JPH0319661A - Production of retort packed boiled rice - Google Patents

Abstract

PURPOSE:To obtain high quality boiled rice of retort packaging, having improved browning by immersing steamed or boiled rice in an aqueous solution adjusted to proper pH with an organic acid, packing into a packaging bag and adjusting the rice in such a way that the rice has specific pH after sterilizing by heating under pressure. CONSTITUTION:Raw material rice is washed, immersed in water for a given time, further steamed or boiled, packed into a packaging bag and sterilized by heating under pressure. In the operation, the following procedure is carried out. Namely, the steamed or boiled rice is immersed in an aqueous solution adjusted to proper pH with an organic acid, packed into a packaging bag and adjusted in such a way that the rice has pH5.8-6.2 after sterilizing by heating under pressure. The reason why pH of rice itself is limited after packing the rice into the packaging bag and sterilizing by heating under pressure is that adjustment pH to <5.8 is effective for preventing browning but luster on the surface of rice grain is lost and commercial value of boiled rice of retort packaging is reduced. On the other hand, when pH exceeds 6.2, browning preventing effect is not shown.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing retort-packed white rice.

[Prior Art and Problems] Conventionally, retort-packed white rice has been produced by washing raw rice, soaking it in water for a desired period of time, steaming it, filling it into a packaging bag, and sterilizing it by heat and pressure.

The above-mentioned heat sterilization is carried out under the conditions of Fo = 4 or more, which is a standard for sterilization to kill Bacterium botulis, based on the provisions of the Food Sanitation Act, but in reality, F
. Heat sterilization is performed so that the ratio is 4.5 to 5.0. However, when sterilization is carried out under such conditions, browning of rice grains is accelerated due to the Maillard reaction, resulting in a significant loss of quality.

On the other hand, there is known a method for producing portable cooked rice (Japanese Patent Publication No. 49-17581) which has already been filed and patented by the present manufacturer. In this method, raw rice is washed and washed at 20 to 40°C in order to suppress the excess starch that flows out when rice grains are steamed and to eliminate stickiness.
This is a method of soaking for 0 to 120 minutes, which prevents browning.
” It's not about that.

The present invention was made in order to solve the above-mentioned conventional problems, and it is possible to produce high-quality retort-packed white rice that does not brown even if the pressure and heat sterilization is increased to a range of Fo = 4.5 to 5.0. It is intended to provide a broad range of information.

[A Thousand Steps to Solve Sectional Problems] The present invention involves washing lGt cooked rice, soaking it in water for a desired period of time,
After further steaming, the rice is filled into a packaging bag and sterilized by heating under pressure. This is a method for producing white rice packaged in white rice, which is characterized by adjusting the I) value of the rice itself after heat sterilization to be 58 to 6.2.

Examples of organic acids used as pH adjusters for aqueous solutions include citric acid and lactic acid. This aqueous solution is adjusted to be more acidic than the I) content of the rice itself after heat sterilization.

The reasons for limiting the pH of the rice itself after heat-killing are: I) Is it effective to prevent browning if H is less than 5.8? Rice t☆. The title song becomes dull and the product value decreases, and on the other hand, when the pH is 6.
This is because if it exceeds 2, the browning effect of 11/I+l cannot be achieved.

The pressurization by the above-mentioned sakan I samurai is performed to prevent the contents inside the packaging bag from expanding due to heating and crushing the bag. Such pressurized pasting is performed by I. It is preferable to carry out the test at 100 to 118°C at 100 kg/cJ or more.

[According to the invention, rice after steaming is immersed in 7'8 of adjusted water, filled in a packaging bag, and heat-killed.
By adjusting the I) H value of the rice white body after heating to 58-62, the quality is maintained without browning even if the pressure and heat killing m is repeated 1r in the range of FO = 4.5-50. +i
You can get 1% of the packaged white rice.

In addition, the rice after boiling is soaked in an aqueous solution whose pH is adjusted with an organic acid.
By applying organic acids, the rice grains are well penetrated into the packaging bag, and the pH of the rice r+ body after being pasted and killed is reduced to 5.
8 to 62, it is possible to shorten the processing time with a pH adjustment of 1-1.

[Length example] Hereinafter, a practical example of the present invention will be described in detail.

Large Example 1 First, 500 g of Urji rice was washed twice (2.5 minutes) in a washing container with water overflowing, and after draining, it was immersed in water for 2 hours. Subsequently, the water was thoroughly drained, and the mixture was stored in a steamer lined with bleached cloth, and after being leveled, it was steamed for about 15 minutes. Immediately after steaming, it was immersed in a pH-adjusted aqueous solution (pH-adjusting immersion liquid) having the following composition for several seconds, and then taken out. At this time, the pH of the rice white body was 575.

(Composition of immersion liquid for pH adjustment. pH = 3.6
8) Water 2000g Salt
20g Grin 5g Citric acid 1.6g Next, 200 g of rice taken out from the above pH adjustment soaking liquid
g was placed in a packaging bag made of a three-layer laminate film of stretched propylene/vinylidene chloride/unstretched polypropylene, degassed and packaged, and then packed at 1.5 kg/cIl1211 [i°C
The rice was then heated under pressure for 25 minutes to produce rettle and packaged white rice. The pH of the white rice after pressure and heat sterilization was 620.

5 Practical Example 2 Le 1 roux packaged white rice was prepared in the same manner as in Example 1 except that the pH 7' dipping solution prepared by F. was used. In addition, the pH of the white rice body taken out after soaking and treatment was 530, and the pH of the white rice body after pressure and heat sterilization was 589.

(1 ffl nail of dipping liquid for pH adjustment; pH = 3
．． 32) Water 2000g Salt 20g Green 5g Citric acid 3g Comparative Example Rice after inhalation was adjusted to pH. J. Retort-packed rice was prepared in the same manner as in Example 1, except that it was not treated with the 'J cleaning immersion llk' method. The pH of the white rice itself after pressure and heat sterilization was 679.

Reference Example - Except for using the 1-component immersion filter LFK for pH adjustment,
] A 1-roux packaged white rice was prepared using the same JJ method as in Example 1. The pH of the rice itself taken out after being treated with the soaking liquid was 5.21, and the pH of the rice itself after pressure and heat sterilization was 5.69.

(Composition of dipping liquid for pH adjustment. pH = 2.8
1) Water 2000g Salt 20g Green 5g Citric acid 4g The retort-packed white rice of the obtained Example], 2, Comparative Example and Reference Example all have Fo, which is a standard for sterilization, of 4.5 to
It was 5.0. In addition, the browning state of each retort-packed white rice was measured using a color difference meter (trade name: Σ-80, Z- manufactured by Nippon Denshoku Kogyo).
n OPTICAL SENSOI? ) was measured and determined. In addition, a sensory evaluation was conducted by a panel. The results are shown in Table 1 below. In addition, in color difference evaluation, L
is 80 or more, a is -1.7 or less, and b* is 7.5 or less, it is determined that there is no browning.

From the results in Table 1 above, the rice after steaming is immersed in an aqueous solution whose pH has been adjusted with organic acid (citric acid) and filled into a packaging bag.
In Examples 1 and 2, where the pH of the rice itself after heat sterilization was adjusted to 5.8 to 6.2, Fo = 4.5 to 6.2.
It can be seen that even if the pressure and heat sterilization is increased to the range of 5.0, high quality retort-packed white rice without browning can be obtained. On the other hand, in the comparative example, which is a conventional method in which the pH of the rice itself is on the neutral side from 5.8 to 62, F. =4.5~5.0
Browning occurs when pressure and heat sterilization is carried out within this range. In addition, in a reference example where the pH of the rice itself is 5.8 to 6.2 on the acidic side,
F. Even if pressure and heat sterilization is performed in the range of =4.5 to 5.0, browning will not occur, but gloss and transparency will be lost and the commercial value will decrease.

[Effects of the Invention] It is possible to provide a method for producing high-quality retort-packed white rice through simple steps.

Claims (1)

[Claims] The raw rice is washed, immersed in water for a desired period of time, further steamed, then packed into packaging bags and sterilized by pressure and heating. pH of rice itself after being filled into a packaging bag and sterilized by heat and pressure
A method for producing retort-packed white rice, the method comprising: adjusting the temperature to be 5.8 to 6.2.