HU200667B - Method for producing blanched rice - Google Patents

Abstract

The invention relates to a method for producing parboiled rice. The method is applicable to long grain, medium grain and round grain rice. The object of the invention is to show process conditions for the hydrothermal treatment of paddy rice, which lead to rice with high Weiszgrad, high yield of wholegrain and to a shortening of the Prozeszdauer over known methods. According to the present invention, the object is achieved by subjecting a paddy rice paddy rice to a microwave treatment in excess water, reaching a product temperature of 100 ° C. over a period of one minute and holding it, then separating the excess water and removing the rice Microwave treatment of the paddy rice is continued until a humidity of * at the same temperature is reached, after which the rice is further processed in a known manner. {Parboiling Prozesz; Parboiled rice; Paddy rice; Hydrothermal treatment; microwaves; Weisz degrees; Whole grain; Yield}

Description

(57) EXTRAS

The present invention relates to a process for the production of pre-cooked rice which is heated after addition of paddy water and soaked to a moisture content of 25-35%, subjected to further hydrothermal treatment, and subsequently dried, milled, polished and polished.

The object of the invention is to subject the soaked paddy rice to a microwave treatment of excess water by raising the temperature of the rice product to 100 ° C within 1-10 minutes and then maintaining the temperature for 15 minutes, after which excess water is removed in a known manner. continue to heat the microwave at a temperature of 15-20%.

Scope of the description: 4 pages, without figure

HU 200 667 B

-1HU 200667 Β

The present invention relates to a process for the production of pre-cooked rice. The invention can be used in the food industry for the production of high-protein precooked rice. The process is suitable for the production of long, medium and round rice grains.

The stems of rice cut off from the stalk are surrounded on the outside by a hard, silica-containing shell (paddy). The multilayer membrane located below it, the so-called. the silver membrane, which encloses the core itself, contains important ingredients rich in vitamins, minerals, protein and fat. In the production of white rice (fine rice), this silver membrane and germ are removed by grinding and polishing the husked rice, and at the same time, the substances essential for nutrition are removed. To preserve these materials, a pre-cooking process is used. In addition to improving nutritional physiology, the pre-brewing process results in an improvement in process characteristics, in particular in the overall yield and the cooking properties of rice. The pre-cooking process consists of hydrothermal treatment of paddy rice or paddy rice. During this process, minerals and vitamins migrate from the silver membrane to the core. The hydrothermal onset is also used for loosening the shell and hardening and / or hardening of the rice grain (endosperm). leads to cornea by starch gelatinization. This results in hardening of the whole rice structure and leads to a higher whole grain yield than husking, grinding and polishing. , used in the production of instant rice. Unlike pre-cooked rice, a fast loose and porous structure is desirable for quick cook rice.

The pre-cooking process consists of the following steps: soaking, steaming, cooking and drying rice. The treated rice is then husked, polished and polished.

Different process engineering solutions are known for each process step. The soaking is preferably carried out in warm water, where the water temperature ranges from 60-70 ° C until the moisture content reaches 25-35%. Generally, soaking takes 2-4 hours. The operation can be performed at lower temperatures, however, but the treatment takes 10-16 hours.

U.S. Patent No. 2,358,251. According to U.S. Pat. The gelatinization of rice starch by steaming or soaking rice soaked. cooking. U.S. Patent No. 4,361,593. According to U.S. Patent No. 3,600, rice soaked in vacuum at 38% moisture is treated with saturated steam for 15 minutes while rice is treated with ca. It does not warm up to 90 ° C. The 45% rice is then held at 45 ° C for 6 hours, then preheated to 66 ° C and then dried with gradual reduction in temperature until the moisture content is reduced to 12.5%.

U.S. Pat. U.S. Patent No. 3,600,123 discloses a method wherein the rice arranged in a thin layer 2 is soaked at a temperature close to 100 ° C and in a quantity of water not exceeding 100% saturation of the rice grain, followed by rice, also arranged in a thin layer, treated. Meanwhile, the temperature should be close to 100 'C, but you can't reach that value. During steaming, the rice absorbs water until it reaches a saturation point and at the same time the starch gelatinization process is completed. The rice is then air dried at 80 ° C. U.S. Pat. No. 2,571,555. Patent Patent No. 5121 is a similar but very expensive procedure. U.S. Patent No. 2,909,114. and U.S. Patent No. 4,102,125 discloses an apparatus in which rice is steamed under pressure.

U.S. Patent No. 3,674,514. U.S. Patent No. 4,268,125 discloses an apparatus for the production of pre-cooked rice which substantially reduces the risk of soaking, steaming or steaming rice. cooking and drying time. In particular, the soaking time, which can work up to 10 hours under normal pressure, should be reduced by pre-treating the rice with hot air at 150 'Con. The steamed rice is dried with spinning air at 100-400 ° C. Such high temperatures, especially pre-treatment with spinning air, adversely affect the desired grain structure of the rice.

In addition to the already mentioned advantages, known processes for the production of pre - cooked rice are not included. improving nutritional physiology — their disadvantage is that the rice kernel takes on a yellow to dark brown color during pre-cooking. The causes of this undesirable discoloration are enzymatic staring reactions (eg phenol oxidase) or chemical reactions.

During hydrothermal treatment, free amino acids and reducing sugars are formed, which react with each other to form dark brown Maillard products. To avoid these discolorations, sodium bisulfite is added to the soaking water in the wake of Jayanarayanan (Nahrung, Berlin & (1964), pp. 129-137). However, this has a negative effect on the vitamins in the rice, thus seriously questioning the value of the pre-cooking process.

U.S. Pat. No. 3,660,109. The use of potassium permanganate to prevent discolouration, described in U.S. Pat.

A further disadvantage of the repeated technical solutions of the pre-cooking process is the loss of material due to the partial opening of the husk during the hydrothermal treatment. Primarily starch particles are released from the endosperm, leading to an increase in the stickiness of rice

Several processes are known for the production of instant hot rice, i.e., white rice with a loose endosperm structure, hydrothermally treated. Without being exhaustive, here are some examples.

DE 2.632.121. According to Publication Publication No. 3, the instant cooking rice is produced by swelling the rice at a level of about 6 to 16 times the original volume, e.g. heat treated with high frequency waves followed by a condensing agent, dried and shrunk.

-2HU 200667 Β

DE 1,538,076. U.S. Patent No. 5,198, when cooking instant rice, mixes rice with a coating after soaking and before steaming. After dehydration, when the moisture content is reduced to less than 35%, the rice is pressed and then heated again in a microwave to loosen the structure 5.

DE 3,506,099. U.S. Patent No. 5,123,125 discloses a method of opening cereal grains which is characterized in that various varieties of cereals having a moisture content of 10-15%, such as rice, are subjected to microwave treatment. Opening is carried out in an unpasteurized state, so that after treatment, the grain has a very high water absorption capacity due to the loosening of the structure (puffing effect), thus not meeting the requirements of the pre-cooked rice.

The object of the invention is to provide excellent application properties, e.g. production of pre-cooked rice with a high whiteness and a low yield of husks and polishes 20. The degree of whiteness must not differ significantly from that of white rice. It is a further object of the present invention to reduce the duration of the process in comparison with the known methods. 25

SUMMARY OF THE INVENTION It is an object of the present invention to provide process conditions for the hydrothermal treatment of paddy rice which, in contrast to known methods, shorten the process time and at the same time result in high whiteness and high wheat grain yields.

To accomplish this object, we have developed a process wherein the paddy rice is heated after addition of water and soaked to a moisture content of 25-35%, subjected to further hydrothermal treatment, and subsequently dried, milled, polished and polished. It is an object of the present invention to subject the soaked paddy rice to a microwave treatment of excess water by raising the rice product temperature to 100 ° C within ΙΙΟ minutes and maintaining this temperature for 1-5 minutes, after which excess water is removed in a known manner. continue to heat the microwave at a temperature of 15-20%. 45

Preferably, the soaked paddy rice is continuously passed through one or more microwave units by means of a microwave conveying device, preferably adjusting the frequency of the microwaves to between 2370 and 2450 MHz.

It has been shown that if the hydrothermal treatment of paddy rice is carried out by subjecting the rice completely submerged in water to a short-term microwave treatment, the rice coloring characteristic of the pre-cooking process does not occur and at the same time the rice structure is strengthened and during the polishing process, as opposed to the known methods, the whole eye yield will be higher. Microwave transmission of the energy necessary for starch gelatinization leads to very rapid, complete warming of the rice grain. As a result, starch-inducing enzymes are deactivated and, in the short term, when the rice is heated to a specific temperature, less the amount of reducing sugar and free amino acid formed which are the starting products of the Maillard reaction. In addition, the duration of the Maillard reaction is limited. However, using microwaves, while maintaining a high whiteness of rice, the pre-cooking effect is not yet achieved. Only the process according to the invention can be solved when microwaves act on soaked rice which is completely covered with water. excess water used to counteract pressure in the grain and prevent water vapor from escaping In addition, the process of the present invention results in an amount of water penetrating through the otherwise inactive shell and pre-cooking water. necessary to produce an effect. Thus, unlike instant cooking rice, the structure of the rice is not loosened, but the complete gelatinization of the starch leads to hardening of the endospenium structure in the seed enclosed by the husks.

A further advantage of the process according to the invention over known pre-cooked rice production methods is that after the rice is soaked, the microwave treatment does not increase the proportion of open husked grains. This is also due to the fact that the time required for the complete gelatinization process is greatly reduced.

The invention will now be described in more detail with reference to the following examples.

Example 1

Purify 100 g of paddy rice, heat with 0 / 2.1 water to 70 ° C and soak for 5 hours at this temperature. After that, the moisture content of the rice will be 32%. The rice, together with the water used for soaking, is filled into a glass container on a conveyor belt or hanging on a conveyor. Meanwhile, the water completely covers the grain The glass container filled with rice then passes through a microwave tunnel Ski. The microwave frequency for the treatment is 2450 MHz and the lead time is 4 minutes. After two minutes, the rice temperature reaches 100 ° C. After a further 2 minutes, the rice endosperm is completely gelatinized. After passing through the tunnel, it is separated from the rice! excess water by passing the rice on a perforated tape. Then the rice, separated from the water, once again passes through the microwave tunnel. Meanwhile, it is pre-dried for 5 minutes until the moisture content reaches 20% and is then further processed

Example 2

Purify 100 g of paddy rice, heat with 0.21 water to 70 ° C and soak for 4 hours at this temperature. The moisture content of the rice will be 28%. According to Example 1, the rice is microwave-treated with water for soaking. Meanwhile, the water completely covers the grain. 2450 MHz frequency3

At 200667 Β, traveling through the microwave tunnel takes 8 minutes. The product temperature reaches 100 ° C after 3 minutes and is maintained for another 5 minutes by microwave treatment. The rice is separated from the water by means of a perforated strip and preheated for 8 minutes in the microwave tunnel until it has a moisture content of 15%.

Example 3

According to Example 1, paddy long-grained rice is soaked at 70 ° C for 5 minutes (until it has a moisture content of 32%, but in this case the water-completely covered rice container is placed in a microwave oven at 2370 MHz; reach 100 ° C, remove after another 2 minutes of treatment. After decanting off the water, place the container in the mik * h ”oven for another 5 minutes to preheat the rice until 3% moisture content is reached. oL The rice is then further processed.

Claims (3)

PATENT CLAIMS A process for the production of pre-cooked rice, wherein the paddy rice is heated after addition of water and soaked to a moisture content of 25-35%, then subjected to further hydrothermal treatment, followed by drying, milling, grinding and polishing: the excess soaked paddy rice is subjected to a microwave treatment to increase the rice product temperature to 100 ° C within 1-10 minutes and maintain this temperature for 1-5 minutes, then the excess water is removed in a known manner and the paddy rice is treated at this temperature, The microwave treatment is continued until the moisture content is 15-20%. Method according to claim 1, characterized in that the steamed paddy rice is conveyed continuously through one or more microwave equipment, depending on the performance of the equipment, by means of a device conveying the paddy rice. 3. The method of claim 1, wherein the microwave frequency is 2370-2450 MHz.