CN115777763A - Preservation method for prefabricated selenium-rich pork - Google Patents

Abstract

The invention discloses a fresh-keeping method for prefabricated selenium-enriched pork, which comprises the following steps: Step 1: selecting raw meat; 0.040kg of lysine hydrochloride is loaded together in a 300L tumbler for low-temperature vacuum tumbling and marinating; step 3: slice, and cut the meat in step 2 into steaks of 250-300g/part; step 4 : quick freezing, immerse and freeze the steak in step 3 in liquid nitrogen for 4 to 5 minutes, take it out and place it in a black packaging box made of PP material and wait for packaging; step 5: packaging, packaging and frozen storage Compared with the advantages: natural preservative preservation, ultra-low temperature quick freezing, high oxygen modified packaging and other processes are organically combined, so that the water loss rate, lipid and protein oxidation of prefabricated selenium-enriched pork after 3 months of storage after thawing The rate is significantly reduced, and the flesh color and elastic stability are significantly enhanced.

Description

A kind of fresh-keeping method of prefabricated selenium-enriched pork

technical field

The invention relates to the technical field of food preservation methods, in particular to a method for preserving the freshness of prefabricated selenium-enriched pork.

Background technique

Selenium is very important to human health, and selenium-containing diet is the only way for human body to absorb selenium. Since my country is a big selenium-deficient country, more than 70% of the regions are deficient in selenium to varying degrees. With the improvement of the living standards of Chinese residents and the improvement of health awareness, selenium-enriched pork as a high-end selenium supplement product has emerged at the historic moment. The prefabricated meat products processed by selenium pork have been very popular among consumers in recent years due to their healthy, nutritious, delicious and convenient attributes.

Selenium-enriched pork is the same as ordinary pork. If it is not stored properly, it is prone to spoilage under the dual action of microorganisms and endogenous enzymes, and there will be a large amount of water loss, elasticity and color deterioration of the product. This is mainly due to the microorganisms in pork. activities, excessive oxidation of proteins and lipids. There are also differences between selenium-enriched pork and ordinary pork. Some studies at home and abroad have found that selenium-enriched pork has stronger oxidative stability than ordinary pork, and the shelf life under refrigerated conditions is longer than ordinary pork, but some studies have found that there is no difference between the two. So far, there is no fresh-keeping method for high-end selenium-enriched pork products in China. Therefore, the research and development of prefabricated selenium-enriched pork fresh-keeping technology has very important guiding significance for the development and processing of high-end selenium-enriched pork prefabricated dishes. .

Under normal circumstances, the preservation of prefabricated pork products adopts the addition of chemical preservatives (preservatives and antioxidants) during the pickling process. The prefabricated products are packaged in vacuum or low oxygen, and directly frozen and stored at -18 ~ -16 ° C Methods. The shelf life of products processed by this method can reach 3 months or even longer, and the processing cost and energy consumption are also low. However, this method also has three major defects: potential safety problems caused by chemical additives, odor and color deterioration caused by lipid and protein oxidation caused by psychrophilic microorganisms, and freeze-thaw dehydration caused by slow freezing speed Problem with elastic change. In addition, at this stage, selenium-enriched pork products are aimed at the mid-to-high-end meat consumer market. This conventional fresh-keeping method is no longer suitable for maintaining the original quality of the product and meeting consumers' health needs.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the above technical defects and provide a fresh-keeping method for prefabricated selenium-enriched pork, which organically combines processes such as natural preservative preservation, ultra-low temperature quick freezing, and high-oxygen modified packaging, so that prefabricated selenium-enriched pork can be stored Three months later, the water loss rate after thawing, the oxidation rate of lipids and proteins were significantly reduced, and the meat color and elasticity stability were significantly enhanced.

In order to solve the above technical problems, the technical solution provided by the present invention is: a method for preserving the freshness of prefabricated selenium-enriched pork, comprising the following steps:

Step 1: Selection of raw meat

Select selenium-enriched pork hind legs, spine and front legs that have passed the quarantine inspection and are slaughtered intensively in the processing plant as raw materials, remove the skin, fat and surface tendons, tendons, lymph, and membranes, debone and divide the meat Make meat pieces with a specification of about 400-600g/part, and then transfer the divided meat pieces to the low-temperature aseptic workshop for the next step of processing;

Step 2: Marinate and season

Take 200kg of meat in step 1, 5kg of secret marinade, 0.034kg of nisin, and 0.040kg of polylysine hydrochloride, and load them together in a 300L tumbler for low-temperature vacuum tumble marinade, and control the temperature of the tumbler. The vacuum degree is 70±10kPa, the tumbling temperature is 2±2°C, the speed is 10 rpm, tumbling for 6 hours, every tumbling for 20 minutes, stop working for 10 minutes and then leave the barrel;

Step Three: Slicing

Cut the meat in step 2 into steaks of 250-300g/part;

Step 4: Quick Freeze

Immerse and freeze the steak in step 3 in liquid nitrogen for 4-5 minutes, take it out and place it in a black PP box for packaging;

Step 5: Packing, packaging and freezing

Immediately use a modified atmosphere packaging machine to remove the air in the box in step 4, fill it with a mixed gas of carbon dioxide and oxygen, and pack it with a PET/CPP double-layer composite film with a thickness of 40 microns. The packaged product is promptly transferred to -18 Store in a freezer at -16°C.

The temperature of the low-temperature aseptic workshop in step one is less than 10°C.

Step 5 The ratio of carbon dioxide to oxygen in the mixed gas is 3:2.

Compared with the prior art, the present invention has the advantages of: according to the market positioning of the product and the high oxidation stability of selenium-enriched pork, with the aim of maximally maintaining the original quality of selenium-enriched pork, according to the principle of food fresh-keeping fences, comprehensive utilization of Prefabricated selenium-enriched pork was kept fresh by natural preservatives, ultra-low temperature freezing, and high-oxygen modified packaging, which significantly reduced the water loss rate, lipid and protein oxidation rate of the prefabricated selenium-enriched pork after thawing after storage for 3 months, and the meat color and The elastic stability is significantly enhanced, and good results have been achieved. At the same time, the safety risks brought by chemical preservatives are reduced, and the original quality of selenium-enriched pork is greatly maintained.

Detailed ways

The present invention will be described in further detail below.

A kind of prefabricated selenium-enriched pork fresh-keeping method, comprises the following steps:

Step 1: Selection of raw meat

Select selenium-enriched pork hind legs, spine and front legs that have passed the quarantine inspection and are slaughtered intensively in the processing plant as raw materials, remove the skin, fat and surface tendons, tendons, lymph, and membranes, debone and divide the meat Make meat pieces with a specification of about 400-600g/part, and then transfer the divided meat pieces to the low-temperature aseptic workshop for the next step of processing. The temperature of the low-temperature aseptic workshop is less than 10°C;

Step 2: Marinate and season

Take 200kg of meat in step 1, 5kg of secret marinade, 0.034kg of nisin, and 0.040kg of polylysine hydrochloride, and load them together in a 300L tumbler for low-temperature vacuum tumble marinade, and control the temperature of the tumbler. The vacuum degree is 70±10kPa, the tumbling temperature is 2±2°C, the speed is 10 rpm, tumbling for 6 hours, every tumbling for 20 minutes, stop working for 10 minutes and then leave the barrel;

More and more evidence shows that chemically synthesized preservatives are potentially harmful to human health. At present, most consumers cannot accept any chemically synthesized ingredients in food. In the future, they must be replaced by natural and harmless biological preservatives.

Step Three: Slicing

Cut the meat in step 2 into steaks of 250-300g/part;

Step 4: Quick Freeze

Immerse and freeze the steak in step 3 in liquid nitrogen for 4-5 minutes, take it out and place it in a black PP box for packaging;

The freezing speed directly affects the water loss rate and elasticity of the meat after thawing. Ultra-low temperature rapid freezing can freeze more than 88% of the free water in the muscle. Due to the lack of available water, the activity of microorganisms is limited; in addition, due to the fast freezing speed, the formation of The ice crystals in the meat are tiny and will hardly damage the internal structure of the muscle tissue. After the muscle is thawed, there will be less water seepage, which is very conducive to maintaining the original eating quality of the meat.

Step 5: Packing, packaging and freezing

Immediately use a modified atmosphere packaging machine to remove the air in the box in step 4, fill it with a mixed gas of carbon dioxide and oxygen, the ratio of carbon dioxide and oxygen in the mixed gas is 3:2, and use a PET/CPP double-layer composite film with a thickness of 40 microns Film-covered packaging, the packaged products are promptly transferred to a freezer at -18 to -16°C for frozen storage.

Although a higher partial pressure of oxygen is not good for inhibiting microbial activities, a proper increase in partial pressure of oxygen is helpful for the maintenance of muscle color. This technology changes the conventional ratio of carbon dioxide and oxygen from 7:3 to 3:2, and has achieved good results.

When the present invention was implemented, the selenium-enriched pork of the test was derived from the selenium-enriched commodity Rong binary pig (big gram boar × Rongchang sow) fed by the breeding pig farm in Chongqing, with a body weight of 110-130kg and a muscle selenium content of 0.3～0.5mg/kg.

The total number of bacterial colonies and volatile basic nitrogen are the main indicators reflecting the shelf life of meat products, while the oxidation of lipids and proteins will lead to muscle water loss, deterioration of meat color and elasticity. This test is provided with 1 experimental group and 1 control group, and wherein control group adopts conventional fresh-keeping technology (potassium sorbate+modified atmosphere packaging+frozen storage (-18～-16 ℃)), test group adopts fresh-keeping method of the present invention , other raw materials and processing technology two groups of experiments are exactly the same.

After the product was stored for 0, 1, 2, and 3 months, the total number of colonies, volatile basic nitrogen (TVB-N), lipid oxidation index (thiobarbituric acid, Sensory evaluation of TBARS), protein oxidation index (tryptophan loss, Tryloss), water loss rate, elasticity and flesh color. The result is as follows:

(1) Total number of colonies

The determination of the total number of colonies refers to GB 4789.2-2016 "Determination of the total number of bacterial colonies in food microbiological examination of national food safety standards". The determination results are shown in Table 1.

Table 1 Changes in the total number of bacterial colonies of prefabricated selenium-enriched pork during storage from 0 to 3 months

It can be seen from Table 1 that the total number of colonies in the control group and the test group showed a certain upward trend during the 3-month shelf life, but the total number of colonies did not exceed the national standard for fresh meat (105/g) after 3 months, but the test group The total number of bacterial colonies during the storage period was lower than that of the control group, indicating that this method can slow down the activity of psychrophilic microorganisms compared with the conventional method, which is beneficial to prolong the shelf life of the product and stabilize the product quality.

(2)TVB-N

TVB-N refers to GB 5009.228-2016 "Determination of Volatile Basic Nitrogen in Food in National Food Safety Standards", and the results are shown in Table 2.

Table 2 Changes in TVB-N of prefabricated selenium-enriched pork during storage period from 0 to 3 months

It can be seen from Table 2 that the change rule of TVB-N in the two groups is basically consistent with the change rule of their total number of colonies. After 3 months, TVB-N still maintains the first-grade fresh meat level (10-15mg/100g). It shows that both methods can effectively inhibit muscle protein breakdown during storage.

(3)TBARS

Determination of TBARS: Weigh 10g of meat sample and grind it finely, place it in a conical flask, add 50ml of 7.5% trichloroacetic acid-EDTA mixture (containing 0.1% EDTA), shake for 30min, filter with double-layer filter paper for 2 Once, accurately weigh 5ml of the above-mentioned filtrate, add 5ml of 0.02mol/L TBA (2-thiobarbituric acid) solution, incubate in a water bath at 90°C for 40min, take it out and cool it for 1h, and centrifuge for 5min (1600r/min), the supernatant Add 5ml of chloroform to the solution and shake well, after static layering, take the supernatant, compare the color at 532nm and 600nm respectively, record the extinction value, and use the following formula to calculate TBARS. Calculated as follows:

The measurement results are shown in Table 3.

Table 3 Changes in TBARS of prefabricated selenium-enriched pork during storage period from 0 to 3 months (n=9)

Note that the superscripts of different letters in the data in the same column are significantly different (P<0.05)

The size of TBARS reflects the degree of lipid oxidation in meat and meat products. It can be seen from Table 3 that the TBARS values of the experimental group were significantly lower than those of the control group from 1 to 3 months (P<0.05), indicating that this method can significantly reduce the lipid oxidation degree of prefabricated selenium-enriched pork.

(4) Loss of Tryptophan (Try)

The concentration of Try is measured by fluorescence spectrophotometry, and the specific method refers to "Measurement of Food Nutrient Components-Determination of Tryptophan in Food--Fluorescence Spectrophotometry" compiled by "Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine" (Third Version).

The loss of tryptophan is shown in Table 4.

Table 4 Loss of tryptophan in prefabricated selenium-enriched pork during storage period from 0 to 3 months (n=9)

Note Different superscript letters in each column of data in the table mean significant difference (P<0.05).

Tryptophan is one of the most oxidation-sensitive amino acids, and it is a major marker of protein oxidation in muscle. With the oxidative degradation of protein, the concentration of Try gradually decreased. It is not difficult to see from Table 4 that the loss rate of tryptophan in the test group was significantly lower than that in the control group (P<0.05), indicating that this method has a significant effect on slowing down the protein oxidation of prefabricated selenium-enriched pork.

(5) Water loss rate

Take 5g of raw meat, centrifuge at 1500r/min for 30min, take it out, absorb the water on the surface of the meat with filter paper, weigh it and record it as m. Then calculate the water loss rate W according to the formula.

The water loss rate is shown in Table 5.

Table 5 Water loss rate of prefabricated selenium-enriched pork during storage period from 0 to 3 months (n=9)

Note that the superscripts of different letters in the data in the same column are significantly different (P<0.05)

It can be seen from Table 5 that the water loss rate of the test group was significantly lower than that of the control group, indicating that the test group had a better water retention effect, lower dry consumption, and better meat quality.

(7) Sensory evaluation

The sensory index of the product can be borrowed from the sensory index evaluation standard of chilled fresh pork, using a conventional 10-point scoring system, and evaluated by a professional sensory evaluation team. The specific standards are shown in Table 6 and the scores are shown in Table 7.

Table 6 Evaluation Criteria for Sensory Indicators of Chilled Fresh Pork

Table 7 Sensory evaluation scores of prefabricated selenium-enriched pork during storage period from 0 to 3 months

As can be seen from Table 7, except that the odor test group and the control group have little change, the color and elasticity test group is obviously stronger than the control group, and the flesh color and elasticity of the whole storage period have little change, indicating that this method can maintain the flesh color. And the effect of muscle elasticity is outstanding.

The present invention and its embodiments are described above without limitation. All in all, if a person of ordinary skill in the art is inspired by it, and without departing from the inventive concept of the present invention, without creatively designing a structure and an embodiment similar to the technical solution, it shall fall within the scope of protection of the present invention.

Claims (3)

1. a prefabricated selenium-enriched pork preservation method, is characterized in that: comprise the following steps: Step 1: Selection of raw meat Select selenium-enriched pork hind legs, spine and front legs that have passed the quarantine inspection and are slaughtered intensively in the processing plant as raw materials, remove the skin, fat and surface tendons, tendons, lymph, and membranes, debone and divide the meat Make meat pieces with a specification of about 400-600g/part, and then transfer the divided meat pieces to the low-temperature aseptic workshop for the next step of processing; Step 2: Marinate and season Take 200kg of meat in step 1, 5kg of secret marinade, 0.034kg of nisin, and 0.040kg of polylysine hydrochloride and load them together in a 300L tumbler for low-temperature vacuum tumbling and marinating, and control the temperature of the tumbler. The vacuum degree is 70±10kPa, the tumbling temperature is 2±2°C, the speed is 10 rpm, tumbling for 6 hours, every tumbling for 20 minutes, stop working for 10 minutes and then leave the barrel; Step Three: Slicing Cut the meat in step 2 into steaks of 250-300g/part; Step 4: Quick Freeze Immerse and freeze the steak in step 3 in liquid nitrogen for 4-5 minutes, take it out and place it in a black PP box for packaging; Step 5: Packing, packaging and freezing Immediately use a modified atmosphere packaging machine to remove the air in the box in step 4, fill it with a mixed gas of carbon dioxide and oxygen, and pack it with a PET/CPP double-layer composite film with a thickness of 40 microns. The packaged product is promptly transferred to -18 Store in a freezer at -16°C. 2. The fresh-keeping method of prefabricated selenium-enriched pork according to claim 1, characterized in that: the temperature of the low-temperature aseptic workshop in step 1 is less than 10°C. 3. The fresh-keeping method of prefabricated selenium-enriched pork according to claim 1, characterized in that the ratio of carbon dioxide to oxygen in the mixed gas in step 5 is 3:2.