Method for sterilizing and preserving chicken by using low-temperature plasma technology

Abstract

The invention belongs to the technical field of food science, and particularly relates to a method for sterilizing and preserving chicken by using a low-temperature plasma technology, which specifically comprises the following steps of: unfreezing chicken, deboning, cutting into chicken blocks, and drying to obtain dried chicken blocks; one of the following two modes is adopted for treatment: (1) activated water treatment: quickly soaking the chicken blocks with activated water treated by LTP; and (2) LTP direct treatment: directly treating the chicken blocks by utilizing LTP. Experiments prove that the LTP technology has high efficiency and safety in the aspects of sterilization and preservation of the chicken thigh meat, and a theoretical basis and a practical reference can be provided for application of the LTP technology in the aspect of preservation of the chicken thigh meat.

Description

Technical Field

[0001] This invention belongs to the field of food science and technology, specifically relating to a method for sterilizing and preserving chicken using low-temperature plasma technology. Background Technology

[0002] Chicken is one of the most popular meats globally, with chicken thigh meat holding a significant position in the food market due to its tender texture and rich flavor. However, chicken thigh meat is highly susceptible to microbial contamination during production, processing, transportation, and storage. These microorganisms not only cause spoilage and shorten shelf life but can also lead to foodborne illnesses, threatening consumer health. Common microorganisms contaminating chicken thigh meat include pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, and Salmonella, as well as various spoilage bacteria. Under suitable conditions, these bacteria multiply rapidly, causing serious food safety issues. Traditional sterilization methods, such as heat sterilization and chemical sterilization, while achieving some sterilization effect, can adversely affect the nutritional components, flavor, and quality of chicken. Therefore, developing a safe, efficient, non-thermal, and environmentally friendly new sterilization method is of great importance for chicken preservation.

[0003] Traditional food sterilization methods, such as heat sterilization and chemical sterilization, while able to control microbial numbers to some extent, have significant limitations. The high temperatures involved in heat sterilization can easily damage the nutrients in chicken, such as protein denaturation and vitamin loss, while also altering the texture and flavor, thus reducing product quality. Chemical sterilization may result in chemical residues, posing potential health hazards, and long-term use of chemical disinfectants may lead to antibiotic resistance in microorganisms, further increasing food safety risks. Low-temperature plasma (LTP), as a novel non-thermal sterilization technology, generates reactive oxygen species (ROS), ultraviolet light, and charged particles to efficiently inactivate microorganisms at low temperatures (<60℃) while maintaining food quality. In recent years, the application of LTP in meat sterilization has made significant progress, with studies demonstrating its effectiveness in sterilizing and preserving fruits, vegetables, aquatic products, and grains. However, research on the sterilization effect of LTP on chicken leg meat and its impact on chicken quality is relatively limited. Therefore, its bactericidal effect and mechanism of action on chicken leg meat (including the complex structure of skin, fat and muscle) still need further research.

[0004] Chicken thigh meat differs from other foods in its tissue structure and composition, exhibiting higher fat and protein content and unique moisture distribution. These factors may influence the sterilization effect of LTP and its mechanism of action on chicken quality. In-depth research into the sterilization effect of LTP on chicken thigh meat, clarifying the sterilization patterns under different treatment parameters, and exploring its impact on chicken thigh meat quality indicators (such as pH value, color, tenderness, and nutritional components) is of significant theoretical and practical value for promoting the practical application of LTP technology in the field of meat preservation. Simultaneously, it provides a scientific basis for further optimizing LTP treatment processes and developing new technologies suitable for chicken thigh meat preservation, helping to meet market demand for high-quality, safe chicken products and promoting the healthy development of the meat food industry. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for sterilizing and preserving chicken using low-temperature plasma technology.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows:

[0007] This invention provides a method for sterilizing and preserving chicken using low-temperature plasma technology, which specifically includes the following steps:

[0008] Thaw and debone the chicken, then cut it into pieces. Process the chicken using one of the following two methods:

[0009] ① Activated water treatment: Quickly soak chicken pieces in activated water treated with LTP;

[0010] ②LTP direct processing: Chicken pieces are processed directly using LTP.

[0011] In a preferred embodiment, in method ①, the LTP processing time is 20s-100s.

[0012] In a preferred embodiment, in method ①, the chicken pieces are quickly soaked in activated water treated with LTP for 3-5 minutes.

[0013] In a preferred embodiment, in method ①, the power of the LTP process is 70-100W.

[0014] In a preferred embodiment, in method ②, the direct processing time of the LTP is 20s-100s.

[0015] In a preferred embodiment, in method ②, the power directly processed by the LTP is 70-100W.

[0016] As a preferred embodiment, method ① is superior to method ② in terms of sterilization effect.

[0017] As a preferred embodiment, in terms of pH value, neither method ① nor method ② has a significant effect on the pH value of chicken leg meat.

[0018] As a preferred embodiment, method ② is superior to method ① in terms of the impact on flesh color.

[0019] As a preferred embodiment, method ② is superior to method ① in terms of cooking loss.

[0020] As a preferred embodiment, in terms of hardness, method ① is higher than method ②.

[0021] As a preferred embodiment, in terms of flexibility, method ① is stable, while method ② is highly variable.

[0022] The beneficial effects of this invention are:

[0023] This invention focuses on the sterilization effect and quality impact of LTP on chicken leg meat. Using a dielectric barrier discharge LTP device, different LTP treatment times (0s, 20s, 40s, 60s, 80s, 100s) were set. Direct treatment and activated water immersion treatment were conducted at a power of 80W. The number of microorganisms before and after treatment was measured. Changes in quality indicators such as pH, color, texture, and cooking loss were also studied, and shelf life was verified. The experimental results are as follows:

[0024] (1) The total number of colonies in the LTP direct treatment group and the activated water treatment group decreased with the extension of treatment time from 0s to 40s, but increased from 60s to 100s. The sterilization effect of the LTP direct treatment group was significantly better than that of the activated water treatment group, and the total number of colonies and fungi was significantly reduced, indicating that LTP can significantly reduce the number of microorganisms on the surface of chicken leg meat in a short time.

[0025] (2) The LTP treatment had little effect on pH value. Both groups showed a trend of first increasing and then decreasing, but the values ​​did not change much.

[0026] (3) Regarding color difference, the L value of the LTP direct treatment group increased at 40s and the a value increased at 80s, while the b value of the activated water treatment group increased. This indicates that different treatment methods and treatment times will change the color difference of the chicken.

[0027] (4) The cooking loss rate of the LTP direct treatment group was 12.36% to 22.95%. The cooking loss rate of the activated water treatment group was 19.10% to 28.90%. It can be seen that the activated water treatment group will increase the cooking loss.

[0028] (5) The hardness of the LTP-treated group increased, and the viscosity changes of both groups were quite complex, but the numerical range and trend of change were different.

[0029] (6) In terms of flexibility, the LTP direct treatment group showed relatively large variations, while the activated water treatment group was relatively stable.

[0030] In summary, LTP treatment within the 0s to 80s time period had minimal impact on the pH, color, texture, and cooking loss of chicken drumsticks, while exhibiting good antibacterial effects. Therefore, the above experimental results demonstrate that LTP technology is both highly efficient and safe in the sterilization and preservation of chicken drumsticks, providing a theoretical basis and practical reference for its application in this field. Attached Figure Description

[0031] Figure 1 This invention provides an experimental flowchart of a method for sterilizing and preserving chicken using low-temperature plasma technology.

[0032] Figure 2 To investigate the effect of activated water treatment on bacterial count in chicken leg meat under different LTP treatment times (0s, 20s, 40s, 60s, 80s, 100s) and power (80W).

[0033] Figure 3 To investigate the effect of activated water treatment on fungal counts in chicken leg meat under different LTP treatment times (0s, 20s, 40s, 60s, 80s, 100s) and power (80W).

[0034] Figure 4 To investigate the effect of direct LTP treatment on bacterial count in chicken leg meat.

[0035] Figure 5 To investigate the effect of direct LTP treatment on fungal counts in chicken leg meat.

[0036] Figure 6 This is the result of pH measurement. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] I. Materials and Methods

[0039] 1. Materials and Instruments;

[0040] Chicken thigh meat (commercially available), thawed and refrigerated; plate counting agar (PCA); pH buffer; physiological saline; TAXT Plus texture analyzer (Stable Micro Systems, UK); CR-400 colorimeter (Konica Minolta); pH meter; water bath; electronic balance; petri dishes; sterile sampling tools; laminar flow hood; CTP-2000K low-temperature plasma (Nanjing Suman Plasma Technology Co., Ltd.).

[0041] 2. Test methods;

[0042] (1) LTP treatment;

[0043] Thawed and deboned chicken thigh meat was cut into approximately 5g and 10g pieces. A parallel comparative experiment was designed as follows:

[0044] ① Activated water treatment group: raw chicken leg pieces were quickly soaked in activated water treated under different LTP treatment times (0s, 20s, 40s, 60s, 80s, 100s) and power (80W) for 3 minutes.

[0045] ②LTP Direct Processing Group: Raw chicken leg pieces were directly processed using LTP: Raw chicken leg pieces were directly processed under different LTP processing times (0s, 20s, 40s, 60s, 80s, 100s) and power (80W).

[0046] (2) Total bacterial count determination;

[0047] Weigh 5g of the prepared sample and place it in a sterile homogenizing cup containing 45mL of sterile physiological saline. Homogenize for 2 minutes. In a laminar flow hood, use a pipette to draw 1mL of the 1:10 sample homogenate and slowly pour it along the wall of a sterile test tube containing 9mL of diluent. Shake well to prepare a 1:100 sample homogenate. Repeat the above procedure to prepare 10-fold serial dilutions of the sample homogenate. Use a 1mL sterile pipette or tip for each incremental dilution.

[0048] Choose 10 -3 10-4, 10 -5 For each dilution, homogenize the sample (liquid samples may include the undiluted solution), pipette 1 mL of the homogenate into a sterile petri dish, and prepare three petri dishes for each dilution. Simultaneously, add 1 mL of blank dilution to each of the three sterile petri dishes as a blank control. Incubate at 36℃±1℃ for 48h±2h, then perform a total colony count.

[0049] Petri dish: Plate count agar; Ingredients: trypsin, yeast extract, glucose, agar (pH 7.0±0.2). National standard for total bacterial count: Fresh chicken (fresh and frozen poultry products) according to GB 16869-2005 "Fresh and Frozen Poultry Products" (currently valid version) total bacterial count limit; Fresh poultry products (chilled chicken): ≤1,000,000 CFU / g (i.e., 10... 6 CFU / g); Frozen poultry products (frozen chicken): ≤500,000 CFU / g (i.e., 5×10⁻⁶ CFU / g). 5 CFU / g). The formula for calculating the total bacterial count is as follows:

[0050]

[0051] Where ∑C is the sum of colony counts on all valid plates; n1 is the number of valid plates at the first dilution (lower dilution factor); n2 is the number of valid plates at the second dilution (higher dilution factor); and d is the dilution factor of the first dilution (e.g., 10). -3 Then d = 1000).

[0052] Results of total bacterial count test as follows Figures 2 to 5 As shown.

[0053] Depend on Figure 2 It can be seen that when the LTP treatment time is 0 seconds, the bacterial count is 4.2 log(CFU.g). -1 At 20s, it rose to 4.3log(CFU.g) -1 No significant change was observed, but it decreased to 3.9 log(CFU.g) at 40 s. -1 At 60 seconds, it rose back to 4.1 log(CFU.g). -1 ), reaching 4.35 log(CFU.g) in 80s. -1 ), and after 100s it dropped to 4.2 log(CFU·g) -1 This indicates that activated water treatment has a better bactericidal effect on bacteria at 40 seconds.

[0054] Depend on Figure 3 It can be seen that from 0s to 80s, the fungal count increased from 3.4 log(CFU.g) to... -1 The value gradually increased to 3.9 log(CFU.g) -1 At 100s, it dropped to approximately 3.0 log(CFU.g). -1 The overall trend was first upward and then downward, indicating that the activated water obtained at 100s had the best bactericidal effect on fungi. This may be because there were fewer active substances in the activated water in the early stage, which would promote fungal growth. As the LTP treatment time increased to 100s, the active substances in the activated water accumulated to a level that could inhibit fungal growth.

[0055] Depend on Figure 4 It can be seen that when chicken thigh meat is directly treated with LTP, the bacterial count increases from 5.3 log(CFU·g) when the processing time is increased from 0 s to 40 s. -1 The value rose to 6.3 log(CFU.g) -1 The value shows an upward trend; after 40 seconds, from 60 seconds to 100 seconds, it ranges from 5.6 to 5.7 log(CFU.g). -1 The bacterial count fluctuated, then stabilized, and remained below the peak value at 40 seconds. There were no significant differences in colony counts among the different groups. The initial increase may have been due to the production of active substances or physical effects of LTP treatment on the chicken leg meat, which promoted bacterial growth. However, as the treatment time increased, this effect gradually became inhibitory, and the total bacterial count slowly decreased.

[0056] Depend on Figure 5 It can be seen that when chicken thigh meat is directly treated with LTP, the fungal count increases from 5.0 log(CFU·g) when the treatment time is increased from 0 s to 40 s. -1 The value rose to approximately 5.2 log(CFU.g) -1 After 40 seconds, from 60 to 100 seconds, the fungal count decreased and tended to stabilize at a low level, approximately 5.5–5.4 log(CFU·g). -1 There were no significant differences in colony counts among the groups.

[0057] In summary, the bacterial counts of chicken drumsticks treated with activated water under different LTP treatment times (0s, 20s, 40s, 60s, 80s, 100s) and power (80W) showed significant differences compared to those treated directly with LTP (p < 0.05). The APC levels in chicken drumsticks treated with activated water were lower than those treated directly with LTP, and the bactericidal effect of activated water treatment was superior to that of direct LTP treatment (at a treatment time of 100s). The overall trend of LTP-treated chicken drumsticks within the short timeframe of 0–100s was as follows: an initial increase from 0–40s, followed by a decrease and stabilization from 60–100s, with activated water treatment showing better bactericidal effect than direct LTP treatment.

[0058] (3) pH value measurement;

[0059] Two buffer solutions with known precise pH values ​​(as close as possible to the pH of the test solution) are used to calibrate the pH meter while stirring with a magnetic stirrer at the measurement temperature. 5g of the prepared sample is weighed and placed in a sterile homogenizing vessel containing 45mL of sterile physiological saline. Homogenize for 2 minutes to obtain the sample. A sufficient amount of sample to immerse or embed the electrode is taken, and the electrode is inserted into the sample. The temperature compensation system of the pH meter is adjusted to the sample temperature. If the pH meter does not have a temperature compensation system, the temperature of the test sample should be maintained within the range of 20℃±2℃. The measurement is performed using a procedure suitable for the pH meter used. After the reading stabilizes, it is taken directly, accurate to 0.01. At least two measurements should be performed for the same prepared sample.

[0060] pH measurement results are as follows Figure 6 As shown in the figure, the LTP power was 80W. Under different treatment times, the LTP direct treatment group and the activated water treatment group had little effect on the pH value of the chicken leg meat. However, some data differed between groups. For example, the LTP direct treatment group showed a significant increase at 80s and 40s, and a significant decrease at 60s and 100s. The values ​​of the other groups were similar, mostly around 6.20–6.30. In contrast, the data of the activated water treatment group were relatively stable, with a significant increase at 60s, and other data around 6.20. The fluctuations between groups may be due to the fact that low-temperature plasma increases the acidity of the chicken leg meat surface. Low-temperature plasma contains a large number of reactive active substances, which react with the components in the chicken leg meat to produce acidic substances, changing the acid-base environment of the chicken leg meat system. It is also possible that low-temperature plasma inactivates microorganisms, inhibiting bacterial growth. After microbial growth is inhibited, their metabolic activities change, reducing the production of alkaline metabolites. The active substances produced by low-temperature plasma react with proteins and lipids in the chicken leg meat. On the one hand, this may affect the process of protein decomposition to produce alkaline substances, thus lowering the pH value of the chicken leg meat. On the other hand, reactions such as lipid oxidation may also disrupt the acid-base balance of chicken leg meat.

[0061] Overall, the differences between the LTP direct treatment group and the activated water treatment group were not significant, and the data between the groups were relatively stable. Therefore, it can be concluded that LTP direct treatment and activated water treatment had no significant effect on the pH value of chicken leg meat in the range of 0–100 s.

[0062] (4) Meat color determination;

[0063] Cut chicken thigh meat into 3.5cm×3.5cm×1cm (approximately 10g) pieces. Use a colorimeter to measure the L of the chicken thigh meat. * value, a * value and b * Value. The calibrated colorimeter was placed on the surface of the meat sample with a layer of plastic wrap between it and the sample for measurement, and the measurement was repeated three times.

[0064] L: Indicates the lightness or darkness of a color, ranging from 0 (pure black) to 100 (pure white).

[0065] a: Red-green axis, positive values ​​indicate a red tendency, and negative values ​​indicate a green tendency.

[0066] b: Yellow-blue axis: Positive values ​​indicate a yellow tendency, and negative values ​​indicate a blue tendency.

[0067] The color difference measurement results are shown in Table 1. The L value of the LTP-treated group fluctuated between 51.65 and 60.83. The meat color was good and the L value was the highest at 20s, while it was lower at 40s (51.65). This may be because the structural proteins on the surface of the chicken leg meat changed under the influence of LTP, resulting in different degrees of color change. The a value ranged from 2.74 to 9.49. There were no significant differences at 20s, 60s, and 100s, but there were significant differences compared with 0s and 40s (p<0.05). The a value was the highest at 40s (9.49), and the a value was lower at 100s (2.83). This may be because short-term treatment caused slight oxidation of the chicken leg meat, increasing the a value. Longer treatment time caused slight dehydration of the chicken leg meat surface, forming a dry layer, making the surface color darker, and decreasing the a value and brightness. The b-values ​​ranged from 8.06 to 10.28. The b-values ​​of the LTP-treated groups were all higher than those of the control group, indicating that LTP had a more significant effect on the b-values.

[0068] For the activated water treatment group, the activated water treatment had no significant effect on the L value of the chicken leg meat. Under each time condition, the L value was not significantly different from that of the control group. Regarding the a value, activated water treatment reduced the a value of the chicken leg meat, decreasing its redness. As for the b value, it was highest at 100s. This is likely because the reactive oxygen species (ROS, such as ·OH, O3) generated by the plasma oxidize the unsaturated fatty acids in the chicken leg meat, producing carbonyl compounds such as aldehydes and ketones (e.g., malondialdehyde). These substances are yellow in color, leading to an increase in the b value.

[0069] Comparing the two methods, the a-value of the LTP direct treatment group was higher than that of the activated water treatment group, indicating that LTP direct treatment is beneficial for maintaining the a-value of chicken thigh meat, making the red color of the chicken thigh meat more vibrant, and providing better color protection. At the same time, the LTP direct treatment had a greater impact on the color difference of the chicken thigh meat compared to the activated water treatment.

[0070] Table 1

[0071]

[0072] (5) Determination of cooking loss;

[0073] Cut a 5g sample of chicken thigh meat and weigh it before cooking (M1). Place the sample in a cooking bag and heat it in a 72℃ water bath for 15 minutes until the center temperature reaches 70℃. Remove the sample and cool it to room temperature with running water. Blot dry the surface moisture and weigh the meat after cooking (M2). The cooking loss is calculated using the following formula: Cooking loss (%) = (M1 - M2) / M1 × 100%, where: M1 is the weight of the sample before cooking (g); M2 is the weight of the sample after cooking (g); and 100 is a conversion factor.

[0074] Cooking loss is an important indicator for evaluating the water-holding capacity of meat products. Experiments showed that for the LTP direct treatment group, the pre-cooking mass was slightly lower, and after cooking, it ranged from 7.42 to 8.59, with a loss rate of 12.36% to 22.95%. For the activated water treatment group, the pre-cooking mass was stable, and after cooking, it ranged from 7.11 to 8.09, with a loss rate of 19.10% to 28.90%.

[0075] The results of the cooking loss determination are shown in Table 2. There were significant differences between the groups (p < 0.05). The cooking loss of the activated water treatment group generally increased with time, with the largest cooking loss occurring at 80 seconds. This phenomenon is because LTP treatment may induce the oxidation of fat in chicken leg meat, producing some oxidation products. These oxidation products affect the interaction between fat and protein, altering the stability of fat during cooking and thus affecting cooking loss. For example, oxidation products may weaken the binding force between fat and protein, making fat more likely to precipitate during cooking and increasing cooking loss.

[0076] Under LTP direct short-time treatment, cooking loss is reduced because LTP direct treatment breaks or rearranges the disulfide bonds and other chemical bonds in chicken leg proteins, leading to changes in the protein's tertiary structure, causing the molecules to unfold and expose more polar groups. This enhances the interaction between protein and water during cooking, allowing more water to bind and thus reducing water loss and cooking loss. The cooking loss rate in the LTP direct treatment group showed little variation within the group and was lower than that in the activated water treatment group. Therefore, overall, the activated water treatment group had a higher cooking loss rate, while the LTP direct treatment group performed better.

[0077] Table 2

[0078]

[0079]

[0080] (6) Texture determination;

[0081] Chicken thigh meat was cut into 3.5cm × 3.5cm × 1cm (approximately 10g) samples. The hardness, cohesion, and chewiness were measured using a TA.XTPlus texture analyzer with a P50 probe. Each sample was measured three times. The P50 probe was moved downwards at a constant speed. Parameter settings: pre-test speed 2.00mm / s, test speed 5.00mm / s, post-test speed 5.00mm / s; test mode: strain; strain level 75%; trigger force type: automatic; trigger force 5.0g.

[0082] Texture is one of the most important quality parameters of meat products. It is a comprehensive indicator that includes hardness, elasticity, chewiness, cohesiveness, and adhesiveness.

[0083] Table 3 shows the textural changes of chicken thigh meat in the LTP-treated group. The LTP-treated group exhibited an overall trend of first increasing, then fluctuating, decreasing, and then increasing again. At 0 s, the hardness was 669.45 ± 529.05, reaching a peak of 1849.26 at 40 s, then decreasing, before rising again to 2785.02 ± 795.61 at 80 s. Significant differences in hardness were observed at different time points (p < 0.05), attributed to oxidative cross-linking: reactive oxygen species (ROS) and reactive nitrogen species (RNS) generated by plasma can induce intermolecular cross-linking of myofibrillar proteins (such as myosin and actin), forming a tighter network structure and increasing hardness. Viscosity values ​​were both positive and negative, fluctuating significantly from -28.44 to -10.53 ± 10, indicating complex changes in the viscosity of chicken thigh meat during LTP treatment, possibly related to changes in the internal structure of the chicken thigh meat. The elasticity was relatively stable initially, fluctuating between 0.95 and 0.96. It began to decrease to around 0.8 after 60 seconds, and continued to fluctuate thereafter, reflecting the gradual impact of processing on the elasticity of the chicken thigh meat. Adhesion and cohesion gradually increased from 0.32 to 0.47, indicating that the adhesion and cohesion properties of the chicken thigh meat gradually increased during processing. Chewiness, stickiness, and resilience: Chewiness was 270.92 at 0 seconds, initially increasing, then decreasing, and then increasing again, with a trend somewhat correlated with hardness. Stickiness and resilience also exhibited their own fluctuations, reflecting the complex changes in the mechanical properties of the chicken thigh meat during processing.

[0084] Table 3 shows the textural changes of chicken leg meat in the activated water treatment group. In the activated water treatment group, there were no significant differences in hardness, viscosity, elasticity, cohesion, stickiness, chewiness, and resilience. The hardness values ​​were generally high and fluctuated upwards, from 2085.97 at 0s to 3174.43 at 100s, indicating that the hardness of the chicken leg meat increased continuously over time under the action of activated water. The brittleness was 2787.14 at 0s and decreased to 0 at 40s, followed by fluctuations. This indicates that during the treatment process, chewiness, stickiness, and resilience changed. Chewiness started to change from 650.98, while stickiness and resilience also showed their own fluctuating trends, reflecting the overall change in the textural properties of the chicken leg meat under the action of activated water.

[0085] Compared to the other groups, the initial firmness of the chicken thigh meat in the activated water treatment group was significantly higher than that in the LTP direct treatment group, and the firmness increase trend was more pronounced throughout the treatment process. The viscosity changes in both treatment groups were complex, but the numerical ranges and trends differed. Regarding elasticity, the LTP direct treatment group showed relatively larger changes, while the activated water treatment group remained relatively stable. Overall, different treatment methods had varying degrees and trends of influence on the texture of the chicken thigh meat at different time points.

[0086] Table 3. Effects of direct LTP treatment on chicken leg meat texture.

[0087]

[0088] Table 4. Effects of activated water treatment on the texture of chicken leg meat.

[0089]

[0090]

[0091] In summary, under 80W power conditions, the total bacterial count in both the LTP direct treatment group and the activated water treatment group increased and decreased with treatment time from 0s to 40s. However, from 60s to 100s, the total bacterial count increased. This may be because LTP treatment of chicken leg meat produced active substances or exerted a physical effect, promoting bacterial growth. Nevertheless, it still had an antibacterial effect with increasing treatment time. The antibacterial effect of the LTP direct treatment group was more significant than that of the activated water treatment group, with a significant reduction in both the total bacterial count and the number of fungi.

[0092] Under 80W power conditions, the pH value in the LTP direct treatment group showed a significant difference at 80s, but other data showed no significant differences. This fluctuation between groups may be due to LTP treatment increasing the acidity of the chicken leg meat, altering the acid-base environment, or it may affect the process of protein decomposition producing alkaline substances, thus lowering the pH value. However, there was no significant difference in pH value between the LTP direct treatment group and the activated water treatment group. Therefore, LTP treatment has a relatively small impact on the pH value of chicken leg meat.

[0093] In the color difference determination, the L value was highest at 80s in the LTP direct treatment group. This is because the structural proteins in the chicken leg meat change under the influence of LTP, leading to varying degrees of color change. The a value was highest at 40s, and lower at 100s. This may be because short-term LTP treatment causes slight oxidation of the chicken leg meat, temporarily increasing the a value. Longer treatment times lead to slight dehydration of the chicken leg meat surface, forming a dry layer, making the surface color darker and decreasing the a value. In the activated water treatment group, the b value was highest at 100s. This may be because the reactive oxygen species (ROS, such as ·OH, O3) generated by the plasma oxidize the unsaturated fatty acids in the chicken leg meat, generating carbonyl compounds such as aldehydes and ketones (such as malondialdehyde). These substances are yellow, leading to an increase in the b value. Overall, direct LTP treatment can improve the a value of chicken leg meat, making the red color of the chicken leg meat more vibrant, with better results.

[0094] In the determination of cooking loss, the cooking loss rate in the LTP direct treatment group was 12.36%–22.95%, and the cooking loss rate in the activated water treatment group was 19.10%–28.90%. There were significant differences among the groups. The activated water treatment group had the largest cooking loss at 100 s. The cooking loss rate increased with the increase of treatment time, but overall, the activated water treatment group had a larger cooking loss rate, and the LTP direct treatment group had a better treatment effect.

[0095] In the texture determination, the initial hardness of the activated water treatment group was significantly higher than that of the LTP direct treatment group, and the hardness increase trend was more pronounced throughout the treatment process. The viscosity changes in both groups were complex, but the numerical ranges and trends differed. Regarding elasticity, the LTP direct treatment group showed relatively larger changes, while the activated water treatment group remained relatively stable. Overall, different treatment methods had varying degrees and trends of influence on the texture of chicken leg meat at different time points. Compared to activated water treatment, LTP direct treatment had a smaller impact on the texture of chicken leg meat.

[0096] This invention discloses a method for sterilizing and preserving chicken using low-temperature plasma technology. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the same result. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The product of this invention has been described through preferred embodiments, and those skilled in the art can clearly modify or appropriately change and combine the product described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

Claims

1. A method for sterilizing and preserving chicken using low-temperature plasma technology, characterized in that, Includes the following steps: Thaw and debone the chicken, then cut it into pieces. Process the chicken using one of the following two methods: ① Activated water treatment: Quickly soak chicken pieces in activated water treated with LTP; ②LTP direct processing: Chicken pieces are processed directly using LTP.

2. The method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, In method ①, the LTP treatment time is 20 s-100 s; the chicken pieces are quickly soaked in the activated water after LTP treatment for 3-5 min.

3. The method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, In method ①, the power of the LTP process is 70-100 W.

4. The method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, In method ②, the direct processing time of LTP is 20 s-100 s.

5. The method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, In method ②, the power directly processed by the LTP is 70-100 W.

6. The method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, In terms of sterilization effect, method ① is better than method ②.

7. The method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, Regarding the effect on pH value, neither method ① nor method ② had a significant effect on the pH value of chicken leg meat.

8. A method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, Regarding the influence of flesh color, method ② is superior to method ①.

9. A method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, In terms of cooking loss, method ② is better than method ①.

10. A method for sterilizing and preserving chicken using low-temperature plasma technology according to claim 1, characterized in that, In terms of hardness, method ① is higher than method ②; in terms of elasticity, method ① is more stable, while method ② varies more.

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