JPH05252879A - Quality improver for food - Google Patents

Abstract

PURPOSE:To obtain the subject improver effective in preventing the degradation of a food during the long-term preservation in frozen state or in thawing and useful for an emulsified oily food, etc., such as mayonnaise and white sauce by using a partial decomposition product of a specific cereal protein and xanthan gum, etc., as active components. CONSTITUTION:The objective improver contains, as active components, (A) a partial decomposition product (preferably obtained by a combination of decomposition treatment with an alkali and decomposition with enzyme, etc.) of cereal protein such as wheat and corn and having a weight-average molecular weight of 500-110,000 (preferably 3,000-100,000) and an Mw/Mo ratio of 0.85-0.004, preferably 0.77-0.023 (Mw and Mo are weight-average molecular weights after and before decomposition, respectively) and (B) xanthan gum, gum guaiac or their mixture.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a food quality improving agent. More specifically, mayonnaise, dressing, white sauce, emulsified oily foods such as demiglace sauce, bread, cakes, noodles, cooked rice, starchy foods such as confectionery and hams, sausages, hamburgers, foods such as protein foods such as meatballs, in particular. The present invention relates to a quality improver for frozen foods.

[0002]

2. Description of the Related Art Generally, when a food is frozen, the water content in the food is crystallized into ice. At that time, it is necessary to freeze the food rapidly in order to prevent the formation of large ice crystals in the food. Further, the water in the food becomes ice crystals of pure water up to the fine particles of water, so that the volume occupied by the water in the food becomes large due to crystallization. Then, when this frozen food is subjected to thawing, the ice in the food becomes a liquid state again and is reduced to the original volume. Then, by going through the freezing and thawing steps, the food product has a void between the surrounding components and the moisture. Also, since ice crystals are composed of pure water, substances dissolved in water in food are separated from water, especially in emulsified oily foods where oil is emulsified in water. To do. Further, in the case of a starch or protein food in which the surrounding water is composed of starch or protein, the water is separated, and if the amount is large, it will flow out.
Therefore, the food becomes dull and the surface becomes watery.

Various attempts have heretofore been made in order to prevent the deterioration of the quality of food in the freezing and thawing steps. For example, polyglycerin fatty acid ester has been added to an acidic O / W type emulsion composition such as mayonnaise and emulsion type dressing (Japanese Patent Laid-Open Publication No. 6-68242).
0-118,164). Also, xanthan gum,
Gums, including guar gum, are added to foods as thickening stabilizers, and xanthan gum is known to have a stable water retention capacity even under conditions such as freezing and thawing (Monthly Food Chemical; March 1989). No.).

On the other hand, the inventors of the present invention have emulsified a partially decomposed product of grain protein, a dispersant, mayonnaise as a quality improving agent, an emulsified oily food such as dressing, bread, cake,
It has been found that when added to starchy foods such as noodles and confectionery and protein foods such as ham and sausage, a remarkable quality improving effect can be obtained (JP-A-64-14274, JP-A-1-202). No. 234, JP-A-1-202,235.
JP-A-1-252,245, JP-A-1-281,
068). However, this partially decomposed product of grain protein alone did not provide a sufficiently satisfactory quality improving effect on frozen foods.

In view of the above problems, the present invention improves frozen storage resistance with a small amount of addition, prevents deterioration of quality during thawing, and can maintain its effect for a long time. It is intended to provide an improving agent.

[0006]

[Means and Actions for Solving the Problems] From the above viewpoints, the present inventors have conducted various studies and studies on the quality improving effect of a partially decomposed grain protein on frozen foods, and particularly, in combination with other emulsifiers and thickeners. As a result, the partial decomposition product of the above grain protein was used as one component, and by using it in combination with xanthan gum, guar gum, or a mixture thereof, it was possible to prevent quality deterioration which was not recognized by conventional quality improvers, and to maintain the same. The present invention has been reached by finding out the fact that a stable effect with properties is obtained. Further, when the composition of this partially decomposed product of grain protein and xanthan gum or guar gum or a mixture thereof is applied to general foods, for example, bread is baked, the texture is good and the finish is fluffy, and ham is chewy. You get good things. Therefore, this composition is also useful as a quality improver for general foods.

Thus, according to the present invention, the weight average molecular weight is in the range of about 500 to about 110,000, and the weight average molecular weight Mw after decomposition and the weight average molecular weight Mo before decomposition.
There is provided a food quality improving agent comprising a partially decomposed product having a ratio (Mw / Mo) of 0.85 to 0.004 and xanthan gum, guar gum or a mixture thereof as active ingredients.

The grain protein partial hydrolyzate used in the present invention has a weight average molecular weight Mw of about 500 to about 1 in the gel filtration method.
The ratio of the weight average molecular weight Mw after decomposition and the weight average molecular weight Mo before decomposition in the range of 10,000 (Mw / M
Suitable is a grain protein having an o) of 0.85 to 0.004 and further having a weight average molecular weight of about 3,000 to about 10.
It is preferable that the ratio (Mw / Mo) of the weight average molecular weight Mw after decomposition and the weight average molecular weight Mo before decomposition is 0.77 to 0.023. In addition, M
w is less than 500, or weight average molecular weight M after decomposition
Ratio of w and weight average molecular weight Mo before decomposition (Mw / M
When o) is less than 0.004, the effect is substantially reduced mainly by amino acids and their oligomers, and 110,0
If it exceeds 00 or the (Mw / Mo) value exceeds 0.85, it is not suitable because it is close to the properties of undecomposed matter and the effect is low.
In addition, these molecular weights are 1,600 as a standard substance,
6,500, 16,000, 65,000, 88,000
Using polystyrene sulfonate having a molecular weight of 0, Sephadex G-75 or G manufactured by Pharmacia
It is a value measured by a gel filtration method using -100 as a carrier.

In the present invention, the grain protein means a protein contained in grain, and examples of grain include wheat (eg wheat), corn, beans (eg soybean) and the like. Of the proteins contained in such grains, wheat protein, for example, contains glutenin and gliadin as main components, and is usually called wheat gluten. Further, corn protein contains zein as a main component and is usually called corn gluten. These are all known substances, and can be obtained by separating or extracting from grains by a conventional method. The method for preparing the partially decomposed grain protein product used in the present invention is described in JP-A-64-14,274.
The method described in the publication can be used.

That is, the grain protein partial hydrolyzate of the present invention is obtained by converting the grain protein obtained as described above into an alkali,
It can be obtained by hydrolysis with an acid, an enzyme, a reducing agent or an oxidizing agent. In addition, such grain protein is
Both crude and purified products may be used, but
It is preferable to use one containing 0% or more.

The hydrolysis treatment with alkali is
It is suitable to carry out by heating in a dilute alkaline aqueous solution. Usually, an aqueous solution or dispersion of grain protein is treated at about 60 to 180 ° C. in the presence of an alkali agent such as sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate.
It is suitable to stir the mixture for about 10 to 600 minutes. Here, it is preferable to use an aqueous solution or dispersion of grain protein in an amount of 2 to 40% by weight, and the amount of the alkaline agent used is preferably 0.1 to 6 g per 20 g of grain protein. ..

Next, the hydrolysis treatment with an acid is preferably carried out by heating in a dilute aqueous acid solution. Usually, it is suitable to stir an aqueous solution or aqueous dispersion of grain protein in the presence of an inorganic acid such as hydrochloric acid or sulfuric acid or an organic acid such as acetic acid at a temperature of about 60 to 120 ° C. for a predetermined time. It is preferably used.
Here, the treatment time is adjusted so as to obtain the above-mentioned predetermined weight average molecular weight, and is usually selected from about 10 to 600 minutes. The amount of acid used is 20 g of grain protein.
However, it is preferably 0.1 to 6 g.

Similarly, the hydrolysis treatment with an enzyme is suitably carried out in a dilute aqueous solution of an enzyme having protease activity. Usually, an enzyme such as pepsin, alkaline protease or papain is usually added to an aqueous solution or aqueous dispersion of grain protein. In the presence of a small amount of
It is carried out at 60 ° C. for about 60 to 600 minutes. Grain protein 20
The amount of enzyme used is preferably 0.02 to 5 g per g.

Similarly, the decomposition treatment with a reducing agent or an oxidizing agent is suitably carried out in a dilute aqueous solution of a reducing agent or an oxidizing agent. Usually, a sulfite salt, a thiol compound, A reducing agent such as erythorbic acid or hydrazine, or a small amount of an oxidizing agent such as hydrogen peroxide or hypochlorite is present at a temperature of about 10 to 100 ° C.
It will take 600 minutes. The quantitative conditions at this time are grain protein 2
0.1 to 5 g of the amount of reducing agent or oxidizing agent used relative to 0 g
Other than the above, the same as above is preferable.

Such decomposition treatment may be performed not only alone but also in combination of two or more kinds. In particular, it may be carried out by a multistage decomposition treatment in which the decomposition treatment (A) with an alkali and the decomposition treatment (B) of one or more of an acid, an enzyme, an oxidizing agent and a reducing agent are combined.

Such a grain protein partial hydrolyzate is characterized by the following physical properties. (a) Weight average molecular weight (by gel filtration method) is 500 to 1
It is in the range of 10,000. (b) The ultraviolet absorption λmax is around 260 to 280 nm, and the infrared absorption is around 1,400, 1,630 and 3,400 cm ⁻¹ . (c) The isoelectric point is in the range of 3.9 to 5.0. (d) pH buffering property (pH of 100 ml of a 5% by weight aqueous solution of this product)
It requires 2 to 25 ml of 1N hydrochloric acid to reduce 6 to 2). (e) It is soluble in water and insoluble in methanol, ethanol, acetone and ether. (f) Appearance is light yellow to reddish brown powder. (g) Color is developed by the xanthoprotein reaction and the ninhydrin reaction. (h) Strong surface tension lowering ability (This product was
The surface tension of pure water is adjusted to 50dy by adding
ne / cm or less (measured by Dunui's surface tensiometer). (i) Strong emulsifying ability (water-soybean oil mixture 10 containing at least 30% by weight of soybean oil by adding 1 g of this product)
0 g completely emulsified (a uniform emulsified state for at least 10 minutes,
Preferably means for 1 hour or more).

This partially decomposed product is distinguished from the usual partially decomposed grain protein products in terms of the surface tension lowering ability (h) and the emulsifying ability (i). The order of the multistage decomposition process is not particularly limited. That is, after the raw material such as wheat gluten is first subjected to the alkali decomposition treatment (A),
It may be subjected to the above-mentioned decomposition treatment (B) (decomposition treatment other than alkali) using an acid, an enzyme, a reducing agent or an oxidant, or two or more kinds thereof, or vice versa. May be. Alternatively, it can be obtained by first subjecting it to a decomposition treatment other than alkali (B), then subjecting it to alkali decomposition treatment (A), and then again subjecting it to a decomposition treatment other than alkali (B). In addition, a neutralization treatment may be appropriately performed between these respective treatments. Among these, the combination of the alkali decomposition treatment (A) and the acid decomposition treatment (B) is most preferable in terms of the quality improving effect.

On the other hand, as xanthan gum or guar gum used in the present invention, known ones can be used, and xanthan gum is particularly suitable.
Here, xanthan gum and guar gum are polysaccharides produced by microorganisms and are usually added to foods as a thickening stabilizer. When these xanthan gum and guar gum were used alone, the quality improvement effect was low and no sustainability was observed under both freezing and thawing conditions.

The quality improving agent of the present invention can be obtained by blending the above grain protein partial decomposition product with xanthan gum or guar gum or a mixture thereof. In this case, the blending ratio of the decomposed product and xanthan gum, guar gum or a mixture thereof is preferably 10: 1 to 1:30, more preferably 5: 1 to 1:20 by weight.

As for the method of blending and the form of the blend, when both are in powder form, simple powder mixing may be used, but after dissolving in water, or as it is, a excipient such as starch hydrolyzate is blended. Various forms are possible, such as a powdered product that is dried after being dried. In addition, in the quality improving agent of the present invention, other emulsifiers (polyglycerin fatty acid ester, quillaja saponin, sucrose, fatty acid ester, etc.), thickening stabilizer (carrageenan) other than the above-mentioned components are included in the quality improving agent. , Alginic acid, processed starch, etc.), extenders, preservatives, coloring agents, fragrances, deodorants (cyclodextrin, etc.) and the like.

When the quality improver of the present invention is used, it is added in an amount of 0.05 to 0.05 based on the emulsified oily food material to be added.
It is suitable to be 10% by weight, preferably 0.1 to 5% by weight, and most preferably 0.5 to 4% by weight. If it is less than 0.05% by weight, the quality improving effect is insufficient, and if it exceeds 10% by weight, the effect commensurate with the increase in the addition amount cannot be expected to be improved, which is not preferable.

As an addition method, it is possible to add it to the raw material of the food in advance or to add it during the food manufacturing process. Among the frozen foods that are the subject of this invention, the emulsified oily foods include various oily foods in which the oil phase and the water phase should be maintained in an emulsified state, such as mayonnaise,
Examples include foods such as shortening, dressing, white sauce and demiglace sauce.

Further, among the frozen foods of the present invention,
Examples of starch-based foods include various foods mainly composed of starch, such as breads, cakes, cookies, biscuits, various noodles and cooked rice.
Furthermore, among the frozen foods of the present invention, as protein foods, various foods containing protein as a main ingredient can be mentioned, for example, ham, sausage, hamburger, meatballs and the like.

Further, various foods such as breads, cakes, noodles, hams, sausages and hamburgers can be cited as foods to which the present invention is applied.

[0025]

EXAMPLES The present invention will be described in detail below with reference to Examples and Comparative Examples. Preparation Examples 1-2 (Preparation of partially decomposed product of wheat gluten by acid) Hydrochloric acid aqueous solution 100 corresponding to 1 g or 2 g in terms of hydrogen chloride
20 g of wheat gluten (reagent product) manufactured by Wako Pure Chemical Industries, Ltd. was added to each of three flasks containing 10 g.
The mixture was heated and stirred at 0 ° C for 60 minutes. Then, it was neutralized with caustic soda and the total amount was 200 g with pure water to obtain Preparation Nos. 1 and 2 containing partially decomposed products. Table 1 shows the decomposition conditions and the weight average molecular weight of the decomposed products. The average molecular weight is a value measured by the GPC method using sodium polystyrene sulfonate as a standard solvent and 1 wt% saline as a solvent (the same applies to the examples described below).

[0026]

[Table 1]

Preparation Example 3 (Preparation of partial hydrolyzate of wheat gluten with alkali) 20 g of wheat gluten used in Comparative Example 1 was mixed with caustic soda 0.
2 g was added to 100 g of the dissolved aqueous solution, and after thorough mixing, the mixture was heated and stirred at 80 ° C. for 30 minutes in the flask. These were neutralized with hydrochloric acid, and the total amount was 200 g with pure water. Got 3. Table 2 shows the decomposition conditions and the average molecular weight of the decomposed products.

[0028]

[Table 2]

Preparation Examples 4 to 6 (Preparation of Decomposition Products of Wheat Gluten by Acid and Subsequent Partial Decomposition by Alkali) Preparation of Decomposition Products of Wheat Gluten by Acid under the same conditions as in Preparation Examples 1 and 2 % Aqueous solution was prepared, 100 g of each was placed in a flask, and an amount of caustic soda within the range of 0.5 to 2 g was added to each separately, and the mixture was heated and stirred at 100 ° C. for 60 minutes. Then, it was neutralized with hydrochloric acid and the total amount was 200 g with pure water. 4-6 were obtained.
Table 3 shows the decomposition conditions and the average molecular weight of the decomposition products.

[0030]

[Table 3]

Example 1 [Emulsion stability effect confirmation test] The preparations Nos. 1 to 6 (partially decomposed products of protein) were obtained by spray drying using an L-8 type spray dryer manufactured by Okawara Kakoki Co., Ltd. An emulsion stability test was carried out using the obtained powder products and various thickeners. Hereinafter, also in each of the examples, as the preparation, the powder product obtained by the above method is used. (Test method) A thickening agent and a preparation were dissolved in 70 g of water, and T.M. manufactured by Tokushu Kika Kogyo Co., Ltd. K. -Homomixer desktop type (M
30 g of soybean oil [white squeezing oil: Showa Sangyo] are added dropwise with stirring using a mold. After the dripping was completed, the rotation speed of the homomixer was set to 8000 rpm, and the mixture was mixed for 5 minutes.
Freeze at 0 ° C. After one month, thaw at room temperature and observe the emulsified state. (Test Results) Table 4 shows the test results.

[0032]

[Table 4]

Example 2 [Freezing resistance test of mayonnaise] I Test method <Compounding>

[0034]

[Table 5] <Preparation Method> Sodium chloride, white sucrose, preparations and combined emulsifier are completely dissolved in a predetermined amount of water (Homo mixer 5000 rpm). The emulsifiers used in combination are all dissolved or suspended in water regardless of their HLB.

When completely dissolved, add oil little by little. After the addition is completed, the stirring is continued for several more minutes. After adding vinegar, continue stirring for a few minutes. The prepared emulsion is passed through a colloid mill twice and used as a sample (colloid mill: Nippon Seiki Seisakusho M
M-1).

The sample is dispensed into a sample bottle and left in a freezer (-20 ° C). <Evaluation method> ... Thaw the sample daily and evaluate the emulsified state. Thaw Samples are removed from the freezer on days 7, 14 and 28 of freezing and thawed at room temperature.

The sample thawed on the 28th day is put in the freezer again and thawed again at room temperature after 3 days. A sample obtained by repeating this operation three times is designated as 3R. Evaluation items Visual determination of emulsified state Measurement of average particle size by particle size distribution meter ................................................................................ II Test results Emulsified state: Determine the emulsified state immediately after preparation and after thawing over time.

[0038]

[Table 6] Average particle size

[0039]

[Table 7] [Discussion] As is clear from the test results, the sample No. In Nos. 1 to 3, it can be seen that even if the sample is frozen and stored for about 1 month and then thawed and frozen again, mayonnaise in a state almost the same as that before thawing is obtained, and an excellent quality improving effect is exhibited. On the other hand, Sample No. which is a comparative example and is a known quality improving agent for frozen foods. In Nos. 4 and 5, oil and water were separated by thawing after 14 days, and it can be seen that the quality is deteriorated. Sample No. which is a comparative example of a partial decomposition product of grain protein alone and xanthan gum alone which are one of the active ingredients of the present invention. It can be seen that in Nos. 6 and 7, the quality improving effect as an emulsifier is insufficient even before freezing. In particular, in the comparative example of the partial decomposed product of grain protein alone, p in the acidic region such as mayonnaise
In H, it has a drawback that the quality improving effect is lowered, and it is surprising that the quality improving agent of the present invention in combination with xanthan gum exerts an excellent quality improving effect in an acidic region. To consider

Example 3 [Freezing resistance test of white sauce] (Test method) <Compounding> Soft flour 25 (g) Butter 25 Milk 200 ^{* 1} Water 200 ^{* 1} Salt 1.8 ^{* 1} Preparation 0.3% to 1 0.0% (total weight) Xanthan gum 0.2% to 0.5% (total weight) * 1 Heat together.

<Preparation Method> Melt butter in a thick pan, add soft flour and fry it without burning (electric cooking heater 65 is used as a heat source).
0W is used). Add a small amount of warm milk and spread well, then add the preparation and gum and mix well. When it becomes uniform, add milk little by little and spread. Boil while stirring, and the weight loss rate is 20%
Remove from heat when it becomes. After allowing to cool at room temperature for about 1 hour, it is put in a plastic bag with a chuck and frozen at -20 ° C. <Results> Thaw after two months of freezing and determine the state of water separation. The results are shown in Table 8.

[0042]

[Table 8]

Example 4 [Test on frozen bread dough ] <Test method> (Preparation method) A dough prepared by adding a preparation and xanthan gum was prepared by a direct kneading method, and each 50 g was molded into a round shape.

Store frozen at -20 ° C (1 month, 2 months). Thaw frozen dough at room temperature. Ferment at 37 ° C for 50 minutes. Bake in an oven (180 ° C, 8 minutes). <Evaluation method> Specific volume: measured by rapeseed method (cc / g) Degree of aging (hardness): 2 days after baking, cut bread into 3 cm squares,
Measure the pushing distance when compressed with a load of 200 g with a rheometer (the longer the length, the softer).

Model: Fudo Kogyo Co., Ltd. NRM-2010J-CW Adapter No.3 φ30mm <Test Results>

[0046]

[Table 9]

Example 5 [ Cake Freezing Tolerance Test] <Test Method> (Preparation Method) A dough is prepared by a common kyozo method (the reagent is used by mixing it with wheat flour) Baking in an oven (180 ° C., 25 minutes) Cut into pieces of shortcake and put in a plastic bag.

Storage frozen at -20 ° C (3 months). Thaw at room temperature. <Evaluation method> Degree of aging (hardness) ... The sample after thawing is cut into 3 cm squares, and the pushing distance when compressed with a load of 200 g with a rheometer is measured.

Model: NRM-20 manufactured by Fudo Kogyo Co., Ltd.
10J-CW Adapter No.3 φ30mm <Test result>

[0050]

[Table 10]

Example 6 [ Freezing Tolerance Test of Ham ] <Test Method> (Preparation Method) Butarose meat is used as a raw material meat. Preparations and various thickeners are dissolved in pickle liquid, which is poured into meat and salted. The amount of pickled liquid to be injected is 30% based on the weight of meat. The salted meat is packed in a casing, dried at 40 to 50 ° C for 2 hours, and then smoked at 60 ° C for 2 to 3 hours. Boil at 75 ° C for 2-3 hours, then cool and package. <Evaluation method> After thawing at -20 ° C for 2 months and thawing at room temperature, it is evaluated.

Water separation amount: The water separation amount per 500 g of the sample is measured. Appearance: Sliced and observed immediately after and after left for 2 hours Texture 〈Test result〉

[0053]

[Table 11] <Discussion> Not only is ham to which the quality improving agent of the present invention is added after freezing for 2 months, the quality (texture) is better than that of the additive-free product before freezing. , Appearance) was excellent.

[0054]

EFFECTS OF THE INVENTION The quality improving agent of the present invention is a product quality during long-term freezing or thawing of emulsified oily foods such as mayonnaise and white sauce, starchy foods such as bread and cake, and protein foods such as ham and sausage. It has the effect of remarkably preventing the decrease. As a result, it becomes possible to freeze-preserve or freeze-transport even foods that have hitherto been considered to be insufficient, and it is possible to extend the life of foods and achieve efficient production resistance.

Further, recently, many frozen foods have been put on the market, and in addition, the repertoire can be increased. In addition, a partially decomposed product of grain protein, which is one of the active ingredients of this quality improving agent, is a food or a food-like substance, is extremely advantageous in that it has no toxicity, and is highly safe as a food additive, Moreover, it is cheap.

Further, the foods to which the quality improving agent of the present invention is added have an excellent quality improving effect such as texture in comparison with non-added foods, and this effect can be obtained regardless of whether frozen or not. Preferred. Therefore, the quality improving agent of the present invention is extremely useful as an additive for frozen foods.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display area A23L 3/36 A // C08L 5/00 LAW 7415-4J 89/00 LSE 7415-4J (72) Inventor Chigusa Kinoshita 2-10-15 Higashi-Awaji, Higashiyodogawa-ku, Osaka-shi Katayama Institute of Chemical Research, Inc. (72) Inventor Yoko Yamamoto 2-10-15 Higashi-Awaji, Higashiyodo-gawa, Osaka-shi Katayama Chemical Industry Research Co., Ltd. In-house

Claims (12)

[Claims] 1. A weight average molecular weight of about 500 to about 110,
And a xanthan gum or guar gum in the range of 000, and a partially decomposed product of grain protein having a ratio (Mw / Mo) of the weight average molecular weight Mw after decomposition and the weight average molecular weight Mo before decomposition of 0.85 to 0.004. Alternatively, a food quality improving agent containing a mixture thereof as an active ingredient. 2. The quality improving agent according to claim 1, wherein the grain protein is wheat, corn or soybean protein. 3. The grain protein is wheat protein.
Quality improver. 4. A partially degraded product of grain protein obtained by subjecting grain protein to a degradation treatment with one or a combination of two or more degradation treatments with an alkali, an acid, an enzyme, a reducing agent or an oxidizing agent. The quality improving agent according to claim 1, wherein 5. A grain protein partially decomposed product is one or more of grain protein decomposed with alkali (A) and acid, enzyme, reducing agent or oxidant (B).
The quality improving agent according to claim 1, which is obtained by a partial decomposition treatment by a combination of 6. The partially decomposed product of grain protein is an acid-alkali combined multistage decomposed product obtained by subjecting grain protein to partial decomposition treatment by a combination of decomposition treatment with alkali and decomposition treatment with acid. Quality improver. 7. The partially decomposed product of grain protein has a weight average molecular weight of about 3,000 to about 100,000, and the weight average molecular weight Mw after the decomposition and the weight average molecular weight M before the decomposition.
The quality improver according to claim 1, which has a ratio (Mw / Mo) of 0.77 to 0.023. 8. The quality improving agent according to claim 1, which contains xanthan gum as an active ingredient. 9. The quality improving agent according to claim 1, which is used for frozen products of emulsified oily foods such as mayonnaise, dressing, white sauce and demiglace sauce. 10. The quality improving agent according to claim 1, which is used for frozen starchy foods such as bread, cakes, noodles, cooked rice and confectionery. 11. A frozen food product such as ham, sausage, hamburger steak and meatballs.
Quality improver. 12. The quality improving agent according to claim 1, wherein the weight ratio of the decomposed product of grain protein to xanthan gum, guar gum or a mixture thereof is 5: 1 to 1:20.