Application of capsaicin in improving fish meat quality

Abstract

The invention discloses an application of capsaicin in improving fish meat quality, and belongs to the technical field of aquaculture. The improvement of the fish meat quality by capsaicin is realized by improving the meat yield, increasing the crude protein content, slowing down the pH decreasing amplitude, reducing the cooking loss, improving the hardness, improving the freshness, increasing the sweet taste and the salty taste, inhibiting the generation of methyl mercaptan and ethanethiol, promoting the synthesis of fresh flavor substances, increasing the contents of ATP, Ca < 2 + >-Mg < 2 + >-ATPase, creatine kinase, HK and glycogen and reducing the lactic acid content. By adding low-dose capsaicin into the fish feed for feeding fish, the flavor quality of aquatic products can be effectively improved, and technical support is provided for application of low-dose natural additives in the field of aquatic product preservation and aroma enhancement.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, specifically to the application of capsaicin in improving fish meat quality. Background Technology

[0002] Fish products have high nutritional value and are an important source of meat for improving dietary structure and enhancing human health. With increasing health awareness, consumers are demanding higher quality aquatic products. However, current intensive aquaculture practices are causing major farmed species like grass carp to face risks of quality degradation, such as loose muscle tissue and loss of flavor compounds, creating a significant supply-demand gap with the growing demand for high-elasticity texture and delicious taste in the context of consumption upgrading. Therefore, breakthroughs in key technologies for muscle quality control under intensive aquaculture are not only crucial for consumers' nutritional satisfaction but also a core driving force for the transformation of the aquaculture industry from "quantity-first" to "quality-led."

[0003] Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), molecular formula C 18 H 27 NO3, with a molecular weight of 305.4 kDa, is a volatile, hydrophobic, tasteless, colorless alkaloid that crystallizes into a waxy state. It possesses pungent, antibacterial, antioxidant, antiviral, anticancer, and digestive-promoting properties. Currently, capsaicin is used as an anticancer agent, antioxidant, food additive (primarily for providing spiciness), dietary supplement, local analgesic, and anti-inflammatory drug. However, there are almost no reports on capsaicin's ability to enhance the muscle quality of fish. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the existing technology, the purpose of this invention is to provide an application of capsaicin in improving the quality of fish meat.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: providing an application of capsaicin in improving the quality of fish meat.

[0006] Furthermore, improving fish meat quality involves increasing meat yield, crude protein content, slowing down pH decline, reducing cooking losses, improving firmness, enhancing freshness, increasing sweetness and saltiness, inhibiting the formation of methanethiol and ethanethiol, promoting the synthesis of fresh flavor compounds, and increasing ATP and calcium levels. 2＋ -Mg 2＋ This is achieved by reducing lactate levels, including ATPase, creatine kinase, HK, and glycogen content.

[0007] Furthermore, the fresh flavoring substances are propionaldehyde, acetone, 2-propanol, 2,3-butanedione, 2-butanol, heptane, hexanal, dimethyl sulfide, diisopropyl ether, acetic acid, 1-penten-3-ol, 1,2-dibromoethane, 3-methylbutanal, thiophene, 2-hexanol, formic acid, trichloroethylene, (Z)-3-hexenal, methyl acrylate, and methyl propionate.

[0008] Furthermore, the above application involves adding capsaicin as an additive to fish feed.

[0009] Furthermore, the fish feed comprises the following components by weight percentage: 3% fishmeal, 3% rapeseed meal, 14% soybean meal, 22.15% dephenolized cottonseed protein, 28% α-starch, 17.085% wheat flour, 2.65% fish oil, 1.38% soybean oil, 1.5% calcium dihydrogen phosphate, 2% microcrystalline cellulose, 0.015% butylated hydroxyanisole, 0.22% L-threonine, and 5% compound premix.

[0010] Furthermore, the amount of capsaicin added is 1.2-1.8 mg per kilogram of fish feed, replacing the corresponding mass of microcrystalline cellulose in the fish feed. Preferably, the amount of capsaicin added is 1.2 mg per kilogram of fish feed, replacing the corresponding mass of microcrystalline cellulose in the basal diet.

[0011] A fish feed for improving fish meat quality, the feed includes capsaicin.

[0012] The present invention has the following beneficial effects: Capsaicin significantly improves the flavor characteristics of grass carp muscle by inhibiting the formation of sulfur-containing compounds (methanethiol / ethanethiol) and promoting the synthesis of esters, aldehydes, and ketones, thus enhancing their fresh flavor profile. Capsaicin also generally reduces the RSD value of volatile substance release, indicating its ability to enhance flavor stability. Adding low doses of capsaicin to fish feed effectively improves the flavor quality of aquatic products, providing technical support for the application of low-dose natural additives in the preservation and flavor enhancement of aquatic products. Attached Figure Description

[0013] Figure 1 The results show the effect of capsaicin on the collagen content in the muscle of grass carp during the later stages of growth.

[0014] Figure 2 Comparison of grass carp flesh color between the basic feed group and the feed group of the present invention.

[0015] Figure 3 The figure shows the results of principal component analysis (PCA) in grass carp muscle.

[0016] Figure 4 This is a comparison chart of the peak values ​​of sensors with a discrimination capability of 0.8 or higher between the control group and the feed group of the present invention.

[0017] Figure 5 The images show the morphological structure of grass carp muscle mitochondria in the control group and the experimental group under high-power transmission microscopes (×4000 and ×12000). Detailed Implementation

[0018] The examples given below are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, conditions in the examples are performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0019] Example 1: This embodiment studies the effect of capsaicin on the muscle quality of grass carp. The specific process is as follows: I. Experimental Grouping and Experimental Feed Formulation One hundred and eighty healthy grass carp with an average weight of 317 g were selected and randomly divided into two treatment groups: a control group and a capsaicin-added group (the feed group of this invention). Each group was treated in three replicates, with 30 fish per replicate. The fish were fed a basal diet and the feed diet of this invention, respectively.

[0020] The basal diet was formulated according to the nutritional standards for grass carp compound feed (GB / T 36205-2018), and its composition and nutrient levels are shown in Table 1: Table 1 Basic Diet for Grass Carp

[0021] Note: 5% of the compound premix provides the vitamins and trace elements needed for grass carp growth.

[0022] The feed diet of this invention replaces the corresponding mass of microcrystalline cellulose in the basal diet with 1.2 or 1.8 mg capsaicin per 1 kg of feed.

[0023] The above feed preparation process is as follows: During preparation, each feed ingredient is crushed until it passes through a 40-mesh sieve and less than 20% of the material passes through a 60-mesh sieve. The ingredients are then mixed in proportion and stirred evenly to form hard pellets with a diameter of 2 mm and a length of 3 mm. After air-drying at room temperature, the pellets are stored in a refrigerator at 4°C for later use.

[0024] II. Feeding Methods Grass carp were raised in 2.0 m × 2.0 m × 2.0 m net cages for 63 days. They were fed four times daily at 7:00, 11:00, 15:00, and 19:00, with the amount gradually increased according to the principle of feeding to satiety, approximately 3-4% of their body weight. During the experiment, the water temperature and pH were maintained at 25.8±2.1℃ and 7.5±0.2, respectively, and dissolved oxygen was maintained at ≥6 mg / L. After the feeding experiment, feeding was stopped for 24 hours, and the fish were anesthetized with ethyl aminobenzoate. The fish were weighed per cage. The average final weight of the basal feed group was 1164.67 g, and the average final weight of the feed group of this invention was 1325.67 g, both at the market weight stage (1-1.5 kg).

[0025] III. Indicator Testing 1. Determination of meat yield and muscle composition The moisture, crude protein, and crude fat content of the muscle samples were determined according to the AOAC (2005) standard method. The results are shown in Table 2. Feeding grass carp with the capsaicin-added feed of this invention increased meat yield by 2.7%, decreased muscle moisture by 4.8%, and increased muscle crude protein by 13.8%. This indicates that capsaicin can significantly improve meat yield and crude protein levels, thereby enhancing the commercial performance of grass carp.

[0026] Table 2. Effects of capsaicin on meat yield and muscle composition of grass carp

[0027] 2. Determination of physical and chemical properties Fish meat, as the main edible part, has key physicochemical properties such as pH value, cooking loss, hardness, and freshness (K value) as indicators for evaluating meat quality.

[0028] pH value is directly related to the freshness of fish. Changes in pH value directly affect the tenderness, water-holding capacity, and other qualities of the meat. A rapid drop in pH value causes muscle proteins to denature and coagulate, thus losing their water-retaining ability and affecting the firmness and tenderness of the meat. Cooking loss refers to the percentage by weight of water and soluble substances lost by fish during heating. The lower the cooking loss value, the better the quality of the fish. Firmness refers to the force required for muscle to maintain its shape under compression. A texture analyzer can be used to measure the physical properties of a muscle sample, thus reflecting changes in meat quality. K value is an important indicator of fish flavor and freshness. K value represents the ratio of HxR and Hx content to the content of ATP-related compounds. The lower the K value, the fresher the meat and the better the taste.

[0029] When measuring pH, muscle samples were placed on ice and the pH of the muscle was measured at 0 hours and 24 hours using a calibrated pH meter (Testo 205 pH meter, Testo AG Company, Lenzkirch, Germany).

[0030] To determine cooking loss, the muscle sample was heated in a 70°C water bath for 20 minutes, and the weight of the muscle sample before and after heating was recorded and calculated.

[0031] Muscle stiffness and other textural parameters were measured using the TPA method in a texture analyzer (CTX, USA).

[0032] The freshness K-value was determined using a meat freshness meter (MFT-2, Beijing, China).

[0033] The test results are shown in Table 3. As can be seen from Table 3, feeding grass carp with the feed containing capsaicin of this invention can significantly improve the physicochemical properties of grass carp muscle. Specifically, the rate of decrease in pH from 0 hours to 24 hours is slowed down by 50%; cooking loss is reduced by 20.5%; hardness is increased by 54.2%; and muscle K value is reduced by 45.6% (the lower the K value, the higher the freshness), thus improving freshness.

[0034] Table 3. Effects of capsaicin on the muscle quality of grass carp

[0035] The firmness of fish flesh is closely related to its collagen content. The main functions of collagen in food include improving skin elasticity, promoting tissue repair, and improving joint health. Compared with collagen from other sources, fish collagen has a smaller molecular weight, making it easier for the human body to absorb and utilize. The collagen content in grass carp muscle is approximately 3-10% (accounting for a percentage of total muscle protein), and Sirius red staining makes the collagen fibers appear red. Therefore, this invention uses the Sirius red staining method to determine the collagen content in grass carp muscle. The specific steps are as follows: After hydration and dewaxing of paraffin-embedded samples, 5 μm sections are prepared, dried at 60℃, dehydrated with graded ethanol, and stained with Sirius red. After microscopic imaging, the area ratio of collagen fibers is quantitatively analyzed using ImageJ software. The results are shown in [Figure number missing]. Figure 1 .

[0036] Depend on Figure 1 It is known that feeding grass carp with the feed containing capsaicin of this invention can significantly increase the collagen content in the grass carp muscle by 28.4%.

[0037] 3. Observe the flesh color By observing the color of grass carp flesh, it can be known that ( Figure 2 The grass carp fed with the basic feed group had dull flesh color, dry and dull surface, loose flesh, and many patterns; while the grass carp fed with the feed group of this invention had bright flesh color, uniform overall appearance, moist surface with a clear luster, semi-transparent cut surface, and firm flesh.

[0038] 4. Taste determination An electronic tongue can convert electronic signals into taste information, thereby eliminating subjective errors in sensory evaluation. The taste of muscle was measured using an electronic tongue (Alpha MOS; ASTREE), whose sensor can respond to different tastes, including umami, sweet, salty, bitter, and sour. The measurement results are shown in Table 4. Table 4 shows that the feed group of this invention can increase the sweetness and saltiness of muscle by 23.9% and 18.6%, respectively; and reduce the bitterness and sourness by 31.9% and 31.1%, respectively.

[0039] Table 4. Effects of capsaicin on the flavor of grass carp muscle in the later stages of growth.

[0040] Note: * indicates a significant difference, P<0.05 5. Odor / Flavor Measurement Odor / flavor was determined using an electronic nose. In this invention, the feed group consisted of replacing the corresponding mass of microcrystalline cellulose in the basal diet with 1.2 mg of capsaicin per 1 kg of feed. The specific determination process is as follows: (1) Data sources and methods The analysis was performed using an ultra-fast gas chromatography electronic nose (Heracles Neo, Alpha MOS, Toulouse, France). This electronic nose utilizes two columns with different polarities: MXT-5 (low polarity) and MXT-1701 (medium polarity). A single injection allows for simultaneous analysis of both columns, with the chromatograms displaying the separation results from both columns simultaneously. Qualitative analysis results and peak area changes were obtained by combining information from the Arochembase database.

[0041] MXT-5 column: This is a nonpolar chromatographic column. Its stationary phase consists of 5% phenyl and 95% dimethylpolysiloxane. It mainly separates compounds based on their boiling points; compounds with lower boiling points elute first, and those with higher boiling points elute later.

[0042] MXT-1701 column: This is a medium-polarity column. Its stationary phase consists of 14% cyanopropylphenyl and 86% dimethylpolysiloxane. Besides boiling point, it is greatly affected by the polarity of the compounds. More polar compounds interact more strongly with the stationary phase, thus resulting in longer retention times.

[0043] Quantitative metrics: mean response (Mean), standard deviation (SD), and relative standard deviation (%RSD) of 6 repeated samples.

[0044] Qualitative basis: preliminary qualitative matching of compounds based on sensor response spectral peaks (peaks with a discrimination capability greater than 80% and peak values ​​greater than 300) (selecting several compounds with the highest correlation coefficient in the sensor combination).

[0045] (2) Core Difference Analysis ① Overall response intensity differences A.MXT-5 sensor The overall response value of the feed group of the present invention was significantly higher than that of the control group, as detailed in Table 5: Key peak (20.65 min) (propionaldehyde, acetone, 2-propanol): The feed group of this invention (12552.63) ≈ 1.9 times that of the control group (6556.99); Key peak (26.25 min) (2,3-butanedione): The feed group of this invention (2077.57) was approximately 1.8 times that of the control group (1136.93).

[0046] Key peak (29.83 min) (2-butanol): The feed group of this invention (2075.16) was approximately 2.5 times that of the control group (846.01).

[0047] Key peak (49.03 min) (heptane): The feed group of this invention (2503.67) was approximately 4.7 times that of the control group (536.10).

[0048] Key peak (78.46 min) (hexanal): The feed group of this invention (4079.93) was approximately 10 times that of the control group (402.46).

[0049] As can be seen from the above, the addition of capsaicin can significantly increase the content of aldehydes, ketones, and alcohols in flavor compounds.

[0050] B.MXT-1701 sensor The feed group of this invention exhibits an extremely strong response at a specific peak, as detailed below: 21.20 min peak (dimethyl sulfide): The feed group of this invention (13323.07) ≈ 5 times the control group (2629.43); Peaks at 22.62 min (diisopropyl ether), 55.54 min (acetic acid), 57.98 min (1-penten-3-ol), and 85.57 min (1,2-dibromoethane): specific responses of the feed group in this invention.

[0051] As can be seen from the above, sulfur-containing / halogenated volatile substances are enriched after capsaicin treatment.

[0052] Table 5 Overall Response Intensity Differences

[0053] ② Changes in the types of characteristic compounds The changes in the types of characteristic compounds are shown in Table 6: Table 6. Changes in the types of characteristic compounds

[0054] ③ Comparison of data stability The feed group of this invention exhibited a lower %RSD: the relative standard deviation of most sensor response values ​​was significantly lower than that of the control group (e.g., the 78.46 min peak of MXT-5: %RSD of the feed group of this invention = 3.50%, %RSD of the control group = 11.23%; the 21.20 min peak of MXT-1701: %RSD of the feed group of this invention = 1.91%, %RSD of the control group = 6.16%). This indicates that capsaicin treatment resulted in a more uniform distribution of volatile substances and improved repeatability.

[0055] Abnormal fluctuations in the control group: some peaks had a %RSD exceeding 45% (e.g., the %RSD of the 43.40 min peak was 223.6%), reflecting the poor stability of the volatile components in the control group.

[0056] ④ Reduced unpleasant odor substances Sulfur-containing compounds significantly inhibited the use of methanethiol (rotten egg / fishy smell), a highly responsive substance in the control group, which was reduced by 42% in the feed group of this invention (MXT-5 18.76-1-A), and the electronic nose response value decreased from 1521.37 to 875.66.

[0057] ⑤ Enhancement of refreshing flavor compounds a. The feed group of this invention specifically detected hexanal (grass / apple scent) and (Z)-3-hexenal (green leaf scent) (MXT-5 78.46-1-A, response value 4079.93), which was 914% higher than the control group (MXT-5 78.46-1-A, response value 402.46).

[0058] b. New esters Methyl acrylate (spicy) and methyl propionate (fruity, rum flavor) appeared only in the feed group of this invention (qualitative correlation > 80%).

[0059] ⑥ Characteristic substance transformation a. Ethanol metabolism The high-response ethanol (sweet) in the control group was converted into acetic acid (pungent, vinegary, MXT-170155.54-2-A response value 794.54) in the feed group of this invention.

[0060] b. Ketone recombination 2,3-Butanedione (caramel flavor, fruit flavor) increased the response level in the feed group of this invention by 83% (2077.57 vs 1136.93).

[0061] (3) Key conclusions and mechanism speculation ① Capsaicin promotes flavor release The feed group of this invention showed a significant increase in the response values ​​of key flavor-related substances such as aldehydes, ketones, sulfides, and organic acids (some by more than 4 times), indicating that capsaicin can effectively promote the release of flavor substances.

[0062] ②Characteristic compound conversion The feed composition of this invention includes the addition of compounds such as thiophene and acetic acid, and the sulfides may shift from simple methanethiol to complex thiophenes (aromatic, garlic-like), which may contribute to the enhancement of the "umami" flavor profile.

[0063] ③ Enhanced data stability The low %RSD value indicates that capsaicin treatment stabilizes the volatile components of fish meat, which is valuable for industrial-scale flavor quality control.

[0064] As shown above, 1.2 mg / kg capsaicin significantly improves the flavor characteristics of grass carp muscle by inhibiting the formation of sulfur-containing compounds (methanethiol / ethanethiol) and promoting the synthesis of esters, aldehydes, and ketones, thus enhancing the flavor profile. The RSD values ​​of volatile substance release in the feed group of this invention were generally reduced by 2-4 percentage points (e.g., MXT-5 78.46-1-A: control group 11.23% → feed group of this invention 3.50%), indicating that capsaicin can enhance flavor stability. This dose of capsaicin treatment can effectively improve the flavor quality of aquatic products, providing technical support for the application of low-dose natural additives in the field of aquatic product preservation and flavor enhancement.

[0065] (4) Results of determination of substance content and types The concentration of a substance is reflected in the peak area; therefore, peak area is used to analyze sample content. After obtaining the peak area and number of different muscle samples using ultra-fast gas chromatography with an electronic nose, peaks with a resolution ≥0.800 and an area ≥300, indicating good separation, are selected as the sensor and identified as the main components for PCA analysis. Higher similarity in the volatile components and their concentrations will result in closer positions on the PCA surface; the magnitude of the difference can be measured by the distance between different samples. Figure 3 It can be seen that the combined contribution of principal component 1 and principal component 2 reaches 99.3115%, therefore, principal component 1 and principal component 2 can well represent the actual situation of the sample. Meanwhile, the discrimination index (DI) is a method used to characterize the degree of discrimination between samples. The effective range of DI values ​​is 80 to 100, and the higher the value, the better the data performance. The DI value in this experiment is 96, indicating that the results are good.

[0066] Furthermore, there were 28 sensor peaks with a discrimination capability of 0.8 or higher. Almost all of these peaks were reached in the feed group of the present invention, and there was a significant difference between the two. This indicates that the feed group of the present invention can enhance the content of flavor compounds in grass carp muscle and has a certain improvement capability.

[0067] Depend on Figure 4 It can be seen that the content and types of compounds identified in the feed group of the present invention are far greater than those in the control group, indicating that the feed group of the present invention can significantly enhance the flavor properties of grass carp muscle.

[0068] 6. Biochemical indicators For ATP, Ca 2＋ -Mg 2＋ - ATPase, creatine kinase, hexokinase (HK), glycogen content, and lactate content were measured. Muscle lactate, ATP, and glycogen content, as well as hexokinase (HK) and creatine kinase activity, were measured according to the kit instructions (Nanjing Jiancheng Biotechnology Research Institute, China, catalog numbers A019-2-1, A095-1-1, A043-1-1, A077-3-1, A032-1-1). Muscle Ca++Mg++-ATPase activity was measured according to the kit description (boxbio, catalog number AKOP002C). The results are shown in Table 7. Table 7 Effects of capsaicin on biochemical parameters of grass carp muscle

[0069] As shown above, capsaicin can effectively increase ATP and calcium levels in grass carp muscle. 2＋ -Mg 2＋ - The content of ATPase, creatine kinase, HK, and glycogen is reduced, and the lactic acid content is decreased, making the fish meat more tender and smooth, with better water retention, more stable texture, clearer texture, and sweeter flavor.

[0070] 7. Microstructure The morphology and structure of mitochondria in grass carp meat were observed using transmission electron microscopy, and the results are shown below. Figure 5 .

[0071] Depend on Figure 5It was found that, compared with the control group, the 1.2 mg / kg capsaicin group had a denser distribution of mitochondria, a significantly increased number of mitochondria per unit area, and the mitochondria were more tightly packed, occupying more cytoplasmic space and exhibiting a more complete and regular morphology. The increased number and enhanced function of mitochondria provide an efficient, stable, and favorable intracellular environment for muscle protein synthesis by providing sufficient ATP energy and regulating key signaling molecules. This greatly benefits and supports protein synthesis, promotes muscle growth, and ultimately affects muscle quality. Strong aerobic metabolic capacity means reduced reliance on anaerobic glycolysis during exercise, thereby reducing lactic acid production and accumulation. Simultaneously, the content and metabolic processes of muscle metabolic substrates (such as glycogen and fat) directly affect the formation of flavor compounds.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Application of capsaicin in improving fish meat quality.

2. The application according to claim 1, characterized in that, Improving fish quality involves increasing meat yield, crude protein content, mitigating pH drop, reducing cooking losses, enhancing firmness, improving freshness, increasing sweetness and saltiness, inhibiting the formation of methanethiol and ethanethiol, promoting the synthesis of fresh flavor compounds, and increasing ATP and calcium levels. 2＋ -Mg 2＋ This is achieved by reducing lactate levels, including ATPase, creatine kinase, HK, and glycogen content.

3. The application according to claim 2, characterized in that, The fresh flavor compounds are propionaldehyde, acetone, 2-propanol, 2,3-butanedione, 2-butanol, heptane, hexanal, dimethyl sulfide, diisopropyl ether, acetic acid, 1-penten-3-ol, 1,2-dibromoethane, 3-methylbutanal, thiophene, 2-hexanol, formic acid, trichloroethylene, (Z)-3-hexenal, methyl acrylate, and methyl propionate.

4. The application according to claim 1, characterized in that, Capsaicin was added as an additive to fish feed.

5. The application according to claim 4, characterized in that, Fish feed comprises the following components by weight percentage: 3% fishmeal, 3% rapeseed meal, 14% soybean meal, 22.15% dephenolized cottonseed protein, 28% α-starch, 17.085% wheat flour, 2.65% fish oil, 1.38% soybean oil, 1.5% calcium dihydrogen phosphate, 2% microcrystalline cellulose, 0.015% butylated hydroxyanisole, 0.22% L-threonine, and 5% compound premix.

6. The application according to claim 5, characterized in that, The amount of capsaicin added is 1.2-1.8 mg per kilogram of fish feed, replacing the corresponding mass of microcrystalline cellulose in the fish feed.

7. The application according to claim 6, characterized in that, The amount of capsaicin added is 1.2 mg per kilogram of fish feed, replacing the corresponding mass of microcrystalline cellulose in the basal diet.

8. A fish feed for improving fish meat quality, characterized in that, The fish feed contains capsaicin.

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