JP7612738B2 - Dry grain-like granules - Google Patents

Description

The present invention relates to additives for cereal-like granules. More specifically, the present invention relates to additives that improve the appearance and taste of cereal-like granules.

In recent years, with the diversification of lifestyles, products such as drinks, gummies, and noodles that are called "optimized nutrition foods" have been launched on the market and are advertised as being able to easily consume the nutrients needed each day. These products contain more than one-third of the daily required amount of essential nutrients as stated in the nutrient labeling standards set by the Ministry of Health, Labor and Welfare and the Dietary Reference Intakes for Japanese people also formulated by the Ministry of Health, Labor and Welfare. In addition to these, there are also products such as semi-optimized foods that are almost optimized diets but lack only a few nutrients, and supplements that only supplement specific nutrients, and many foods have been launched on the market that can easily supplement the necessary nutrients that are lacking in your daily diet.

The above foods are made by adding new ingredients to the original ingredients, and can be said to be ingredients whose composition can be freely set. Furthermore, the method of changing the composition of ingredients is relatively simple. For example, in the case of a drink, new ingredients can be added to the liquid that serves as the solvent and then mixed. Also, in the case of gummies, noodles, etc., new ingredients can be added to the raw materials and then shaped through the normal manufacturing process. In this way, many of them have the aspect that it is relatively easy to add necessary ingredients to the formula and remove unnecessary ingredients.

On the other hand, rice, the staple food of the Japanese, is not a food ingredient whose composition can be freely changed. However, due to the influence of health consciousness in recent years, there is a demand for rice with reduced calorie intake and the addition of new ingredients. In response to this demand, konjac rice, which is made by forming a mixture containing konjac flour into a rice-like shape, has been proposed (see Patent Document 1). By substituting konjac rice for part of the rice before cooking, it is expected that the effects of suppressing the rise in glucose levels in the blood, reducing calorie intake while feeling full, and preventing obesity, can be expected.

A method of cooking rice with resistant dextrin has also been proposed (see Patent Document 2). The addition of resistant dextrin is expected to have physiological effects such as suppressing blood sugar levels, regulating the intestines, and improving lipid metabolism.

Special Publication No. 2020-505903 Patent No. 6125681

However, in the case of Patent Document 1, unlike regular rice, the texture of konjac rice is soft, which creates an unpleasant feeling when eaten. On the other hand, when using a resistant substance as in Patent Document 2, only about 10 to 15% can be added before cooking, and any more than this results in a problem of a texture and flavor that is different from that of regular rice.

The inventors therefore first conducted research into dried grain-like granular materials that would reduce calorie intake and have a texture similar to that of cooked regular rice when cooked. They then discovered that by using a combination of starch derived from high amylose rice and resistant starch, it was possible to reduce calorie intake and achieve a texture similar to that of regular rice.

The resulting dried grain-like granular material had the same luster and transparency as regular cooked rice immediately after cooking. However, if the rice was kept warm at a constant temperature after cooking, a new problem arose in that the luster and transparency were lost and the rice became pale. Furthermore, if the rice was refrigerated or frozen after cooking, not only did the luster and transparency disappear and the rice became pale, but the grain-like granular material, once its appearance had deteriorated, did not improve even if it was subsequently reheated.

The present invention was made in consideration of the above problems. That is, the purpose is to prevent the occurrence of white spots that occur after cooking of dried grain-like granular material whose main components are starch derived from high amylose rice and resistant starch, and to improve the appearance when cooked again.

The inventors have investigated whether the above problem can be solved. As a result of focusing on sticky rice and conducting research, they have discovered that by adding a substance with a specific DE value to dried grain-like granular material and then cooking the rice, the white blurring of the grain-like granular material after cooking is improved, giving it a glossy appearance, which has led to the completion of the present invention.

In order to solve the above problems, the present invention is characterized in that in a quality improver used for grain-like granular materials mainly composed of starch derived from high amylose rice and resistant starch, substances with a DE value of 0 to 20 account for 50 to 100% by weight of the total weight of the quality improver. In addition, it is preferable that the substance with a DE value of 0 to 20 is derived from amylopectin with a high content.

By cooking dried grain-like granules, whose main components are starch derived from high amylose rice and resistant starch, together with a substance having a specific DE value, it is believed that the surface of the grain-like granules after cooking is coated with a substance with a DE of 0 to 20. Coating the surface suppresses the evaporation of water and the loss of ingredients, which results in preventing or improving white blurring.

The following describes a preferred embodiment of the present invention. Note that the embodiment described below is an example of a typical embodiment of the present invention, and is not intended to narrow the scope of the present invention.

The dried grain-like granules of the present invention are kneaded materials that have been dried to resemble the shape of grains. Grains here refer to cereal seeds, such as the seeds of rice and other grass family crops, but may also include pseudo-cereals such as buckwheat, amaranth, and quinoa.

The dried grain-like granules of the present invention are mainly composed of starch derived from high amylose rice and resistant starch. Resistant starch means starch that is resistant to amylase digestion, and examples of such starches include retrograded starch, moist heat treated starch, and chemically modified processed starches such as those that have been subjected to strong cross-linking treatment with a cross-linking agent or those that have been ether-substituted. Of these, in the present invention, it is preferable to use resistant starch obtained by cross-linking treatment. The calorie content of the resistant starch used in the present invention is preferably 0 to 2 kcal/g, more preferably 0 to 1 kcal/g, and even more preferably 0 kcal/g. The calorie content is based on the value certified by the Japan Dietary Fiber Society.

The raw material for the resistant starch can be one or more selected from tapioca, wheat, horse mackerel, sweet potato, sago, high amylose corn, cornstarch, waxy corn, rice, and peas. Of these, it is preferable to use rice.

The amount of high amylose rice-derived starch contained in the dried cereal-like granules of the present invention is preferably 30 to 75% by weight, more preferably 40 to 50% by weight, per 100 g of dried cereal-like granules before cooking. The amount of resistant starch contained in the dried cereal-like granules of the present invention is preferably 25 to 70% by weight, more preferably 50 to 60% by weight, per 100 g of dried cereal-like granules before cooking. The blending ratio of resistant starch to high amylose rice-derived starch is preferably 20:80 to 80:20.

When producing dried grain-like granules, secondary raw materials such as sugars, thickeners, gluten, egg whites, colorings, and other nutrients can be used as necessary. Examples of necessary nutrients include vitamins and calcium. Secondary raw materials may also be dissolved in water and used.

The calorie content of cooked rice is said to be about 168 kcal per 100 g. For example, when 0 kcal/g resistant starch is used under the conditions of the examples described below, the calorie content is reduced by 28% to about 122 kcal when 20% of the rice is replaced with resistant starch, and the calorie content is reduced by 64% to about 61 kcal when 60% of the rice is replaced with resistant starch. When 2 kcal/g resistant starch is used under the conditions of the examples described below, the calorie content is reduced by 28% to about 122 kcal when 40% of the rice is replaced with resistant starch, and the calorie content is reduced by 37% to about 106 kcal when 60% of the rice is replaced with resistant starch.

The additive of the present invention is characterized by being a substance with a DE value of 0 to 20. The DE value is an index that indicates the degree to which starch has been decomposed, with 0 to 20 indicating a state close to starch that has barely been decomposed. On the other hand, a DE value of 80 to 100 indicates a state close to monosaccharides that have been decomposed. The additive of the present invention is characterized by being mainly composed of a substance with a DE value of 0 to 20, which accounts for 50 to 100% by weight of the entire additive. The additive of the present invention is preferably added at a ratio of 3 to 10% of the total amount of grain-like granular material. If it is less than 3%, the effect is weak. If it is more than 10%, it will deteriorate the texture of the rice.

There are no particular limitations on the substance with a DE of 0-20, so long as it is derived from amylopectin with a high content, but examples include cereals such as wheat or rice, corn, potatoes such as horse mackerel or sweet potato, and beans. These derived substances may be used after being gelatinized, or they may be used without being gelatinized. In the present invention, it is preferable that the substance is derived from rice.

Furthermore, in the present invention, flavor oils, food additives, such as sweeteners, colorants, preservatives, thickening stabilizers, antioxidants, bittering agents, acidulants, emulsifiers, strengthening agents, and flavorings may be used together with the additives as necessary. In particular, it is preferable to use flavorings for the purpose of imparting aroma during cooking and masking the powdery taste of resistant starch and the bitter taste of nutrients, other than for the purpose of improving the appearance. Flavorings can be used in either liquid or powder form, but it is preferable to add powdered flavorings during kneading, and liquid flavorings during cooking or immediately before eating.

Next, a method for producing dried grain-like granular material will be described. The raw materials can be prepared using an extruder. Specifically, high amylose rice-derived starch, resistant starch, and water are mixed and kneaded using an extruder. The resulting mixture is fed by a screw driven by a screw drive unit and extruded from a die. The mixture extruded from the die is cut into pellets, and grain-like granular material can be obtained. The extruder used can be either a single-screw extruder or a multi-screw extruder with two or more screws, but a twin-screw type is preferable from the viewpoint of quality stability. Any extruder can be used as long as it has a raw material supply port, a mechanism for feeding raw materials in a screw inside the barrel, mixing, compressing, and heating, and a die attached to the tip of the barrel.

The barrel temperature in the extruder is suitably 80 to 140°C, preferably 100 to 130°C. In the present invention, the pressure applied to the die is suitably 0 to 20 Bar, preferably 0.5 to 10 Bar. By changing the shape of the die, grain-like granules of various shapes, such as long grain rice and short grain rice, can be obtained. In the present invention, it is preferable to cut the grain-like granules to an appropriate size with a rotary blade provided at the tip of the die. When making the grain-like granules into a rice shape, it is preferable to slice the grain-like granules to a thickness of about 2 mm. After extruding like noodles, the grain-like granules may be cut to the desired size using a cutter or the like.

Finally, the resulting grain-like granules are dried to produce dried grain-like granules. There are no particular limitations on the drying method, and examples include hot air drying, vacuum freeze drying, microwave drying, and low-temperature air drying. Drying can also be performed using a combination of these methods. In the present invention, it is preferable to dry the dried grain-like granules until the moisture content is 15% or less.

The present invention will be explained in more detail below based on examples. Here, the explanation will be given using an example in which a grain-like granular material whose main components are starch derived from high amylose rice and resistant starch is used. In addition, commercially available rice (Koshihikari) was used as a reference example.

Preparation of cereal-like granules
First, 4 kg of starch derived from high amylose rice and 6 kg of 0 kcal/g resistant starch were mixed. Next, using a twin-screw extruder, the mixture was kneaded while adding water so that the flour and water were 1:1. At this time, the extruder was set under the following conditions: barrel temperature 100°C to 130°C, screw speed (dough conveying speed) 60 rpm. The extruder die shape was a bale-shaped 2.0 x 6.5 mm. The kneaded material extruded from the die was cut into short grain rice size (thickness 2 mm) with a rotary blade provided at the tip of the die. Next, the cut kneaded material was dried for 20 minutes under 60°C conditions. After storing at room temperature for 60 minutes, it was dried at 60°C for 50 minutes to obtain a dried grain-like granular material with a moisture content of 15% or less.

<Additives>
As additives according to the present invention, additives (Examples 1 to 5) using only substances having DE values based on the table below were prepared.
The additive was added in an amount of 10 g, calculated as solid content, per 200 g of dry cereal-like granules.

(Comparative Examples 1 to 6)
Comparative Examples 1 to 5 are the same as Example 1, except that substances with different DE values were used. The substances used are as shown in Table 2. Comparative Example 6 is the same as Example 1, except that no additive was added.

First, an experiment was conducted on the effect of additives during warm keeping. The prepared grain-like granules of each Example and Comparative Example were cooked with a water content of 160%, and the Reference Example was cooked with a water content of 140%. The time immediately after cooking was set as 0 minutes, and the condition (taste, appearance) of the grains of each Example and Comparative Example was compared with that of the Reference Example at 0, 10, 30, 60, 90, 120, and 240 minutes, and evaluated according to the following evaluation criteria. During the observation over time, all of the Examples, Comparative Examples, and Reference Examples were kept warm using the rice cooker's warm keeping function. The appearance results are shown in Table 3, and the taste results in Table 4.

Appearance 5: There is a transparent film-like substance on the surface of the grain, the surface is smooth, and the grains shine due to the light reflected by the film.
4: A thin transparent film-like layer is present on the surface of the grain, and the surface is smooth.
3: There is a thin, transparent film on the surface of the grain, but the light reflection from the film is weak and the grains do not shine well. 2: There is a transparent film in patches on the surface of the grain, and the grains shine slightly. 1: There is no transparent film on the surface of the grain, the surface is rough, and the grains do not shine.

Taste 3: When chewing, you feel a slight sweetness. Taste 2: When chewing, you feel a sweetness. Taste 1: When chewing, you feel a strong sweetness.

As is clear from Table 3, the evaluations of all the Examples and Comparative Examples, including the Reference Example, declined over time. This is thought to be because moisture constantly evaporated from the surface of the rice or granules due to the warming, causing them to dry out over time. In particular, Comparative Examples 1 to 6 were prone to moisture evaporation, and the surface shine began to fade 30 minutes after the start of warming, and almost no shine was observed after 60 minutes. From this, it was inferred that the function of preventing moisture evaporation by forming a coating on the surface is weak in DE 25 to 100. In contrast, in Examples 1 to 5, a thin film-like thing was visible on the surface of the granules until 90 minutes had passed since the start of warming, and the surface was smooth and shiny. In addition, even after 90 minutes, a weak shine was observed. In particular, the appearance of Example 2 was rated the same as that of the Reference Example. In addition, in Example 5, almost no shine was observed 240 minutes after the start of warming, but until then, it maintained a greater shine than the Comparative Examples. From this, it was inferred that the lower the DE value, the stronger the ability of the material to form a film on the surface and prevent water evaporation.

Next, the taste will be confirmed. Usually, when cooked rice is chewed, the starch is broken down by the amylase contained in saliva, and a slight sweetness is felt. As shown in Table 4, in this embodiment, the reference example also had a slight sweetness felt by chewing, regardless of the elapsed time of keeping warm. Similarly, in Examples 1 to 5 and Comparative Example 6, a slight sweetness was felt by chewing, regardless of the elapsed time of keeping warm. On the other hand, in Comparative Examples 1 to 3, the sweetness was felt more prominently than in normal cooked rice when chewed regardless of the elapsed time, and it was unnatural. This is thought to be because in Comparative Examples 1 to 3, starch that had been decomposed to a certain extent was added as an additive, so that it was easily broken down into monosaccharides by the amylase contained in saliva, and the sweetness was easily noticeable. Furthermore, in Comparative Examples 4 and 5, the sweetness was felt strongly whether or not chewed, and it was a taste that was clearly different from that felt when chewing normal cooked rice. This is thought to be because the additives used in Comparative Examples 4 and 5 were almost monosaccharides or close to monosaccharides, making the sweetness more noticeable from the start.

These findings suggest that by using additives with a DE of 0 to 20, it is possible to produce rice that looks and tastes similar to commercially available cooked rice, even if the rice is kept warm for a long time.

Next, cooked cereal-like granules were frozen and stored, and the effect of additives on the appearance and taste when thawed was examined. The effects were verified for Example 2, Comparative Example 5, Comparative Example 6, and Reference Example, based on the results of the previous examples.

The verification was carried out as follows. First, 150 g of each of Example 2, Comparative Example 5, Comparative Example 6 and Reference Example was transferred to a tray and left at room temperature for 5 minutes to cool. After that, it was flash frozen at -40°C and kept as it was for 30 minutes. Next, it was cooked in a microwave oven at 500W for 2 minutes and 10 seconds while still on the tray. Evaluation was performed according to the above-mentioned evaluation criteria at 10, 30, 60 and 120 minutes, with 0 minutes being immediately after cooking, after freezing, after microwave cooking and immediately after microwave cooking. However, the taste after freezing was not evaluated. After microwave cooking, the tray was left open at room temperature without a lid. The appearance results are shown in Table 5 and the taste results in Table 6.

As is clear from Table 5, all samples lost their surface shine due to freezing. Furthermore, by heating in a microwave oven, all samples regained some shine, although to different degrees. However, all samples received lower ratings than immediately after cooking. In particular, Comparative Examples 5 and 6 showed a significant drop in rating, with both receiving the lowest rating after 10 minutes. In contrast, Example 2 and Reference Example maintained their ratings for up to 30 minutes after cooking in the microwave. The reason for the rapid drop in rating compared to the results of the warming test described above is thought to be that in the warming test, the rice cooker lid was closed, so the moisture content in the rice cooker was maintained to a certain extent, whereas in this test, the lid was left open even after microwave cooking, which led to a faster loss of moisture.

On the other hand, the reason why the Reference Example and Example 2 received high ratings is thought to be related to the surface structure. The surface of the cooked rice in the Reference Example is covered with sticky rice. Therefore, it is thought that the sticky rice plays an important role in suppressing moisture evaporation and in appearance. If that is the case, it is thought that the surface of the grain-like granular material in Example 2, which showed the same tendency as the Reference Example, is also covered with a component similar to sticky rice. In other words, it is thought that in this embodiment, the DE0 additive played a role similar to sticky rice, resulting in better results than Comparative Examples 5 and 6.

Next, the taste was examined. As with the results of the heat retention test described above, all samples except Comparative Example 5 had a slight sweetness that could be felt by chewing, regardless of the time that had passed since cooking in the microwave. On the other hand, Comparative Example 5 had a strong sweetness that could be felt with or without chewing, and had a taste that was clearly different from that felt when chewing regular cooked rice.

These results suggest that by using the additive of the present invention, it is possible to produce cooked rice that looks and tastes similar to commercially available cooked rice, even after freezing.

Claims (2)

A quality improver for grain-like granular materials whose main components are high amylose rice-derived starch and resistant starch,
A quality improver for use in cereal-like granular materials, the quality improver comprising 50-100% by weight of a substance having a DE value of 0-20 based on the total weight of the quality improver. The quality improver for use in the grain-like granular material according to claim 1, wherein the substance with DE 0-20 is derived from amylopectin with a high content.