JP3763308B2 - Preservability improver for cooked rice - Google Patents

Description

  When cooking rice, if the amount of water is increased with respect to the rice, the particles of the rice will be broken and the stickiness and elasticity unique to the rice will be lost, resulting in stickiness. In addition, when the rice is cooked with a small amount of water, the starch particles of the rice are not completely pre-gelatinized and become hard and non-sticky rice, both of which lose their value as food. Therefore, the amount of water at the time of cooking is slightly different depending on the type of rice or the new and old of the rice, so it can not be specified unconditionally, but it is normal to cook with the amount of water most suitable for the type of rice and the cooking conditions, dare There is no such thing as adding a large amount of water and cooking rice with the intention of increasing the amount of rice by increasing the amount of water and increasing the amount of rice.

  In addition, in order to improve the texture, sugars such as sugar and syrup or starchy substances such as dextrin may be added during cooking, but in such cases the amount of water can be increased, but the amount of water added. , The sweetness of cooked rice is strong, contrary to today's trend to avoid obesity, and tends to be avoided by consumers. Moreover, when it carries out high temperature / high pressure sterilization (retort sterilization), it may brown at the time of rice cooking or heat retention, and quality is reduced remarkably. Therefore, it is very difficult to improve the yield of cooked rice without changing the texture.

  When rice is mass-produced industrially, the texture and quality are significantly impaired. In that case, polysaccharides such as xanthan gum, guar gum, locust bean gum, tara gum, karaya gum, pectin, alginic acid, gum arabic, arabinogalactan, cyclodextrin, dextrin, modified starch, cellulose may be added as quality improvers However, these do not have the effect of improving the yield of cooked rice, and if the rice is cooked with excess water added, the rice particles are crushed as in the case of no addition, and the value as a food is not recognized.

  The present invention is a method for improving the yield of cooked rice, which can cook more cooked cooked rice than usual without changing the quality and texture even when adding excess water when producing cooked rice, And it aims at providing the manufacturing method of the cooked rice using the said yield improving agent.

  As a result of intensive studies in view of the above points, the present inventors have found that water-soluble hemicellulose, in particular, water-soluble hemicellulose derived from beans, has an effect on improving the yield of cooked rice, that is, the amount of water added when cooking rice. It has been found that even if it is excessive, the amount of cooked rice after cooking can be increased without changing the texture, which is effective and practical as a so-called yield improver. Furthermore, the rice cooked by adding the water-soluble hemicellulose of the present invention, when stored at a low temperature of 10 ° C. or less, the so-called chilled temperature zone, the quality of the starch deteriorates such as aging and hardening. Has been found to provide a function of maintaining a good texture over a long period of time. The present invention has been completed based on such findings.

  That is, the present invention is a rice yield improvement agent comprising water-soluble hemicellulose as an active ingredient, and adding water-soluble hemicellulose during cooking, and the amount of water in the rice at the time when 30 minutes have elapsed after cooking. A method for producing cooked rice, comprising adding water and cooking so as to be 55 wt% to 75 wt%.

  Conventionally, water-soluble hemicellulose is mainly added to foods and intestinal preparations as dietary fibers, as well as stabilizing milk protein beverages, improving the structure of bakery products (softening), application fields of adhesives, edible films Used in combination with production and gelling agents to inhibit gelation and improve the looseness of processed cereal foods. However, when cooking rice, it is possible to increase the amount of cooked rice without changing the quality such as texture by adding water-soluble hemicellulose and adding excess water for cooking. It was not known at all.

  By adding water-soluble hemicellulose, even if the amount of water added during cooking is increased, stickiness of cooked rice can be suppressed, and the particles of cooked rice can be prevented from being crushed. As a result, the yield of cooked rice can be improved. In addition, the cooked rice added with the water-soluble hemicellulose of the present invention is stored at a low temperature of 10 ° C. or lower, that is, in a so-called chilled temperature zone, and the quality of the starch deteriorates such as aging and hardening. Is suppressed and has an effect of maintaining a good texture over a long period of time.

  The water-soluble hemicellulose can be used with any molecular weight, but is preferably a polymer, and has an average molecular weight of several thousand to several million, specifically 5,000 to 1,000,000. If the molecular weight is too large, the viscosity increases too much and the workability deteriorates. The average molecular weight of the water-soluble hemicellulose is a value determined by an intrinsic viscosity method that measures viscosity in a 0.1 molar NaNO3 solution using standard pullulan (Showa Denko KK) as a standard substance. In addition, uronic acid was measured by Blumenkrantz method, and neutral sugar was measured by GLC method after alditol acetate formation.

  Water-soluble hemicellulose can be extracted from a raw material containing hemicellulose by water extraction or, in some cases, heated and eluted under acid or alkaline conditions, or decomposed and eluted by an enzyme. An example of a method for producing water-soluble hemicellulose is as follows.

  Oil seeds such as soybeans, palms, palms, corns, cottonseeds and other shells from which oils and proteins have been removed, or grains such as rice, wheat, beets, etc. can do. If the raw material is soy, tokara, soy milk, and okara produced as a by-product when producing separated soy protein can be used.

  The water-soluble hemicellulose in the present invention is preferably derived from beans, particularly soybeans, especially those derived from cotyledons. Further, it is preferable that the protein content contained in soybean hemicellulose is small, specifically 12 wt% or less, and desirably 8 wt% or less.

  These raw materials are thermally decomposed under acidic or alkaline conditions, preferably at a pH near the isoelectric point of each protein, preferably 80 ° C. or higher and 130 ° C. or lower, more preferably 100 ° C. or higher and 130 ° C. or lower. The water-soluble polysaccharide can be obtained by fractionating the soluble fraction and drying it as it is, or by removing the hydrophobic substance or low molecular weight substance by, for example, activated carbon treatment, resin adsorption treatment or ethanol precipitation treatment and drying. it can. Alternatively, it may be decomposed and extracted with hemicellulase, pectinase or the like.

  This water-soluble hemicellulose is a polysaccharide containing galactose, arabinose, xylose, fucose, rhamnose and galacturonic acid as constituent sugars. Details of the analysis results of the constituent components of water-soluble hemicellulose obtained by hydrolysis are described in JP-A-4-325058.

  In the present invention, water-soluble hemicellulose can be used alone or in an emulsified state with fats and oils to obtain the effect of improving the yield of cooked rice, but may be used in combination with other quality improvers and additives as appropriate. it can. Other quality improvers and additives include emulsifiers such as lecithin, glycerin fatty acid esters and sucrose fatty acid esters, or oily substances such as general animal and vegetable oils and fat-soluble vitamins such as tocopherol, sucrose, maltose and trehalo. Sugars such as sugar, sugar alcohol, dextrin, cloth nori, agar, carrageenan, fur celerin, tamarind seed polysaccharide, tara gum, caraya gum, pectin, xanthan gum, sodium alginate, togant gum, gwar gum, locust bean gum, pullulan, gellan gum, Various gums such as gum arabic, hyaluronic acid, cyclodextrin, chitosan, carboxymethylcellulose (CMC), propylene glycol alginate, modified starch, hydrolysates of these polysaccharides, gelatin, whey, etc. Examples include protein substances such as bumine, sodium caseinate, soluble collagen, egg white, egg yolk powder, soybean protein, salts such as calcium fortifier, and pH adjusters such as sodium acetate. Therefore, the yield improver according to the present invention is distributed and sold not only in the powder state but also in an emulsified or suspended state with fats and oils or a solution added to an organic acid solution such as water, saline or acetic acid. Can do.

  The amount of water-soluble hemicellulose to be added is not particularly limited, but it is 0.01% to 10% by weight, preferably 0.05% to 5% by weight, based on rice (in terms of dry matter). preferable.

There is no restriction | limiting in particular also about the time which adds the yield improvement agent for cooked rice of this invention, You may mix the rice and water which were washed with water, may melt | dissolve beforehand in the water, and may add just before cooking rice. The amount of water cannot be defined in general depending on the type of rice or the new and old of the rice, but after cooking for 30 minutes, the water content of the cooked rice is 55% to 75% by weight, preferably 57 to 70% by weight. More preferably, it may be experimentally confirmed in advance so that the amount is 60 to 65% by weight. The cooked rice in the present invention is characterized by having a higher water content than conventional cooked rice, and the moisture content of conventional cooked rice is about 53% by weight.
EXAMPLES Hereinafter, although an Example is given and this invention is further demonstrated, this invention is not restrict | limited by these illustrations. In the examples, both part and% mean weight basis.

  The water-soluble hemicellulose prepared by the following method was used. That is, twice the amount of water was added to the raw okara obtained in the process for producing separated soybean protein, the pH was adjusted to 4.5 with hydrochloric acid, and the mixture was extracted by heating at 120 ° C. for 1.5 hours. After cooling, centrifugation (10000 G × 30 minutes) was performed to separate the supernatant and the precipitate. Add an equal weight of water to the precipitate thus separated, centrifuge again, mix the supernatant with the previous supernatant, pass through the activated charcoal column, purify and dry to water-soluble hemicellulose Got.

Examples 1-4
Rice was cooked by the method described below, and the moisture content and texture at the time when 30 minutes had elapsed after cooking were compared. In each example, the water content is shown as a value measured by taking 10 g of rice and drying at 105 ° C. for 4 hours when 30 minutes have passed after cooking.

Control district 1
320 g of water was added to 320 g of rice (1 time the amount of rice), and rice was cooked using a household rice cooker (manufactured by Sanyo Electric Co., Ltd., microcomputer rice cooker ECJ-EA18).

Control district 2
In Control Zone 1, rice was cooked in exactly the same manner except that the amount of water added during cooking was 384 g (1.2 times the amount of rice).

Control district 3
In Control Zone 1, rice was cooked in exactly the same manner except that the amount of water added during cooking was 480 g (1.5 times the amount of rice).

  In Control Group 2, rice was cooked in exactly the same manner except that 0.64 g of water-soluble hemicellulose prepared above (0.2% based on rice) was added and dissolved in water.

  In Control Group 2, rice was cooked in exactly the same manner except that 1.6 g of water-soluble hemicellulose (0.5% based on rice) was added to water and dissolved.

  In Control Group 3, rice was cooked in exactly the same manner except that 0.64 g of water-soluble hemicellulose (0.2% based on rice) was added to water and dissolved.

  In Control Group 3, rice was cooked in exactly the same manner except that 1.6 g of water-soluble hemicellulose (0.5% based on rice) was added to water and dissolved.

  576 g of water (1.8 times the amount of rice) was added to 320 g of rice, 1.6 g of water-soluble hemicellulose (0.5% of rice) was added to water, and rice was cooked in the same manner.

  As mentioned above, the moisture content and texture of rice are summarized as follows. In addition, the food texture of the rice was indicated by ◎ (very good), ◯ (good), △ (somewhat inferior), and × (poor) from the good one in reference to the control group 1.

Water content and texture of rice ────────────────────────────────────
Addition of water Amount of water-soluble hemicellulose added (% by weight of rice)
Amount (0% to rice 0.2% 0.5%
Double vs. ───────── ───────── ─────────
Amount) Moisture Texture Yield Moisture Texture Yield Moisture Texture Yield
(%) (%) (%) (%) (%) (%)
───────────────────────────────────
Control Zone 1 53.0 ◎ 100
(1.0)
───────────────────────────────────
Control Zone 2 56.2 △ 112
(1.2)
───────────────────────────────────
Control 3 3 61.3 × 124
(1.5)
───────────────────────────────────
Example 1 55.9 ◎ 108.9
(1.2)
───────────────────────────────────
Example 2 56.8 ◎ 113.8
(1.2)
───────────────────────────────────
Example 3 60.7 ○ 118.1
(1.5)
───────────────────────────────────
Example 4 60.4 ◎ 125.3
(1.5)
───────────────────────────────────
Example 5 71.2 ◎ 142.5
(1.8)
───────────────────────────────────
Note) Yield indicates the yield after each cooking when the amount of rice obtained after cooking in Control Zone 1 is 100%.

  As a result of the above, adding 0.5% of water-soluble hemicellulose to the rice, it is abbreviated as rice cooked with the same amount of water as rice even if the amount of water added during cooking is increased to 1.5 times the amount of rice. An equivalent texture was obtained. Further, in Example 4, the yield was greatly improved to 25.3% over the control group 1 without impairing the texture unique to cooked rice. The cooked rice particles are easily crushed in the control group 3 to which no water-soluble hemicellulose is added, whereas in Example 4, the particles are solid as in the control group 1 or the control group 2, and In Example 5 in which the amount of water added during cooking was increased to 1.8 times the amount of rice and cooked, good cooked rice could be obtained and the yield improved to 42.5%.

Comparative Examples 1-4
Rice was cooked by the method shown below, and it was examined whether there was a difference in yield improvement depending on the type of polysaccharide. In each example, the water content is shown as a value measured by taking 10 g of rice and drying at 105 ° C. for 4 hours when 30 minutes have passed after cooking.

Comparative Example 1
In Example 4, rice was cooked in exactly the same manner except that 1.6 g of gum arabic (0.5% based on rice) was added instead of water-soluble hemicellulose.

Comparative Example 2
In Example 4, rice was cooked in exactly the same manner except that 1.6 g of pectin (0.5% based on rice) was added instead of water-soluble hemicellulose.

Comparative Example 3
In Example 4, rice was cooked in the same manner except that 1.6 g of maltodextrin (0.5% based on rice) was added instead of water-soluble hemicellulose.

Comparative Example 4
In Example 4, rice was cooked in the same manner except that 1.6 g of xanthan gum (0.5% based on rice) was added instead of water-soluble hemicellulose.

  As mentioned above, the moisture content and texture of rice are summarized as follows. In addition, the food texture of the rice was indicated by ◎ (very good), ◯ (good), △ (somewhat inferior), and × (poor) from the good one in reference to the control group 1.

Moisture content and texture of rice ─────────────────────────────────
Amount of water added Amount of water-soluble hemicellulose added (% by weight of rice)
(0% for rice 0.5%
──────────── ────────────
Moisture texture Yield Moisture texture Yield
(%) (%) (%) (%)
────────────────────────────────
Control Zone 1 53.0 ◎ 100
(1.0)
────────────────────────────────
Control 3 3 61.3 × 124
(1.5)
────────────────────────────────
Example 4 60.4 ◎ 125.3
(1.5)
────────────────────────────────
Comparative Example 1 59.9 × 128.9
(1.5)
────────────────────────────────
Comparative Example 2 60.8 △ 123.3
(1.5)
────────────────────────────────
Comparative Example 3 61.4 × 128.7
(1.5)
────────────────────────────────
Comparative Example 4 61.9 × 125.1
(1.5)
────────────────────────────────
Note) Yield indicates the yield after each cooking when the amount of rice obtained after cooking in Control Zone 1 is 100%.

  As mentioned above, even if polysaccharides other than water-soluble hemicellulose were added to cooked rice, no improvement in yield was observed. Although the texture was slightly reduced by the addition of pectin in Comparative Example 2, the other polysaccharides were not significantly different from Control Group 3.

Examples 6-9, Comparative Examples 5-8
Rice was cooked by the method shown below, and water-soluble hemicellulose was used in the state of a solution added to water and various organic acids to examine whether there was a difference in yield improvement. In each example, the water content is shown as a value measured by taking 10 g of rice and drying at 105 ° C. for 4 hours when 30 minutes have passed after cooking.

  In Control Group 3, instead of using powdered water-soluble hemicellulose, 12.8 g of 15% water-soluble hemicellulose aqueous solution was added (4.0% solution to rice, 0.6% in terms of water-soluble hemicellulose solids). We cooked rice in the same way.

  In Control Group 3, instead of using powdered water-soluble hemicellulose, 12.8 g of 15% water-soluble hemicellulose solution containing 25% acetic acid (4.0% solution to rice, 0.6% in terms of water-soluble hemicellulose solids) added I cooked rice in exactly the same way.

  In Control Group 3, instead of using powdered water-soluble hemicellulose, 12.8 g of 15% water-soluble hemicellulose solution containing 25% sodium acetate (4.0% of the amount of solution to rice, 0.6% in terms of water-soluble hemicellulose solids) ) Rice was cooked in exactly the same way except that it was added.

  In Control Group 3, instead of using powdered water-soluble hemicellulose, 12.8 g of 15% water-soluble hemicellulose solution containing 25% lactic acid (4.0% solution to rice, 0.6% in terms of water-soluble hemicellulose solids) The rice was cooked in exactly the same manner except that it was added.

  In Control Group 3, instead of using powdered water-soluble hemicellulose, 12.8 g of a 15% water-soluble hemicellulose solution containing 25% citric acid (4.0% solution to rice, 0.6% in terms of water-soluble hemicellulose solids) ) Rice was cooked in exactly the same way except that it was added.

Comparative Example 5
In Example 7, rice was cooked in the same manner except that no water-soluble hemicellulose was added and only 12.8 g of a 25% acetic acid solution was added. At 30 minutes after cooking, 10 g of rice was taken and the amount of water was measured.

Comparative Example 6
In Example 8, rice was cooked in exactly the same manner except that no water-soluble hemicellulose was added and only 12.8 g of a 25% sodium acetate solution was added.

Comparative Example 7
In Example 9, rice was cooked in exactly the same manner except that no water-soluble hemicellulose was added and only 12.8 g of a 25% lactic acid solution was added.

Comparative Example 8
In Example 10, rice was cooked in the same manner except that no water-soluble hemicellulose was added and only 12.8 g of a 25% citric acid solution was added.

  As mentioned above, the moisture content of rice, the texture, and the preservability stored at 20 ° C. for 24 hours are summarized as follows. In addition, the preservability of rice was determined by whether the hardness, stickiness, and appearance of the rice grains maintained the state immediately after cooking. The evaluation is based on the control group 1 immediately after storage, and the texture evaluation is also based on the control group 1, and in order from the best, ◎ (very good), ○ (good), △ (slightly inferior), × ( Inferior).

Moisture content and texture of rice ───────────────────────────────────
Addition amount of water-soluble hemicellulose as solids (% by weight with respect to rice)
0% 1.0%
─────────────── ─────────────
Moisture texture Yield storage stability Moisture texture Yield storage stability
(%) (%) (%) (%)
──────────────────────────────────
Control 3 3 61.3 × 124 ×
──────────────────────────────────
Example 6 60.9 ◎ 115.3 ◎
──────────────────────────────────
Example 7 60.2 ◎ 118.9 ○
──────────────────────────────────
Example 8 61.2 ◎ 113.3 ◎
──────────────────────────────────
Example 9 61.1 ◎ 118.7 ◎
──────────────────────────────────
Example 10 61.0 ◎ 115.1 ○
──────────────────────────────────
Comparative Example 5 61.2 × 111 ×
──────────────────────────────────
Comparative Example 6 62.3 × 118 ×
──────────────────────────────────
Comparative Example 7 62.8 × 112 ×
──────────────────────────────────
Comparative Example 8 61.9 × 117 ×
──────────────────────────────────
Note) Yield indicates the yield after each cooking when the amount of rice obtained after cooking in Control Zone 1 is 100%.

  Even when water-soluble hemicellulose was added to various acids (such as organic acids) and salts thereof and used in a solution state, it was confirmed that the yield improvement effect was maintained and the storage stability was also good. On the other hand, without using water-soluble hemicellulose, various acids (organic acids, etc.) known as preservatives and salts thereof alone were not able to obtain the yield improvement effect and the storage stability was not improved. .

Examples 11-12
When rice was cooked by the method shown below and stored at a low temperature, it was examined whether there was a difference in the quality of the rice over time.
Control district 1
320 g of water was added to 320 g of rice (1 time the amount of rice), and rice was cooked using a household rice cooker (manufactured by Sanyo Electric Co., Ltd., microcomputer rice cooker ECJ-EA18). 100 g was divided into plastic containers, wrapped so as not to dry, and then stored in a thermostat at 10 ° C. and 20 ° C. for 48 hours. Sensory evaluation of the taste over time and the taste value by a boiled rice taste meter ("STA1A": manufactured by Satake Seisakusho Co., Ltd.) were measured.

  For control group 3, 100 g was similarly subdivided into plastic containers, wrapped so as not to dry, and then stored in a 10 ° C. and 20 ° C. incubator for 48 hours. Sensory evaluation of taste and taste values were measured in the same manner over time.

  In Control Group 2, rice was cooked in exactly the same manner except that 3.2 g of water-soluble hemicellulose (1.0% based on rice) was added to water and dissolved. 100 g was divided into plastic containers, wrapped so as not to dry, and then stored in a thermostat at 10 ° C. and 20 ° C. for 48 hours. Sensory evaluation of taste and taste values were measured in the same manner over time.

  In Control Group 3, rice was cooked in exactly the same manner except that 3.2 g of water-soluble hemicellulose (1.0% based on rice) was added to water and dissolved. 100 g was divided into plastic containers, wrapped so as not to dry, and then stored in a 10 ° C. and 20 ° C. incubator for 48 hours. Sensory evaluation of taste and taste values were measured in the same manner over time.

  In the same manner as in Examples 2 and 4, 100 g was divided into plastic containers after boiled rice, wrapped so as not to dry, and then stored in a thermostat at 10, 20 ° C. for 48 hours. Sensory evaluation of taste and taste values were measured in the same manner over time.

  The sensory evaluation feeling of rice is summarized as follows. In addition, the food texture of the rice was indicated by ◎ (very good), ◯ (good), △ (somewhat inferior), and × (poor) from the good one in reference to the control group 1.

Rice texture (sensory evaluation)
───────────────────────────────────
Addition of water Amount of water-soluble hemicellulose added (% by weight of rice)
Amount (0% on rice 0.5% 1.0%
───────── ───────── ─────────
Storage temperature 10 ℃ 20 ℃ 10 ℃ 20 ℃ 10 ℃ 20 ℃
───────── ───────── ─────────
Storage time 0 24 48 0 24 48 0 24 48 0 24 48 0 24 48 0 24 48
(time)
───────────────────────────────────
Control Zone 1 ◎ △ × ◎ ○ △
(1.0)
───────────────────────────────────
Control district 3 ○ ×× ○ ××
(1.5)
───────────────────────────────────
Example 2 ◎ ○ △ ◎ ○○
(1.2)
───────────────────────────────────
Example 4 ◎ ○○ ◎ ◎ ○
(1.5)
───────────────────────────────────
Example 11 ◎ ○○ ◎ ◎ ○
(1.2)
───────────────────────────────────
Example 12 ◎ ◎ ○ ◎ ◎ ○
(1.5)
───────────────────────────────────

  Rice cooked with soy-derived hemicelluloses maintains a good texture without being sticky, even if the rice is cooked with 1.5 times the amount of water. It was. On the other hand, when the additive-free product was cooked by adding 1.5 times the amount of water to the rice, it was sticky and lost its texture and flavor as rice.

Texture of rice (analysis value of taste meter)
───────────────────────────────────
Addition of water Amount of water-soluble hemicellulose added (% by weight of rice)
Amount (0% on rice 0.5% 1.0%
Double
Amount) ───────── ───────── ─────────
Storage temperature 10 ℃ 20 ℃ 10 ℃ 20 ℃ 10 ℃ 20 ℃
───────── ───────── ─────────
Storage time 0 24 48 0 24 48 0 24 48 0 24 48 0 24 48 0 24 48
(time)
───────────────────────────────────
Control Zone 1 71 36 30 71 51 31
(1.0)
───────────────────────────────────
Control Zone 3 74 39 31 74 61 41
(1.5)
───────────────────────────────────
Example 2 72 59 48 72 66 59
(1.2)
───────────────────────────────────
Example 4 76 71 66 76 68 65
(1.5)
───────────────────────────────────
Example 11 74 61 49 74 66 61
(1.2)
───────────────────────────────────
Example 12 77 74 69 77 70 68
(1.5)
───────────────────────────────────
Note) The taste meter analysis value is a perfect score of 100. The higher the score, the better the texture and taste.

  Rice cooked with the addition of soy-derived hemicellulose lost little over time even when stored at 10 ° C. On the other hand, when the additive-free product increases the amount of water at the time of cooking, when it is stored at 10 ° C for 48 hours, it becomes a rough texture, while those with added hemicellulose remain sticky, Curing was suppressed.

Claims (2)

An anti-aging agent for cooked rice in a chilled temperature zone containing water-soluble hemicellulose as an active ingredient. A method for producing cooked rice, characterized by adding water-soluble hemicellulose, cooking rice, and storing in a chilled temperature zone .