阅读说明：本技术 一种冷冻品的辐照灭菌方法 (Irradiation sterilization method for frozen product ) 是由 邹伟权 罗志平 王梦玲 于 2020-11-27 设计创作，主要内容包括：本发明属于食品保鲜技术领域,具体涉及一种冷冻品的辐照灭菌方法。本发明通过添加天然物质组成的保鲜剂,并采用电子束辐照技术结合高压脉冲电场处理的方式,最后辅助低温贮藏保鲜的方法,有效提高了对于冷冻品的灭菌效果,抑制储存过程中的细菌增长,同时,还能有效保证肉质品的质量和新鲜程度,防止冷冻肉制品营养流失和腐败变质,延长保鲜期。(The invention belongs to the technical field of food preservation, and particularly relates to an irradiation sterilization method for a frozen product. According to the invention, through adding the preservative made of natural substances, adopting a mode of combining an electron beam irradiation technology with high-voltage pulse electric field treatment, and finally assisting in low-temperature storage and preservation, the sterilization effect on frozen products is effectively improved, the growth of bacteria in the storage process is inhibited, meanwhile, the quality and freshness of meat products can be effectively ensured, the nutrition loss and the spoilage of the frozen meat products are prevented, and the preservation period is prolonged.)

1. A method for sterilizing frozen products by irradiation is characterized by comprising the following steps:

s1, cleaning the meat product at 0-10 ℃, cutting the meat product into meat blocks with the thickness of 6-20 cm, soaking the meat blocks in a preservative for 20-30 min, draining, and sucking water for later use;

s2, subjecting the meat blocks obtained in the step S1 to high-voltage pulse electric field treatment for 10-30 min, and then respectively filling the meat blocks into aseptic packaging bags to obtain pre-packaged meat products;

s3, placing the pre-packaged meat product obtained in the step S2 at normal temperature, starting an electron beam accelerator to perform double-sided irradiation treatment, wherein the irradiation dose is 6-10 kGy;

and S4, after the irradiation is finished, freezing the irradiated meat product obtained in the step S3 at the temperature of-18 to-25 ℃ for 20 to 40min, and then storing at the temperature of-2 to-8 ℃ to obtain the meat product.

2. The method for radiation sterilization of a frozen product according to claim 1, wherein the fresh-keeping agent in step S1 is prepared by mixing the following components:

5-10 parts of chitosan oligosaccharide, 20-28 parts of a Chinese violet extract, 6-12 parts of levo-limonene and 80-120 parts of deionized water.

3. The method for radiation sterilization of a frozen product according to claim 2, wherein the fresh-keeping agent in step S1 is prepared by mixing the following components: 7 parts of chitosan oligosaccharide, 25 parts of Chinese violet extract, 8 parts of levo-limonene and 100 parts of deionized water.

4. The method for radiation sterilization of a frozen product according to claim 2 or 3, wherein the molecular weight of the chitosan oligosaccharide is less than or equal to 2000 Da.

5. The method for radiation sterilization of a frozen product according to claim 1, wherein the radiation dose in step S3 is 8 kGy.

6. The method for sterilizing frozen products by irradiation of claim 1, wherein the electric field strength during the high-voltage pulsed electric field treatment in step S2 is 20-40 kV/cm, the pulse width is 1-5 μ S, and the pulse frequency is 300-680 Hz.

7. The method for radiation sterilization of a frozen product according to claim 6, wherein the electric field strength in the high-voltage pulse electric field treatment of step S2 is 30kV/cm, the pulse width is 2.5. mu.s, and the pulse frequency is 500 Hz.

8. The method for radiation sterilization of a frozen product according to claim 1, wherein the electron beam irradiation treatment in step S3 is performed for 5 to 15min, with a beam intensity of 1400 to 2000 μ Α and a pulse repetition frequency of 600 to 660 pps.

9. The method for radiation sterilization of a frozen product according to claim 8, wherein the electron beam irradiation treatment in step S3 is performed for 12min with a beam intensity of 1600 μ Α and a pulse repetition frequency of 630 pps.

Technical Field

The invention belongs to the technical field of food preservation, and particularly relates to an irradiation sterilization method for a frozen product.

Background

The meat product is one of important animal food on the dining table of people at present, and can provide high-quality protein and necessary fatty acid. However, meat products are rich in nutrition, high in water activity, easy to grow and reproduce spoilage microorganisms, various raw and auxiliary materials used for processing are used, sources are complex, source pollution and secondary pollution are difficult to thoroughly control, meat product processing in China is still in a primary stage, and although a low-temperature processing sterilization technology is adopted, the problems of incomplete product sterilization, short product quality guarantee period and poor safety exist, wherein the main reason is microbial pollution. High-temperature heat treatment is one of the safest and most reliable meat product preservation methods, and the heating treatment is to utilize high-temperature lethal microorganisms, but the high-temperature lethal microorganisms have the defects of poor product flavor and taste, serious nutrient loss and the like.

The electron beam radiation processing technology is a high and new technology which has been widely focused since the 90 s of the 20 th century, and irradiation of electron beams with certain energy can be generated by an electron beam accelerator. The irradiation technology is developing at a fast pace in the global scope as a new food preservation technology, has the advantages of thorough sterilization, no unpacking, energy conservation, low consumption, environmental protection, no secondary pollution and the like, and has outstanding performances in the aspects of agricultural products, fresh fruits and vegetables, prepackaged foods, inspection and quarantine, and the like.

Chinese patent CN101313692B discloses a comprehensive quality guarantee method for goose products, which comprises the steps of cooking goose, vacuum packaging, soaking the vacuum packaged product in a water bath with the temperature of 50-80 ℃ for 30-40 minutes, refrigerating at the ambient temperature of 0-10 ℃, carrying out nuclear irradiation at the dose of 3-10 kGy, refrigerating at the ambient temperature of 0-10 ℃ for 2-3 days, and storing at normal temperature. Although the method can effectively sterilize the meat product, the irradiation treatment of the meat product can change the position and the number of carbonyl double bonds of fat molecules in fat of the meat product or break molecular chains, and the change or the chain breakage causes the change of the texture of the meat product and the deterioration of the mouthfeel; lipid substances are oxidized, deteriorated in color, and generate odor, etc. The Chinese patent application CN105918425A discloses an irradiation preservation process of fresh animal-derived food, which comprises the following steps: step one, taking cold fresh meat, and cutting the cold fresh meat into a plurality of meat blocks with the thickness of 15-20 cm; step two, packaging the meat blocks in bags; placing a single layer of the packaged meat blocks under an electron beam irradiation device for irradiation, wherein the irradiation dose is 1.4-2.2 kGy, and the irradiation dose rate is 2200-2600 Gy/s; and step four, refrigerating the irradiated meat blocks. In the invention, although the lower irradiation dose can better reduce irradiation damage and keep the texture, color, nutrition and flavor of the original meat product, the content of volatile basic nitrogen is increased along with the increase of the storage time of the meat product, and the long-term preservation effect of the meat is poorer.

Therefore, in order to solve the above technical problems, it is necessary to provide a radiation sterilization method suitable for frozen products, which can prolong the preservation time of frozen meat products and prevent the deterioration of meat quality while achieving sterilization, preservation and quality control.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a method for sterilizing frozen products by irradiation. According to the invention, through adding the preservative made of natural substances, adopting a mode of combining an electron beam irradiation technology with high-voltage pulse electric field treatment, and finally assisting in low-temperature storage and preservation, the sterilization effect on frozen products is effectively improved, the growth of bacteria in the storage process is inhibited, meanwhile, the quality and freshness of meat products can be effectively ensured, the nutrition loss and the spoilage of the frozen meat products are prevented, and the preservation period is prolonged.

The technical scheme of the invention is as follows:

a method for radiation sterilization of frozen products comprises the following steps:

s1, cleaning the meat product at 0-10 ℃, cutting the meat product into meat blocks with the thickness of 6-20 cm, soaking the meat blocks in a preservative for 20-30 min, draining, and sucking water for later use;

s2, subjecting the meat blocks obtained in the step S1 to high-voltage pulse electric field treatment for 10-30 min, and then respectively filling the meat blocks into aseptic packaging bags to obtain pre-packaged meat products;

s3, placing the pre-packaged meat product obtained in the step S2 at normal temperature, starting an electron beam accelerator to perform double-sided irradiation treatment, wherein the irradiation dose is 6-10 kGy;

and S4, after the irradiation is finished, freezing the irradiated meat product obtained in the step S3 at the temperature of-18 to-25 ℃ for 20 to 40min, and then storing at the temperature of-2 to-8 ℃ to obtain the meat product.

Further, the preservative in the step S1 is prepared by mixing the following components:

5-10 parts of chitosan oligosaccharide, 20-28 parts of a Chinese violet extract, 6-12 parts of levo-limonene and 80-120 parts of deionized water.

Furthermore, the preservative in the step S1 is prepared by mixing the following components: 7 parts of chitosan oligosaccharide, 25 parts of Chinese violet extract, 8 parts of levo-limonene and 100 parts of deionized water.

Further, the molecular weight of the chitosan oligosaccharide is less than or equal to 2000 Da.

Further, the irradiation dose in the step S3 is 8 kGy.

Further, the electric field intensity in the high-voltage pulse electric field treatment process of the step S2 is 20-40 kV/cm, the pulse width is 1-5 mus, and the pulse frequency is 300-680 Hz.

Further, the electric field intensity in the high voltage pulse electric field treatment of step S2 is 30kV/cm, the pulse width is 2.5 μ S, and the pulse frequency is 500 Hz.

Furthermore, the time of the electron beam irradiation treatment in the step S3 is 5-15 min, the beam intensity is 1400-2000 muA, and the pulse repetition frequency is 600-660 pps.

Further, the time of the electron beam irradiation treatment in step S3 is 12min, the beam intensity is 1600 μ a, and the pulse repetition frequency is 630 pps.

Further, the meat product in the step S1 includes livestock and poultry products and fish.

In the sterilization method provided by the invention, under the condition of not adding a chemical preservative, the common technical problems of the frozen product in the industry of texture change and generation of peculiar smell due to oxidation caused by overhigh radiation dose of the meat product are effectively solved by adding the preservative consisting of natural and safe components such as chitosan oligosaccharide, a Chinese violet extract, levo-limonene and the like, the sterilization effect is effectively improved, and meanwhile, the growth of bacteria can be inhibited for a long time in the storage process.

In addition, the irradiation sterilization method of the frozen product provided by the invention combines the high-voltage pulse electric field treatment and the electron beam irradiation treatment, and the irradiation treatment is carried out by placing the frozen product at-8 to-3 ℃, the process steps can more fully kill microorganisms, enhance the effect of irradiation sterilization, ensure that nutrient substances of the frozen product are not lost in the long-term storage process, have better fresh-keeping effect and can be detected, the detection results of volatile basic nitrogen in the frozen beef stored for half a year after being thawed are below 7.5mg/100g in the embodiments 1-3 of the invention, the frozen product has good long-term fresh-keeping effect and less nutrient loss after the sterilization method is adopted.

Compared with the prior art, the irradiation sterilization method for the frozen product provided by the invention has the following advantages:

(1) according to the irradiation sterilization method for the frozen product, the added preservative comprising the natural and safe components such as chitosan oligosaccharide, the viola yedoensis makino extract and the levo-limonene can effectively ensure that the texture, the flavor and the color of the meat product are not changed along with the increase of the preservation time, the generation of peculiar smell is avoided, the preservation effect is excellent, and the preservation time is longer.

(2) According to the irradiation sterilization method for the frozen product, provided by the invention, the high-voltage pulse electric field treatment and the electron beam irradiation treatment are combined, so that the microorganisms can be more fully killed, the irradiation sterilization effect is enhanced, the growth of the bacteria is inhibited for a long time, the loss of nutrient substances is effectively avoided, and the frozen food which is more green and healthy, safe and pollution-free is obtained.

Detailed Description

The present invention is further illustrated by the following description of specific embodiments, which are not intended to limit the invention, and various modifications and improvements can be made by those skilled in the art based on the basic idea of the invention, but the invention is within the protection scope of the invention.

Chitosan oligosaccharide, cat # C875644-5g, available from Shanghai Michelin Biotech, Inc.; herba Violae extract, purchased from Sailan-Tianrui biotechnology, Inc.; levo-limonene, purchased from new agro-chemical materials, ltd, mansion.

EXAMPLE 1 method for radiation sterilization of frozen product

The irradiation sterilization method of the frozen product comprises the following steps:

s1, cleaning the beef product at 0 ℃, cutting the beef product into meat blocks with the thickness of 6cm, soaking the meat blocks in the preservative for 20min, draining, and sucking water for later use;

s2, subjecting the meat blocks obtained in the step S1 to high-voltage pulse electric field treatment for 10min, and respectively filling the meat blocks into aseptic packaging bags to obtain pre-packaged meat products; the high-voltage pulse electric field intensity is 20kV/cm, the pulse width is 1 mus, and the pulse frequency is 300 Hz;

s3, placing the pre-packaged meat product obtained in the step S2 at normal temperature, starting an electron beam accelerator to perform double-sided irradiation treatment, wherein the irradiation dose is 6 kGy; the time of electron beam irradiation treatment is 5min, the beam intensity is 1400 muA, and the pulse repetition frequency is 600 pps;

and S4, after the irradiation is finished, freezing the irradiated meat product obtained in the step S3 at the temperature of minus 25 ℃ for 20min, and then storing at the temperature of minus 8 ℃ to obtain the meat product.

The preservative in the step S1 is prepared by mixing the following components:

5 parts of chitosan oligosaccharide, 20 parts of Chinese violet extract, 6 parts of levo-limonene and 80 parts of deionized water.

The molecular weight of the chitosan oligosaccharide is less than or equal to 2000 Da.

EXAMPLE 2 method for radiation sterilization of frozen product

The irradiation sterilization method of the frozen product comprises the following steps:

s1, cleaning the beef product at 5 ℃, cutting the beef product into meat blocks with the thickness of 12cm, soaking the meat blocks in the preservative for 25min, draining, and sucking water for later use;

s2, subjecting the meat blocks obtained in the step S1 to high-voltage pulse electric field treatment for 20min, and respectively filling the meat blocks into aseptic packaging bags to obtain pre-packaged meat products; the high-voltage pulse electric field intensity is 30kV/cm, the pulse width is 2.5 mu s, and the pulse frequency is 500 Hz;

s3, placing the pre-packaged meat product obtained in the step S2 at normal temperature, starting an electron beam accelerator to perform double-sided irradiation treatment, wherein the irradiation dose is 8 kGy; the time of electron beam irradiation treatment is 12min, the beam intensity is 1600 muA, and the pulse repetition frequency is 630 pps;

and S4, after the irradiation is finished, freezing the irradiated meat product obtained in the step S3 at the temperature of minus 22 ℃ for 30min, and then storing at the temperature of minus 6 ℃ to obtain the meat product.

The preservative in the step S1 is prepared by mixing the following components:

7 parts of chitosan oligosaccharide, 25 parts of Chinese violet extract, 8 parts of levo-limonene and 100 parts of deionized water.

The molecular weight of the chitosan oligosaccharide is less than or equal to 2000 Da.

EXAMPLE 3 irradiation Sterilization method of frozen product

The irradiation sterilization method of the frozen product comprises the following steps:

s1, cleaning the beef product at 10 ℃, cutting the beef product into meat blocks with the thickness of 20cm, soaking the beef blocks in the preservative for 30min, draining, and sucking water for later use;

s2, subjecting the meat blocks obtained in the step S1 to high-voltage pulse electric field treatment for 30min, and then respectively filling the meat blocks into aseptic packaging bags to obtain pre-packaged meat products; the high-voltage pulse electric field intensity is 40kV/cm, the pulse width is 5 mus, and the pulse frequency is 680 Hz;

s3, placing the pre-packaged meat product obtained in the step S2 at normal temperature, starting an electron beam accelerator to perform double-sided irradiation treatment, wherein the irradiation dose is 10 kGy; the time of electron beam irradiation treatment is 15min, the beam intensity is 2000 muA, and the pulse repetition frequency is 660 pps;

and S4, after the irradiation is finished, freezing the irradiated meat product obtained in the step S3 at the temperature of minus 18 ℃ for 40min, and then storing at the temperature of minus 2 ℃ to obtain the meat product.

The preservative in the step S1 is prepared by mixing the following components:

10 parts of chitosan oligosaccharide, 28 parts of Chinese violet extract, 12 parts of levo-limonene and 120 parts of deionized water.

The molecular weight of the chitosan oligosaccharide is less than or equal to 2000 Da.

Comparative example 1 irradiation sterilization method of frozen product

Compared with example 2, comparative example 1 is different in that chitosan oligosaccharide is not added to the preservative, and other parameters and operations are the same as those of example 2.

Comparative example 2 irradiation sterilization method of frozen product

Compared with the example 2, the difference of the comparative example 2 is that the preservative is not added with the levo-limonene, and other parameters and operation are the same as the example 2.

Comparative example 3 irradiation sterilization method of frozen product

Compared with example 2, comparative example 3 is different in that the added chitosan oligosaccharide in the preservative has a molecular weight of 10000Da, and other parameters and operation are the same as those of example 2.

Comparative example 4 irradiation sterilization method of frozen product

The irradiation sterilization method of the frozen product comprises the following steps:

s1, cleaning the beef product at 5 ℃, cutting the beef product into meat blocks with the thickness of 12cm, soaking the beef blocks in a preservative for 25min, draining, sucking water, and respectively filling the beef blocks into aseptic packaging bags to obtain pre-packaged meat products;

s2, placing the pre-packaged meat product obtained in the step S1 at normal temperature, starting an electron beam accelerator to perform double-sided irradiation treatment, wherein the irradiation dose is 8 kGy; the time of electron beam irradiation treatment is 12min, the beam intensity is 1600 muA, and the pulse repetition frequency is 630 pps;

and S3, after the irradiation is finished, freezing the irradiated meat product obtained in the step S2 at the temperature of minus 22 ℃ for 30min, and then storing at the temperature of minus 6 ℃ to obtain the meat product.

The fresh-keeping agent in step S1 is the same as in example 2.

Comparative example 4 is different from example 2 in that the sterilization process is not performed with the high voltage pulse electric field treatment, and other parameters and operations are the same as example 2.

Comparative example 5 method for sterilizing frozen product

The sterilization method of the frozen product comprises the following steps:

s1, cleaning the beef product at 5 ℃, cutting the beef product into meat blocks with the thickness of 12cm, soaking the meat blocks in the preservative for 25min, draining, and sucking water for later use;

s2, subjecting the meat blocks obtained in the step S1 to high-voltage pulse electric field treatment for 20min, and respectively filling the meat blocks into aseptic packaging bags to obtain pre-packaged meat products; the high-voltage pulse electric field intensity is 30kV/cm, the pulse width is 2.5 mu s, and the pulse frequency is 500 Hz;

s3, freezing the meat product treated by the high-voltage pulse electric field of the step S2 at the temperature of minus 22 ℃ for 30min, and then storing at the temperature of minus 6 ℃ to obtain the meat product.

The fresh-keeping agent in step S1 is the same as in example 2.

In comparison with example 2, comparative example 5 is different in that the sterilization process is not performed with electron beam irradiation sterilization treatment, and other parameters and operations are the same as those of example 2.

Test example I measurement of microbial content in meat product

1. Test subjects: examples 1 to 3, comparative examples 1 to 5.

2. The test method comprises the following steps: after the sterilized frozen beef products prepared in examples 1 to 3 and comparative examples 1 to 5 were stored for half a year, they were taken out and thawed.

(1) The total number of colonies was determined according to the method provided in GB 4789.2-2016 (national food safety Standard food microbiological inspection Total number of colonies test).

(2) The salmonella is detected according to the method provided by GB 4789.4-2016 national food safety Standard food microbiology for Salmonella detection.

3. Test results

The test results are shown in table 1.

TABLE 1 determination of microbial content in meat products

Group of	Colony assemblyNumber (CFU/g)	Salmonella (CFU/g)
			Example 1	62	Not detected out
Example 2	58	Not detected out
			Example 3	71	Not detected out
Comparative example 1	260	Not detected out
			Comparative example 2	240	Not detected out
Comparative example 3	350	Not detected out
			Comparative example 4	810	53
Comparative example 5	940	110

As can be seen from Table 1, after the frozen beef products prepared by the sterilization methods of the embodiments 1-3 of the invention are stored for half a year, the total number of colonies is only 58CFU/g, and salmonella is not detected, wherein the best effect of the embodiment 2 is the best embodiment of the invention. The frozen beef products prepared by the comparative examples 1-3 are stored for half a year, and the detection shows that the total number of bacterial colonies reaches more than 200CFU/g, and salmonella is not detected, which proves that the bacteriostatic effect of the frozen products at the later stage can be influenced by the preservative not prepared by the invention, while the total number of bacterial colonies is respectively up to 810CFU/g, 940CFU/g and salmonella is respectively 53CFU/g and 110CFU/g after the frozen beef products prepared by the comparative examples 4 and 5 are stored for half a year, which indicates that the sterilization effect and the bacteriostatic effect of the frozen beef products after storage are greatly influenced by the non-adoption of high-voltage pulse electric field treatment in the comparative example 4 and the non-adoption of electron beam irradiation treatment in the comparative example 5, and indicates that the steps and the adopted components in the sterilization method have synergistic effect and can better play a role in sterilization and bacteriostatic effects, the quality of the frozen product stored for a long time is ensured.

Test example two meat product Performance test

1. Test subjects: examples 1 to 3, comparative examples 1 to 5.

2. The test method comprises the following steps: after the sterilized frozen beef products prepared in examples 1 to 3 and comparative examples 1 to 5 were stored for half a year, they were taken out and thawed.

(1) The beef products of the examples and comparative examples were tested according to the automatic kjeldahl method provided in GB 5009.228-2016, "determination of volatile basic nitrogen in national food safety standards".

And (4) judging the standard: the volatile basic nitrogen specified in GB 2707-2016 food safety national standard fresh (frozen) livestock and poultry products is less than or equal to 15mg/100 g.

(2) Observing the appearance color, the tissue state and the like of the meat product.

3. Test results

The test results are shown in table 2.

TABLE 2 meat product Performance test after half-year storage

As shown in Table 2, after the frozen beef products prepared by the sterilization methods of the embodiments 1 to 3 are stored for half a year, the content of volatile basic nitrogen is below 7.5mg/100g, the meat quality is glossy, bright red, good in elasticity, and concave after finger pressing, and the fresh-keeping effect is good immediately after finger pressing, wherein the best effect of the embodiment 2 is the best embodiment of the invention, while the frozen beef products prepared by the comparative examples 1 to 3 are detected after half a year, wherein the content of volatile basic nitrogen is above 20mg/100g, which exceeds the national standard, and the meat products are dull, brown, general in elasticity, and slow in concave recovery after finger pressing, which proves that the preservative prepared by the method has a great influence on the quality of the frozen beef products after long-term storage. After the frozen beef products prepared by the comparative examples 4 and 5 are stored for half a year, the content of volatile basic nitrogen is 31.25mg/100g and 33.48mg/100g respectively, the meat quality is glossy or dark in color, but is dark red, which shows that the quality and the fresh-keeping effect of the obtained frozen beef products after being stored for half a year are greatly influenced by the fact that the comparative example 4 does not adopt high-voltage pulse electric field treatment or the comparative example 5 does not adopt electron beam irradiation treatment.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.