Green tea cookies with high antioxidant activity and sensory quality and preparation method of green tea cookies

Abstract

The invention discloses green tea cookies with high antioxidant activity and sensory quality and a preparation method of the green tea cookies, and belongs to the technical field of food processing. The green tea cookies disclosed by the invention are prepared from the following raw materials in parts by mass: 5-11 parts of pretreated green tea powder, 0.2-0.4 part of stevioside, 70-80 parts of butter, 50 parts of eggs and 70-100 parts of flour. By optimizing the formula and process parameters of the cookies, the green tea cookies which take pretreated green tea powder, stevioside, butter and low-gluten wheat flour as raw materials are designed. The product prepared by the preferable preparation scheme disclosed by the invention is obviously superior to the traditional green tea cookies in the aspects of texture characteristics (moderate hardness and stable fracture work), sensory quality (uniform color, crisp taste and strong tea fragrance) and antioxidant activity (tea polyphenol content, flavone content and free radical scavenging rate).

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, in particular to a green tea cookie with high antioxidant activity and sensory quality and a preparation method thereof. Background Art

[0002] As an important component of baked goods, cookies occupy an important position in the global food market with their crispy texture, convenient eating method and wide taste adaptability. However, traditional cookie recipes generally rely on a high proportion of sucrose (usually 20-35% of the recipe) and saturated fat (butter added at 25-40%), resulting in a generally high calorie density of the product. At the same time, in order to maintain texture stability and shelf life, artificial emulsifiers (such as monoglycerides), preservatives (such as potassium sorbate) and synthetic pigments are often added. These ingredients are in significant conflict with contemporary consumers' demands for "clean labels" and health. In this context, replacing traditional high-calorie raw materials with natural functional ingredients to develop cookie products that have both sensory quality and health attributes has become one of the key research directions of the food science and industry communities.

[0003] Among these, the use of natural functional ingredients to replace traditional raw materials has become a research hotspot due to their safety and significant nutritional benefits. Natural functional ingredients not only reduce the caloric density of products but also impart physiological activities such as antioxidant, anti-inflammatory, and gut microbiome regulation, enabling the evolution of cookies from "common snacks" to "functional health foods."

[0004] While some research has attempted to improve cookie recipes using natural ingredients such as plant polyphenols, dietary fiber, and plant protein, numerous technical difficulties remain in practical application. For one thing, the addition of natural ingredients can negatively impact the product's texture, leading to increased hardness, decreased crispness, and a rough texture. Furthermore, natural functional ingredients are less stable and prone to oxidative degradation during high-temperature baking, hindering their full nutritional benefits. Furthermore, the interaction mechanisms between natural ingredients and traditional raw materials remain unclear, and a lack of systematic theoretical support for process optimization has resulted in technical bottlenecks in the industrialized production of functional cookies.

[0005] Therefore, in-depth research on the mechanism of action of natural functional ingredients in cookie systems, achieving a balance between product sensory quality and health attributes through scientific process optimization, and developing low-calorie functional cookies that are nutritious and have a good taste can not only fill the gaps in existing technologies and provide a theoretical basis and practical guidance for nutritional improvement technologies in the field of deep food processing, but also promote the healthy and sustainable development of the baking food industry and meet consumers' urgent needs for healthy, nutritious and diversified foods. It has important academic value and industrial application prospects. Summary of the Invention

[0006] The object of the present invention is to provide a green tea cookie with high antioxidant activity and sensory quality and a preparation method thereof, so as to solve the above-mentioned problems in the background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention is to provide a green tea cookie, the raw materials of which are calculated by weight and include:

[0009] 5-11 parts of pre-processed green tea powder, 0.2-0.4 parts of stevia, 70-80 parts of butter, 50 parts of eggs and 70-100 parts of flour.

[0010] Preferably, the pretreated green tea powder is β-cyclodextrin-encapsulated green tea powder.

[0011] Preferably, the preparation method of the β-cyclodextrin embedded green tea powder comprises the following steps:

[0012] Beta-cyclodextrin is dissolved in water, and then green tea powder is added and stirred to obtain an inclusion compound, and then solid-liquid separation is performed to obtain the beta-cyclodextrin embedded green tea powder.

[0013] Preferably, the mass ratio of the β-cyclodextrin to the green tea powder is 5:1.

[0014] Preferably, the stirring and mixing time is 2 hours.

[0015] Preferably, the raw materials of the green tea cookies are, by mass, as follows:

[0016] 8 parts of pretreated green tea powder, 0.4 parts of stevia, 80 parts of butter, 50 parts of eggs and 90 parts of flour.

[0017] The second technical solution of the present invention is to provide a method for preparing the above-mentioned green tea cookies, comprising the following steps:

[0018] Beat the butter and stevioside together, then add the remaining ingredients to obtain the cookie batter;

[0019] The cookie batter is extruded into a cookie shape to obtain a cookie green body, and the green tea cookie is baked to obtain the green tea cookie.

[0020] Preferably, the baking temperature is 150° C. and the baking time is 20 minutes.

[0021] The beneficial technical effects of the present invention are as follows:

[0022] The present invention designs a green tea cookie with pretreated green tea powder, steviol glycosides, butter, and low-gluten wheat flour as raw materials by optimizing the formula and process parameters of cookies. The product prepared by the preferred preparation scheme of the present invention is significantly superior to traditional green tea cookies in terms of texture characteristics (moderate hardness, stable breaking work), sensory quality (uniform color, crisp taste, rich tea aroma) and antioxidant activity (tea polyphenol content, flavonoid content, free radical scavenging rate). Microbiological testing shows that the total colony count, coliform group and mold of the prepared green tea cookies were not detected, which meets the food safety standards. The research results of the present invention provide a theoretical basis and technical reference for the development of low-sugar, high-antioxidant functional baked foods, and promote the application of deep processing of green tea in the food industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 The three-dimensional response surface plots and contour plots of the two-factor interaction for the sensory scores of the green tea cookies in Example 1 are shown. (a) shows the three-dimensional response surface plot and contour plot for butter and flour, (b) shows the three-dimensional response surface plot and contour plot for stevia and pretreated green tea powder, and (c) shows the three-dimensional response surface plot and contour plot for pretreated green tea powder and flour.

[0025] Figure 2 The three-dimensional response surface plot and contour plot of the two-factor interaction for the sensory scores of the green tea cookies in Example 1. (a) is the three-dimensional response surface plot and contour plot for butter and pretreated green tea powder, and (b) is the three-dimensional response surface plot and contour plot for stevia and flour.

[0026] Figure 3 The three-dimensional response surface diagram and contour map of the two-factor interaction of hardness of the green tea cookies in Example 1.

[0027] Among them, (a) is the three-dimensional response surface diagram and contour map of butter and flour, and (b) is the three-dimensional response surface diagram and contour map of pretreated green tea powder and flour.

[0028] Figure 4 The three-dimensional response surface diagram and contour diagram of the two-factor interaction of the fracture work of the green tea cookies in Example 1 are shown.

[0029] Among them, (a) is the three-dimensional response surface diagram and contour map of stevia and pretreated green tea powder, and (b) is the three-dimensional response surface diagram and contour map of butter and stevia.

[0030] Figure 5 The three-dimensional response surface diagram and contour map of the two-factor interaction of color difference of the green tea cookies in Example 1 are shown.

[0031] Among them, (a) is the three-dimensional response surface diagram and contour map of butter and pretreated green tea powder, and (b) is the three-dimensional response surface diagram and contour map of butter and flour.

[0032] Figure 6 The three-dimensional response surface diagram and contour map of the two-factor interaction of color difference of the green tea cookies in Example 1 are shown.

[0033] Among them, (a) is the three-dimensional response surface diagram and contour map of butter and stevia, and (b) is the three-dimensional response surface diagram and contour map of stevia and pretreated green tea powder.

[0034] Figure 7 The DPPH radical scavenging rate comparison of green tea cookie dilutions of different mass concentrations and vitamin C prepared using the product of Example 1 is shown in FIG. (a) shows green tea cookie dilutions of different mass concentrations, and (b) shows vitamin C.

[0035] Figure 8 Comparison of DPPH radical scavenging rates of cookie diluents of varying concentrations prepared using the product of Comparative Example 1 and commercially available green tea cookies. (a) shows cookie diluents of varying concentrations, and (b) shows commercially available green tea cookies. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0037] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0038] Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention pertains. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention. It should be noted that any details not described herein are conventional procedures in the art and are not the focus of the present invention.

[0039] The terms “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0040] Green tea powder and steviol glycosides, as natural and healthy ingredients, show significant potential in improving the high-sugar and high-fat properties of cookies. Studies have shown that green tea, rich in tea polyphenols (such as epigallocatechin gallate (EGCG)), has outstanding antioxidant activity (with a DPPH free radical scavenging rate of >70%), which can extend the shelf life of products by effectively inhibiting lipid oxidation and reduce risk factors associated with chronic diseases. As a high-intensity, low-calorie natural sweetener (approximately 300 times sweeter than sucrose and only 1 / 300 of the calories of sucrose), steviol glycosides can not only significantly reduce product calories, but also have physiological functions such as lowering blood lipids and blood sugar and anti-oxidation, making it an ideal choice for replacing sucrose. The application of steviol glycosides in the cookie baking process can also inhibit the formation of harmful substances such as acrylamide. Given these functional properties, it can be used as an auxiliary ingredient in functional foods.

[0041] This study aims to explore the application of deep-processing technology in improving food nutrition and developing novel foods. By analyzing experimental data, the study investigates the impact of deep-processing technology on food quality, with the goal of developing nutritious, flavorful, and diverse foods, thereby providing new ideas and methods for the healthy development of the food industry. Using green tea powder and steviol glycosides as the primary raw materials, the study optimized the processing parameters of green tea cookies using a single-factor combined with a response surface methodology.

[0042] This study focuses on the influence of key factors such as green tea powder, steviol glycosides, butter, and flour addition on the overall quality of cookies (including indicators such as color, taste, texture, and antioxidant activity). The aim is to establish the optimal ratio of each raw material in order to develop nutritious, low-calorie cookies with excellent taste. The study also provides an in-depth analysis of their antioxidant activity and mechanism of action, providing new ideas and methods for the deep processing and utilization of green tea. This study not only provides a new direction for the healthier upgrading of cookie products and expands the application of green tea deep processing, but also provides a theoretical basis and practical guidance for the application of food deep processing technology in improving the nutritional value of food and developing new healthy foods, thereby promoting the development of the food industry towards a healthier, more nutritious, and diversified direction to meet the needs of consumer upgrades.

[0043] The main raw materials and reagents used in the experimental process of the present invention are shown in Table 1-1, and the main instruments and equipment are shown in Table 1-2.

[0044] Table 1-1 Main raw materials and reagents

[0045]

[0046]

[0047] Table 1-2 Main instruments and equipment

[0048] Experimental equipment model Manufacturer Galanz household oven KW40-PQ4 Guangdong Galanz Electric Appliance Manufacturing Co., Ltd. CT3 Texture Analyzer 10KA Brookfield, Inc. High-speed crusher FW100 Tianjin Test Instrument Co., Ltd. Integrated freeze dryer SCIENTZ-100F / A Guangzhou Ruifeng Experimental Equipment Co., Ltd. Colorimeter CM-700D Konica Minolta (China) Investment Co., Ltd. electronic scales 305 Yiming Electronic Instrument Co., Ltd. UV spectrophotometer Uc-5500PC Shanghai Yuanxi Instrument Co., Ltd.

[0049] The pretreated green tea powder of the present invention is β-cyclodextrin-encapsulated green tea powder. The specific preparation method is as follows: β-cyclodextrin is prepared into a saturated aqueous solution. At a constant temperature of 50°C, green tea powder is slowly added to the solution until the mass ratio of β-cyclodextrin to green tea powder is 5:1. Stirring is continued for 2 hours to allow the green tea powder to fully enter the cavity of the β-cyclodextrin to form an inclusion complex. After the reaction is completed, the solution is cooled to room temperature and allowed to stand for 12 hours. The precipitate is then collected by filtration and vacuum dried (40°C, vacuum degree -0.08 MPa) to obtain the encapsulated green tea powder.

[0050] Unless otherwise specified, the "room temperature" in the present invention is 10-30°C.

[0051] The raw materials used in the following examples and comparative examples of the present invention are all commercially available products.

[0052] Example 1

[0053] A method for preparing green tea cookies, which requires the following steps: softening butter → beating sugar and oil → pouring in whole egg yolk liquid → adding dry powder → shaping → baking → cooling → finishing. The specific steps are as follows:

[0054] (1) Soften the butter and beat the sugar and oil

[0055] Place butter (70g, 75g, 80g, 85g, and 90g) at room temperature and wait until softened enough to be easily pressed with your finger. Then, add stevioside (0.2g, 0.3g, 0.4g, 0.5g, and 0.6g) and beat the butter with an electric whisk for 5 minutes, until the butter lightens in color, expands in volume, and develops a smooth texture. Next, gradually add 50g of beaten egg to the beaten butter in three additions, stirring thoroughly after each addition to ensure the egg is completely incorporated into the butter.

[0056] (2) Mixed powder materials

[0057] Sift 100-mesh pretreated green tea powder (5 g, 8 g, 11 g, 14 g, 17 g), low-gluten wheat flour (70 g, 80 g, 90 g, 100 g, 110 g) and 1 g of edible salt in sequence, mix with the raw material system of step (1), use a rubber spatula to stir gently from bottom to top, avoid rotating stirring to prevent the flour (low-gluten wheat flour) from forming gluten, until there is no dry powder in the mixture, to obtain cookie batter.

[0058] (3) Shaping and baking

[0059] Place the cookie batter into a piping bag and evenly shape the cookies onto a baking sheet lined with baking paper, ensuring each cookie is the same size. This will create the cookie dough. Preheat the oven to 150°C for 10 minutes. Place the cookie dough in the oven, set the top and bottom heat to 150°C, and bake for 20 minutes. Monitor the cookies as they brown.

[0060] (4) Cooling and finished products

[0061] After baking, the cookies were immediately taken out of the oven and placed on a cooling rack to cool to room temperature in a natural environment, thereby completing the cookie production process (the sample with 8 g of pretreated green tea powder, 0.4 g of stevioside, 80 g of butter, and 90 g of low-gluten wheat flour was recorded as the optimal finished product of green tea cookies).

[0062] Comparative Example 1

[0063] The only difference between the optimal finished green tea cookie of Example 1 and that of Example 1 is that the addition of pre-treated green tea powder is omitted.

[0064] Comparative Example 2

[0065] The only difference between the optimal finished green tea cookies of Example 1 and the pre-treated green tea powder is that the pre-treated green tea powder is replaced with an equal mass of sodium alginate-encapsulated green tea powder. The specific preparation method of the sodium alginate-encapsulated green tea powder is as follows:

[0066] First, sodium alginate is prepared into a 2wt% aqueous solution. After fully dissolving, green tea powder is added (sodium alginate to green tea powder mass ratio is 3:1) and stirred to form a uniform dispersion. Next, calcium chloride solution (concentration of 0.5 mol / L) is added to crosslink the sodium alginate to form a gel, within which the green tea powder is embedded. Mechanical agitation is used to break up the gel, forming microspheres. Finally, the embedded product is centrifuged, washed, and freeze-dried.

[0067] Comparative Example 3

[0068] The only difference between the optimal finished green tea cookies of Example 1 and the pretreated green tea powder is that the chitosan-embedded green tea powder of the same mass is replaced. The specific preparation method of the chitosan-embedded green tea powder is as follows:

[0069] Chitosan was dissolved in a 1wt% acetic acid solution to prepare a 3wt% chitosan solution. Green tea powder was then added (to a chitosan to green tea powder mass ratio of 4:1). Ultrasonic dispersion was performed for 30 minutes to ensure uniform mixing. Spray drying was performed at an inlet air temperature of 160°C, an outlet air temperature of 70°C, and a feed rate of 20 mL / min to produce microcapsules encapsulating the green tea powder.

[0070] Effect verification

[0071] 1. Experimental Methods

[0072] 1.1 Single-factor experiment

[0073] Taking the sensory score, hardness, breaking work and color difference of cookies as indicators, single factor experiments were conducted to investigate the effects of the addition amount of pretreated green tea powder, stevioside, butter and flour on the quality of green tea cookies.

[0074] 1.1.1 Addition amount of pre-treated green tea powder

[0075] Set 0.4g of stevioside, 80g of butter, and 100g of flour as fixed parameters, and set 5 gradients of pretreated green tea powder addition (5g, 8g, 11g, 14g, 17g). The effects on the quality of cookies were systematically studied to determine the optimal addition amount of pretreated green tea powder.

[0076] 1.1.2 Stevioside addition amount

[0077] Under a constant formula of 80g butter, 8g pretreated green tea powder, and 100g flour, five levels of steviol glycoside addition were set at 0.2g, 0.3g, 0.4g, 0.5g, and 0.6g to evaluate their effects on cookie quality and ultimately determine the optimal ratio of steviol glycosides.

[0078] 1.1.3 Butter addition amount

[0079] Taking 0.4g of stevioside, 8g of pretreated green tea powder and 100g of flour as the benchmark conditions, five groups of butter addition amounts were set, namely 70g, 75g, 80g, 85g and 90g, and their effects on the quality of cookies were analyzed to determine the ideal amount of butter addition.

[0080] 1.1.4 Flour addition amount

[0081] Based on a fixed combination of 0.4g stevioside, 8g pretreated green tea powder and 80g butter, five levels of flour (low-gluten wheat flour) addition were set at 70g, 80g, 90g, 100g and 110g to investigate their effects on the quality of cookies and ultimately determine the optimal amount of flour.

[0082] 1.2 Response surface optimization experiment

[0083] Based on a single-factor experiment, a Box-Behnken experimental design was used to develop an optimization plan. Four variables were selected as experimental factors: pretreated green tea powder dosage (A), steviol glycoside ratio (B), butter content (C), and flour content (D). Response surface methodology was used to conduct the optimization experiment, using cookie sensory evaluation scores (Y), hardness (Z), work of fracture (K), and color difference (X) as responses. The level coding of each factor is detailed in Tables 1-3. A mathematical model was established to explore the impact of the interactions between these factors on product quality.

[0084] Table 1-3 Response surface experiment table

[0085]

[0086] 1.3 Sensory evaluation method

[0087] The sensory evaluation was conducted by a team of 10 food sensory assessors within a 20-minute window after sample preparation. A quantitative assessment was conducted based on a system of indicators, including color, appearance, texture, flavor, and foreign matter content. Specific scoring criteria are provided in Tables 1-4. The final sensory score was calculated by weighting each indicator and taking the arithmetic mean.

[0088] Table 1-4 Sensory evaluation of green tea cookies

[0089]

[0090]

[0091] 1.4 Green Tea Biscuit Quality Analysis

[0092] 1.4.1 Determination of color difference of green tea cookies

[0093] The color difference of green tea cookies was measured using a CM-700 colorimeter. The center of the front of the sample was selected as the measurement location, and the L*, a*, and b* values, along with the color difference description, were recorded. Each sample was tested in triplicate. The Hunter (Lab) color system was used, with L* representing brightness and a* and b* representing chromaticity. The color difference was calculated using the following formula:

[0094] Color difference value = 100-[(100-L*)²+a*²+b*2]1 / 2

[0095] 1.4.2 Determination of Green Tea Cookie Texture

[0096] Texture was measured using a CT3 texture analyzer equipped with a TA7 three-point bend probe and a TA-TPB base. The optimal finished product of green tea cookies was used as the test object. The sample was placed on the base bracket, and the blade was adjusted to be directly above the product. Three parallel measurements were performed to determine hardness and fracture work.

[0097] 1.4.3 Determination of total polyphenols and flavonoids in green tea cookies

[0098] (1) Determination of total polyphenol content: 2.0 g of the best finished product of green tea cookies was accurately weighed, and 70% ethanol solution was added to 100 mL. Ultrasonic extraction was performed at 45°C and 300 W for 15 min. The extract was then centrifuged at 5000 r / min for 15 min, and the supernatant was collected and set aside.

[0099] Based on the Folin-ciocalteus method, gallic acid was used as the standard, the absorbance was measured at a wavelength of 760 nm, and the total polyphenol content was calculated according to the following formula:

[0100]

[0101] Where: Y is the total polyphenol content, mg / g; n is the dilution factor; C is the total polyphenol concentration in 1 mL of sample solution, mg / mL; V is the sample dilution volume, mL; m is the sample mass, g.

[0102] (2) Determination of total flavonoid content: The NaNO2-Al(NO3)3 method was used, with rutin as the standard. The absorbance was measured at a wavelength of 510 nm, and the total flavonoid content was calculated according to the following formula:

[0103]

[0104] Where: Y is the total flavonoid content, mg / g; n is the dilution factor; C is the total flavonoid concentration in 1 mL of sample solution, mg / mL; V is the sample dilution volume, mL; m is the sample mass, g.

[0105] 1.4.4 DPPH free radical scavenging ability determination

[0106] The antioxidant activity of green tea cookies was evaluated using a DPPH free radical scavenging test. The specific test method was as follows: 5.000 g of the optimal green tea cookie product was accurately weighed and diluted to 100 mL with distilled water. Ultrasonic extraction was performed at 45°C and 300 W for 1 hour. The extract was then centrifuged at 5000 rpm for 20 minutes. The precipitate was discarded, and the supernatant was collected and diluted to 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, 10.0, 12.0, 14.0, and 16.0 mg / mL of green tea cookie dilution. 2.00 mL of each green tea cookie dilution was then added, followed by 2.00 mL of a 0.1 mol / L DPPH solution. The mixture was reacted in the dark for 50 minutes, and the absorbance (A1) was measured at 517 nm. Take 2.00mL of deionized water as a blank and measure the absorbance as A0; take another 2.00mL of sample extract, add 2.00mL of anhydrous ethanol, measure the absorbance A2, and calculate the DPPH free radical scavenging rate (Q) of samples with different concentrations according to the DPPH free radical scavenging rate. Use the sample mass concentration as the horizontal axis and the DPPH free radical scavenging rate as the vertical axis to construct a standard curve. Calculate the half-maximal inhibitory concentration IC50 based on the standard regression equation. All samples were measured in triplicate, and the scavenging rate results were averaged. The calculation formula for the DPPH free radical scavenging rate (Q) is as follows:

[0107]

[0108] Where: A1—sample absorbance; A2—absorbance of anhydrous ethanol reagent; A0—absorbance of distilled water blank.

[0109] 1.4.5 Microbial content

[0110] The determination of total colony count is carried out in accordance with the relevant provisions of the "National Food Safety Standard - Determination of Total Colony Count for Food Microbiological Examination" (GB4789.2-2022) and the standard method for coliform count is carried out in accordance with the "National Food Safety Standard - Coliform Count for Food Microbiological Examination" (GB 4789.3-2022).

[0111] 1.5 Data Analysis and Processing

[0112] Single-factor experimental data were processed using Microsoft Excel 2019 and presented as mean ± standard deviation. Data from the response surface optimization experiment were processed and analyzed using Design-Expert 13.0 software, and data visualization charts were created using Origin Pro 24 software.

[0113] 2 Results and Analysis

[0114] 2.1 Single-factor experimental results

[0115] Table 2-1 Effects of various addition amounts on the sensory quality, color difference, hardness, and breaking work of the green tea cookies of Example 1

[0116]

[0117] 2.1.1 Effect of the amount of pretreated green tea powder added on the sensory quality and color difference of green tea cookies

[0118] Pre-treated green tea powder has a unique tea aroma, and its tea polyphenols provide antioxidant properties, which can effectively extend the shelf life of foods. Table 2-1 shows how the sensory quality and color of cookies are affected by the amount of pre-treated green tea powder added.

[0119] As the proportion of pre-treated green tea powder added gradually increased, the sensory scores of the green tea cookies showed an upward and then downward trend. A detailed analysis revealed that when the pre-treated green tea powder addition level was below 8g, the cookies' appearance was primarily brown, and the green tea flavor was relatively weak. When the pre-treated green tea powder addition level exceeded 8g, the cookies' color became too emerald green, and a bitter taste emerged, masking the cookie's original aroma. At 8g, the cookies' color appeared natural, their aroma was rich, and their sensory evaluation reached its peak, with a sensory score of 83 points.

[0120] Pretreated green tea powder, a featured ingredient in green tea cookies, not only imparts a distinctive green appearance but also significantly impacts their color difference and sensory quality. Table 2-1 shows that as the amount of pretreated green tea powder added increases, the color difference values ​​of the cookies initially increase and then decrease, demonstrating that moderate addition of pretreated green tea powder can enhance the cookies' greenness and sensory appeal. However, excessive addition can lead to excessive color darkening, impacting sensory quality. Specifically, when the amount of pretreated green tea powder added ranges from 5g to 11g, the color difference values ​​increase, the cookie's greenness is enhanced, and the sensory quality improves, with a vibrant and uniform color and a balanced taste and aroma. However, when the amount added exceeds 8g, the color difference values ​​decrease, the cookie's color becomes dull, and the taste becomes bitter and rough. An addition of 8g of pretreated green tea powder optimally balances greenness and sensory quality.

[0121] 2.1.2 Effect of Stevioside Addition on Sensory Quality and Color Difference of Green Tea Cookies

[0122] As a low-calorie sweetener, stevioside provides sweetness without significantly increasing calories, helping to improve the taste and shelf life of cookies, making them suitable for healthy eating. Table 2-1 details the effect of stevioside addition on the sensory quality of cookies. Experimental data shows that as the stevioside addition level increases, the sensory evaluation scores of cookies show a pattern of first increasing and then decreasing. When the stevioside addition level is below 0.4g, the sensory scores of the cookies show no significant difference. At 0.4g, the sensory score reaches a maximum of 79.6 points, indicating that the cookies have an appropriate sweetness, a balanced taste, and a rich aroma. Further increases in stevioside addition lead to a continuous decline in the sensory scores. This is because excessive stevioside content weakens the non-enzymatic browning reaction during baking, resulting in a lighter color, a bitter aftertaste, and increased hardness. Therefore, a stevioside addition level of 0.4g is recommended.

[0123] The color difference and sensory quality of green tea cookies show a pattern of first increasing and then decreasing as the amount of stevia added varies. When the stevia addition level is within the optimal range of 0.4g, the color difference values ​​gradually increase, improving the cookie's color and overall sensory quality. However, when the stevia addition level exceeds 0.4g, the color difference values ​​begin to decrease, becoming dull and overly sweet. Table 2-1 shows that a stevia addition level of 0.4g achieves the optimal balance between color difference and sensory quality.

[0124] 2.1.3 Effect of Butter Addition Amount on Sensory Quality and Color Difference of Green Tea Cookies

[0125] As the proportion of butter added increases, the sensory scores of the cookies show a trend of first increasing and then decreasing. When the butter addition exceeds 80g, the excessive butter leads to insufficient dough cohesion, making the batter too thin and difficult to shape. The resulting cookies appear collapsed, have a fuzzy texture, and are oily and have an odor, which reduces their overall eating experience. When the butter addition is less than 80g, the low butter content causes the cookies to be too dry or lack sufficient fat, making the dough hard and difficult to squeeze, affecting their overall taste and flavor.

[0126] When the amount of butter added was 80g, the sensory score of the cookies reached the highest point of 78.1 points, indicating that at this amount of butter, the cookies performed best in terms of taste, aroma and appearance.

[0127] As the amount of butter added gradually increases, the color difference values ​​of the cookies show a pattern of first increasing and then decreasing. When the butter addition ranges from 70g to 80g, the color difference values ​​increase, the cookie's color brightness increases, and the sensory quality improves. However, when the addition exceeds 80g, the color difference values ​​decrease, and the cookie's color becomes dull and uneven. Table 2-1 shows that an addition of 80g of butter optimally balances the cookie's color brightness and sensory quality.

[0128] 2.1.4 Effect of flour addition on sensory quality and color difference of green tea cookies

[0129] Flour, rich in gluten and starch, effectively regulates the dough's network structure, resulting in crispy, crispy cookies with a distinct texture. The correlation between flour addition and cookie sensory quality is shown in Table 2-1.

[0130] As the amount of flour added increases, the sensory scores of the cookies show a trend of first increasing and then decreasing. When the amount of flour used exceeds 100g, the excessive flour will make the dough less cohesive, resulting in a batter that is too thin and difficult to shape. The baked cookies will collapse, the surface texture will be blurred, and there will be oil stains and a strange smell, affecting the overall eating experience. When the amount of flour used is less than 100g, the low flour content will make the cookies too dry or lack fat, the dough will become hard, and it will be difficult to squeeze flowers, affecting the taste and flavor of the cookies. When the amount of flour used is 100g, the sensory score of the cookies reaches the highest point of 80.2 points, indicating that at this amount, the cookies have the best taste, aroma, and appearance.

[0131] As flour usage increases, the color variation of cookies shows a trend of first increasing and then decreasing. When the flour addition level is between 70-100g, color variation increases, and the cookies achieve a relatively balanced color, texture, and aroma. Above 100g, color variation decreases, the color becomes too dark or unevenly distributed, and the texture tends to be dry and rough. Table 2-1 shows that a flour addition level of 100g achieves the optimal balance between color uniformity and sensory quality.

[0132] 2.1.5 Texture Analysis of Green Tea Cookies

[0133] 2.1.5.1 Analysis of the effect of pre-treated green tea powder addition on the texture of green tea cookies

[0134] Table 2-1 shows that as the amount of pretreated green tea powder added increases, the textural and sensory qualities of the biscuits initially increase and then decrease. When the amount of pretreated green tea powder added is between 5g and 8g, the biscuits' hardness and work of fracture increase, demonstrating a firmer texture and greater resistance to fracture. At this point, the biscuits' taste, aroma, and overall sensory experience are more balanced. When the amount of pretreated green tea powder added exceeds 8g, the hardness and work of fracture decrease, the texture becomes brittle and fragile, and a bitter or rough taste is introduced, affecting the biscuits' overall taste and sensory quality.

[0135] 2.1.5.2 Analysis of the effect of stevia addition on the texture of green tea cookies

[0136] As shown in Figure 2-1, the textural sensory quality of green tea cookies shows an initial upward and then downward trend with increasing stevia addition. When stevia addition levels range from 0.2g to 0.4g, the hardness and work of fracture of the cookies gradually increase, improving the texture. The cookies become firmer and less prone to breakage, achieving a balanced taste and aroma. However, when stevia addition levels exceed 0.4g, the hardness and work of fracture begin to decrease, the texture becomes brittle and easily breakable, and unwanted sweetness or roughness is introduced, affecting the overall taste and sensory quality of the cookies.

[0137] 2.1.5.3 Analysis of the effect of butter addition on the texture of green tea cookies

[0138] Table 2-1 shows that the textural sensory qualities of green tea cookies initially increase and then decrease with increasing butter addition. When the butter addition level is between 70g and 80g, the cookie's hardness and work of fracture gradually increase, improving its textural properties and achieving a more balanced taste and aroma. However, when the butter addition level exceeds 80g, the hardness and work of fracture begin to significantly decrease, and the texture becomes brittle and fragile. This also introduces an excessive greasiness, impacting the cookie's overall taste and sensory quality. This indicates that a butter addition level of 80g achieves the optimal balance of the cookie's textural sensory qualities.

[0139] 2.1.5.4 Analysis of the effect of flour addition on the texture of green tea cookies

[0140] Table 2-1 shows that increasing the amount of flour added significantly impacts the texture and sensory quality of the green tea cookies, with an overall trend of increasing hardness and initially decreasing and then increasing work of fracture. Table 2-1 shows that when the flour addition is 100g, the cookies achieve the highest hardness and work of fracture, achieving a moderate crispness without breaking easily.

[0141] 2.2 Response surface optimization test results

[0142] 2.2.1 Response surface model establishment and variance analysis

[0143] The present invention designed and carried out a response surface optimization experiment with three levels for the four factors affecting the quality of green tea cookies. The experimental design scheme and results are shown in Table 2-2. After performing multivariate fitting analysis on each response value, the quadratic regression equation was obtained:

[0144] Y=89.62-0.2750A+0.5667B-1.48C+0.2417D+0.1750AB-2.12AC+3.38AD+3.77BC-2.00BD+3.20CD-5.26A 2 -4.88B 2 -4.88C 2 -5.04D 2

[0145] Z=+2600.00+74.50A-1.58B+90.00C-25.75D+3.00AB-12.25AC-105.25AD-21.50BC-30.25BD-173.25CD-384.83A 2 -288.96B 2 -149.58C 2 -78.96D 2

[0146] K=+12.84-0.6417A+0.1142B-0.7958C-0.1450D+0.7250AB-0.5750AC-0.3750AD-1.39BC-0.2125BD+0.3275CD-3.48A 2 -2.13B 2 -2.97C 2 -2.65D 2

[0147] X=+45.44-0.3267A-0.3642B-0.4233C+0.1375D+0.7775AB-0.8575AC+0.9000AD+0.8150BC-0.1150BD+0.0075CD-1.18A 2 -1.95B 2 -0.6264C 2 -0.5977D 2

[0148] Response surface design and results

[0149] Table 2-2 Response surface experimental design and results

[0150]

[0151]

[0152] 2.3 Two-factor interaction analysis

[0153] 2.3.1 Contour lines and response surface plots of two-factor interactions in sensory evaluation

[0154] Figure 1 The three-dimensional response surface plots and contour plots of the two-factor interaction for the sensory scores of the green tea cookies in Example 1 are shown. (a) shows the three-dimensional response surface plot and contour plot for butter and flour, (b) shows the three-dimensional response surface plot and contour plot for stevia and pretreated green tea powder, and (c) shows the three-dimensional response surface plot and contour plot for pretreated green tea powder and flour.

[0155] Figure 2 The three-dimensional response surface plot and contour plot of the two-factor interaction for the sensory scores of the green tea cookies in Example 1. (a) is the three-dimensional response surface plot and contour plot for butter and pretreated green tea powder, and (b) is the three-dimensional response surface plot and contour plot for stevia and flour.

[0156] Depend on Figure 1 、 Figure 2 It can be seen that the response surface plots of the three groups of factors, butter and pretreated green tea powder (AC, F = 18.35, p = 0.0008), butter and flour (AD, F = 46.28, p < 0.0001), and stevia and pretreated green tea powder (BC, F = 57.90, p < 0.0001), are steep and the contour lines are obviously elliptical, indicating that their interaction has the most significant effect on the sensory score.

[0157] Among them, the F value for stevia and pretreated green tea powder (BC) was the highest (57.90), and the p-value was highly significant (<0.0001), indicating that the interaction between the two had the most significant effect on the sensory quality of the biscuits. The interaction between butter and flour (AD) was second (F=46.28), but the response surface curve was more complex, indicating a nonlinear effect. Furthermore, the interaction between pretreated green tea powder and flour (CD) (F=41.60, p<0.0001) was also significant, but its contour ellipse was slightly lower than that of BC and AD. These results were fully consistent with the analysis of variance.

[0158] 2.3.2 Contour lines and response surface plots for the two-factor interaction of hardness

[0159] Figure 3 The three-dimensional response surface diagram and contour map of the two-factor interaction of hardness of the green tea cookies in Example 1.

[0160] Among them, (a) is the three-dimensional response surface diagram and contour map of butter and flour, and (b) is the three-dimensional response surface diagram and contour map of pretreated green tea powder and flour.

[0161] Depend on Figure 3 It can be seen that the response surface curves of flour addition (D) and butter addition (A), and flour addition (D) and pretreated green tea powder addition (C) are steep, and the contour lines are significantly elliptical, indicating that the effect of their interaction on hardness is the most prominent. The above results are completely consistent with the variance analysis.

[0162] 2.3.3 Contour lines and response surface plots of the two-factor interaction of fracture work

[0163] Figure 4 The three-dimensional response surface diagram and contour diagram of the two-factor interaction of the fracture work of the green tea cookies in Example 1 are shown.

[0164] Among them, (a) is the three-dimensional response surface diagram and contour map of stevia and pretreated green tea powder, and (b) is the three-dimensional response surface diagram and contour map of butter and stevia.

[0165] Depend on Figure 4 As can be seen, the response surface plots for the addition of stevia (B) and pretreated green tea powder (C) show steep curves and significant elliptical contours, indicating that their interaction has the most significant impact on the work of fracture. Furthermore, the response surface plots for the addition of butter (A) and stevia (B) (AB, F = 4.89, p = 0.0441) also show some surface variation, indicating a significant but weak interaction effect between their ratios on texture. These results are consistent with the ANOVA results.

[0166] 2.3.4 Color Difference Two-Factor Interaction Contour Lines and Response Surface Plots

[0167] Figure 5 The three-dimensional response surface diagram and contour map of the two-factor interaction of color difference of the green tea cookies in Example 1 are shown.

[0168] Among them, (a) is the three-dimensional response surface diagram and contour map of butter and pretreated green tea powder, and (b) is the three-dimensional response surface diagram and contour map of butter and flour.

[0169] Figure 6 The three-dimensional response surface diagram and contour map of the two-factor interaction of color difference of the green tea cookies in Example 1 are shown.

[0170] Among them, (a) is the three-dimensional response surface diagram and contour map of butter and stevia, and (b) is the three-dimensional response surface diagram and contour map of stevia and pretreated green tea powder.

[0171] Figure 2-6 In the figure, the left figure is a three-dimensional response surface diagram, and the right figure is a contour diagram.

[0172] Depend on Figure 5 、 Figure 6The response surface curves for butter and stevia (AB, F = 30.43, p < 0.0001), butter and pretreated green tea powder (AC, F = 37.01, p < 0.0001), butter and flour (AD, F = 40.77, p < 0.0001), and stevia and pretreated green tea powder (BC, F = 33.44, p < 0.0001) were steep, with contour lines showing significant elliptical shapes, indicating that the interaction between these factors significantly affected the response values. The response surface contour lines corresponding to the addition of butter and flour exhibited a highly elliptical shape, indicating that the interaction between the two factors was the most prominent, significantly affecting the color quality of the biscuits more than the other factors. This conclusion is consistent with the results of the analysis of variance.

[0173] 2.3.5 Variance Analysis of Sensory Evaluation Regression Model

[0174] Table 2-3 Variance analysis of sensory evaluation regression model

[0175] Sources of variance sum of squares degrees of freedom mean square F-number P-value Significance Model 626.52 14 44.75 45.45 <0.0001 ** A 0.9075 1 0.9075 0.9217 0.3533 B 3.85 1 3.85 3.91 0.0679 C 26.40 1 26.40 26.82 0.0001 ** D 0.7008 1 0.7008 0.7118 0.4130 AB 0.1225 1 0.1225 0.1244 0.7295 AC 18.06 1 18.06 18.35 0.0008 * AD 45.56 1 45.56 46.28 <0.0001 ** BC 57.00 1 57.00 57.90 <0.0001 ** BD 16.00 1 16.00 16.25 0.0012 * CD 40.96 1 40.96 41.60 <0.0001 ** <![CDATA[A 2 ]]> 179.75 1 179.75 182.57 <0.0001 ** <![CDATA[B 2 ]]> 154.26 1 154.26 156.68 <0.0001 ** <![CDATA[C 2 ]]> 154.26 1 154.26 156.68 <0.0001 ** <![CDATA[D 2 ]]> 164.71 1 164.71 167.30 <0.0001 ** residuals 13.78 14 0.9846 Lack of Fit 10.58 10 1.06 1.32 0.4247 Pure error 3.21 4 0.8020 sum 640.31 28

[0176] Note: ** indicates that the difference is extremely significant (P<0.01), and * indicates that there is a significant difference (P<0.05).

[0177] The results of variance analysis of the regression model are presented in Table 2-3. From the data in Table 2-3, it can be seen that the model has extremely significant significance (P<0.0001), while the lack of fit term does not show significance (P>0.05), and the correlation coefficient R 2 =0.9785 shows that the model can explain 97.85% of the data variation, indicating that the model has a good goodness of fit. Based on the relative size of the F value, it can be clearly seen that the order of influence of each factor on the sensory quality of green tea cookies is: C>B>A>D, that is, the amount of pretreated green tea powder added>the amount of stevia added>the amount of butter added>the amount of flour added. Among the influencing factors, the linear term C, the interaction terms AD, BC, CD, and the quadratic term A 2 、B 2 、C 2 、D 2 It has a very significant effect on the sensory quality of green tea cookies (P<0.0001); the effect of the interaction term BD on the sensory quality of green tea cookies reaches a significant level (P<0.05).

[0178] 2.3.6 Variance Analysis Table of Hardness Regression Model

[0179] Table 2-4 Variance analysis of hardness regression model

[0180] Sources of variance sum of squares degrees of freedom mean square F-number P-value Significance Model 1.588E+06 14 1.134E+05 99.62 <0.0001 ** A 48641.33 1 48641.33 42.72 <0.0001 ** B 1850.08 1 1850.08 1.62 0.2232 C 94696.33 1 94696.33 83.17 <0.0001 ** D 7252.08 1 7252.08 6.37 0.0243 * AB 5041.00 1 5041.00 4.43 0.0539 AC 600.25 1 600.25 0.5272 0.4797 AD 44310.25 1 44310.25 38.92 <0.0001 ** BC 1849.00 1 1849.00 1.62 0.2233 BD 3660.25 1 3660.25 3.21 0.0946 CD 1.153E+05 1 1.153E+05 101.23 <0.0001 ** <![CDATA[A 2 ]]> 9.362E+05 1 9.362E+05 822.30 <0.0001 ** <![CDATA[B 2 ]]> 5.233E+05 1 5.233E+05 459.64 <0.0001 ** <![CDATA[C 2 ]]> 1.716E+05 1 1.716E+05 150.75 <0.0001 ** <![CDATA[D 2 ]]> 54951.36 1 54951.36 48.26 <0.0001 ** residuals 15939.75 14 1138.55 Lack of Fit 12659.75 10 1265.98 1.54 0.3588 Pure error 3280.00 4 820.00 sum 1.604E+06 28

[0181] Note: ** indicates that the difference is extremely significant (P<0.01), and * indicates that there is a significant difference (P<0.05).

[0182] The results of variance analysis of the regression model are listed in Table 2-4. Analyzing the data in this table, it can be seen that the regression model shows extremely significant differences (P<0.0001), while the difference in the lack of fit term is not significant (P=0.3588>0.05). At the same time, the model correlation coefficient R 2 The value of F value is 0.9901, which means that 99.01% of the observed data can be accurately described by this model, indicating that the model has an excellent fitting effect. According to the ranking results of F value, the order of the effect of each factor on the hardness of cookies is: C>A>D>B, among which the effect of the amount of pre-treated green tea powder added is the most significant, followed by the amount of butter added, the amount of flour added and the amount of stevia added. The linear terms C, A, D, the interaction terms AD, CD and the quadratic term A 2 、B 2 、C 2 、D 2 The effect on hardness reached an extremely significant level; the effect of the linear term D on hardness was significant (P<0.05).

[0183] 2.3.7 Analysis of variance of fracture work regression model

[0184] Table 2-5 Analysis of variance of fracture work regression model

[0185]

[0186]

[0187] Note: ** indicates that the difference is extremely significant (P<0.01), and * indicates that there is a significant difference (P<0.05).

[0188] The variance analysis results of the fracture work regression model are listed in Table 2-5. According to the data in the table, the model reached an extremely significant level (P<0.0001), while the lack of fit term did not show a significant difference (P=0.3807>0.05), and the correlation coefficient R 2 Reaching 0.9645 means that the model can effectively explain 96.45% of the data variation, showing a good fitting effect. Based on the F value, the influence of each factor on the fracture work is: C>A>D>B, that is, the influence of the amount of pre-treated green tea powder is the most prominent, followed by the amount of butter and flour, and the influence of stevia is relatively the smallest. Further analysis found that the linear terms C, A and the quadratic term A 2 、B 2 、C 2 、D 2The effect on the fracture work of green tea cookies reached an extremely significant level (P<0.0001); and the effects of the interaction terms AB and BC on the fracture work also showed significant differences (P<0.05).

[0189] 2.3.8 Analysis of variance of color difference regression model

[0190] Table 2-6 Analysis of variance of color difference regression model

[0191]

[0192]

[0193] Note: ** indicates that the difference is extremely significant (P<0.01), and * indicates that there is a significant difference (P<0.05).

[0194] The variance analysis results of the color difference regression model are shown in Table 2-6. From the data in the table, it can be seen that the model is extremely significant (P<0.0001), the lack of fit item has no significant difference (P=0.6539>0.05), and the correlation coefficient R 2 The value of F value is 0.9763, which means that the model can effectively explain 97.63% of the data variation, showing a good fitting effect. According to the F value, the influence of each factor is ranked, and the order of influence on the fracture work is: C>B>A>D. That is, the influence of the amount of pre-treated green tea powder is the most prominent, followed by the amount of stevia and butter, and the amount of flour has the least influence. Further analysis found that the linear terms C, A, B and the quadratic term A 2 、B 2 、C 2 、D 2 The effect on green tea cookies reached an extremely significant level (P<0.0001); and the interaction terms AB, AC, AD, and BC also significantly affected their sensory quality (P<0.05).

[0195] 2.4 Verification Experiment

[0196] In the present invention, with the help of response surface optimization design experimental method, the optimal formula parameter combination of green tea cookies was successfully clarified. The results obtained after optimization showed that when the raw material addition amount was set to 8.68g of pre-treated green tea powder, 0.42g of stevia, 79.98g of butter, and 90.12g of flour, the product sensory score could reach 89.62 points, the hardness was 2613g, the fracture work was 12.84mJ, and the color difference was 45.442. For ease of actual operation, the formula was adjusted to 8g of pre-treated green tea powder, 0.4g of stevia, 80g of butter, and 90g of flour. The actual sensory score after adjustment was 90.2 points, which was highly consistent with the theoretical prediction value. This not only verified the reliability of the experimental data, but also proved that the response surface optimization scheme adopted was practical. This result shows that the formula parameters after appropriate rounding can still maintain the best quality characteristics of the product.

[0197] 2.5 Results and analysis of microbial indicators of green tea cookies

[0198] Based on the optimal finished green tea cookie product in Example 1, a green tea cookie preparation experiment was conducted, and the finished product was tested for microbiological indicators. The final quality inspection results are summarized in Tables 2-7.

[0199] Table 2-7 Analysis of microbial indicators

[0200] Test items Standard indicators Test results <![CDATA[Total number of colonies / CFU·g -1 > <![CDATA[≤10 5 ]]> Not detected <![CDATA[Coliform group / CFU·g -1 > <![CDATA[≤10 2 ]]> Not detected <![CDATA[mold / CFU·g -1 > Not to be detected Not detected

[0201] 2.6 Results and analysis of antioxidants in green tea cookies

[0202] Based on the optimal finished product of green tea cookies in Example 1, the antioxidant active ingredients in the green tea cookie samples were quantitatively tested. After determination using a standardized process, the antioxidant functional substance content results are summarized in Tables 2-8.

[0203] Table 2-8 Analysis of antioxidant active substances

[0204] Test items content National indicators <![CDATA[Polyphenol / mg·g -1 > 11.2±0.5 - <![CDATA[Flavonoid / mg·g -1 > 3.52±0.67 -

[0205] The data in Tables 2-8 show that the green tea cookies of the present invention are rich in various antioxidant active ingredients, such as flavonoids and polyphenols. These ingredients significantly enhance the product's health-promoting properties through their antioxidant mechanism of scavenging free radicals. This not only enhances the nutritional value of the cookies but also provides scientific support for the research, development, and marketing of new functional foods.

[0206] 2.7 DPPH free radical scavenging rate results and analysis

[0207] In the present invention, vitamin C was selected as the positive control for DPPH radical scavenging ability, and the DPPH radical scavenging ability of substances with antioxidant activity in green tea cookies was determined. In the study, Excel 2019 and Origin pro2024 software were used to complete the drawing of the standard curve and the derivation of the regression equation, and the DPPH radical scavenging rate data curve and equation of vitamin C and green tea cookie extracts with different mass concentrations were obtained.

[0208] Figure 7 The DPPH radical scavenging rate comparison of green tea cookie dilutions of different mass concentrations and vitamin C prepared using the product of Example 1 is shown in FIG. (a) shows green tea cookie dilutions of different mass concentrations, and (b) shows vitamin C.

[0209] like Figure 7 As shown in the figure, the scavenging effect of green tea cookie dilution on DPPH free radicals showed a concentration-dependent characteristic. When the concentration was ≤0.10 mg / mL, the scavenging rate increased linearly with the increase of concentration, and the fitting equation was Y=4.5117X+0.0980(R 2 =0.9991), demonstrating an excellent correlation. Notably, the growth rate of DPPH radical scavenging slowed significantly after the concentration exceeded 0.12 mg / mL, indicating that the system reached saturation in free radical scavenging. The calculated half-maximal inhibitory concentration (IC50) value for this extract was 5.56 mg / mL, indicating that the antioxidant activity of total phenolic compounds was positively correlated with free radical scavenging activity within the range of ≤0.12 mg / mL.

[0210] Figure 8 Comparison of DPPH radical scavenging rates of cookie diluents of varying concentrations prepared using the product from Comparative Example 1 and commercially available matcha red bean cookies (Bibizan Matcha Red Bean Cookies, sample after removing the red bean). (a) shows cookie diluents of varying concentrations, and (b) shows commercially available green tea cookies.

[0211] Depend on Figure 8 It can be seen that there is a significant correlation between the DPPH free radical scavenging rate and mass concentration of cookies without pre-treated green tea powder. When the mass concentration is in the range of 0.00-0.20 mg / mL, the scavenging rate increases linearly with the increase of concentration, and the fitting equation is Y=0.3403X-0.3944(R 2 =0.9886), indicating that its antioxidant activity is highly correlated with concentration. Notably, the equation showed a clearance rate of 0.24% at a low concentration of 0.02 mg / mL, while at 0.20 mg / mL, the clearance rate reached 3.18%, indicating that cookies without pretreated green tea powder had weak antioxidant capacity.

[0212] The relationship between DPPH free radical scavenging rate and mass concentration of commercially available green tea cookies is as follows: Figure 8 As shown in (b), the fitting equation is Y=185.14X+3.638(R 2 =0.9694). At a low concentration of 0.02 mg / mL, the clearance rate reached 5.8%, and when the concentration was increased to 0.20 mg / mL, the clearance rate reached 36.9%. However, there is still a certain gap compared with the product of Example 1 of the present invention.

[0213] 2.8 Effects of different green tea powder pretreatment schemes on product performance

[0214] The products of Comparative Examples 2-3 and the product of Example 1 (each sample contained 8g of green tea powder, 0.4g of stevia, 80g of butter, and 90g of flour, respectively) were subjected to sensory evaluation and DPPH free radical scavenging rate testing (during the DPPH free radical scavenging rate test, the cookie samples were prepared into a 0.2mg / mL cookie diluent before testing). The test results are shown in Tables 2-9 and 2-10.

[0215] Table 2-9 Sensory evaluation results

[0216]

[0217] Table 2-10 DPPH free radical scavenging rate test results

[0218] Experimental groups DPPH free radical scavenging rate (%) Example 1 80 Comparative Example 2 35 Comparative Example 3 75

[0219] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A green tea cookie, characterized in that: Raw materials, calculated by mass, include: 5-11 parts of pre-processed green tea powder, 0.2-0.4 parts of stevia, 70-80 parts of butter, 50 parts of eggs and 70-100 parts of flour.

2. The green tea cookie according to claim 1, characterized in that: The pretreated green tea powder is beta-cyclodextrin embedded green tea powder.

3. The green tea cookie according to claim 2, characterized in that: The preparation method of the β-cyclodextrin embedded green tea powder comprises the following steps: Beta-cyclodextrin is dissolved in water, and then green tea powder is added and stirred to obtain an inclusion compound, and then solid-liquid separation is performed to obtain the beta-cyclodextrin embedded green tea powder.

4. The green tea cookie according to claim 3, characterized in that: The mass ratio of the β-cyclodextrin to the green tea powder is 5:

1.

5. The green tea cookie according to claim 3, characterized in that: The stirring and mixing time is 2 hours.

6. The green tea cookie according to claim 1, characterized in that: The raw materials of the green tea cookies are calculated by weight as follows: 8 parts of pretreated green tea powder, 0.4 parts of stevia, 80 parts of butter, 50 parts of eggs and 90 parts of flour.

7. A method for preparing the green tea cookie according to any one of claims 1 to 6, characterized in that: The following steps are involved: Beat the butter and stevioside together, then add the remaining ingredients to obtain the cookie batter; The cookie batter is extruded into a cookie shape to obtain a cookie green body, and the green tea cookie is baked to obtain the green tea cookie.

8. The preparation method according to claim 7, characterized in that The baking temperature is 150° C. and the baking time is 20 minutes.

Images