A polyphenol additive for improving the frozen storage quality of unwashed surimi and its application

Abstract

A polyphenol additive for improving the frozen storage quality of unwashed surimi and its application. The polyphenol additive for improving the frozen storage quality of unwashed surimi has active ingredients including polyphenols that can inhibit the activity of acid phosphatase, polyphenols that can inhibit the activity of adenosine deaminase, and polyphenols that can inhibit the activity of xanthine oxidase. The present invention also includes the application of the polyphenol additive for improving the frozen storage quality of unwashed surimi. The present invention can effectively reduce the contents of inosine and hypoxanthine in frozen unwashed surimi, delay the increase of K value, and improve the gel strength of frozen unwashed surimi. The usage method is simple and the application range is wide. It is derived from edible plants and has high safety. The product has low cost, simple processing technology, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to an additive for improving the frozen storage quality of unwashed surimi and its application, and specifically relates to a polyphenol additive for improving the frozen storage quality of unwashed surimi and its application. Background Art

[0002] Frozen surimi is deeply loved by people because of its convenient consumption and high nutritional value. The traditional frozen surimi production process includes processes such as mechanical mincing, washing, dehydration, and frozen storage. Washing can improve the frozen storage quality of surimi and extend the shelf life. However, after multiple washings, a large amount of fat and protein are lost, the nutritional value is reduced, and a large amount of wastewater is generated. Unwashed surimi has a higher surimi yield because there is no washing process, and the nutritional components of fish meat are retained. But also because of no washing, a large amount of metabolic enzymes remain in the surimi, causing rapid degradation of substances such as proteins, fats, and ATP in the fish meat, and the quality deteriorates; specifically, it is manifested as an increase in the K value and a decrease in gel strength during frozen storage.

[0003] The K value is the percentage of the sum of the degradation products of adenosine triphosphate (ATP), hypoxanthine riboside (HxR) and hypoxanthine (Hx) to the total amount of ATP-related compounds (ATP + ADP + AMP + IMP + HxR + Hx). The K value is generally positively correlated with the storage time of fish meat and is a recognized freshness index. At the same time, since HxR and Hx have a bitter taste, while ADP, AMP, and IMP have a umami taste, the K value can also characterize the taste quality of fish meat.

[0004] Improving the frozen storage quality of unwashed surimi has become an urgent need in the industry. There are many studies on improving the gel strength of unwashed surimi. For example, the research by Bao Jiatong et al. shows that the gel strength of unwashed surimi added with 6% tapioca starch is the best, and the gel strength is increased by 758.08 g·mm (Bao Jiatong, Ning Yunxia, Yang Qiyue, et al. Effects of different starch types on the gel properties of unwashed Clarias gariepinus surimi [J]. Meat Research, 2020, 34(4): 27-33.). Bao Yirui et al. found that adding 0.08 mol / L Ca 2+ can significantly improve the gel strength of unwashed surimi (Bao Yirui, Wu Yanyan, Zhao Qiancheng, Wang Yueqi. Effects of calcium ion addition amount on the gel properties of unwashed sea bass surimi [J]. Fishery Modernization, 2021, 48(4): 106-112.)

[0005] Although the above methods have improved the gel strength of unwashed surimi, there is still no effective method to delay the increase in the K value and the decline in taste quality of unwashed surimi. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the above-mentioned defects existing in the prior art and provide a polyphenol additive that can delay the increase of K value, improve the gel strength of unfrozen washed surimi, and improve the frozen storage quality of unfrozen washed surimi and its application.

[0007] The technical solution adopted by the present invention to solve its technical problems is as follows: A polyphenol additive that can improve the frozen storage quality of unfrozen washed surimi, and the active ingredients include polyphenols that can inhibit the activity of acid phosphatase, polyphenols that can inhibit the activity of adenosine deaminase, and polyphenols that can inhibit the activity of xanthine oxidase.

[0008] Preferably, the binding energy of the polyphenol that can inhibit the activity of acid phosphatase docked with acid phosphatase molecules is lower than -7.8 kcal / mol.

[0009] Preferably, the binding energy of the polyphenol that can inhibit the activity of adenosine deaminase docked with adenosine deaminase molecules is lower than -10 kcal / mol.

[0010] Preferably, the binding energy of the polyphenol that can inhibit the activity of xanthine oxidase docked with xanthine oxidase molecules is lower than -9 kcal / mol.

[0011] Preferably, the active ingredient is a polyphenol that can simultaneously inhibit the activities of acid phosphatase, adenosine deaminase, and xanthine oxidase.

[0012] Preferably, it is obtained by extracting the crushed raw materials, collecting the filtrate, and removing the solvent.

[0013] Preferably, the extractant is water or an ethanol solution with a volume concentration ≤ 75%.

[0014] Preferably, the polyphenol additive that can improve the frozen storage quality of unfrozen washed surimi is extracted from edible plants.

[0015] Preferably, the edible plant is one or more of grape skin, pomegranate skin, olive leaf, pomelo peel, sesame, oats, rosemary, strawberry, blueberry, mint, verbena, turmeric, lotus seed, and tea seed.

[0016] Preferably, the functional components include one or more of punicalagin, procyanidin trimer EEC, naringin 6'-malonic acid, procyanidin dimer B2, procyanidin dimer B3, isocoumarin, lariciresinol-sesquilignan, diosmin, demethyloleuropein, rhoifolin, oleuropein, 2-S-glutathione caffeic acid, procyanidin dimer B1, neohesperidin, narirutin, chuanxiong glycoside, (-)-epicatechin-O-gallate, sesamol, fraxiresinol, 7-hydroxypinoresinol, 7-oxopinoresinol, arctigenin, curcumin, nobiletin, dimethylmatairesinol, poncirin, wikstroemol, sesaminolin, isohydroxymatairesinol, sesamin, salvianol, piceatannol, (+)-sesaminol, rosmarinic acid, genistein, (±)-pinoresinol, 5,6-dihydroxy-7,8,3',4'-tetramethoxyflavone, 3-methoxyflavone, bisdemethoxycurcumin, isosesamin, sesamin, demethoxycurcumin, oleuropeigenin, 5,6-dihydroxy-7,8,3,4-tetramethoxyflavone, 5-O-galloylquinic acid, rosmaridiphenol, 5-p-coumaroylquinic acid, 3'-methoxythricetin, 5-nonadecylresorcinol, avenanthramide 2f, oleoside-11-methyl ester, avenanthramide 2c, paeoniflorin, feruloyl tartaric acid, 3,4-dihydroxyphenethyl acrylate dialdehyde, eupafolin, avenanthramide K, [6]-gingerol, pelargonidin chloride, cyanidin, oleocanthal, avenanthramide 2p, (+)-gallocatechin, caffeoyl tartaric acid, morin, 6-methoxygartanin, neochlorogenic acid, anthocyanin, p-coumaroyl tartaric acid.

[0017] Theoretical simulation software such as Auto Dock and Auto Dock-Vina can be used to perform molecular docking of polyphenol monomers with acid phosphatase (PDB ID 1D2T, http: / / www.rcsb.org / ), adenosine deaminase (PDB ID 1VFL, http: / / www.rcsb.org / ), and xanthine oxidase (PDB ID 1FIQ, http: / / www.rcsb.org / ). Based on the calculated binding energy, polyphenols can be screened theoretically or the experimental results can be interpreted. Table 1 lists the calculation results of the preferred schemes of the functional components.

[0018] Table 1 Molecular docking results of some polyphenols with acid phosphatase, adenosine deaminase, and xanthine oxidase

[0019]

[0020]

[0021]

[0022] The polyphenol additive of the present invention can effectively inhibit the activities of acid phosphatase, adenosine deaminase and xanthine oxidase, reduce the hydrolysis rate of inosinic acid, and decrease the production of hypoxanthine, inosine and uric acid; adding a small amount of the polyphenol additive prepared by the method of the present invention to unwashed surimi can effectively delay the increase of the K value of unwashed surimi and improve the frozen storage quality of unwashed surimi.

[0023] Application of the polyphenol additive that can improve the frozen storage quality of unwashed surimi of the present invention, mixing the polyphenol additive that can improve the frozen storage quality of unwashed surimi with unwashed surimi evenly to obtain non-washed surimi, and making surimi products according to the production method using washed surimi as raw material.

[0024] Advantages of the present invention:

[0025] 1. The present invention can effectively reduce the contents of inosine and hypoxanthine in frozen unwashed surimi, delay the increase of the K value, and improve the gel strength of frozen unwashed surimi;

[0026] 2. The method of the present invention is simple to use and has a wide application range; it is derived from edible plants and has high safety;

[0027] 3. The product of the present invention has low cost and simple processing technology, and is suitable for industrial production. Description of the Drawings

[0028] Figure 1 is the concentration diagram of ATP, ADP and AMP of the surimi in Example 1 and Comparative Example 1 of the present invention.

[0029] Figure 2 is the concentration diagram of IMP, HxR and Hx of the surimi in Example 1 and Comparative Example 1 of the present invention.

[0030] Figure 3 is the K value and gel strength diagram of the surimi in Example 1 and Comparative Example 1 of the present invention.

[0031] Figure 4 is the concentration diagram of ATP, ADP and AMP of the surimi in Example 2 and Comparative Example 2 of the present invention.

[0032] Figure 5 is the concentration diagram of IMP, HxR and Hx of the surimi in Example 2 and Comparative Example 2 of the present invention.

[0033] Figure 6 is the K value and gel strength diagram of the surimi in Example 2 and Comparative Example 2 of the present invention.

[0034] Figure 7 is the concentration diagram of ATP, ADP and AMP of the surimi in Example 3 and Comparative Example 3 of the present invention.

[0035] Figure 8It is the graphs of IMP, HxR, and Hx concentrations of surimi in Example 3 and Comparative Example 3 of the present invention.

[0036] Figure 9 It is the graphs of K value and gel strength of surimi in Example 3 and Comparative Example 3 of the present invention. Detailed implementation manners

[0037] The present invention will be further described below in conjunction with examples and drawings.

[0038] The raw materials used in the examples of the present invention are all obtained through conventional commercial channels.

[0039] The methods for measuring the content of ATP and its related substances in unwashed surimi and calculating the K value in each example and comparative example are as follows.

[0040] Sample treatment. After adding or not adding polyphenol additives to the unwashed surimi, it is frozen at -20 °C for 23 h and thawed at room temperature for 1 h. The freeze-thaw cycle is repeated 3 times for the surimi to be measured; 5 g of the sample is taken from the surimi to be measured, 10 mL of pre-cooled 5% perchloric acid solution is added, homogenized and pre-cooled for 10 min, centrifuged at 2900 g for 5 min, and the supernatant is taken; the precipitate is washed with 5% perchloric acid and centrifuged again to take the supernatant; the supernatants are combined, the pH value is adjusted to 6.4 - 6.5 with saturated NaOH solution, left standing for 5 min, filtered and added to a 50 mL volumetric flask, and made up to the mark with ultrapure water, and passed through a 0.45 μm membrane for use.

[0041] Determination of K value by chromatography. The chromatographic conditions are modified according to the Scherer method: chromatographic column AQ-C18 (4.6 mm × 150 mm), particle size 5 μm, mobile phase A is a buffer solution of 0.02 mol / L KH2PO4 - 0.02 mol / L KH2PO4 (pH = 6.78), flow rate is 0.97 mL / min; mobile phase B is methanol, flow rate 0.03 mL / min; column temperature 40 °C, detection wavelength 254 nm, injection volume 20 μL. The types of ATP-related substances are determined by retention time, and their contents are determined in combination with the peak areas. The K value is obtained from the following formula:

[0042] K = [(HxR + Hx) / (ATP + ADP + AMP + IMP + HxR + Hx)] × 100%

[0043] In the formula, ATP, ADP, AMP, IMP, HxR, and Hx are the concentrations of the corresponding substances, expressed in mg / kg.

[0044] The methods for measuring the gel strength in each example and comparative example are as follows.

[0045] Sample preparation. The unfrozen grass carp surimi samples were thawed at 4 °C until the central temperature reached -3 to -5 °C, then chopped in a chopper for 2 min without adding any ingredients at a temperature below 10 °C, and then chopped with 3% salt for 4 min. The water content in the surimi was controlled at 78%. During chopping, polyphenol additives (polyphenol extracts) were added or not added to the surimi. The chopped surimi was filled into plastic casings with a diameter of 30 mm and gelled at 90 °C for 30 min. Then it was immediately cooled to room temperature with tap water, left standing at 4 °C for 24 h, and then left standing at room temperature for 2 h for further testing.

[0046] Gel strength test. A S / 0.5 probe was used to conduct a breaking test with a texture analyzer at room temperature. The specific test parameters were as follows: pre-test speed 3.0 mm / s, test speed 1.0 m / s, post-test speed 10.0 mm / s, deformation 15 mm, and induction force 0.049 N. Among them, the breaking force (g) reflects the hardness of the gel, the breaking distance (cm) reflects the elasticity of the gel, and the gel strength (g·cm) is the product of the two. Each sample was tested 6 times and the average value was taken.

[0047] Example 1

[0048] In this example, punicalagin was used as the active ingredient of the polyphenol additive that can improve the frozen storage quality of unfrozen surimi. The binding energies of punicalagin with acid phosphatase, adenosine deaminase, and xanthine oxidase obtained by molecular docking were -20.1 kcal / mol, -25.1 kcal / mol, and -17.7 kcal / mol, respectively (see Table 1), indicating that punicalagin has good inhibitory effects on acid phosphatase, adenosine deaminase, and xanthine oxidase.

[0049] The content of punicalagin in pomegranate peel is relatively high. In this example, pomegranate peel was selected as the raw material for the extraction of polyphenol additives: the dry pomegranate peel was crushed by a pulverizer and then extracted with pure water. The filtrate was collected, concentrated, and dried to obtain pomegranate peel polyphenol extract. The polyphenol content in the pomegranate peel polyphenol extract was determined to be 49.4% by the Folin-Ciocalteu method.

[0050] The obtained pomegranate peel polyphenol additive was applied to the processing of unfrozen surimi, and 0.5 g of pomegranate peel polyphenol extract was used per 100 g of surimi. The K value and gel strength were calculated according to the test method described above. The test results are shown in Figures 1 to 3 , and the "pomegranate" group corresponds to Example 1. In the unfrozen surimi added with 0.5% pomegranate peel polyphenol extract, the release of inosine and hypoxanthine was significantly slower. After 3 freeze-thaw cycles, the K value of the unfrozen surimi added with 0.5% pomegranate peel polyphenol extract was 8.08%, and the gel strength was 71.0 g·cm.

[0051] Comparative Example 1

[0052] This comparative example uses the same unwashed surimi as in Example 1, without adding polyphenol additives, and calculates the K value and gel strength according to the test method described above. The K value of the unwashed surimi was measured to be 16.55%, and the gel strength was 52.7 g·cm. The specific test results are shown in Figures 1 to 3 , and the "blank" group corresponds to Comparative Example 1.

[0053] Example 2

[0054] This example uses oleuropein as the active ingredient of the polyphenol additive that can improve the frozen storage quality of unwashed surimi. The binding energies of oleuropein with acid phosphatase, adenosine deaminase, and xanthine oxidase in molecular docking reach -11.1 kcal / moL, -14.3 kcal / moL, and -11.0 kcal / moL (see Table 1), and it has good inhibitory effects on acid phosphatase, adenosine deaminase, and xanthine oxidase.

[0055] Oleuropein has a relatively high content in olive leaves. In this example, olive leaves were selected as the raw material for the extraction of polyphenol additives: the dry olive leaves were crushed by a pulverizer and extracted with pure water, and the filtrate was collected and concentrated and dried to obtain the olive leaf polyphenol extract. The polyphenol content in the olive leaf polyphenol extract was determined to be 10.1% by the Folin-Ciocalteu method.

[0056] The obtained olive leaf polyphenol additive was applied to the processing of unwashed surimi, and 0.5 g of olive leaf polyphenol additive was used per 100 g of surimi. The K value and gel strength were calculated according to the test method described above. The test results are shown in Figures 4 to 6 , and the "olive" group corresponds to Example 2. The K value of the unwashed surimi added with 0.5% olive leaf polyphenol extract was 11.84%, and the gel strength was 103.5 g·cm.

[0057] Comparative Example 2

[0058] This comparative example uses the same unwashed surimi as in Example 2, without adding polyphenol additives, and calculates the K value and gel strength according to the test method described above. The K value of the unwashed surimi was measured to be 16.55%, and the gel strength was 52.7 g·cm. The specific test results are shown in Figures 4 to 6 , and the "blank" group corresponds to Comparative Example 2.

[0059] Example 3

[0060] This example uses caffeoyl tartaric acid as the active ingredient of the polyphenol additive that can improve the frozen storage quality of unwashed surimi. The binding energies of caffeoyl tartaric acid with acid phosphatase, adenosine deaminase, and xanthine oxidase in molecular docking reach -8.1 kcal / moL, -10.4 kcal / moL, and -9.0 kcal / moL (see Table 1), and it has good inhibitory effects on acid phosphatase, adenosine deaminase, and xanthine oxidase.

[0061] The content of caffeoyl tartaric acid in grape skins is relatively high. In this example, grape skins were selected as the raw material for the extraction of polyphenol additives: the dried grape skins were crushed by a crusher and extracted with pure water, and the filtrate was collected and concentrated and dried to obtain grape skin polyphenol extract. The polyphenol content in the grape skin polyphenol extract was determined by the Folin-Ciocalteu method to be 57.5%.

[0062] The obtained grape skin polyphenol additive was applied to the processing of unwashed surimi, and 0.5 g of grape skin polyphenol additive was used per 100 g of surimi. The K value and gel strength were calculated according to the test method described above. The test results are shown in Figures 7 to 9 ,"Grape" group corresponds to Example 3. The K value of the unwashed surimi added with 0.5% grape skin polyphenol extract was 13.71%, and the gel strength was 75.3 g·cm.

[0063] Comparative Example 3

[0064] In this comparative example, the same unwashed surimi as in Example 3 was used, and no polyphenol additive was added. The K value and gel strength were calculated according to the test method described above. The measured K value of the unwashed surimi was 16.55%, and the gel strength was 52.7 g·cm. The specific test results are shown in Figures 7 to 9 ,"Blank" group corresponds to Comparative Example 3.

Claims

1. Application of punicalagin, oleuropein or caffeoyl tartaric acid in delaying the increase of K value of frozen storage non-rinsed surimi, and the specific method is to mix the punicalagin, oleuropein or caffeoyl tartaric acid with non-rinsed surimi evenly to obtain non-rinsed surimi, and produce surimi products according to the production method using rinsed surimi as raw material.

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