JPH0372850A - Rice cooking method - Google Patents

Abstract

PURPOSE:To prepare cooked rice having soft and glutinous texture and good palatability by adding an additive composed of gluconodelta-lactone and a specific deodorant, etc., to rice-cooking liquid. etc., and cooking rice with the liquid, thereby effectively gelatinizing starch. CONSTITUTION:Rice-cooking liquid or rice grain is added with an additive for rice grain composed of glucono-delta-lactone, a non-volatile acid (e.g. malic acid or citric acid), a deodorant such as cyclodextrin, ginger or protease and a flavor (e.g. orange oil or aliphatic acid ester) and the rice is cooked to obtain the objective cooked rice.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a rice cooking method for improving the taste of cooked rice.

(Conventional technology) The quality of rice, especially its taste, depends on its variety, production area, cultivation method,
There are a wide variety of factors, including those determined by production methods such as harvesting methods, those determined at post-harvest processing stages such as drying, storage, and milling, and those affected during rice cooking. It is said that the biggest influence on the production stage is the production stage, followed by the variety.

Traditionally, rice taste evaluation involves cooking white rice, having multiple expert examiners eat the cooked rice, and comparing various aspects such as the appearance, aroma, taste, stickiness, and hardness of the rice to be evaluated. This is done through a so-called sensory test, in which rice is repeatedly tested to see how superior or inferior it is to the standard rice used as the basis for evaluation, and the average value is taken.

In recent years, the composition and physical and chemical properties of rice have been chemically measured and analyzed, and the correlation between them and the taste evaluation values obtained in the aforementioned sensory tests has been investigated, and finally, the scientifically obtained measured values As a result of research that attempts to evaluate the quality of rice, it has been found that among the components that make up rice, those that are particularly important in evaluating the quality of rice are amylose and amylopectin, which make up the starch of rice. It is becoming clear that the ratio, protein content and water content.

Next, we will explain how the content of each component that makes up rice affects its taste. In general, Koshihikari and Sasanishiki are popular brands of rice with good taste in Japan. - As an example, Table 1 shows a comparison of the protein content and amylose content of starch in several brands of white rice, including Koshihikari and Sasanishiki, with standard milling levels. . Note that the ingredients of the same brand are not always the same as those shown in Table 1, but may differ depending on the geological conditions (soil quality, water quality) and meteorological conditions (temperature, sunshine hours, rainfall, etc.) of the production area. It goes without saying that the content of the ingredients varies slightly. From Table 1,
Compared to other general brands of rice, Koshihikari and Sasanishiki are
It has a low protein content and a low amylose content in starch.

Table 1 Ingredients (%) (Protein content is the weight ratio, amylose content is the ratio to 100% starch.) As mentioned above, the protein content and the amylose content ratio in the starch are different from rice. Apart from having a large effect on the taste of rice, the moisture content of white rice also has a large effect on the taste in relation to the viscosity and hardness of the cooked rice.

If the moisture content of white rice is around 15%, the rice will not crack even when soaked in water and will be cooked into perfect rice grains. Water absorption progresses rapidly from the ventral side of polished rice (where there are relatively many intercellular spaces for water to penetrate) to the endosperm, and cracks occur instantaneously due to the volume strain caused by the water difference between the dorsal side (where the intercellular spaces are extremely small). When rice is raised and cooked, starch particles blow out from the cracks, resulting in sticky, low-quality rice that is neither chewy nor sticky.

It is also known that broken rice absorbs water all at once, resulting in sticky cooked rice, and that the rice is crumbly, resulting in low-quality cooked rice that lacks chewiness and stickiness.

On the other hand, rice producers tend to supply rice that is too dry because they are overly concerned about exceeding the government's upper limit of 15% for moisture testing. It is known that 0.5% to 1.0% of water is lost from rice grains.

Therefore, humidity control is performed by bringing rice grains (brown rice, white rice) into contact with water (steam) to maintain the moisture content of the rice grains at 15%. However, in old rice and rice that has a poor taste, the intercellular spaces are narrow, so even when soaked, water cannot be absorbed into every corner of the rice grain.
When the rice is cooked, the degree of gelatinization is low, resulting in rice with poor taste.

[Problem to be solved by the invention]

This invention enables efficient gelatinization of starch when polished rice grains (white rice) are soaked in water and cooked, resulting in cooked rice with good taste and aroma that has appropriate softness, firmness, and stickiness after cooking. The objective is to provide a method of cooking rice that can yield rice grains with the following properties.

[Means to solve the problem]

An additive for rice grains is obtained by using glucono delta lactone or a nonvolatile acid and a deodorant or fragrance such as cyclodextrin, ginger, or protease.

The rice grain additive may be added as a solid grain material, powder, or a liquid dissolved in a material to rice or rice with water added before cooking, or its aqueous solution or rice grain additive. and a solvent such as water are separately made into a mist or the like and added to the rice grains in the air.

[Action and effect of invention]

By adding the rice grain additive of the present invention to polished rice grains,
Coupled with the hydrolysis effect of starch in cooking rice, it increases the efficiency of starch gelatinization and improves the stickiness of rice grains, as well as softens and improves the taste of rice grains. Unpleasant odors that occur when cooking rice can be completely eliminated by using deodorants or fragrances.

In addition, examples of nonvolatile acids include malic acid, citric acid, tartaric acid, curconic acid, succinic acid, and glutamic acid.

[Embodiments of the invention]

When cooking rice, glucono delta lactone 10111M
Two types of tests were conducted: one using this as a rice cooking liquid and the other using ordinary water as a rice cooking liquid. Akihikari from Hokkai Dosan was used as the test rice.

The rice was evaluated using a texturometer.

Hardness, stickiness, and balance measured by a texturometer are used as factors to determine the quality of rice taste.

The texturometer uses a plunger to repeatedly press and pull rice grains placed in a saucer, matching the chewing speed of humans, and calculates this value by dividing the tensile force, or stickiness, by the pressing force, or hardness. It is a measure of balance, and it is generally said that the higher the balance, the better the taste.

Rice cooked without glucono delta lactone had hardness H = 2.76, stickiness per day = 0.21, balance -H/low 0.08, whereas rice with glucono delta lactone added The balance level is -H/Low 0.
．． No. 11, there was a statistically significant difference in hardness, stickiness, and balance.

Note that the same effect can be obtained by using the above-mentioned non-volatile acids such as malic acid in place of glucono delta-lactone.

However, if only glucono delta lactone or a non-volatile acid is used as an additive for rice grains, an unpleasant odor may be generated in the cooked rice depending on the amount added. Therefore, deodorants that contain odor substances such as zychlodextrin and ginger, and deodorants that prevent protein denaturation such as proteases are added to glucono delta lactone or non-volatile acids for rice grains. When the agent is added to a rice cooking liquid or rice grains to cook rice, the unpleasant odor caused by glucono delta lactone or a non-volatile acid is eliminated, resulting in cooked rice with improved taste.

In addition, if a flavoring agent is added instead of the above deodorant and used as an additive for rice grains, and it is added to the rice cooking liquid or rice grains to cook rice, the unpleasant odor caused by glucono delta-lactone or non-volatile acids will be eliminated. This results in cooked rice with a good aroma and improved taste.

Incidentally, the fragrance may be a natural fragrance or a synthetic fragrance. Natural fragrances include orange oil, grapefruit oil, lime oil, vanilla, saffron, etc., and synthetic fragrances include aliphatic acid esters, aromatic acid esters, aliphatic higher aldehydes. There are other types such as Nootkatone and Nootkaton.

Furthermore, even if the additive for rice grains is dissolved in water and sprayed to absorb it from the surface of the rice grains into the rice grains when conditioning the humidity of the rice grains, some effects may be obtained, although some elution may occur during cooking. I can.

As mentioned above, when conditioning rice grains, instead of dissolving the rice grain additive in water and spraying it, glucono delta lactone or a non-volatile acid and a deodorizing agent or fragrance are added in advance and then the moisture is conditioned. This allows it to be reliably attached to the rice grains and also to penetrate into the interior of the rice grains.

In addition, a certain amount of the rice grain additive is infiltrated into the interior of the rice grain in advance, or rice grains that have been coached on the surface of the rice grain are prepared, and then mixed with white rice grains that have not been subjected to the above treatment at the time of measuring and packaging or cooking rice. You can still get the appropriate effect.

Glucono delta lactone is an intramolecular esterification of gluconic acid, and the substance itself is not an acid.

When dissolved in water, it dissociates to form an acid. When the temperature of the aqueous solution is high, the degree of dissociation increases, so its properties as an acid increase. When the temperature is low, its character as an acid decreases. Rice is low P
Cooking rice in the sun improves its balance, but using regular acid will result in rice that is too sour.

After cooking rice, glucono delta-lactone partially returns to ester when the water content is relatively low and the temperature is relatively low, so the acidity of rice is less than that of ordinary acids.

In addition, glucono delta-lactone and the like are obtained as crystals, so they can be obtained with very high purity, and side effects such as coloring of rice are small.

When cooking rice, glucono delta-lactone works together with its starch or proteolytic action to effectively gelatinize starch, producing rice that is soft, sticky, and delicious.

In addition, glucono delta-lactone has no side effects on the human body and can effectively achieve the purpose of the present invention.

Claims (1)

[Claims] A rice cooking method characterized by adding a rice grain additive consisting of glucono delta lactone or a non-volatile acid and a deodorant or fragrance such as cyclodextrin, ginger, or proteases to a rice cooking liquid or rice grains, and then cooking the rice. .