JPH02291236A - Additive for rice grain and its use - Google Patents

Abstract

PURPOSE:To obtain an additive for rice grain which efficiently makes starch into paste during boiling of polished rice and provides boiled rice having proper softness, tension, glutinousness and good flavor after boiling, comprising glucono delta lactone. CONSTITUTION:An additive for rice grain comprising glucono delta lactone. The additive is made into solid granule, powder or a liquid dissolved in a solvent and added to rice or a mixture of rice and water or an aqueous solution of the additive or the additive for rice grain and a solvent such as water are separately processed into a mist state and added to rice grain in air. In the operation, lecithin, vitamins, calcium, etc., may be added to rice besides the additive for rice grain and the additive for rice grain may be blended with an alcohol to give a liquefied additive. Glucono delta lactone is a substance wherein gluconic acid is esterified in the molecule, the substance itself is not an acid but is dissolved and dissociated in water into an acid. Since glucono delta lactone is partially returned to an ester after rice boiling when water content and temperature are relatively low, glucono delta lactone has lower acidity of boiled rice than a common acid.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an additive for rice grains and a method of using the same.

[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 scientifically 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 degrees. 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 (%) (The protein content is the weight ratio, and the amylose content is the ratio to 100% starch.) As mentioned above, the protein content and the amylose content ratio in the starch are 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, causing instantaneous cracks due to the volume strain caused by the difference in water content with 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 similarly absorbs water all at once, resulting in sticky cooked rice, and 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 rice is cooked, the degree of gelatinization is low (resulting in cooked 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 rice grains that have good taste and have appropriate softness, firmness, and stickiness after cooking. An object of the present invention is to provide an additive for rice grains and a method for using the same.

[Means to solve the problem]

Glucono delta lactone is used to obtain an additive for rice grains.

The rice grain additive may be added as a solid grain material, powder, or a liquid dissolved in a solvent 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.

At this time, in addition to the rice grain additives, lecithin, vitamins, calcium, etc. may be added, or alcohol may be added to form a liquefied additive.

〔Effect of the invention〕

By adding the rice grain additive of the present invention to polished rice grains,
In combination with the hydrolyzing action of starch in cooking rice, it increases the efficiency of starch gelatinization and improves the stickiness of rice grains, as well as softening them and improving their taste.

[Embodiments of the invention]

Two types of tests were conducted: one in which 10mM (millimol) of gluconodelta-lactone was prepared during rice cooking, and one in which this was used as a rice cooking liquid, and the other in which ordinary water was used as a rice cooking liquid. Akihikari from Hokkaido was used as the test rice. The rice was evaluated using a texture meter.

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

The Textu Mouth Meter uses a plunger to repeatedly press and pull rice grains placed in a saucer in accordance with the chewing speed of a human, then divides the tensile force, or stickiness, by the pressing force, or hardness, and calculates this value as a balance. It is generally said that the more balanced the taste, the better the taste.

Rice cooked without glucono delta-lactone had hardness H = 2.76, stickiness - H = 0.21, and balance - H/H = 0.08, whereas rice cooked without glucono delta-lactone had What is added is hardness H=2.65, stickiness H=0.29, and balance H/H=0.1! There were statistically significant differences in hardness, stickiness, and balance.

In the above, the acid was added to the rice cooking liquid during rice cooking, but the same result can be obtained by adding the acid to the rice grains and then adding the rice cooking liquid afterwards.

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 the rice grains, instead of dissolving the rice grain additive in water and spraying it, by adding glucono delta lactone in advance and conditioning the humidity afterwards, it is possible to ensure that it adheres to the rice grains. It can also be penetrated into the inside of rice grains.

In addition, rice grains are prepared by infiltrating a certain amount of the rice grain additive into the interior of the rice grains or coating the surface of the rice grains, and then mixed with untreated white rice grains 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 under hydrogen improves the 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, since glucono delta-lactone is obtained as crystals, it can be obtained with very high purity, and side effects such as coloring and odor on rice are small.

If the amount of glucono delta-lactone added is sufficiently large, the rice texture will be further improved, but side effects such as sourness and odor will also increase, so to avoid this, glucono delta-lactone and protein-degrading enzymes such as protease are added There is also a method of adding them in combination so that the amount of glucono delta-lactone added is not increased unnecessarily.

Additionally, fragrant substances may be used in combination to reduce or eliminate side effects such as odor.

Glucono-delta-lactone acts on starch or protein during cooking, and in combination with its proteolytic action, it effectively gelatinizes 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 (2)

[Claims] (1) An additive for rice grains characterized by comprising glucono delta lactone. (2) A method of using a rice grain additive, which comprises adding the rice grain additive made of glucono delta lactone to a rice cooking liquid or rice grains to cook rice.