CN108813273A - Half dry rice flour and its preservation method - Google Patents

Abstract

The invention provides semi-dry rice noodles and a preservation method thereof. The fresh-keeping method of the present invention comprises (1) putting semi-dry rice flour into a plastic container with a single-ended opening, wherein the water content of the semi-dry rice flour is 15% by weight-40% by weight; (2) placing the plastic container The air in the container is sucked out, and filled with a compound gas containing nitrogen and carbon dioxide; (3) Press down the heat-sealing strip, and seal the open end by hot pressing. The fresh-keeping method of the invention can prevent the rice noodles from sticking and breaking while inhibiting the growth of bacteria, and the fresh-keeping period can reach 15 days at normal temperature.

Description

Semi-dry rice noodles and its preservation method

technical field

The invention relates to the field of food preservation, in particular to a preservation method for semi-dried rice noodles.

Background technique

Semi-dry rice noodles are an intermediate product that is different from wet rice noodles and dry rice noodles. Its water content is higher than that of dry rice noodles and its shelf life is shorter. However, compared with dry rice noodles, semi-dry rice noodles can be cooked quickly without pre-soaking. cooked; due to the lower water content of semi-dry rice noodles than wet rice noodles, the shelf life of semi-dry rice noodles is slightly longer than that of wet rice noodles, but it is not as easy to cook as wet rice noodles. Due to the high moisture content, the shelf life of semi-dry rice noodles is still very short. It can usually only be stored for one day in summer without refrigeration, no more than two days in winter, and no more than one week in a low temperature environment of 1-5°C. Because semi-dry rice noodles are inconvenient to store and transport, without using fresh-keeping technology, its market can only be limited to a small local area, because in order to meet the requirements of express delivery, the shelf life needs to be at least 3 days, so semi-dry rice noodles It is a product that cannot be delivered by express delivery at all.

In order to solve the problem of preservation and transportation and realize the express delivery of semi-dry rice noodles, there are mainly two kinds of existing technical solutions, one is to adopt refrigeration technology, and the other is to adopt vacuum packaging technology. The technical solution for cold storage is to accompany the semi-dry rice noodles with ice packs and send them in foam boxes. The disadvantage of cold storage technology for express delivery is that the packaging cost is high, and the cost of foam boxes and ice packs increases the overall cost. Damaged packaging causes water leakage and deterioration of rice noodles. At the same time, it is not environmentally friendly and basically does not have practical value for large-scale use. In addition, simple refrigeration technology cannot extend the shelf life of semi-dry rice noodles to more than seven days.

The vacuum packaging solution is to put semi-dry rice noodles into a vacuum packaging bag, and then vacuumize the rice noodles to keep them in a vacuum state. Since the vacuum can inhibit most microorganisms from multiplying, the shelf life can be extended to more than 6 days. Vacuum technology uses vacuum packaging to solve the problem, which means that wet rice noodles and semi-dry rice noodles are packed in vacuum packaging to extend the shelf life and enable express delivery. However, on the one hand, vacuum packaging cannot inhibit the reproduction of microorganisms such as Listeria, and there is a risk of deterioration after more than 6 days in vacuum packaging. On the other hand, due to the effect of atmospheric pressure in vacuum packaging, long-term extrusion of the rice noodles in the packaging bag will cause the rice noodles to stick and break easily, which seriously affects the eating experience of the rice noodles.

Contents of the invention

In order to solve at least part of the above-mentioned technical problems, the present invention provides a semi-dry rice noodle food and its fresh-keeping method, which can prevent the rice noodle from sticking and breaking while inhibiting bacterial growth, and the fresh-keeping period can reach 15 days at room temperature. Specifically, the present invention includes the following contents.

In one aspect of the present invention, there is provided a kind of fresh-keeping method of semi-dried ground rice, and it comprises the following steps:

(1) putting the semi-dry rice flour into a plastic container with a single-ended opening, wherein the content of the semi-dry rice flour is 15% by weight-40% by weight;

(2) the air in the plastic container is taken out, and filled with a composite gas containing nitrogen and carbon dioxide;

(3) Press down the heat sealing strip, and seal the open end by heat pressing.

According to the preservation method of the present invention, preferably, the plastic container in the step (1) is a composite packaging container, which is composed of a BOPP layer and a CPP layer, and the BOPP layer is an inner layer of the plastic container.

According to the preservation method of the present invention, preferably, the volume ratio of nitrogen and carbon dioxide in the composite gas is 3-1:1.

According to the preservation method of the present invention, preferably, the raw materials of the semi-dry rice flour include 95-99 parts by weight of rice and 0.5-5 parts by weight of additives.

According to the preservation method of the present invention, preferably, the additive is composed of 0.2-4 parts by weight of modified starch, 0.1-1 part by weight of sodium stearoyl lactylate and 0.1-1 part by weight of sucrose ester.

According to the fresh-keeping method of the present invention, preferably, the preparation of the semi-dry rice flour includes the following steps: rice fermentation, crushing, material mixing, extrusion, aging, re-steaming, and cutting. Preferably, the aging conditions include a temperature of 50°C and a relative humidity of 75-85%.

According to the preservation method of the present invention, preferably, the plastic container is at least one selected from the group consisting of a plastic bag, a plastic box and a plastic barrel.

Another aspect of the present invention provides a semi-dry rice noodle food, which is kept fresh by the method of the present invention.

1. The shelf life of semi-dry rice noodles can be extended to 15 days or even longer. In comparison, the original preservation technologies for semi-dry rice noodles mainly include refrigeration and vacuum packaging. The storage period of semi-dry rice noodles under refrigeration technology is no more than seven days, and the storage period of vacuum packaging is generally about 6 days.

2. The fresh-keeping method of the present invention will not destroy the physical characteristics of rice noodles, and will not cause extrusion adhesion and broken or broken rice noodles caused by vacuum packaging, and can more effectively protect the original physical form of rice noodles, and can perfectly maintain The original state of rice noodles keeps the physical form of rice noodles consistent with the factory, and the eating experience is excellent. Due to the extrusion effect of atmospheric pressure, vacuum packaging will cause the rice noodles to stick together, and the extrusion effect will also make the rice noodles in a state of stress for a long time, which will cause the rice noodles to break into small pieces of rice noodles, making the rice noodles "broken", and the customer experience is extremely poor.

3. Compared with cold storage technology, the preservation method of the present invention is more conducive to express packaging and transportation.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail. The detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features and embodiments of the present invention.

It should be understood that the terminology described in the present invention is only used to describe specific embodiments, and is not used to limit the present invention. In addition, regarding the numerical ranges in the present invention, it should be understood that the upper and lower limits of the range and every intermediate value therebetween are specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded from the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials in connection with which the documents are described. In case of conflict with any incorporated document, the contents of this specification control.

The "semi-dry rice flour" mentioned in the present invention refers to a product with humidity between dry rice flour and wet rice flour, and its humidity or water content is generally 15% by weight-40% by weight, preferably 20% by weight-35% by weight , more preferably 24% by weight - 30% by weight. The preservation of semi-dry rice noodles is different from that of dry rice noodles and wet rice noodles, and has its unique properties.

"Fresh preservation" in the present invention not only refers to inhibiting the growth or multiplication of bacteria in food, but also includes maintaining the physical form, flavor, taste and other textures of the food itself.

The fresh-keeping method of the semi-dry rice flour of the present invention comprises the following steps: (1) putting the semi-dry rice flour into a plastic container with a single-end opening, wherein the water content of the semi-dry rice flour is 15% by weight-40% by weight; 2) taking out the air in the plastic container, and filling it with a compound gas containing nitrogen and carbon dioxide; (3) pressing down the heat-sealing strip, and sealing the open end by hot pressing.

In step (1), the semi-dry rice flour can be general semi-dry rice flour, which is made from common raw materials such as rice. In order to improve the fresh-keeping effect, additives beneficial to fresh-keeping can be added to the raw materials of the semi-dried rice noodles. The amount of the additive is usually 0.5-5 parts by weight, preferably 0.8-4 parts by weight, more preferably 1-4 parts by weight. The consumption of rice is generally 95-99 parts by weight, preferably 95-98 parts by weight, more preferably 95-97 parts by weight. Preferably, the additive of the present invention includes modified starch, sodium stearoyl lactylate and sucrose ester, preferably, consists of the above three components.

The addition of modified starch in the present invention is beneficial to the ratio of amylose to amylopectin in the rice flour, and its reasonable content is 0.2-4 parts by weight, preferably 0.3-3 parts by weight.

The sodium stearoyl lactylate in the present invention has hydrophilic and hydrophobic groups, can form a complex with amylose, prevent the rearrangement of starch molecules, make the internal structure of the starch more stable, delay aging, and prevent rice noodles from breaking during long-term storage. The amount of sodium stearoyl lactylate is 0.1-1 parts by weight, preferably 0.2-0.5 parts by weight.

The sucrose ester in the present invention is similar to sodium stearoyl lactylate, and can form a complex with amylose to prevent rearrangement of starch molecules, make the internal structure of starch more stable, delay aging, and prevent rice flour from breaking during long-term storage. The dosage is 0.1 -1 part by weight, preferably 0.2-0.5 part by weight.

The plastic bag in the step (1) of the present invention is preferably a composite packaging container. The present invention finds that when the packaging bag is composed of BOPP layer and CPP layer, it has excellent moisture and gas barrier properties, especially for the compound gas barrier properties of the present invention. The BOPP layer is a biaxially stretched polypropylene layer, and the CPP layer is an unstretched polypropylene layer. When the BOPP layer is used as the inner layer of the plastic container, it has stronger barrier properties and is therefore more preferred.

The volume ratio of nitrogen and carbon dioxide in the composite gas of the present invention is 3-1:1, preferably 1.5-1:1. That is, the volume of nitrogen in the present invention needs to be greater than or equal to the volume of carbon dioxide. In the present invention, carbon dioxide is a very important gas medium that can inhibit the reproduction and bacteria-fixing effect of spoilage bacteria and molds in gas and modified atmosphere packaging, slow down metabolism and prolong the fresh-keeping period and shelf life of food. Nitrogen is an inert gas, which is an important filling gas in modified atmosphere packaging, and its main function is filling. The composite gas with specific composition of the present invention can form an anaerobic environment on the one hand, and can inhibit the reproduction of microorganisms on the other hand, wherein carbon dioxide can further inhibit the growth of microorganisms, thereby prolonging the fresh-keeping period and shelf life of rice noodles.

In the preparation of the exemplary semi-dry rice flour, it includes the following steps: rice fermentation, crushing, material mixing, extruding, aging, re-steaming, and cutting. Preferably, the aging is carried out at a temperature of 50° C. and a relative humidity of 75-85%.

Example 1

The raw material of semi-dry rice flour in the present embodiment comprises 95 parts by weight of rice, 4.2 parts by weight of additives (4 parts by weight of modified cornstarch, 0.1 part by weight of sodium stearoyl lactylate and 0.1 part by weight of sucrose ester). Its preservation method is as follows:

(1) Rice fermentation: Weigh 9.5 kg of rice and 1.2 kg of tap water at a temperature of 25°C. 0.8% of the mass percentage of tap water is added to the fermented liquid fermented in the previous batch for 24 hours, stirred evenly, and then added with rice. The mixture was fermented at 37°C for 48 hours, then washed until there was no adherent on the surface, and centrifuged for 3 minutes;

(2) the filtered rice is pulverized by a pulverizer, put into a mixing tank, and take 4.2 kilograms of additives and put into a mixing tank;

(3) Material mixing: Mix the above materials evenly, test the water content of the mixture to 30%, and continue stirring until the mixture has no obvious lumps and is in the shape of bean dregs;

(4) Screw extrusion: put the above-mentioned mixed material into the hopper of the screw extruder, adjust the feeding speed of the extruder, the rotating speed of the extruder, discard the initial rice flour of the extruder material, and wait until the temperature at the outlet of the material rises obviously, and the material Turn on the cooling fan when the degree of ripening is ≥90%, and start normal sampling;

(5) Aging: Put the sample taken on the hanging rod and place it on the shelf in the aging room, and let the material stand for aging for 2 hours; aging conditions: aging temperature 50°C, aging relative humidity 75-85%; aging After the end, the average water content of the rice flour was 27%;

(6) Re-steaming: Put the aged rice noodles into the steamer and steam the noodles for 4 minutes;

(7) Cutting and washing powder: cut off the re-steamed rice noodles with a fixed length of 300mm, and put them into warm water at 30°C to wash the rice noodles loose, take them out after soaking for 2 minutes, and detect the water content of the rice noodles at 15%;

(8) Packing: packed in 200g/bag. The semi-dry rice flour is put into a plastic bag (inner layer BOPP/outer layer CPP) with a single-ended opening, the air in the plastic container is taken out, and filled with a compound compound containing nitrogen and carbon dioxide (volume ratio 2:1). Gas; depress the heat seal strip and seal the open end with heat and pressure.

Example 2

The raw materials of the semi-dry rice flour in this embodiment include 94 parts by weight of rice, 4 parts by weight of modified cornstarch, 0.2 parts by weight of sodium stearoyl lactylate and 0.2 parts by weight of sucrose ester. The water content of the semi-dry rice noodles is 30 parts by weight. Its preservation method is as follows:

The semi-dry ground rice is put into the plastic container that has single-ended opening, the air in the plastic container is taken out, and is filled with the compound gas that contains nitrogen and carbon dioxide (volume ratio 3:1); Depress heat-seal bar, pass Heat press to seal the open end.

Comparative example 1

Except not adding denatured cornstarch, carry out preservation in the same manner as Example 1.

Comparative example 2

Except not adding sodium stearoyl lactylate and sucrose ester and using a PET plastic bag, keep fresh in the same manner as in Example 1.

Comparative example 3

In the same manner as in Example 1, fresh-keeping was carried out except that carbon dioxide was not contained in the composite gas.

Comparative example 4

The raw materials of the semi-dry rice flour in this comparative example include 94 parts by weight of rice, 4 parts by weight of modified cornstarch, 0.2 parts by weight of sodium stearoyl lactylate and 0.2 parts by weight of sucrose ester. The water content of the semi-dry rice noodles is 30 parts by weight. Its preservation method is as follows:

The semi-dry ground rice is put into the plastic container that has single end opening, the air in the plastic container is taken out, and fills into the compound gas that contains nitrogen and carbon dioxide (volume ratio 1:2); Depress heat-seal bar, pass Heat press to seal the open end.

Fresh-keeping effect of different methods in table 1

*Non-sticking means that the rice noodles are not sticky when lightly pressed with hands, and easy-sticking means that the rice noodles are sticky when lightly pressed with fingers.

It will be apparent to those skilled in the art that various modifications and changes can be made in the specific embodiments of the present invention described herein without departing from the scope or spirit of the present invention. Other embodiments will be apparent to the skilled person from the description of the present invention. The specification and examples in this application are exemplary only.

Claims (9)

1. a fresh-keeping method of semi-dry rice noodles, which comprises the following steps: (1) putting the semi-dry rice flour into a plastic container with a single-ended opening, wherein the content of the semi-dry rice flour is 15% by weight-40% by weight; (2) the air in the plastic container is taken out, and filled with a composite gas containing nitrogen and carbon dioxide; (3) Press down the heat sealing strip, and seal the open end by heat pressing. 2. the fresh-keeping method of semi-dry rice flour according to claim 1, wherein said plastic container in said step (1) is composite packaging container, and it is made up of BOPP layer and CPP layer, and described BOPP layer is plastic container the inner layer. 3. the fresh-keeping method of semi-dry rice flour according to claim 1, wherein the volume ratio of nitrogen and carbon dioxide in the composite gas is 3-1: 1. 4. The fresh-keeping method of semi-dry rice noodles according to claim 1, wherein the raw materials of said semi-dry rice noodles include 95-99 parts by weight of rice and 0.5-5 parts by weight of additives. 5. The fresh-keeping method of semi-dry rice flour according to claim 4, wherein the additive is composed of 0.2-4 parts by weight of modified starch, 0.1-1 parts by weight of sodium stearoyl lactylate and 0.1-1 part by weight of sucrose ester. 6. The fresh-keeping method of semi-dry rice noodles according to claim 4, wherein the preparation of said semi-dry rice noodles comprises the following steps: rice fermentation, crushing, material mixing, extruding, aging, re-steaming, cutting. 7. The fresh-keeping method of semi-dry rice noodles according to claim 6, wherein the aging conditions include a temperature of 50° C. and a relative humidity of 75-85%. 8. The fresh-keeping method of semi-dry rice noodles according to claim 1, wherein said plastic container is at least one selected from the group consisting of plastic bags, plastic boxes and plastic barrels. 9. A kind of semi-dry rice flour food, it carries out fresh-keeping treatment by the method according to any one of claim 1-8.