molecular weight of 0 to 50,000. 5. Partially hydrolyzing a protein derived from silk fibroin until the amount of free amino acids produced is 1 to 70%,
A method for producing a food that suppresses cholesterol rise, which comprises adding the obtained partially hydrolyzed protein.