JPH0358707B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing cooked rice and noodles with excellent preservability. In general, heating or adding preservatives are the first methods to improve the preservability of foods. Heating is a method that has been used for a long time to increase the shelf life of food, but in order to achieve complete heat sterilization, harsh heating conditions must be set, and in this case, the nutritional content of the food The value of the food itself decreases due to the collapse of the food or the loss of the original palatability of the food. Therefore, in reality, heating conditions are set to be relaxed to some extent, and complete sterilization by heating cannot be achieved. Furthermore, even in the sealed packaged foods that have become mainstream these days, there is a risk of spoilage or food poisoning due to residual heat-resistant bacteria. In order to avoid these risks, preservatives are further added. Generally, preservatives are broadly classified into synthetic preservatives specified by the Food Sanitation Act, other food additives that have a food preservative effect, and natural products. However, the safety of synthetic preservatives,
In particular, the effect on the human body is considered a problem, and there is a tendency to refrain from adding it. As a result, research has been conducted on the use of antibacterial substances contained in natural products as an alternative to synthetic preservatives, but sufficient effects have not been obtained. The present inventors conducted studies focusing on the fact that protamine, as an antibacterial substance in this natural product, exhibits a specific bactericidal effect. Protamine is a strong basic protein with a relatively small molecular weight and high arginine content that exists in the sperm nucleus of vertebrates as nucleoprotamine bound to deoxyribonucleic acid. Protamine is known to exist in chickens, and is said to exist in mammals as well. Protamine is generally used as a long-acting insulin preparation that is a complex with insulin or as an antiheparin agent. Furthermore, various studies have been conducted on protamine for a long time, and the basic functions of protamine have been elucidated. For example, it has antibacterial activity against general bacteria in in vitro tests, the effect of antibacterial activity is higher when the pH of the medium is on the alkaline side, and the effect of antibacterial activity varies depending on the components in the medium. It is also known that protamine is a relatively heat-stable protein and is not easily denatured by heat. In examining protamine, the present inventors discovered that the antibacterial effect of protamine is synergistically increased by heating. That is, the presence of protamine alone does not give much promise for its antibacterial activity, but by applying heat to protamine, the antibacterial activity of protamine is dramatically increased. This antibacterial effect is strong against heat-resistant bacteria that have spores, and even against heat-resistant bacteria that may remain after high-temperature heating, the antibacterial effect of protamine can be suppressed by pre-existing protamine and then heating at high temperatures. Since the expression of is increased, these heat-resistant bacteria can be sufficiently suppressed. The present inventors further investigated the expression of antibacterial activity of protamine in actual food systems, and found that in foods that underwent a heating process in the presence of protamine, the expression of antibacterial activity of protamine was extremely high. However, in foods that do not undergo a heating process, the antibacterial activity of protamine is low, and no improvement in preservability was observed. Therefore, in order to effectively express the antibacterial activity of protamine, a heating step is essential, and this is a finding made clear for the first time by the present inventors. This is a method for producing cooked rice and noodles with excellent preservability, which is characterized by heating after adding protamine. In the present invention, heating includes heating for cooking to make it edible by steaming, baking, deep-frying, etc., as well as heating for high-temperature and high-pressure sterilization of canned goods, bottles, retort pouches, etc., and heating for packaging. This also includes reheating for sterilization. In the present invention, the target foods are cooked rice and noodles such as udon and Chinese noodles. The protamine used in the present invention only needs to be separated from the nucleic acid, and does not have antibacterial activity in the form of nucleoprotamine. However, protamine generally has low solubility in water, so when adding it to food, it must be added to an aqueous solution containing an acid or salt to completely dissolve the protamine in advance, or it must be used in a state where the protamine is completely dissolved. It is preferable to use Examples of solubilized protamine include mineral salt forms of protamine, such as protamine hydrochloride and sulfate. When carrying out the present invention, protamine is first added to the food. There is no particular restriction on the method of addition, and when an aqueous protamine solution is used, the aqueous solution may be sprayed onto the food, or the food may be immersed in the aqueous solution. There is no particular limit to the amount of protamine added, but considering the development of antibacterial activity and the influence on the palatability of the food itself, it is recommended to add 0.001 to 10% of protamine.
Particularly preferred is 0.003 to 5%. When this food is then heat-treated, a food with excellent preservability can be obtained. The heating temperature may be a normal temperature for cooking, sterilization, etc., but a temperature of 50° C. or higher is preferable. According to the present invention, it is possible to produce a food with excellent preservability due to the excellent bactericidal effect of protamine present in the food when combined with heating. Furthermore, as an effect of adding protamine in the present invention, the heating conditions during food production can be relaxed. Particularly in the case of heating for the purpose of sterilization, deterioration of the quality of the food itself becomes a problem. According to the invention,
Since the antibacterial properties of protamine are activated by heating, protamine effectively suppresses the bacteria that remain after heating that occurs when the heating conditions are relaxed, making it possible to relax the heating conditions. Test example Combined effect of protamine and heating in a test tube Sterilize a nutrient liquid medium containing 0.5% glucose, take a predetermined amount of it into a test tube, and add sterilized protamine sulfate (prepared from herring testis) to the test tube.
was added to prepare media with protamine sulfate concentrations of 10, 20, 30, 40, and 50 μg/ml. Heat-resistant Bacillus ritsukenihomis spore suspension ( ¹⁰⁷ spores/ml)
was prepared and inoculated into the above-mentioned medium at a rate of 10 ³ cells/ml, heated at 90°C, and then cultured at 37°C to examine the growth state of the bacteria. The results are shown in Table 1. The numbers in the table indicate the number of days until bacterial growth was observed, and the - mark indicates that no growth was observed for 7 days.

【table】

[Table] Example 1 Add 240 ml of water in which protamine sulfate (prepared from salmon testis) was dissolved to 0.05% and 0.1% of the total amount before cooking to 200 g of washed and polished rice, and boil in a commercially available electric rice cooker. Cooked for 15 minutes. After steaming the cooked rice for 10 minutes, 120 g of the rice was collected into sterilized storage bottles, stored at 30°C, and the number of viable bacteria was measured over time to examine the preservative effect. A general count of viable bacteria of ¹⁰⁶ or more was considered rotten. The results are shown in Table 2.

[Table] Examples of mold and yeast counts in parentheses 2 For 1 kg of wheat flour, 0.5 g of protamine sulfate (prepared from herring testis), 10 g of common salt, 6 g of powdered kansui, and 0.4 g of edible yellow coloring were each dissolved in 360 ml of water. The resulting mixture was used as sprinkling water, kneaded for 10 minutes, rolled, and cut into noodle strings with incisors (#10) to produce fresh Chinese noodles. Furthermore, a portion is steamed at 98℃ or above for 6 minutes, washed with water, and drained, then 40g
Each sample was packaged in a polyethylene bag and heated at 85°C for 30 minutes. 10 pieces of Chinese noodles obtained in this way were added to each test area.
Each piece was stored at 30°C, the appearance was observed over time, and the preservative effect was evaluated based on the following rating criteria. The results are shown in Table 3. The numbers in the table indicate the average score of the score. As shown in Table 3, there is almost no effect of protamine on unheated raw Chinese noodles, but it is known that the storage stability of heated steamed Chinese noodles is dramatically improved by adding protamine. .

【table】

[Table] *The number of days until the average score of the above score becomes 1 point is the effective storage number of days.

[Table] Example 3 To 1 kg of wheat flour, 350 ml of 6% saline solution containing protamine sulfate (prepared from salmon testis) dissolved at 0.05% and 0.1%, respectively, was added, kneaded for 10 minutes, and then rolled. The noodle strings were cut out using the incisors (#8). Boil these raw noodles at 98℃ or higher for 15 minutes,
After washing and draining, 60 g each was packaged in polyethylene bags and reheated at 80°C or 90°C for 15 minutes. Using the thus obtained boiled udon noodles, a tensile test was performed using a food rheometer to measure the firmness (elasticity) of the boiled udon noodles, which was then stored at 30°C and its appearance observed over time. The preservative effect was determined. The results are shown in Table 4. The elasticity of boiled udon noodles was determined using the following formula. Elasticity (g cm) = Force at break (g) x Elongation at break (cm)

【table】

[Table] Reference Example A seasoning liquid was prepared by adding 80 g of seasoning extract to 600 ml of water, boiling it, and then cooling it. this thing
600g, 400g of whole eggs and 0.05% of the total amount, 0.1
% of protamine sulfate (prepared from herring testis) was added, 90 g each was filled into vinylidene chloride casings, and heated at 90° C. for 30 minutes to produce egg tofu. This egg tofu was stored at 25°C, and the number of viable bacteria was measured over time to examine the preservative effect. In addition, the number of general viable bacteria is 10 ⁶
More than one person was considered corruption. The results are shown in Table 5.

【table】

Claims (1)

[Claims] 1. A method for producing cooked rice and noodles with excellent preservability, which comprises heating after adding protamine. 2. The method according to claim 1, characterized in that 0.003 to 5% by weight of protamine is added to the cooked rice or noodles.