Preparation method of flavored walnuts

Abstract

The invention relates to a preparation method of flavored walnuts. The preparation method comprises the following steps: step 1, preparing a Maillard flavor peptide product; step 2, preparing flavored walnuts; step 3, drying oven treatment; and step 4, baking. According to the method, the walnuts are quickly tasty by adopting ultrasonic vacuum boiling, the Maillard flavor peptide product, the tea polyphenol, the glycyrrhizic acid and the rosmarinic acid are respectively compounded into three groups of natural seasonings, and the optimal seasoning formula proportion is explored by adopting a response surface method; and the influence of the seasoning on the storage stability of the flavored walnuts under the optimal flavoring condition is researched. The result shows that when the concentration of the Maillard flavor peptide product is 7.9% and the concentration of the tea polyphenol is 0.18%; the concentration of the Maillard flavor peptide product is 5%, and the concentration of glycyrrhizic acid is 0.21%; the concentration of the Maillard flavor peptide product is 6.2%, and the concentration of rosmarinic acid is 0.17%; the corresponding groups of walnuts are optimal in flavor.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a method for preparing flavored walnuts. Background Art

[0002] Walnut, belonging to the Juglandaceae family, is mainly produced in temperate regions and is the fruit of the walnut tree. China is the country with the highest walnut production in the world, with an annual output of more than 100,000 tons. However, the current walnut processing industry is small in scale, simple in technology, and lacks market specialization, which restricts economic benefits. In order to meet the market demand for high-quality and diversified walnut products, it is necessary to accelerate the upgrading and development of the walnut processing industry.

[0003] Walnuts are rich in high-quality fats, and their oil content ranks among the top in all woody oils. They are mainly composed of rich unsaturated fatty acids, among which linoleic acid, linolenic acid and oleic acid are the main components. Studies have shown that these rich ω-3 polyunsaturated fatty acids have a positive effect on weight management, prevention and treatment of fatty liver. In addition, the ratio of linoleic acid and α-linolenic acid in walnut oil is particularly suitable for preventing the occurrence of complications of type II diabetes. The phospholipids in walnut fat are beneficial to the brain and can improve neurasthenia. In addition, walnuts also contain a variety of nutrients such as protein and carbohydrates, and are rich in minerals such as phosphorus, potassium, calcium, iron, etc. and a variety of vitamins such as vitamin A, vitamin B1, vitamin B2, vitamin E, etc., as well as rich amino acids, especially glutamic acid, arginine, etc., which are beneficial to human health and nervous system development. Vitamin E has the effect of anti-oxidation and anti-aging. Therefore, walnuts are generally regarded as a natural health food.

[0004] In recent years, with the change of people's lifestyle and the rise of the snack food market, the walnut industry is also facing new development opportunities and challenges. In addition to traditional walnut dried fruits and walnut kernels, a variety of processed products such as walnut milk, instant powder, and walnut essence have gradually emerged in the market, but there are relatively few flavored walnut products in shells.

[0005] Walnut products face the problem of difficult flavor preservation and short shelf life during processing, mainly due to the special structure and high fat content of walnuts. In order to meet consumers' taste needs and extend the shelf life of products, it is necessary to develop processing technologies that can overcome the difficulty of walnut flavor preservation and improve storage resistance. Summary of the invention

[0006] The purpose of the invention is to provide a method for preparing flavor walnuts.

[0007] To achieve the above-mentioned purpose and other related purposes, the technical solution provided by the present invention is: a method for preparing flavored walnuts, comprising the following steps:

[0008] Step 1: Preparation of Maillard flavor peptide products

[0009] The walnut meal is added into water, and the mixture is placed in a water bath at 85-95°C for 10-30 minutes. After cooling, the pH value is adjusted to 6.8-7.2, and then the enzyme is added, and the mixture is placed in a water bath at 45-55°C for 1-5 hours. After the enzyme is inactivated, the mixture is centrifuged and the supernatant is taken to obtain a peptide solution. After the glucose, proline and peptide solution are mixed, the pH value is adjusted to 8.8-9.2, and then the mixture is placed in an oil bath at 140-160°C for 1-3 hours to obtain a Maillard flavor peptide product.

[0010] Step 2: Flavored Walnut Preparation

[0011] Put the walnuts into boiling water for 2-5 minutes; take out the walnuts and immerse them in the soaking liquid, vacuumize and then perform ultrasonic treatment;

[0012] The impregnation liquid is obtained by mixing the Maillard flavor peptide product with at least one of tea polyphenols, glycyrrhizic acid and rosmarinic acid and then dispersing the mixture in water;

[0013] Step 3: Oven treatment

[0014] Place the walnuts obtained in step 2 at 75-85°C for 4-8 hours;

[0015] Step 4: Bake

[0016] The walnuts obtained in step 3 are baked at 110-125° C. for 10-25 minutes to obtain flavored walnuts.

[0017] The preferred technical solution is: before adding the walnut meal into water, the walnut meal is first crushed and passed through an 80-mesh sieve; and water and the walnut meal are mixed in a mass ratio of 1:8-12.

[0018] The preferred technical solution is that the enzyme is at least one of papain, flavor enzyme and neutral enzyme.

[0019] The preferred technical solution is: the process parameters of centrifugation are: rotation speed 7000-10000r / min, time 18-25min.

[0020] The preferred technical solution is: the mass ratio of glucose, proline and polypeptide solution is 1:0.3-0.8:10-30.

[0021] The preferred technical solution is: tea polyphenol flavor: tea polyphenol flavor walnut: the mass concentration of the Maillard flavor peptide product solution is 5%-15%, and the mass concentration of tea polyphenol is 0.1%-0.3%.

[0022] The preferred technical solution is: flavored walnuts with sweet and sour glycyrrhizic flavor: the mass concentration of the Maillard flavor peptide product solution is 5%-15%, and the mass concentration of glycyrrhizic acid is 0.1%-0.3%.

[0023] The preferred technical solution is: flavored walnuts with rosmarinic acid flavor: the mass concentration of the Maillard flavor peptide product solution is 5%-15%, and the mass concentration of rosmarinic acid is 0.1%-0.3%.

[0024] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0025] The present invention uses response surface methodology to explore the optimal seasoning formula ratio; and explores the effect of seasoning on the storage stability of flavored walnuts under the optimal flavoring conditions. The results show that when the concentration of Maillard flavor peptide product is 7.9% and the concentration of tea polyphenols is 0.18%; when the concentration of Maillard flavor peptide product is 5% and the concentration of glycyrrhizic acid is 0.21%; when the concentration of Maillard flavor peptide product is 6.2% and the concentration of rosmarinic acid is 0.17%; the corresponding group of walnuts has the best flavor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The interactive effects of Maillard flavor peptides and tea polyphenols on sensory evaluation.

[0027] Figure 2 This is the interactive effect of Maillard flavor peptides and tea polyphenols on moisture.

[0028] Figure 3 This is the interactive effect of Maillard flavor peptides and tea polyphenols on hardness.

[0029] Figure 4 This is the interactive effect of Maillard flavor peptides and tea polyphenols on the degree of impregnation.

[0030] Figure 5 This is the interactive effect of Maillard flavor peptides and tea polyphenols on L value.

[0031] Figure 6 This is the interactive effect of Maillard flavor peptides and tea polyphenols on the a value.

[0032] Figure 7 This is the interactive effect of Maillard flavor peptides and tea polyphenols on b value.

[0033] Figure 8 The interactive effects of Maillard flavor peptides and glycyrrhizic sweet and sour on sensory evaluation.

[0034] Fig. 9 The interactive effect of Maillard flavor peptides and glycyrrhizic sweet acid on moisture.

[0035] Fig.10 The interactive effect of Maillard flavor peptides and glycyrrhizic sweet acid on hardness.

[0036] Fig.11 The interactive effect of Maillard flavor peptides and glycyrrhizic sweet acid on the infusion degree.

[0037] Fig.12 This is the interactive effect of Maillard flavor peptides and glycyrrhizic acid on L value.

[0038] Fig.13 This is the interactive effect of Maillard flavor peptides and glycyrrhizic sweet and sour on the a value.

[0039] Fig.14 This is the interactive effect of Maillard flavor peptides and glycyrrhizic acid on b value.

[0040] Fig.15 The interactive effects of Maillard flavor peptides and rosmarinic acid on sensory evaluation.

[0041] Fig.16 The interactive effects of Maillard flavor peptides and rosmarinic acid on moisture.

[0042] Fig.17 The interactive effect of Maillard flavor peptides and rosmarinic acid on hardness.

[0043] Fig.18 The interactive effects of Maillard flavor peptides and rosmarinic acid on the degree of impregnation.

[0044] Fig.19 This is the interactive effect of Maillard flavor peptides and rosmarinic acid on L value.

[0045] Fig. 20 This is the interactive effect of Maillard flavor peptides and rosmarinic acid on the a value.

[0046] Fig.21 This is the interactive effect of Maillard flavor peptides and rosmarinic acid on b value.

[0047] Fig. 22 Comparison of the impregnation scores between room temperature treatment and vacuum cooking treatment.

[0048] Fig.23 Comparison of sensory evaluation scores between room temperature treatment and vacuum cooking treatment.

[0049] Fig.24 Shown are the changes in sensory evaluation scores during storage with different treatments.

[0050] Fig.25 The changes in hardness during storage under different treatments.

[0051] Fig.26 The changes of L value during storage with different treatments.

[0052] Fig. 27 The changes of a value during storage with different treatments.

[0053] Fig.28 The changes of b value during storage with different treatments.

[0054] Fig.29 The changes of acid value during storage with different treatments.

[0055] Fig.30 Shown are the changes in peroxide value during storage under different treatments.

[0056] Fig.31 This is the process flow chart of flavored walnut production. DETAILED DESCRIPTION

[0057] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0058] See also Figure 1-31 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0059] Experimental materials: commercially available walnut meal, thin-skinned walnuts, tea polyphenols, sweet and sour liquorice, rosmarinic acid, and THBQ.

[0060] The process of the present invention:

[0061] 1. Preparation of Maillard flavor peptide products

[0062] The specific process is as follows:

[0063] Walnut meal → crush and sieve (80 mesh) → add water to dissolve → adjust pH (pH7.0) → enzymatic hydrolysis → inactivate enzyme, cool → centrifuge → add glucose and proline → adjust pH (Ph9.0) → oil bath → Maillard flavor peptide product.

[0064] Operation points:

[0065] (1) Dissolve in water

[0066] Mix distilled water and walnut meal in a ratio of 1:10. Take 100g of walnut meal and add 1000mL of distilled water in a beaker to dissolve it. Place it in a 90℃ water bath for 20 minutes and cool it down.

[0067] (2) Enzymatic hydrolysis

[0068] Add three enzymes according to the proportion: papain, flavor enzyme, and neutral enzyme, and bathe in 50℃ water for 3h.

[0069] (3) Centrifugation:

[0070] The mixture was centrifuged at 8000 r / min for 20 min to obtain the corresponding peptide solution.

[0071] (4) Oil bath

[0072] Glucose, proline and polypeptide solution were added to the flask at a ratio of 1:0.5:20, and the pH was adjusted (pH 9.0) to facilitate the Maillard reaction. The flask was then placed in an oil bath at 150°C for 2 hours to obtain a Maillard flavor peptide product.

[0073] 2. Preparation of flavored walnuts

[0074] The specific process is as follows:

[0075] Remove astringency and kill the green leaves → vacuum ultrasonic boiling → oven treatment → baking → flavored walnuts.

[0076] Operation points

[0077] (1) Remove astringency and kill the green color: Take a certain amount of walnuts and put them into boiling water for 3 minutes after the water boils.

[0078] (2) Vacuum ultrasonic cooking

[0079] Tea polyphenol flavor: The concentration of Maillard flavor peptide product solution ranged from 5% to 15%, and the concentration of tea polyphenols ranged from 0% to 0.3%. The two solutions were compounded using the response method and divided into 13 treatment groups. 13 groups of Maillard-tea polyphenol solutions were prepared with solutions of different concentrations, and walnuts and the prepared solutions were placed in a conical flask, which was vacuumed and treated at 70% ultrasonic power, 50°C, and 30 minutes.

[0080] Licorice sweet and sour flavor: The concentration of Maillard solution ranged from 5% to 15%, and the concentration of glycyrrhizic acid ranged from 0% to 0.3%. The two solutions were compounded by the response method and divided into 13 treatment groups. 13 groups of Maillard-licorice sweet and sour solutions were prepared with solutions of different concentrations. Walnuts and the prepared solutions were placed in a conical flask, which was vacuumed and ultrasonically treated at 70% power, 50°C, and 30 minutes.

[0081] Rosemarinic acid flavor: The concentration of Maillard solution ranged from 5% to 15%, and the concentration of rosmarinic acid ranged from 0% to 0.3%. The two solutions were compounded using the response method and divided into 13 treatment groups. 13 groups of Maillard-rosmarinic acid solutions were prepared with solutions of different concentrations. Walnuts and the prepared solutions were placed in a conical flask, which was vacuumed and ultrasonically treated at 70% power, 50°C, for 30 minutes.

[0082] (3) Oven treatment

[0083] Place the walnuts in an oven at 80°C for 6 hours to dry the moisture in them.

[0084] (4) Baking

[0085] Bake at 120°C for 20 minutes, watching the walnuts to avoid them being burnt, to obtain flavored walnuts.

[0086] 3. Determination of impregnation degree

[0087] Weigh the un-withered walnuts, and record the weight as m1; weigh the walnuts after vacuum ultrasonic boiling, and record the weight as m2. The calculation formula of the impregnation degree is as follows:

[0088]

[0089] 4. Sensory evaluation

[0090] Sensory evaluation was used to determine the optimal ratio of Maillard flavor peptides and three different food additives. Four sensory attributes (color, mouthfeel, flavor and texture) were selected to evaluate the combined effects of Maillard flavor peptides and food additives on walnuts.

[0091] The evaluation team consists of 8 members and the scoring is based on a 25-point system. The strength evaluation standards are: 10-14 points (poor), 15-19 points (good), 20-25 points (excellent).

[0092] Table: Sensory scoring standards for flavored walnuts

[0093]

[0094]

[0095] 5. Hardness measurement

[0096] Using the texture analyzer, select the appropriate test type and measurement parameters according to the properties of the walnuts and the test requirements. According to the shape and size of the walnuts, select the corresponding test fixture or clamp, fix it, and calibrate the instrument. After starting the test, the probe is pressed down to the sample placed (or fixed) on the workbench at the set test speed and test distance. During the test, the instrument will continuously monitor the correlation between the changes in the two parameters of load force and time / distance. After the test is completed, the texture analyzer will output the relevant parameter values ​​to analyze and evaluate the hardness and other characteristics of the sample.

[0097] During the test, samples with uniform shape, size and texture should be selected as much as possible, and the sample measurement environment (such as temperature, humidity, air flow rate, etc.) should be kept uniform to prevent test errors.

[0098] 6. Comparison of flavoring efficiency

[0099] The optimal solution compounding ratio (the compounding ratio of Maillard flavor peptide product solution and natural antioxidant) was taken to prepare flavored walnuts, and the impregnation degree and sensory evaluation were carried out with room temperature impregnation as the control to analyze the flavoring efficiency.

[0100] 7. Storage period evaluation

[0101] Walnuts were prepared according to the optimal flavoring conditions. Untreated walnuts and walnuts with 0.2% TBHQ added were used as the control group. The walnuts were accelerated to oxidize in a 60°C oven. Samples were taken at regular intervals for sensory evaluation, hardness, color difference, peroxide value, and acid value.

[0102] 1. Processing research of tea polyphenols flavored walnuts

[0103] (1) Response surface model (RSM) design and analysis

[0104] In this example, RSM was used to analyze the interaction between Maillard flavor peptide (X1) and tea polyphenol (X2) on walnut processing characteristics. The response surface design is shown in the table, and the response values ​​include sensory properties (Y1, score), moisture (Y2, %), hardness (Y3, N), impregnation degree (Y4, %), acid value (Y5, mg / g), peroxide value (Y6, g / 100g), L (Y7), a (Y8), and b (Y9). According to the data of Y1-Y9, a quadratic polynomial equation model was used, as shown in the following formula:

[0105]

[0106] Among them, Y i Represents the predicted response value, A0, A i , A ij and A ii They represent the unknown coefficients of intercept, linear, interaction and quadratic terms, respectively, and X iThe variables studied included Maillard flavor peptides (X1) and tea polyphenols (X2). Experimental design, regression analysis, and graphical analysis were all completed on Design Expert software.

[0107] Table: Central composite design of walnuts treated with tea polyphenols natural flavor group

[0108]

[0109]

[0110] (2) Data analysis and model fitting

[0111] Each design conducted 13 experiments under two variables. According to the results of ANOVA. Due to the low p-value (Y1 is 0.0121, Y2 is 0.0421, Y3 is 0.0005, Y4 is 0.0406, Y7 is 0.0046, Y8 is 0.0365, Y9 is 0.0328), all models except Y5 and Y6 are significant. The Rsquared value is high (Y1 is 0.7721, Y2 is 0.7533, Y3 is 0.9361, Y4 is 0.7561, Y7 is 0.7191, Y8 is 0.7642, Y9 is 0.7721), indicating that the model fits well. Therefore, the established regression model is successful, can accurately represent the variables selected in the experimental area, and can well show the trend of the results. The complete quadratic model is shown in the following table.

[0112] Table: Regression models for different response values

[0113]

[0114] Table: Results of the central design experiment on walnuts treated with natural tea polyphenols

[0115]

[0116]

[0117] Note: X1: Maillard flavor peptide solution (%), X2: tea polyphenols (%), Y1: sensory evaluation (points), Y2: moisture (%); Y3: hardness (N); Y4: impregnation degree (%); Y5: acid value (mg / g); Y6: peroxide value (g / 100g); Y7: L; Y8: a; Y9: b.

[0118] Table: ANOVA results of the effects of Maillard flavor peptides and tea polyphenols on walnut quality

[0119]

[0120] (3) Effects of Maillard flavor peptide products and tea polyphenols on sensory evaluation of walnuts

[0121] The sensory evaluation scores are used to assess consumers’ acceptance of food. Figure 1 It can be seen that the highest score is obtained when the concentration of Maillard flavor peptide product is 10% and the concentration of tea polyphenol is 0.15%. The concentration of Maillard flavor peptide is around 10%, and the score is relatively high; while the concentration of tea polyphenol is between 15% and 30%, and the score is relatively high, which means that the flavor is best when the concentration of tea polyphenol is in the middle or above, too low and there is no flavor of tea polyphenol, and too high and it is somewhat bitter.

[0122] (4) Effects of Maillard flavor peptides and tea polyphenols on walnut moisture

[0123] Moisture describes the moistness and water content of food, which affects the taste, texture and shelf life of the food. Figure 2 It can be seen that the moisture content is the highest when the concentration of Maillard flavor peptide is 5% and the concentration of tea polyphenol is 0.15%; the moisture content is the lowest when the concentration of Maillard flavor peptide is 15% and the concentration of tea polyphenol is 0.3%. In general, the moisture content is low, the taste of walnuts is crisper, and it is conducive to preservation.

[0124] (5) Effects of Maillard flavor peptides and tea polyphenols on walnut hardness

[0125] Hardness describes the texture and taste of food and is related to the freshness and quality of food. The hardness of food refers to its resistance to compression or deformation under the action of force. Figure 3 It can be seen that the hardness is the highest when the concentration of Maillard flavor peptide is 10% and the concentration of tea polyphenol is 0.15%; the hardness is the lowest when the concentration of Maillard flavor peptide is 15% and the concentration of tea polyphenol is 0.3%. Figure 3 As shown in the figure, the response surface diagram is saddle-shaped, indicating that Maillard flavor peptides and tea polyphenols have a significant interactive effect on the hardness of walnuts.

[0126] (6) Effects of Maillard flavor peptides and tea polyphenols on walnut soaking degree

[0127] The degree of impregnation describes the flavoring effect of the walnuts. The degree of impregnation is directly related to the depth of its taste and flavor. As the degree of impregnation increases, the walnuts are more able to fully absorb the seasoning liquid, making the flavor more intense and uniform. Figure 4 It can be seen that when the concentration of Maillard flavor peptides is 10% and the concentration of tea polyphenols is 0.15%, the impregnation degree is the highest and the flavoring effect is the best. Figure 4 It can be concluded that Maillard flavor peptides and tea polyphenols have a significant interactive effect on the impregnation degree of walnuts.

[0128] (7) Effects of Maillard flavor peptides and tea polyphenols on the acid value of walnuts

[0129] Acid value is an indicator that describes the content of acidic substances in food, usually expressed as acidity. The acidity of food directly affects its taste, flavor and shelf life. After the acid value of walnuts was measured, the acid value of this batch of walnuts was relatively low, with an average of 0.57 mg / g. Since this batch of walnuts has not been stored for too long and the oil inside has not undergone significant oxidation reaction, Maillard flavor peptides and tea polyphenols have no significant effect on its acid value.

[0130] (8) Effects of Maillard flavor peptides and tea polyphenols on the peroxide value of walnuts

[0131] Peroxide value is an indicator that describes the degree of oxidation in food, and is usually used to evaluate the freshness and quality loss of food. It reflects the degree of lipid oxidation and free radical generation in food. After the peroxide value of walnuts was measured, the peroxide value of this batch of walnuts was low, with an average of 0.013g / 100g. Since this batch of walnuts was not stored for too long, the lipids inside were less exposed to the air, and no oxidation reaction occurred to produce free radicals. Maillard flavor peptides and tea polyphenols did not have a significant effect on its peroxide value.

[0132] (9) Effects of Maillard flavor peptides and tea polyphenols on walnut color

[0133] Color is one of the important indicators to describe food quality. The L value indicates the lightness or darkness of the food color. A higher L value indicates a brighter color, while a lower L value indicates a darker color. Figure 5 As shown, when the Maillard flavor peptide is 5% and the tea polyphenols are 0%, the L value is the highest and the walnut has a better color. The a value indicates the degree of deviation of the food color in the red-green direction. A higher a value indicates that the food has a red hue, and a lower a value indicates that the food has a green hue. Since walnuts will turn brown in the air, a lower a value indicates that the walnuts are of better quality. Similarly, the b value indicates the degree of deviation of the food color in the yellow-blue direction. A high b value indicates that the food has a yellow hue, and a lower b value indicates that the food has a blue hue. A lower b value indicates that the walnuts are of better quality. Figure 6 As shown in the figure, when the Maillard flavor peptide is 10% and the tea polyphenols is 0.15%, the a value is the lowest; Figure 7 As shown, when the Maillard flavor peptide content was 10% and the tea polyphenol content was 0.15%, the b value was the lowest.

[0134] Based on the model, the optimal ratio of natural substance groups was predicted, and sensory evaluation was selected as the most important indicator in optimization. The optimal solution was 7.9% for Maillard flavor peptides and 0.18% for tea polyphenols. The experiment was repeated three times under the optimal conditions, and the average sensory evaluation score was 85 points, which was close to the predicted value, fully demonstrating that the response surface methodology can be used to optimize the ratio of walnut flavor substance groups.

[0135] 2. Processing research of licorice sweet and sour flavor walnut

[0136] (1) Response surface model (RSM) design and analysis

[0137] In this example, RSM was used to analyze the interaction between Maillard flavor peptide (X1) and glycyrrhizic acid (X2) on walnut processing characteristics. The response surface design is shown in the following table, and the response values ​​include sensory properties (Y1, score), moisture (Y2, %), hardness (Y3, N), impregnation degree (Y4, %), acid value (Y5, mg / g), peroxide value (Y6, g / 100g), L (Y7), a (Y8), and b (Y9).

[0138] According to the data of Y1-Y9, a quadratic polynomial equation model is adopted, as shown below:

[0139]

[0140] Among them, Y i Represents the predicted response value, A0, A i , A ij and A ii They represent the unknown coefficients of intercept, linear, interaction and quadratic terms, respectively, and X i The variables studied included Maillard flavor peptides (X1) and glycyrrhizic acid (X2). Experimental design, regression analysis, and graphical analysis were all completed on Design Expert software.

[0141] Table: Central composite design of walnuts treated with licorice sweet and sour natural flavor group

[0142]

[0143] (2) Data analysis and model fitting

[0144] Each design conducted 13 experiments under two variables. According to the results of ANOVA. Due to the low p-value (Y1 is 0.0092, Y2 is 0.0373, Y3 is 0.0180, Y4 is 0.0342, Y7 is 0.0227, Y8 is 0.0483, Y9 is 0.0156), all models except Y5 and Y6 are significant. The Rsquared value is high (Y1 is 0.8459, Y2 is 0.7625, Y3 is 0.8108, Y4 is 0.7561, Y7 is 0.6370, Y8 is 0.7422, Y9 is 0.8189), indicating that the model fits well. Therefore, the established regression model is successful, can accurately represent the variables selected in the experimental area, and can well show the trend of the results. The complete quadratic model is shown in the following table:

[0145] Table: Regression models for different response values

[0146]

[0147]

[0148] Table: Results of the central design experiment on walnuts treated with the natural liquorice sweet and sour substance group

[0149] Group No. <![CDATA[X1]]> <![CDATA[X2]]> <![CDATA[Y1]]> <![CDATA[Y2]]> <![CDATA[Y3]]> <![CDATA[Y4]]> <![CDATA[Y5]]> <![CDATA[Y6]]> <![CDATA[Y7]]> <![CDATA[Y8]]> <![CDATA[Y9]]> 1 10 0.3 76 0.79 62.412 41.527 0.38 0.035 29.84 10.25 21.94 2 15 0.15 82 1.63 80.33 68.3 0.48 0.021 32.37 8.5 15.4 3 15 0 68 0.67 40.873 49.87 0.41 0.023 40.45 9.03 19.8 4 10 0 60 0.54 31.925 28.53 0.54 0.013 38.99 10.88 22.75 5 10 0.15 82 1.93 104.2 72.09 0.39 0.025 35.26 9.36 21.24 6 10 0.15 93 2.11 83.452 76.95 0.49 0.017 34.89 7.93 16.76 7 10 0.15 82 1.71 89.27 54.78 0.43 0.011 32.79 6.89 18.53 8 10 0.15 86 1.63 94.639 69.89 0.54 0.022 30.83 8.06 17.63 9 5 0.3 87 1.67 82.5 61.26 0.36 0.032 38.43 9.7 19.88 10 5 0 65 0.47 58.0465 37.64 0.37 0.023 32.96 10.91 21.54 11 5 0.15 80 0.89 86.472 61.26 0.33 0.033 38.01 9.94 16.14 12 10 0.15 88 1.97 120.6885 70.91 0.57 0.022 36.3 8.05 17.97 13 15 0.3 70 0.62 50.9915 61.26 0.51 0.019 30.79 11.21 22.12

[0150] Note: X1: Maillard flavor peptide solution (%), X2: tea polyphenols (%), Y1: sensory evaluation (score), Y2: moisture (%); Y3: hardness (N); Y4: impregnation degree (%); Y5: acid value (mg / g); Y6: peroxide value (g / 100g); Y7: L; Y8: a; Y9:

[0151] Table: ANOVA results of the effects of Maillard flavor peptides and glycyrrhizic acid on walnut quality

[0152]

[0153]

[0154] (3) Effects of Maillard flavor peptides and glycyrrhizic acid on sensory evaluation of walnuts

[0155] The sensory evaluation scores are used to assess consumers’ acceptance of food. Figure 8 It can be seen that the score is relatively high when the concentration of glycyrrhizic acid is between 0.15% and 0.3%, which means that when the concentration of glycyrrhizic acid is high, the flavor is best, sweeter, and more in line with people's taste needs. Maillard flavor peptides add a mellow feeling to walnuts. Figure 8 It can be seen that the effect of glycyrrhizic sweetness and sourness on sensory evaluation is more significant than that of Maillard flavor peptides.

[0156] (4) Effects of Maillard flavor peptides and glycyrrhizic acid on walnut moisture

[0157] Moisture describes the moistness and water content of food, which affects the taste, texture and shelf life of the food. Fig. 9 It can be seen that the moisture content is the highest when the Maillard flavor peptide concentration is 10% and the glycyrrhizic acid concentration is 0.15%, and the moisture content is the lowest when the Maillard flavor peptide concentration is 5% and the glycyrrhizic acid concentration is 0%. In general, the moisture content is low, the walnut tastes crisper, and is conducive to preservation.

[0158] (5) Effects of Maillard flavor peptides and glycyrrhizic acid on walnut hardness

[0159] Hardness describes the texture and taste of food and is related to the freshness and quality of food. The hardness of food refers to its resistance to compression or deformation under the action of force. Fig.10It can be seen that the hardness is the highest when the concentration of Maillard flavor peptide is 10% and the concentration of glycyrrhizic acid is 0.15%; the hardness is the lowest when the concentration of Maillard flavor peptide is 10% and the concentration of glycyrrhizic acid is 0%. Fig.10 As shown in the results, Maillard flavor peptides and tea polyphenols had a significant interactive effect on the hardness of walnuts.

[0160] (6) Effects of Maillard flavor peptides and glycyrrhizic acid on walnut soaking degree

[0161] The degree of impregnation describes the flavoring effect of the walnuts. The degree of impregnation is directly related to the depth of its taste and flavor. As the degree of impregnation increases, the walnuts are more able to fully absorb the seasoning liquid, making the flavor more intense and uniform. Fig.11 It can be seen that when the concentration of Maillard flavor peptide is 10% and the concentration of glycyrrhizic acid is 0.15%, the impregnation degree is the highest and the flavoring effect is the best. Fig.11 The response surface diagram is saddle-shaped, and Maillard flavor peptides and glycyrrhizic acid have significant interactive effects on the impregnation degree of walnuts.

[0162] (7) Effects of Maillard flavor peptides and glycyrrhizic acid on walnut acid value

[0163] Acid value is an indicator that describes the content of acidic substances in food, usually expressed as acidity. The acidity of food directly affects its taste, flavor and shelf life. After the acid value of walnuts was measured, the acid value of this batch of walnuts was relatively low, with an average of 0.45 mg / g. Because this batch of walnuts has not been stored for too long, and the oil inside has not undergone significant oxidation reaction. Maillard flavor peptides and glycyrrhizic acid have no significant effect on its acid value.

[0164] (8) Effects of Maillard flavor peptides and glycyrrhizic acid on the peroxide value of walnuts

[0165] Peroxide value is an indicator that describes the degree of oxidation in food and is usually used to evaluate the freshness and quality loss of food. It reflects the degree of lipid oxidation and free radical generation in food. After the peroxide value of walnuts was measured, the peroxide value of this batch of walnuts was low, with an average of 0.023g / 100g. Because this batch of walnuts was not stored for too long, the lipids inside were less exposed to the air, and no oxidation reaction occurred to produce free radicals. Maillard flavor peptides and glycyrrhizic acid did not have a significant effect on its peroxide value.

[0166] (9) Effects of Maillard flavor peptides and glycyrrhizic acid on walnut color

[0167] Color is one of the important indicators to describe food quality. The L value indicates the lightness or darkness of the food color. A higher L value indicates a brighter color, while a lower L value indicates a darker color. Fig.12As shown, when the Maillard flavor peptide is 15% and the glycyrrhizic acid is 0%, the L value is the highest and the walnut has a better color. The a value indicates the degree of deviation of the food color in the red-green direction. A higher a value indicates that the food has a red hue, and a lower a value indicates that the food has a green hue. Since walnuts will turn brown in the air, a lower a value indicates that the walnuts are of better quality. Similarly, the b value indicates the degree of deviation of the food color in the yellow-blue direction. A higher b value indicates that the food has a yellow hue, and a lower b value indicates that the food has a blue hue. A lower b value indicates that the walnuts are of better quality. As shown Fig.13 When the Maillard flavor peptide is 10% and the glycyrrhizic acid is 0.15%, the a value is the lowest; Fig.14 As shown, when the Maillard flavor peptide content is 15% and the glycyrrhizic acid content is 0.15%, the b value is the lowest.

[0168] Based on the model, the optimal ratio of natural substance groups was predicted, and sensory evaluation was selected as the most important indicator in optimization. The optimal solution was 5% Maillard flavor peptide and 0.21% glycyrrhizic acid. The experiment was repeated 3 times under the optimal conditions, and the average sensory evaluation score was 88 points, which was close to the predicted value, fully demonstrating that the response surface methodology can be used to optimize the ratio of walnut flavor substance groups.

[0169] 3. Processing research of rosemary acid flavored walnuts

[0170] (1) Response surface model (RSM) design and analysis

[0171] In this paper, RSM analysis was used to analyze the interactive effects of Maillard flavor peptides (X1) and rosmarinic acid (X2) on walnut processing characteristics. The response values ​​included sensory properties (Y1, score), moisture (Y2, %), hardness (Y3, N), impregnation degree (Y4, %), acid value (Y5, mg / g), peroxide value (Y6, g / 100g), L (Y7), a (Y8), and b (Y9). Based on the data of Y1-Y9, a quadratic polynomial equation model was used, as shown in the following formula:

[0172]

[0173] Among them, Y i Represents the predicted response value, A0, A i , A ij and A ii They represent the unknown coefficients of intercept, linear, interaction and quadratic terms, respectively, and X i are the variables studied, including Maillard flavor peptides (X1) and rosmarinic acid (X2). Experimental design, regression analysis, and graphical analysis were all completed on Design Expert 8.0.6 software.

[0174] Table: Central composite design of walnuts treated with rosemary acid natural flavor group

[0175]

[0176]

[0177] 3.3.2 Data analysis and model fitting

[0178] Each design conducted 13 experiments under two variables. According to the results of ANOVA. Due to the low p-value (Y1 is 0.0251, Y2 is 0.0410, Y3 is 0.0469, Y4 is 0.0379, Y7 is 0.0403, Y8 is 0.0032, Y9 is 0.0436), all models except Y5 and Y6 are significant. The rsquared value is high (Y1 is 0.7902, Y2 is 0.7553, Y3 is 0.7446, Y4 is 0.7613, Y7 is 0.7566, Y8 is 0.6824, Y9 is 0.7505), indicating that the model fits well. Therefore, the established regression model is successful, can accurately represent the variables selected in the experimental area, and can well show the trend of the results. The complete quadratic model is shown in the following table.

[0179] Table: Regression models for different response values

[0180]

[0181] Table 3.1 Central design experimental results of walnuts treated with rosmarinic acid natural substance group

[0182]

[0183]

[0184] Note: X1: Maillard flavor peptide solution (%), X2: tea polyphenols (%), Y1: sensory evaluation (points), Y2: moisture (%); Y3: hardness (N); Y4: impregnation degree (%); Y5: acid value (mg / g); Y6: peroxide value (g / 100g); Y7: L; Y8: a; Y9: b.

[0185] Table: ANOVA results of the effects of Maillard flavor peptides and rosmarinic acid on walnut quality

[0186]

[0187] (3) Effects of Maillard flavor peptides and rosmarinic acid on sensory evaluation of walnuts

[0188] The sensory evaluation scores are used to assess consumers’ acceptance of food. Fig.15It can be seen that the score is relatively high when the concentration of rosmarinic acid is 0.15%; this shows that when the concentration of rosmarinic acid is in the middle, the flavor is best, if it is too low, there is no flavor of rosmarinic acid, and if it is too high, the taste is irritating.

[0189] (4) Effects of Maillard flavor peptides and rosmarinic acid on walnut moisture

[0190] Moisture describes the moistness and water content of food, which affects the taste, texture and shelf life of the food. Fig.16 It can be seen that the moisture content is the highest when the concentration of Maillard flavor peptide is 10% and the concentration of rosmarinic acid is 0.15%, and the moisture content is the lowest when the concentration of Maillard flavor peptide is 5% and the concentration of rosmarinic acid is 0.3%. In general, the moisture content is low, the taste of walnuts is crisper, and it is conducive to preservation.

[0191] (5) Effects of Maillard flavor peptides and rosmarinic acid on walnut hardness

[0192] Hardness describes the texture and taste of food and is related to the freshness and quality of food. The hardness of food refers to its resistance to compression or deformation under the action of force. Fig.17 It can be seen that the hardness is the highest when the Maillard flavor peptide concentration is 10% and the rosmarinic acid concentration is 0.15%; the hardness is the lowest when the Maillard flavor peptide concentration is 5% and the rosmarinic acid concentration is 0%. Fig.17 As shown in the results, Maillard flavor peptides and tea polyphenols had a significant interactive effect on the hardness of walnuts.

[0193] (6) Effects of Maillard flavor peptides and rosmarinic acid on walnut soaking degree

[0194] The degree of impregnation describes the flavoring effect of the walnuts. The degree of impregnation is directly related to the depth of its taste and flavor. As the degree of impregnation increases, the walnuts are more able to fully absorb the seasoning liquid, making the flavor more intense and uniform. Fig.18 It can be seen that when the concentration of Maillard flavor peptide is 15% and the concentration of glycyrrhizic acid is 0.15%, the impregnation degree is the highest and the flavoring effect is the best.

[0195] (7) Effects of Maillard flavor peptides and rosmarinic acid on walnut acid value

[0196] Acid value is an indicator that describes the content of acidic substances in food, usually expressed as acidity. The acidity of food directly affects its taste, flavor and shelf life. After the acid value of walnuts was measured, the acid value of this batch of walnuts was relatively low, with an average of 0.57 mg / g. Because this batch of walnuts has not been stored for too long and the oil inside has not undergone significant oxidation reaction. Maillard flavor peptides and glycyrrhizic acid have no significant effect on its acid value.

[0197] (8) Effects of Maillard flavor peptides and rosmarinic acid on the peroxide value of walnuts

[0198] Peroxide value is an indicator that describes the degree of oxidation in food and is usually used to evaluate the freshness and quality loss of food. It reflects the degree of lipid oxidation and free radical generation in food. After the peroxide value of walnuts was measured, the peroxide value of this batch of walnuts was low, with an average of 0.013g / 100g. Since this batch of walnuts was not stored for too long, the lipids inside were less exposed to the air, and no oxidation reaction occurred to produce free radicals. Maillard flavor peptides and glycyrrhizic acid did not have a significant effect on its peroxide value.

[0199] (9) Effects of Maillard flavor peptides and rosmarinic acid on walnut color

[0200] Color is one of the important indicators to describe food quality. The L value indicates the lightness or darkness of the food color. A higher L value indicates a brighter color, while a lower L value indicates a darker color. Fig.19 As shown, when the Maillard flavor peptide is 10% and the rosmarinic acid is 0.30%, the L value is the highest and the walnut has a better color. The a value indicates the degree of deviation of the food color in the red-green direction. A higher a value indicates that the food has a red hue, and a lower a value indicates that the food has a green hue. Since walnuts will turn brown in the air, a lower a value indicates that the walnuts are of better quality. Similarly, the b value indicates the degree of deviation of the food color in the yellow-blue direction. A high b value indicates that the food has a yellow hue, and a lower b value indicates that the food has a blue hue. A lower b value indicates that the walnuts are of better quality. As shown Fig. 20 As shown in the figure, when the Maillard flavor peptide is 5% and the rosmarinic acid is 0.30%, the a value is the lowest; Fig.21 As shown, when the Maillard flavor peptide content is 5% and the glycyrrhizic acid content is 0.30%, the b value is the lowest.

[0201] Based on the model, the optimal ratio of natural substance groups was predicted, and sensory evaluation was selected as the most important indicator in optimization. The optimal solution was 6.2% Maillard flavor peptide and 0.17% rosmarinic acid. The experiment was repeated three times under the optimal conditions, and the average sensory evaluation score was 84 points, which was close to the predicted value, fully demonstrating that the response surface methodology can be used to optimize the ratio of walnut flavor substance groups.

[0202] Analysis of the taste efficiency of three seasonings

[0203] (1) Impregnation degree

[0204] like Fig. 22 As shown in the figure, the impregnation degree of the three flavors of walnuts under vacuum ultrasonic cooking is about 5 times higher than that under normal temperature. This shows that the flavoring efficiency of vacuum ultrasonic cooking is higher than that under normal temperature, and a better flavoring effect can be obtained, achieving the demand of rapid flavoring.

[0205] (2) Sensory evaluation

[0206] like Fig.23 As shown in the figure, the walnuts flavored by vacuum ultrasonic cooking have an overall sensory evaluation score higher than those flavored at room temperature. This also shows that vacuum ultrasonic cooking has a better flavoring effect and a richer walnut flavor.

[0207] Changes in sensory evaluation scores during storage

[0208] 1. During the accelerated storage stage, the trend of sensory evaluation scores is as follows: Fig.24 As shown, it is in a descending form. Fig.24 It can be seen that during the storage stage, the sensory evaluation scores of the control group and the TBHQ group were lower than those of the sample group, and from the slope of the curve, it can be seen that compared with the control group, the lower slope of the sample group indicates that its quality changes are less during the accelerated storage stage and it has relatively good quality.

[0209] 2. Changes in hardness during storage

[0210] Hardness is one of the important indicators for evaluating the quality and taste of walnuts. During the accelerated storage stage, the change trend of hardness is as follows: Fig.25 As shown, it is in a descending form. Fig.25 It can be seen that during the storage period, the hardness of the control group and the TBHQ group was lower than that of the sample group, and the decline in the curve showed that the hardness change between the sample group and the control group was not much different.

[0211] 3. Changes in color difference during storage

[0212] L value is usually used to describe the brightness or lightness of an object, reflecting the uniformity of the color, the good appearance and the freshness of the walnut. Fresh walnuts usually have a higher L value, a shiny surface and uniform color. During the accelerated storage stage, the change trend of L value is as follows: Fig.26 As shown. Fig.26 It can be seen that during the storage period, the L values ​​of the control group and the TBHQ group were lower than those of the sample group, and the L value of the sample group changed less, indicating that the walnuts in the sample group obtained better storage quality during the storage period.

[0213] The a value in color difference indicates the color change between red and green. Fresh walnut kernels usually have a lower a value. During storage, if the storage conditions are not appropriate, oxidation will occur and the alpha value of the walnut will increase. During the accelerated storage stage, the change trend of the a value is as follows: Fig. 27 As shown. Fig. 27 It can be seen that during the storage period, the a values ​​of the control group and TBHQ group were mostly higher than those of the sample group, and the increase in the a values ​​of the control group and TBHQ group was greater than that of the sample group, indicating that the walnuts in the sample group underwent oxidation and other chemical reactions at a slower rate during the storage period.

[0214] The b value indicates the color change between blue and yellow. Normally, fresh walnut kernels have a lower b value. However, during storage, if the storage conditions are not suitable, the walnut kernels will oxidize, and the b value will increase. During the accelerated storage stage, the change trend of the b value is as follows: Fig.28 As shown. Fig.28 It can be seen that during the storage period, the increase in the b value of the control group and the TBHQ group was greater than that of the sample group, indicating that the walnuts in the sample group underwent oxidation and other chemical reactions at a slower rate during the storage period.

[0215] 4. Changes in acid value during storage

[0216] Acid value is an important indicator for evaluating the degree of oxidative rancidity of oils and fats, and it directly reflects the changes in the free fatty acid content in oils and fats. Fig.29 As shown in the figure, during the accelerated storage process, the acid value of the sample and its control group showed an upward trend. This upward trend is likely due to the oxidation and rancidity of the rich oil in the walnut kernel under the combined action of moisture and air. During the entire storage period, the oil acid value and its growth rate of the sample group remained at a low level, with a lower acid value than the control group and TBHQ group. This shows that the sample group has better antioxidant properties during storage. Whether it is the control group, TBHQ group or sample group, their acid value did not exceed the acid value limit of 3.0mg(KOH) / g specified in GB 19300-2014 "Food Safety and National Standard for Nuts and Seeds" during the entire storage period.

[0217] 5. Changes in peroxide value during storage

[0218] During the accelerated storage stage, the change trend of peroxide value is as follows Fig.29 As shown. Fig.29 It can be seen that the peroxide value of the control group was higher than that of the sample group during the storage period, and with the increase of storage time, the difference between the peroxide values ​​of the control group and the sample group gradually increased, indicating that the oxidation degree of the sample group was significantly lower than that of the control group under the same storage conditions. The change range of the peroxide value of the sample group at the beginning and end of storage was smaller than that of the control group, indicating that the oxidation rate of the sample group was low during the same storage period and the storage quality was good. The peroxide value of the sample group did not exceed the limit value of 0.08g / 100g in GB 19300--2014 "Food Safety and National Standard Nuts and Seed Foods" during the storage period, while the control group and TBHQ group exceeded the limit value of the national standard.

[0219] Example 2: A method for preparing flavored walnuts

[0220] A method for preparing flavored walnuts comprises the following steps:

[0221] Step 1: Preparation of Maillard flavor peptide products

[0222] Walnut meal was added into water, and the mixture was placed in a water bath at 85°C for 10 minutes. After cooling, the pH value was adjusted to 6.8, and then enzyme was added, and the mixture was placed in a water bath at 45°C for 1 hour. After the enzyme was inactivated, the mixture was centrifuged and the supernatant was obtained to obtain a peptide solution. Glucose, proline and the peptide solution were mixed, and the pH value was adjusted to 8.8, and then the mixture was placed in an oil bath at 140°C for 1 hour to obtain a Maillard flavor peptide product.

[0223] Step 2: Flavored Walnut Preparation

[0224] Put the walnuts into boiling water for 2 minutes; take out the walnuts and immerse them in the soaking liquid, evacuate the water and then perform ultrasonic treatment;

[0225] The impregnation liquid is obtained by mixing the Maillard flavor peptide product with at least one of tea polyphenols, glycyrrhizic acid and rosmarinic acid and then dispersing the mixture in water;

[0226] Step 3: Oven treatment

[0227] The walnuts obtained in step 2 were placed at 75°C for 4 hours;

[0228] Step 4: Bake

[0229] The walnuts obtained in step 3 are baked at 110° C. for 10 minutes to obtain flavored walnuts.

[0230] The preferred technical solution is: before adding the walnut meal into water, the walnut meal is first crushed and passed through an 80-mesh sieve; and water and the walnut meal are mixed in a mass ratio of 1:8-12.

[0231] The preferred technical solution is that the enzyme is a mixture of papain, flavor enzyme and neutral enzyme in a mass ratio of 1:2:1.

[0232] The preferred technical solution is: the centrifugal process parameters are: speed 7000r / min, time 18min.

[0233] The preferred technical solution is: the mass ratio of glucose, proline and polypeptide solution is 1:0.3:10.

[0234] The mixture is divided into: the mass concentration of the Maillard flavor peptide product solution is 8%, the mass concentration of tea polyphenols is 0.2; the mass concentration of glycyrrhizic acid is 0.1%; and the mass concentration of rosmarinic acid is 0.1%.

[0235] The above description is only used to explain the preferred embodiments of the present invention, and is not intended to limit the present invention in any form. Therefore, any modifications or changes made to the present invention under the same inventive spirit should still be included in the scope of protection intended by the present invention.

Claims

1. A method for preparing flavored walnuts, characterized in that: The following steps are involved: Step 1: Preparation of Maillard flavor peptide products The walnut meal is added into water, and the mixture is placed in a water bath at 85-95°C for 10-30 minutes. After cooling, the pH value is adjusted to 6.8-7.2, and then the enzyme is added, and the mixture is placed in a water bath at 45-55°C for 1-5 hours. After the enzyme is inactivated, the mixture is centrifuged and the supernatant is taken to obtain a peptide solution. After the glucose, proline and peptide solution are mixed, the pH value is adjusted to 8.8-9.2, and then the mixture is placed in an oil bath at 140-160°C for 1-3 hours to obtain a Maillard flavor peptide product. Step 2: Flavored Walnut Preparation Put the walnuts into boiling water for 2-5 minutes; take out the walnuts and immerse them in the soaking liquid, vacuumize and then perform ultrasonic treatment; The impregnation liquid is obtained by mixing the Maillard flavor peptide product with at least one of tea polyphenols, glycyrrhizic acid and rosmarinic acid and then dispersing the mixture in water; Step 3: Oven treatment Place the walnuts obtained in step 2 at 75-85°C for 4-8 hours; Step 4: Bake The walnuts obtained in step 3 are baked at 110-125° C. for 10-25 minutes to obtain flavored walnuts.

2. The method for preparing flavored walnuts according to claim 1, characterized in that: The walnut meal is crushed and passed through an 80-mesh sieve before being added into water; water and walnut meal are mixed in a mass ratio of 1:8-12.

3. The method for preparing flavored walnuts according to claim 1, characterized in that: The enzyme is at least one of papain, flavor enzyme, and neutral enzyme.

4. The method for preparing flavored walnuts according to claim 1, characterized in that: The process parameters of centrifugation are: speed 7000-10000r / min, time 18-25min.

5. The method for preparing flavored walnuts according to claim 1, characterized in that: The mass ratio of glucose, proline and polypeptide solution is 1:0.3-0.8:10-30.

6. The method for preparing flavored walnuts according to claim 1, characterized in that: Tea polyphenols flavored walnuts: The mass concentration of the Maillard flavor peptide product solution is 5%-15%, and the mass concentration of tea polyphenols is 0.1%-0.3%.

7. The method for preparing flavored walnuts according to claim 1, characterized in that: Licorice sweet and sour flavored walnuts: the mass concentration of the Maillard flavor peptide product solution is 5%-15%, and the mass concentration of glycyrrhizic acid is 0.1%-0.3%.

8. The method for preparing flavored walnuts according to claim 1, characterized in that: Flavored walnuts with rosmarinic acid flavor: the mass concentration of the Maillard flavor peptide product solution is 5%-15%, and the mass concentration of rosmarinic acid is 0.1%-0.3%.

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