EGCG (epigallocatechin gallate) and beta-lactoglobulin compound, preparation method thereof and application of EGCG and beta-lactoglobulin compound in reducing heterocyclic amine in fried food

Abstract

The invention relates to the technical field of food, in particular to an EGCG (epigallocatechin gallate) and beta-lactoglobulin compound, a preparation method thereof and application of the EGCG and beta-lactoglobulin compound in reducing heterocyclic amine in fried food. The EGCG and beta-lactoglobulin compound is prepared from EGCG and beta-lactoglobulin; the weight ratio of EGCG to beta-lactoglobulin is (5: 1)-(1: 5). The EGCG and the beta-lactoglobulin are compounded to form a stable EGCG and beta-lactoglobulin compound, so that the activity and the stability of polyphenol are effectively improved, and the content of heterocyclic amine in fried food can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the field of food technology, and in particular to an EGCG and beta-lactoglobulin complex, a preparation method thereof, and application thereof in reducing heterocyclic amines in fried foods. Background Art

[0002] Heterocyclic aromatic amines (HAAs) are a class of heterocyclic aromatic hydrocarbon compounds composed of carbon, hydrogen and nitrogen that have carcinogenic and mutagenic properties. Compared with other typical mutagens, heterocyclic amines are more mutagenic, 10 to 100 times more potent than polycyclic aromatic hydrocarbons and nitrites. Early studies have found that heterocyclic amines can induce cancer in multiple organs in animals, and long-term intake of foods containing heterocyclic amines by humans greatly increases their risk of cancer.

[0003] Fried pork balls are one of the traditional delicacies, with golden appearance, delicious taste, convenient and ready-to-eat, and long-lasting storage. However, fried pork balls contain high levels of carbohydrates, fats and proteins, which induce a variety of chemical reactions during frying, including Maillard reaction, lipid oxidation and protein denaturation. These reactions are the main ways to produce flavor characteristics and thermal processing-related hazardous substances during frying, and are also the main inducement for the production of heterocyclic amines.

[0004] Lowering the frying temperature and shortening the frying time are effective means to reduce the formation of heterocyclic amines, but frying at low temperature or for a short time may make the food not crispy enough or not fully cooked, affecting the taste and flavor of the food.

[0005] Adding antioxidants, such as natural extracts or spices such as polyphenols and flavonoids, during frying can reduce the formation of heterocyclic amines by scavenging free radicals and reaction intermediates. The drawback of this method is that it is necessary to ensure that the added antioxidants remain stable during high-temperature frying and do not introduce new harmful substances. In addition, the cost and safety of antioxidants are also factors that need to be considered. Summary of the invention

[0006] The present invention provides an EGCG (epigallocatechin gallate) and β-lactoglobulin complex, a preparation method thereof, and an application thereof in reducing heterocyclic amines in fried foods. The inventors found that after EGCG and β-lactoglobulin are compounded, a stable EGCG and β-lactoglobulin complex is formed, which effectively improves the activity and stability of polyphenols and can effectively reduce the content of heterocyclic amines in fried foods.

[0007] An EGCG and β-lactoglobulin complex comprises EGCG and β-lactoglobulin; wherein the weight ratio of EGCG to β-lactoglobulin is (5:1)-(1:5).

[0008] The present inventors unexpectedly discovered that the complex formed by EGCG and β-lactoglobulin within this ratio range has a synergistic effect in reducing the formation of heterocyclic amines in fried foods, and its effect is much greater than that of using EGCG or β-lactoglobulin alone.

[0009] Preferably, in the EGCG and β-lactoglobulin complex, the weight ratio of EGCG to β-lactoglobulin is (3:1)-(1:3).

[0010] Specifically, in the EGCG and β-lactoglobulin complex, the weight ratio of EGCG to β-lactoglobulin is 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4 or 1:5.

[0011] The inventors have found that when the weight ratio of EGCG to β-lactoglobulin in the EGCG and β-lactoglobulin complex is 1:1, the stability is the highest and the effect of reducing the content of heterocyclic amines in fried foods is the best.

[0012] Preferably, the EGCG and β-lactoglobulin complex is prepared by freeze-drying EGCG and β-lactoglobulin.

[0013] The present invention also provides a method for preparing the EGCG and β-lactoglobulin complex, comprising: preparing EGCG and β-lactoglobulin into solutions respectively, mixing them in proportion, and freeze-drying them.

[0014] In some embodiments, the step of pulverizing after freeze-drying is also included, usually pulverizing into powder.

[0015] The present invention also provides the use of the EGCG and β-lactoglobulin complex in reducing heterocyclic amines in fried foods. The fried foods include fried meat products, fried flour products, fried bean products, fried vegetables, such as fried pork balls, fried dough sticks, fried tofu, fried sweet potatoes, etc.

[0016] The inventors have found that the EGCG and β-lactoglobulin complex has a better effect of reducing heterocyclic amines in fried pork meatballs.

[0017] Generally, the EGCG and β-lactoglobulin complex can be mixed with raw materials of fried food before frying, and then fried.

[0018] The present invention also provides a method for reducing heterocyclic amines in fried food based on the complex of EGCG and beta-lactoglobulin, comprising mixing raw materials of fried food and the complex of EGCG and beta-lactoglobulin, and then frying.

[0019] The present invention also provides a fried food, which is obtained by mixing raw materials of fried food and the EGCG and beta-lactoglobulin complex and then frying.

[0020] Preferably, based on the total weight of the fried food, the amount of the EGCG and β-lactoglobulin complex is 0.01 wt%-2 wt%, for example 2 wt%.

[0021] The heterocyclic amines of the present invention include PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline), Harman (1-methyl-9H-pyrido[3,4-b]indole), and Norharman (9H-pyrido[3,4-b]indole).

[0022] Experiments have shown that when the weight ratio of EGCG to β-lactoglobulin in the EGCG and β-lactoglobulin complex is 1:1, the inhibition rates of four heterocyclic amines, PhIP, MeIQx, Harman, and Norharman, in fried pork balls are 46.5%, 55.4%, 16.3%, and 52.1%, respectively.

[0023] The present invention solves the technical problem of high heterocyclic amine content in fried foods by compounding EGCG with β-lactoglobulin, and at the same time has little effect on the taste of fried foods, and can better retain its original flavor, thereby helping to improve product quality. The process of the present invention is simple and efficient, low in cost, low in energy consumption, and is conducive to industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It shows the content of heterocyclic amines in the fried pork meatball samples of the embodiments and comparative examples.

[0025] Figure 2 The following are appearance photos of fried pork meatball samples of the embodiment and comparative example.

[0026] Figure 3 The taste of the fried pork meatball samples of the embodiment and the comparative example is shown.

[0027] Figure 4 The texture of the fried pork meatball samples of the embodiment and the comparative example is shown. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or obtained by existing methods.

[0030] Example 1

[0031] This embodiment provides an EGCG and β-lactoglobulin complex, comprising EGCG and β-lactoglobulin; wherein the weight ratio of EGCG to β-lactoglobulin is 5:1.

[0032] The preparation method of the EGCG and β-lactoglobulin complex in this example is as follows:

[0033] (1) Dissolve 5 g EGCG and 5 g β-LG (β-lactoglobulin) in pure water respectively, mix the EGCG solution and the β-LG solution in a weight ratio of 5:1, and stir them thoroughly with a magnetic stirrer to ensure that the two are evenly mixed.

[0034] (2) The mixed solution was placed in a -20°C refrigerator for pre-freezing until it was completely frozen.

[0035] (3) The pre-frozen sample was placed in a freeze dryer. The freeze drying conditions were: cold trap temperature -80 °C, power 980 W, vacuum pressure 2 Pa, and drying time 48 h.

[0036] (4) After the sample is completely dried, take it out of the freeze dryer and grind it into powder in a mortar, which is the EGCG and β-lactoglobulin complex. Put the obtained powdered complex into a sealed container and store it in a cool and dry place for later use.

[0037] This embodiment also provides a fried pork meatball, the preparation method is as follows:

[0038] (1) Chop fresh pork into minced meat, take 20 g of minced meat, add 2% by weight of the EGCG and β-lactoglobulin complex powder prepared in this example, mix well, and knead into a ball shape.

[0039] (2) Add enough palm oil to the frying pan and heat it to 200°C. When the oil temperature reaches the required level, gently place the pork meatballs into the frying pan. Fry each meatball for 1.5 minutes and remove it immediately. During this period, the meatballs can be turned over appropriately to ensure that they are heated evenly.

[0040] Place the fried meatballs on paper towels or kitchen paper to absorb excess grease before subsequent analysis.

[0041] Example 2

[0042] This embodiment provides an EGCG and β-lactoglobulin complex, comprising EGCG and β-lactoglobulin; wherein the weight ratio of EGCG to β-lactoglobulin is 3:1.

[0043] The preparation method of the EGCG and β-lactoglobulin complex of this embodiment is as follows: 5 g EGCG and 5 g β-LG are dissolved in pure water respectively, the EGCG solution and the β-LG solution are mixed in a weight ratio of 3:1, and a magnetic stirrer is used to fully stir to ensure that the two are evenly mixed. The subsequent steps refer to Example 1.

[0044] This embodiment also provides a fried pork meatball, and the preparation method is different from that of Example 1 only in that an equal amount of the EGCG and β-lactoglobulin complex prepared in this embodiment is used.

[0045] Example 3

[0046] This embodiment provides an EGCG and β-lactoglobulin complex, comprising EGCG and β-lactoglobulin; wherein the weight ratio of EGCG to β-lactoglobulin is 1:1.

[0047] The preparation method of the EGCG and β-lactoglobulin complex of this embodiment is as follows: 5 g EGCG and 5 g β-LG are dissolved in pure water respectively, the EGCG solution and the β-LG solution are mixed in a weight ratio of 1:1, and a magnetic stirrer is used to fully stir to ensure that the two are evenly mixed. The subsequent steps refer to Example 1.

[0048] This embodiment also provides a fried pork meatball, and the preparation method is different from that of Example 1 only in that an equal amount of the EGCG and β-lactoglobulin complex prepared in this embodiment is used.

[0049] Example 4

[0050] This embodiment provides an EGCG and β-lactoglobulin complex, comprising EGCG and β-lactoglobulin; wherein the weight ratio of EGCG to β-lactoglobulin is 1:3.

[0051] The preparation method of the EGCG and β-lactoglobulin complex of this embodiment is as follows: 5 g EGCG and 5 g β-LG are dissolved in pure water respectively, the EGCG solution and the β-LG solution are mixed in a weight ratio of 1:3, and a magnetic stirrer is used to fully stir to ensure that the two are evenly mixed. The subsequent steps refer to Example 1.

[0052] This embodiment also provides a fried pork meatball, and the preparation method is different from that of Example 1 only in that an equal amount of the EGCG and β-lactoglobulin complex prepared in this embodiment is used.

[0053] Example 5

[0054] This embodiment provides an EGCG and β-lactoglobulin complex, comprising EGCG and β-lactoglobulin; wherein the weight ratio of EGCG to β-lactoglobulin is 1:5.

[0055] The preparation method of the EGCG and β-lactoglobulin complex of this embodiment is as follows: 5 g EGCG and 5 g β-LG are dissolved in pure water respectively, the EGCG solution and the β-LG solution are mixed in a weight ratio of 1:5, and a magnetic stirrer is used to fully stir to ensure that the two are evenly mixed. The subsequent steps refer to Example 1.

[0056] This embodiment also provides a fried pork meatball, and the preparation method is different from that of Example 1 only in that an equal amount of the EGCG and β-lactoglobulin complex prepared in this embodiment is used.

[0057] Comparative Example 1

[0058] This comparative example also provides a fried pork meatball, and the preparation method is different from that of Example 1 only in that no EGCG and β-lactoglobulin complex is added.

[0059] Comparative Example 2

[0060] This comparative example also provides a fried pork meatball, and the preparation method is different from that of Example 1 only in that the EGCG and β-lactoglobulin complex is replaced by an equal amount of EGCG.

[0061] Comparative Example 3

[0062] This comparative example also provides a fried pork meatball, and the preparation method is different from that of Example 1 only in that the EGCG and β-lactoglobulin complex is replaced by an equal amount of β-LG (β-lactoglobulin).

[0063] Experiment 1

[0064] The four heterocyclic amines PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline), Harman (1-methyl-9H-pyrido[3,4-b]indole) and Norharman (9H-pyrido[3,4-b]indole) in the pork balls of the above embodiments and comparative examples were quantitatively analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry. The specific process includes:

[0065] The pork balls were crushed, 25 mL of 0.1 mol / L hydrochloric acid was added to 4 g of fried meatball powder sample, homogenized with a high-speed disperser for 1 min and ultrasonically extracted for 15 min, then the supernatant was centrifuged (11363×g, 4°C), the residue was extracted with hydrochloric acid once again, the supernatant after centrifugation was combined, trichloroacetic acid solution was added to a final concentration of 5% to precipitate protein, and the protein precipitate was removed by centrifugation. After the pH of the above extract was adjusted to about 3.0 by adding 4 mol / L sodium hydroxide solution, solid phase extraction was performed for purification. The Oasis MCX solid phase extraction column was first activated and balanced with 6 mL of methanol, 6 mL of ultrapure water, and 6 mL of ethyl acetate in turn; after the extract was loaded, 6 mL of 0.1 mol / L hydrochloric acid and 6 mL of methanol were used to elute and remove impurities, and finally, 6 mL of methanol-ammonia (95:5, V / V) was used for elution. After the eluent was dried by nitrogen at 45°C, 500 μL of methanol was added to re-dissolve it, and it was filtered through a 0.22 μm pinhole filter and tested on the machine.

[0066] Results Figure 1 and Table 1.

[0067] Table 1 Contents of different heterocyclic amines in fried meatballs at different ratios

[0068]

[0069] The content of heterocyclic amines was used as an indicator to evaluate the ability of 5 ratios of EGCG and β-lactoglobulin complexes to reduce the amount of heterocyclic amines generated during the frying of pork balls. Among the four heterocyclic amines, most of the complexes had a better inhibitory effect on heterocyclic amines than EGCG alone. When the ratio of EGCG to β-LG was 1:1, the inhibitory effect on heterocyclic amines was the best, and the inhibition rates of PhIP, MeIQx, Harman, and Norharman were 46.5%, 55.4%, 16.3%, and 52.1%, respectively.

[0070] Figure 1 In the above, blank, EGCG, and β-LG are respectively the fried pork balls of comparative examples 1-3, and 5:1, 3:1, 1:1, 1:3, and 1:5 are respectively the fried pork balls of embodiments 1-5. The same applies below.

[0071] Experiment 2

[0072] The appearance photos of the fried pork balls of the samples of Examples 1-5 and Comparative Examples 1-3 are shown in Figure 2 The color test results are shown in Table 2 (the surface color difference of the fried pork balls was observed using a colorimeter).

[0073] Table 2 Color of fried meatballs at different proportions

[0074]

[0075] Depend on Figure 2 As shown in Table 2, compared with the blank sample in the control group, the L* of the meatballs in the treated group decreased significantly, and a* and b* increased significantly (P<0.05). The addition of EGCG or β-LG may have affected the light reflection properties of the surface of the fried pork balls, resulting in a decrease in brightness. The red and yellow tones of the fried pork balls increased, which may be due to the non-enzymatic browning of EGCG and β-LG as substrates, resulting in a color change shift toward red or yellow.

[0076] Experiment 3

[0077] The electronic tongue was used to detect the taste changes of fried pork balls after adding different ratios of EGCG and β-lactoglobulin complex. The results are shown in Figure 3 .

[0078] Depend on Figure 3 It can be seen that the taste response values ​​of fried pork balls changed after adding exogenous additives. After adding the complex of EGCG and β-LG in a ratio of 1:1, the richness, sourness, and astringency of the pork balls increased compared with the control group, and the bitterness, umami, and saltiness decreased slightly (P<0.05). In general, after adding the complex of EGCG and β-LG in a ratio of 1:1, the flavor of the pork balls was moderate.

[0079] Experiment 4

[0080] The physical properties of fried pork balls after adding different proportions of EGCG and β-lactoglobulin complex were tested by texture analyzer. Figure 4 .

[0081] Depend on Figure 4 It can be seen that when the ratio of EGCG to β-LG is 1:1, the hardness of the fried pork balls increases, but the elasticity, cohesion, adhesion, chewiness and resilience do not change significantly, which means that after adding the complex of EGCG and β-LG in a ratio of 1:1, the original taste of the fried pork balls can be better maintained.

[0082] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An EGCG and β-lactoglobulin complex, characterized in that: It includes EGCG and β-lactoglobulin; wherein the weight ratio of EGCG to β-lactoglobulin is (5:1)-(1:5).

2. The EGCG and β-lactoglobulin complex according to claim 1, characterized in that The weight ratio of EGCG to β-lactoglobulin is (3:1)-(1:3).

3. The EGCG and β-lactoglobulin complex according to claim 1, characterized in that: The weight ratio of EGCG to β-lactoglobulin is 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4 or 1:

5.

4. The EGCG and β-lactoglobulin complex according to any one of claims 1 to 3, characterized in that The EGCG and β-lactoglobulin complex is prepared by freeze-drying EGCG and β-lactoglobulin.

5. The method for preparing the EGCG and β-lactoglobulin complex according to any one of claims 1 to 4, characterized in that: include: EGCG and β-lactoglobulin were prepared into solutions respectively, mixed according to a certain proportion, and freeze-dried.

6. Use of the EGCG and β-lactoglobulin complex according to any one of claims 1 to 4 in reducing heterocyclic amines in fried foods.

7. The use according to claim 6, characterized in that: The fried foods include fried meat products, fried flour products, fried bean products, and fried vegetables; preferably fried pork balls, fried dough sticks, fried tofu, and fried sweet potatoes.

8. A method for reducing heterocyclic amines in fried foods based on the combination of EGCG and β-lactoglobulin, characterized in that: include: The raw materials of fried food and the EGCG and β-lactoglobulin complex according to any one of claims 1 to 4 are mixed and then fried.

9. A fried food, characterized in that: The fried food is prepared by mixing raw materials of fried food and the EGCG and beta-lactoglobulin complex described in any one of claims 1 to 4, and then frying the mixture.

10. The fried food according to claim 9, characterized in that Based on the total weight of the fried food, the amount of the EGCG and β-lactoglobulin complex is 0.01wt%-2wt%.

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