Method for regulating low-salt meat paste gel performance based on myosin aggregate controlled by water molecule dynamic conversion

Abstract

This invention discloses a method for regulating the gel properties of low-salt minced meat based on myosin aggregates undergoing dynamic water molecule conversion, belonging to the field of protein deep processing technology. The method includes the following steps: Myofibrillar protein extracted and dialyzed in a phosphate buffer solution with a concentration of 0.2M NaCl, followed by sonication for 3-6 minutes to purify and obtain myosin; myosin is then linearly thermally induced to aggregate, constructing three types of myosin aggregates; these three myosin aggregates are then heated at a programmed temperature of 85°C for 20 minutes to form a gel; and a correlation analysis of the gel's water-holding capacity is performed. This invention correlates gel properties with key variables such as aggregate type and the ratio of dynamic water molecule conversion. By constructing the relationship between aggregate type, water molecule migration behavior, and gel water-holding capacity, it elucidates how different initial aggregates, by regulating the binding state and migration path of water molecules, ultimately determine their thermal aggregation behavior and gel quality at a microscopic level.

Description

Technical Field

[0001] This invention belongs to the field of protein deep processing technology, specifically relating to a method for regulating the gel properties of low-salt minced meat based on myosin aggregates of dynamic water molecule conversion. Background Technology

[0002] The trend of reducing the salt content of meat products is an inevitable trend in the development of the industry in line with the national demand for healthy diets. However, the reduction of NaCl concentration will significantly weaken the solubility and dispersion ability of myosin, resulting in disordered aggregation of protein molecules and coarse and uneven three-dimensional network structure during the heat-induced gelation process. Ultimately, this leads to a series of quality problems such as decreased gel water retention and deterioration of texture, which has become the core technical bottleneck restricting the improvement of the quality of low-salt meat products.

[0003] Currently, both domestic and international research primarily focuses on improving the gel properties of low-salt minced meat through physical field modification such as ultrasound and ultra-high pressure, or by adding excipients such as hydrophilic colloids and enzymes. While these methods can improve gel strength and water retention to some extent, they generally target the entire protein system for regulation, failing to adequately consider the decisive role of the morphology, size, and assembly characteristics of the initial aggregates formed during the early stages of thermal aggregation in the subsequent gel network construction. This makes it difficult to achieve precise and targeted control of gel quality. Existing research has shown that the type of initial assembly units in myosin thermal aggregation directly affects the cross-linking pathways and network uniformity of protein molecules during subsequent heating, thereby determining the final gel's microstructure and functional properties. However, a systematic understanding of the differences in gelation and water regulation mechanisms of different types of myosin aggregates in low-salt systems remains lacking.

[0004] Water-holding capacity is one of the most critical quality indicators of meat-based gels, essentially representing the ability of protein aggregation networks to bind water molecules in different states. Low-field nuclear magnetic resonance (NMR) technology, through transverse relaxation time (T2) spectroscopy, can accurately distinguish between bound water, immobile water, and free water, and has become the mainstream technique for characterizing the water distribution and migration behavior of gel systems. However, existing research largely focuses on the static characterization of the water state of the final gel product, failing to track the dynamic transformation of water molecules throughout the entire process from initial aggregate formation to gel network construction. This makes it impossible to precisely control the water-holding capacity of the gel through targeted design of aggregate structures.

[0005] Currently, Wang et al. (10.1016 / j.ultsonch.2023.106349) analyzed the gel properties, water distribution, and microstructural changes of myofibrillar proteins during ultrasound-assisted thermally induced gelation. They confirmed that ultrasound treatment (<600W) can significantly improve gel strength (up to 17.9%) and water-holding capacity (up to 32.7%) by promoting protein structure unfolding (α-helix to β-sheet conversion), enhancing hydrophobic interactions and disulfide bond cross-linking, and forming a dense and homogeneous gel network. It also promotes the conversion of free water to less mobile water. However, this study did not distinguish the differential effects of different initial aggregate types, and therefore could not reveal the microscopic mechanism of aggregate-mediated water regulation. Furthermore, Chinese invention patent application CN113208066A discloses a processing method to improve the gel texture properties of low-salt minced pork. This method involves treating low-salt minced pork (1.6% NaCl + 0.4% MC) with a combination of high-intensity ultrasonic technology and methylcellulose (MC) supplement. The method utilizes ultrasonic water bath (53kHz, 50~150W) pretreatment to improve the hardness, elasticity, chewiness, and adhesiveness of the low-salt minced pork. However, this method treats a complex minced pork system and does not reveal the mechanism of action from the microscopic regulation level of purified myosin aggregates. It also does not construct a quantitative correlation model of aggregate structure-water conversion-gel properties, thus lacking theoretical guidance for actual production.

[0006] In summary, current technologies have not yet clarified the regulatory mechanisms by which different types of myosin aggregates affect the gel's water state and water-holding capacity in low-salt systems. There is a lack of methods for targeted aggregate regulation based on dynamic water molecule conversion mechanisms, thus failing to provide a systematic theoretical basis and technical pathway for precisely improving the quality of low-salt meat paste gels. Therefore, establishing a quantitative structure-activity relationship between aggregate type, water molecule migration behavior, and gel water retention, and developing methods for regulating the performance of low-salt gels based on initial aggregate design, is of significant theoretical importance and engineering application value for promoting the upgrading of low-salt meat product processing technology. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art and provide a method for regulating the gel performance of low-salt minced meat based on myosin aggregates of dynamic water molecule conversion. By constructing a quantitative structure-activity relationship among aggregate type, water molecule migration behavior and gel water retention, the purpose of effectively regulating the gel performance of low-salt minced meat can be achieved.

[0008] To achieve the above objectives, the present invention employs the following technical solution: a method for regulating the gel properties of low-salt meat paste based on myosin aggregates undergoing dynamic water molecule conversion, comprising the following steps: S1. Preparation of myosin: The extracted myofibrillar protein was dialyzed in phosphate buffer with a concentration of 0.2M NaCl and then sonicated for 3-6 minutes to obtain myosin after purification. S2, Thermal induction of myosin aggregates: The myosin treated by ultrasound in step S1 above was linearly thermally induced to aggregate at a temperature of 25℃~85℃ to construct three types of myosin aggregates: spherical aggregates, amorphous aggregates, and fibrous aggregates. S3. Relationship between aggregate type, water molecule migration behavior, and gel water retention: The three myosin aggregates constructed in step S2 above were heated at 85°C for 20 minutes to form a gel. The water-holding capacity (WHC) of the gel and the ratio of non-flowing water (T) 22 A significant positive correlation was observed, r = 0.795, p < 0.01; The water-holding capacity (WHC) of the gel and the ratio of free water (T) 23 A significant negative correlation was observed, r = -0.867, p < 0.001; The water-holding capacity (WHC) of the gel was significantly negatively correlated with the protein molecule aggregation size (Size), r = -0.839, p < 0.01; and significantly negatively correlated with the weight-average molecular weight (Mw), r = -0.797, p < 0.01. The water-holding capacity (WHC) of the gel was positively correlated with the surface hydrophobicity, r=0.62, p<0.05.

[0009] In step S1, the phosphate buffer also contains 20 mM KH2PO4 / K2HPO4 and 10 mM EDTA-Na2, with a pH of 6.5.

[0010] In step S1, the dialysate is changed every 7 hours during the low-salt dialysis treatment, and the dialysis treatment is performed 3 times.

[0011] In step S1, the ultrasonic treatment conditions are 500W, 20kHz, and 60% power.

[0012] The beneficial effects of this invention are: the method of this invention conducts correlation analysis with key variables such as gel performance and aggregate type and dynamic conversion ratio of water molecules. By constructing a quantitative structure-activity relationship among aggregate type, water molecule migration behavior and gel water retention, it clarifies how different initial aggregates determine the microscopic mechanism of their thermal aggregation behavior and gel quality by regulating the binding state and migration path of water molecules. Attached Figure Description

[0013] Figure 1 This is a water-holding capacity distribution diagram of different aggregates measured in an embodiment of the present invention; Figure 2 Electron micrographs of spherical aggregates, amorphous aggregates, and fibrous aggregates of gels as determined in embodiments of the present invention; Figure 3 The heatmap shows the correlation analysis of the structural characteristics, water distribution, and gel water-holding capacity of different myosin aggregates measured in the embodiments of the present invention. Detailed Implementation

[0014] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments.

[0015] Example: This invention provides a method for regulating the gel properties of low-salt minced meat based on myosin aggregates undergoing dynamic water molecule conversion, comprising the following steps: S1. Preparation of myosin: The extracted myofibrillar protein was dialyzed in phosphate buffer with a concentration of 0.2M NaCl, and the dialysate was changed every 7 hours for 3 dialyzing cycles. The protein was then sonicated for 3-6 minutes to purify it into myosin. The sonication conditions were 500W, 20kHz, and 60% power.

[0016] The phosphate buffer also contains 20 mM KH2PO4 / K2HPO4 and 10 mM EDTA-Na2, with a pH of 6.5.

[0017] S2, Thermal induction of myosin aggregates: The myosin treated by ultrasound in step S1 was linearly thermally induced to aggregate at a temperature of 25℃~85℃ to construct three types of myosin aggregates: spherical aggregates, amorphous aggregates, and fibrous aggregates.

[0018] S3. Relationship between aggregate type, water molecule migration behavior, and gel water retention: The three myosin aggregates constructed in step S2 above were heated at 85°C for 20 minutes to form a gel. The water-holding capacity (WHC) of the gel and the ratio of non-flowing water (T) 22 A significant positive correlation was observed, r = 0.795, p < 0.01; The water-holding capacity (WHC) of the gel and the ratio of free water (T) 23 A significant negative correlation was observed, r = -0.867, p < 0.001; The water-holding capacity (WHC) of the gel was significantly negatively correlated with the protein molecule aggregation size (Size), r = -0.839, p < 0.01; and significantly negatively correlated with the weight-average molecular weight (Mw), r = -0.797, p < 0.01. The water-holding capacity (WHC) of the gel was positively correlated with the surface hydrophobicity, r=0.62, p<0.05.

[0019] The water-holding capacity, gel strength, and microstructure of the gel were experimentally determined.

[0020] like Figure 1 As shown, the water-holding capacity test results indicate that the gel formed by fibrous aggregates has a water-holding capacity comparable to the control group myosin gel at a normal salt concentration (0.6M NaCl). In contrast, the water-holding capacity of the globular aggregate gel is significantly reduced, while the water-holding capacity of the amorphous aggregate gel is the lowest. This functional difference is directly attributed to the difference in their microstructure.

[0021] like Figure 2 As shown, scanning electron microscopy (SEM) revealed that the fibrous aggregate gel exhibits a uniform and coherent three-dimensional network structure with small and evenly distributed pores. This regular porous structure can efficiently bind water through capillary action and surface tension. The spherical aggregate gel forms an adhesive but discontinuous layered structure with poor network integrity, resulting in limited water retention. The amorphous aggregate gel, on the other hand, exhibits a dense, irregular mass accumulation, lacking effective water-holding pores and a connected network, thus exhibiting the worst water retention.

[0022] like Figure 3 As shown, the results indicate that the water-holding capacity (WHC) of the gel and the proportion of non-flowing water (T) are related. 22 It showed a significant positive correlation (r=0.795, p<0.01), while it was significantly positively correlated with the proportion of free water T. 23 A significant negative correlation was observed (r = -0.867, p < 0.001). This indicates that the state distribution (dynamic transformation) of water molecules is the core microscopic mechanism determining the final water-retention performance of the gel. The higher the proportion of "non-flowing water" effectively bound by the protein network in the system, the lower the proportion of freely flowing "free water," and the better the gel's water retention. Furthermore, water retention capacity was significantly negatively correlated with protein molecule aggregation size and weight-average molecular weight (Mw) (r = -0.839, p < 0.01; r = -0.797, p < 0.01), while it was positively correlated with surface hydrophobicity (BPB binding rate) (r = 0.62, p < 0.05). Initially formed, uniformly sized and ordered small unit aggregates (such as fibrous structures) can construct a dense and uniform network through sufficient and ordered hydrophobic interactions during thermal processes. This network can maximize the conversion of water molecules into bound "non-flowing water," ultimately achieving excellent water retention. Conversely, initially disordered large aggregates (such as amorphous aggregates) form a coarse, discontinuous network that mainly encapsulates "free water," resulting in poor water retention.

[0023] The method of this invention performs correlation analysis with key variables such as gel properties and aggregate type and dynamic conversion ratio of water molecules. By constructing a quantitative structure-activity relationship among aggregate type, water molecule migration behavior and gel water retention, it elucidates how different initial aggregates determine the microscopic mechanism of thermal aggregation behavior and gel quality by regulating the binding state and migration path of water molecules.

[0024] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for regulating the gel properties of low-salt minced meat based on myosin aggregates undergoing dynamic water molecule conversion, characterized in that: Includes the following steps: S1. Preparation of myosin: The extracted myofibrillar protein was dialyzed in phosphate buffer with a concentration of 0.2M NaCl and then sonicated for 3-6 minutes to obtain myosin after purification. S2, Thermal induction of myosin aggregates: The myosin treated by ultrasound in step S1 above was linearly thermally induced to aggregate at a temperature of 25℃~85℃ to construct three types of myosin aggregates: spherical aggregates, amorphous aggregates, and fibrous aggregates. S3. Relationship between aggregate type, water molecule migration behavior, and gel water retention: The three myosin aggregates constructed in step S2 above were heated at 85°C for 20 minutes to form a gel. The water-holding capacity (WHC) of the gel and the ratio of non-flowing water (T) 22 A significant positive correlation was observed, r = 0.795, p < 0.01; The water-holding capacity (WHC) of the gel and the ratio of free water (T) 23 A significant negative correlation was observed, r = -0.867, p < 0.001; The water-holding capacity (WHC) of the gel was significantly negatively correlated with the protein molecule aggregation size (Size), r = -0.839, p < 0.01; and significantly negatively correlated with the weight-average molecular weight (Mw), r = -0.797, p < 0.

01. The water-holding capacity (WHC) of the gel was positively correlated with the surface hydrophobicity, r=0.62, p<0.

05.

2. The method for regulating the gel properties of low-salt minced meat based on myosin aggregates undergoing dynamic water molecule conversion according to claim 1, characterized in that: In step S1, the phosphate buffer also contains 20 mM KH2PO4 / K2HPO4 and 10 mM EDTA-Na2, with a pH of 6.

5.

3. The method for regulating the gel properties of low-salt minced meat based on myosin aggregates undergoing dynamic water molecule conversion according to claim 1, characterized in that: In step S1, the dialysate is changed every 7 hours during the low-salt dialysis treatment, and the dialysis treatment is performed 3 times.

4. The method for regulating the gel properties of low-salt minced meat based on myosin aggregates undergoing dynamic water molecule conversion according to claim 1, characterized in that: In step S1, the ultrasonic treatment conditions are 500W, 20kHz, and 60% power.

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