A Smooth Taste Evaluation Model, Construction Method and Application of Milk Tea Based on Oral Tribology

Abstract

The present invention belongs to the technical field of food analysis, and specifically relates to a smooth taste evaluation model of milk tea based on oral tribology, a construction method and an application. The present invention conducts sensory evaluation on milk tea samples, and at the same time uses a rheometer to detect the friction coefficient of the milk tea samples, and correlates and analyzes the corresponding relationship between the smoothness score of the milk tea samples and the change law of the friction coefficient of the milk tea samples with the shear rate, so as to construct a smooth taste evaluation model of milk tea based on oral tribology. When using this model to evaluate milk tea, it can quickly, conveniently, accurately, stably and reliably predict the smoothness of milk tea products, meeting the actual needs of the milk tea beverage market.

Description

Technical Field

[0001] The present invention belongs to the technical field of food analysis, and particularly relates to a milk tea smooth taste evaluation model based on oral tribology, a construction method and an application thereof. Background Art

[0002] With the improvement of people's material life and consumption level, milk tea has gradually become a globally popular beverage. Its production cost is low, and the price is within the acceptable range for most young people, so it is loved by the majority of consumers. As a beverage compounded with dairy products and tea products, on the basis of ensuring a certain sweetness and fragrance, a smooth taste is the most critical evaluation criterion. In addition, when consumers consume, they also pay more attention to the quality and taste of milk tea, especially the smooth taste, which is an important consideration factor for consumers to choose milk tea. A pleasant taste smoothness is also considered an important indicator of high-quality milk tea. The taste smoothness of milk tea is a physical process based on a mechanical and tactile mechanism generated by the direct contact between milk tea and the oral cavity (tongue, palate), mainly acting on the mechanical receptors and nerve endings on the surface of the tongue.

[0003] At present, the sensory evaluation of milk tea at home and abroad mostly adopts the overall scoring test method, which makes the accuracy of the evaluation results greatly affected by the subjective factors of the evaluation personnel and the single setting of evaluation indicators. For example, there are differences in the judgment of the smoothness of milk tea among people of different genders, ages, and regions. Moreover, a scientific and complete sensory evaluation process takes a long time and requires a large number of representative evaluators (usually more than 20 people), which limits the speed and convenience of its evaluation. In addition, there is currently a lack of a standardized method for the sensory evaluation of milk tea, resulting in poor reliability and repeatability of the evaluation results. Therefore, the above reasons have led to the lack of a unified reference standard for the evaluation of the smooth taste of milk tea at present, especially the lack of a visual judgment method based on the physical and chemical properties and data of the milk tea system, making it difficult to quickly and accurately predict the smooth taste of milk tea during the milk tea formula design and production process, and unable to ensure the stability of the smooth taste of milk tea.

[0004] Existing studies have shown that the fat content or rheological properties of emulsion system foods (such as milk, cream, milk tea, chocolate, custard, yogurt, etc.) cannot well reflect the smooth taste of these foods. For example, analyzed from the emulsion particle size distribution or viscosity parameters, the corresponding relationship between their change laws and the taste smoothness of milk tea is not significant. Therefore, it is necessary to explore more physical and chemical indexes suitable for the evaluation of the smooth taste of milk tea. Through experiments, it is found that although the smooth taste of milk tea has a low correlation with rheological parameters and viscosity characteristics, it is closely related to oral friction. Therefore, quantifying the smooth sensory quality and expressing it with physical quantities measured by modern instruments have great application prospects in the quality control of milk tea or the research and development of new products. Based on this, the present invention aims to construct a milk tea smooth taste evaluation model based on oral tribology. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention aims to provide a milk tea smooth taste evaluation model, a construction method and an application based on oral tribology. The tribological data is obtained by detecting milk tea samples with a rheometer, and combined with the sensory evaluation scores of milk tea. Based on the correlation between the change trend of the milk tea friction coefficient and the smooth taste of milk tea, a milk tea smooth taste evaluation model based on oral tribology is constructed. When the model constructed by the present invention is used for the sensory evaluation of milk tea, it has the advantages of fast detection speed, convenient detection method, and the obtained friction coefficient can more intuitively and accurately predict the smooth taste of milk tea, with reliable results, good repeatability, and can realize the standardized detection of the smoothness of milk tea taste.

[0006] Based on the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention provides a construction method of a milk tea smooth taste evaluation model based on oral tribology, including the following steps:

[0008] S1: Conduct sensory evaluation on milk tea samples and count the smoothness scores of the milk tea samples;

[0009] S2: Use a rheometer to detect the friction coefficient of the milk tea sample to obtain the change trend of the friction coefficient of the milk tea sample with the shear rate;

[0010] S3: Conduct correlation analysis on the smoothness scores of the milk tea samples in step S1 and the change trend of the friction coefficient of the milk tea samples with the shear rate in step S2, and construct an evaluation standard for the smoothness of milk tea based on oral tribology, that is, a milk tea smooth taste evaluation model based on oral tribology.

[0011] First of all, the milk tea smooth taste evaluation model based on oral tribology constructed by the present invention is faster and more convenient for evaluating the smoothness of milk tea taste.

[0012] The traditional method for judging the smoothness of milk tea is the sensory evaluation of the crowd. This method is time-consuming and laborious. First, testers with a certain number (usually more than 20 people) are required to participate in the evaluation. The evaluation process is relatively complex, and the entire evaluation process usually takes more than 3 hours. The milk tea smooth taste evaluation model based on oral tribology constructed by the present invention is faster and more convenient for evaluating the smoothness of milk tea taste. The detection process only requires one operator, and each sample test can usually be completed within 6 minutes.

[0013] Secondly, the milk tea smooth taste evaluation model based on oral tribology constructed by the present invention has the advantages of high accuracy, visualization, and repeatability in evaluating the smoothness of milk tea taste.

[0014] The traditional sensory evaluation method for the smoothness of milk tea is usually affected by objective and subjective factors of testers, such as gender, age, region, sensitivity to smooth taste, temperature factors in the test environment, etc., resulting in large errors in evaluation results, poor reproducibility, and non-visualization of evaluation results. The results of the method of the present invention are relatively accurate, the results are visualized, and they are reproducible. Because a high-precision rheometer is used in combination with a special tribology component as the detection means, under the condition that factors such as the sample formula and production process are kept consistent, the measurement results are extremely stable and have high repeatability. The measurement data are visual icons and data, which are easy to analyze and judge.

[0015] In addition, the milk tea smooth taste evaluation model based on oral tribology constructed by the present invention can standardize the evaluation of the smoothness of the milk tea taste.

[0016] The traditional sensory evaluation method for the smoothness of milk tea lacks standardized measurement indicators and can only standardize the description of the evaluation process. The method of the present invention can perform standardized detection, and can make standardized regulations on sample preparation, evaluation method, evaluation instrument settings, parameter settings, result analysis, and smoothness judgment, further ensuring the accuracy, reliability, and stability of this method.

[0017] Furthermore, step S2 further includes constructing a taste smoothness evaluation standard model for the milk tea sample based on the change trend between the friction coefficient and the shear rate of the milk tea sample: the standard model is a curve constructed with the logarithm of the shear rate as the abscissa and the logarithm of the friction coefficient as the ordinate;

[0018] The standard model successively includes a boundary lubrication zone, a mixed lubrication zone, and a hydrodynamic lubrication zone; calculate the slope K2 at the inflection point of the curve in the mixed lubrication zone, and the shear rate vR2 at the turning point between the mixed lubrication zone and the hydrodynamic lubrication zone, and analyze whether the milk tea sample has a smooth taste based on the values of K2 and vR2.

[0019] Furthermore, step S3 further includes determining the key components affecting the smooth taste of the milk tea based on the smoothness score of the milk tea sample in step S1 and the taste smoothness evaluation standard model in step S2. Based on the key components, analyze the correlation between the slope K2 at the inflection point of the curve in the corresponding mixed lubrication zone of the key components and the shear rate vR2 at the turning point between the mixed lubrication zone and the hydrodynamic lubrication zone, and construct the milk tea smooth taste evaluation model based on oral tribology of the present invention.

[0020] Among them, the boundary lubrication region: It is defined as the curve range before the logarithm of the friction coefficient logμ on the curve reaches the first maximum value T1(logvR1, logμ1) as the logarithm of the shear rate logvR increases. In the boundary lubrication region, after the milk tea sample enters the oral cavity and contacts the tongue and the upper palate, the frictional force increases, and a lubrication film begins to form until the logarithm of the friction coefficient (logμ) reaches the maximum value (logμ1).

[0021] The mixed lubrication region: It is defined as the curve range between the point T2(logvR2, logμ2) corresponding to the end of the change trend, where after the T1 point on the curve, as the logarithm of the shear rate logvR increases, the logarithm of the friction coefficient begins to show a downward trend different from that in the boundary lubrication region. In the mixed lubrication region, the thickness of the lubrication film existing between the milk tea sample and the oral cavity (tongue, upper palate) gradually increases. The change trend of the curve is mainly affected by the viscosity of the milk tea sample, which is the main interval affecting the smooth taste and the key interval for judging the smooth taste of milk tea. Therefore, the slope K2 at the inflection point of the curve in the mixed lubrication region is used as one of the key indicators for evaluating the smooth taste of milk tea.

[0022] The hydrodynamic region: It is defined as the curve range after T2(logvR2, logμ2). The curve trend is affected by both viscosity and system stability and has no obvious effect on the smooth taste. On the one hand, if the logarithm of the friction coefficient rises as the logarithm of the shear rate increases, it indicates that this milk tea has completely formed a hydrodynamic film, and at this time, the sample contacts the hydrodynamic film in the oral cavity (tongue, upper palate). On the other hand, if the logarithm of the friction coefficient drops to a smaller value as the logarithm of the shear rate increases, it indicates that the fluid structure of this milk tea has been damaged.

[0023] Furthermore, in step S1, the milk tea sample is prepared by mixing tea water, non-dairy creamer, syrup, and ice cubes; the milk tea sample includes milk teas prepared by taking the addition amounts of non-dairy creamer and ice cubes as single-factor variables respectively.

[0024] Furthermore, in step S1, the criteria for sensory evaluation of the milk tea sample are as follows: Coordinated in the mouth, with a soft and smooth taste, having a creamy feeling but no sense of retention, scored 16 - 20 points; relatively smooth taste, no obvious sense of retention, scored 11 - 15 points; thick taste, strong sense of retention; or weak taste, weak creamy feeling, poor smoothness of the taste, scored 6 - 10 points; sticky taste, extremely strong sense of retention, extremely weak sense of fluidity; or tasteless, more like the taste of tea water, no obvious smooth taste, scored 1 - 5 points.

[0025] Further, in step S2, during the process of detecting the friction coefficient of the milk tea sample using a rheometer, the detection temperature is set at 37°C; the shear rate range is 0 - 300 mm / s; and the detection time is 6 minutes.

[0026] Further, each milk tea sample is repeatedly detected three times by the rheometer.

[0027] In a second aspect, the present invention provides a milk tea smoothness evaluation model based on oral tribology, which is constructed by the above method. The milk tea smoothness evaluation model is as follows: the slope K2 at the inflection point of the mixed lubrication region is between -0.232 and -0.0466. When vR2 < 40 mm / s, it is considered that the milk tea has a smooth taste; otherwise, it is considered that the milk tea has an unsmooth taste.

[0028] In a third aspect, the present invention provides an application of the above milk tea smoothness evaluation model based on oral tribology in milk tea R & D.

[0029] In a fourth aspect, the present invention provides a method for evaluating the smoothness of milk tea, including the following steps: using a rheometer to detect the friction coefficient of the milk tea sample to be tested, obtaining the change curve of the friction coefficient with the shear rate, and analyzing the smoothness of the milk tea sample to be tested as poor or good according to the milk tea smoothness evaluation model based on oral tribology.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] The present invention creates a method for evaluating the smoothness of milk tea based on oral tribology. By establishing the corresponding relationship between the milk tea friction coefficient index and the sensory evaluation result, a milk tea smoothness evaluation prediction model is established as a reference standard for evaluating the smoothness of milk tea. The milk tea smoothness evaluation method adopted by the milk tea smoothness evaluation model based on oral tribology constructed by the present invention is optimized through multiple experiments, and can quickly, conveniently, accurately, stably, and reliably predict the smoothness of milk tea products, meeting the actual needs of the milk tea beverage market. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the standard curve of the milk tea smoothness evaluation model;

[0033] Figure 2 It is the change curve of the friction coefficient of milk tea samples with different non-dairy creamer addition amounts with the shear rate;

[0034] Figure 3 It is the change curve of the friction coefficient of milk tea samples with different ice cube addition amounts with the shear rate;

[0035] Figure 4 It is the change curve of the friction coefficient of milk tea samples with different syrup addition amounts with the shear rate;

[0036] Figure 5 Curves of the coefficient of friction of milk tea samples at different brewing times varying with the shear rate;

[0037] Figure 6 Curves of the coefficient of friction of milk tea samples with different amounts of non-dairy creamer and ice added varying with the shear rate. Detailed implementation manners

[0038] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] Unless otherwise specified, the test methods used in the embodiments are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0040] The non-dairy creamer is SUPER non-dairy creamer of Wuxi Chaoke Food Co., Ltd.; the black tea is broken black tea of large-leaf variety.

[0041] The syrup is white granulated sugar syrup; the stirrer is a Little Bear egg beater with a rotation speed of 1290 revolutions per minute; rheometer: Thermo Scientific HAAKE Rotation Rheometer (Typ006-1659); rheometer accessories: adapter container (Adapter plate with TMP design for tribology cell (603-0347)), support bar (Contactsmade of hardened steel for tribology cell (603-0347) 30 pcs.), friction ball (Bearingballs for tribology cell (603-0347) 10 pcs.), rotating bracket (Tribology Cell withinterchangeable inserts for HAAKE MARS 40 / 60with”Connect Assist”).

[0042] Example 1

[0043] The production process of milk tea is relatively simple. Generally, it is made by mixing tea water and fresh milk, tea water and creamer, or tea water and non-dairy creamer in a certain proportion and then adding syrup, ice cubes or other auxiliary materials (such as pearls, taro balls, red beans, fruits, etc.). During the processing, factors such as the tea-milk ratio, syrup content, lipid content, whipping degree, and whether to add ice may have different degrees of influence on the smooth taste of milk tea.

[0044] In this embodiment, the factors affecting the smooth taste of milk tea are first determined, and then a milk tea smooth taste evaluation model is constructed based on the determined influencing factors. The specific method is as follows:

[0045] 1. Determine the factors affecting the smooth taste of milk tea

[0046] (1) Preparation of milk tea samples

[0047] Brew tea at a mass ratio of tea:100°C water = 1:30 for 8 minutes, stir gently, filter and collect the tea soup. Wait for the tea soup to cool to 70°C, take seven 150g portions of the tea soup, and add 5g, 20g, 30g, 40g, 50g, 60g, and 100g of non-dairy creamer respectively. Stir with a Bear brand egg beater at speed 1 for 2 minutes, add 13.5g of syrup respectively. After adding the syrup, stir with a Bear brand blender at speed 1 for 30 seconds, add 100g of edible ice cubes respectively. After adding the ice cubes, stir manually for 30 seconds, and transfer to a shaker and shake by hand for 10 seconds to obtain 7 kinds of milk tea with different non-dairy creamer contents.

[0048] Brew tea at a mass ratio of tea:100°C water = 1:30 for 8 minutes, stir gently, filter and collect the tea soup. Wait for the tea soup to cool to 70°C, take three 150g portions of the tea soup, add 50g of non-dairy creamer, stir with a Bear brand egg beater at speed 1 for 2 minutes, add 13.5g of syrup respectively. After adding the syrup, stir with a Bear brand blender at speed 1 for 30 seconds, add 5g, 50g, and 200g of edible ice cubes respectively. After adding the ice cubes, stir manually for 30 seconds, and transfer to a shaker and shake by hand for 10 seconds to obtain 3 kinds of milk tea with different ice contents.

[0049] Brew tea at a mass ratio of tea:100°C water = 1:30 for 8 minutes, stir gently, filter and collect the tea soup. Wait for the tea soup to cool to 70°C, take five 150g portions of the tea soup, add 50g of non-dairy creamer, stir with a Bear brand egg beater at speed 1 for 2 minutes, add 0% (0g), 3% (4.5g), 6% (9g), 9% (13.5g), and 12% (18g) of syrup respectively. After adding the syrup, stir with a Bear brand blender at speed 1 for 30 seconds, add 100g of edible ice cubes respectively. After adding the ice cubes, stir manually for 30 seconds, and transfer to a shaker and shake by hand for 10 seconds to obtain 5 kinds of milk tea with different syrup contents.

[0050] Brew tea at a mass ratio of tea: 100°C water = 1:30 for 4 min, 8 min, 12 min, 16 min, and 20 min respectively. Gently stir, filter and collect the tea soup. Wait for the tea soup to cool to 70°C. Take five portions of 150 g of tea soup, add 50 g of non-dairy creamer to each portion, stir with a Bear brand egg beater at speed 1 for 2 min, add 13.5 g of syrup to each portion, stir with a Bear brand blender at speed 1 for 30 s after adding the syrup, add 100 g of edible ice cubes to each portion, manually stir for 30 s after adding the ice cubes, and transfer to a shaker and shake by hand for 10 s to obtain 5 kinds of milk tea with different brewing times.

[0051] (2) Sensory evaluation

[0052] Invite 24 volunteers to conduct sensory evaluation on the prepared milk tea according to the scoring criteria described in Table 1, score the smoothness, and statistically calculate the smoothness scores of the above four groups of different milk tea samples.

[0053] Table 1 Sensory scoring criteria for milk tea

[0054]

[0055] The smoothness scores of milk tea samples containing 5 g, 20 g, 30 g, 40 g, 50 g, 60 g, and 100 g of non-dairy creamer are 10.21 points, 11.46 points, 14.96 points, 14.83 points, 15.08 points, 15.04 points, and 10.26 points respectively. Among them, the milk tea sample containing 50 g of non-dairy creamer has the highest smoothness score.

[0056] The smoothness evaluation scores of milk tea samples containing 5 g, 50 g, and 200 g of edible ice cubes are 12.78 points, 14.62 points, and 15.46 points respectively. Among them, the milk tea prepared by adding 200 g of edible ice cubes has the highest smoothness score.

[0057] The smoothness scores of milk tea samples with syrup addition amounts of 0%, 3%, 6%, 9%, and 12% are 11.75 points, 14.79 points, 14.58 points, 16.92 points, and 14.28 points respectively. Among them, the milk tea prepared with a syrup addition amount of 9% has the highest smoothness score.

[0058] The smoothness scores of milk tea samples with brewing times of 4 min, 8 min, 12 min, 16 min, and 20 min are 14.29 points, 16.32 points, 14.92 points, 15.42 points, and 15.71 points respectively. Among them, the milk tea prepared with a brewing time of 8 min has the highest smoothness score.

[0059] (3) Use a rheometer to detect the friction coefficients of the above four groups of milk tea samples

[0060] The oral tribological measurement and analysis of the above four groups of milk tea samples were carried out using a rheometer. Open the built-in software "HAAKE RheoWin Job Manager" of the rheometer, confirm the probe TR 13 45°, select the "tribology measuring" program, set the shear rate range: 0 - 300 mm / s, temperature: 37 °C, zero the instrument, add the sample to 2 / 3 of the height of the accessory, click "continue" to start the measurement, the measurement time: 6 min, and repeat each measurement three times.

[0061] The law of the change of the friction coefficient of the sample detected by the rheometer with the shear rate was studied. Through a large number of experiments and combined with data analysis, the inventor of this application summarized a friction curve with the logarithm of the shear rate (logvR) as the abscissa and the logarithm of the friction coefficient value (logμ) as the ordinate, as Figure 1 shown, and according to the curve Figure 1 shown, the sensory perception of the milk tea sample in the oral cavity was divided into three regions (see the three regions divided by the dotted line). From left to right, they are the boundary lubrication region, the mixed lubrication region, and the hydrodynamic lubrication region.

[0062] Boundary lubrication region: It is defined as the curve range before the logarithm of the friction coefficient logμ on the curve reaches the first maximum value T1 (logvR1, logμ1) with the increase of the logarithm of the shear rate logvR. In the boundary lubrication region, after the milk tea sample enters the oral cavity, it contacts the tongue and the upper palate, and the frictional force increases, and a lubrication film starts to form until the logarithm of the friction coefficient (logμ) reaches the maximum value (logμ1). The changing trend of the curve in this region is mainly affected by the addition amount of non-dairy creamer, because raw materials such as hydrogenated coconut oil and xanthan gum in the non-dairy creamer have the effect of promoting film formation.

[0063] Mixed lubrication region: It is defined as the curve range between the point T2 (logvR2, logμ2) corresponding to the end of the changing trend, where after the T1 point of the curve, with the increase of the logarithm of the shear rate logvR, the logarithm of the friction coefficient starts to show a downward trend different from that in the boundary lubrication region. In the mixed lubrication region, the thickness of the lubrication film between the milk tea sample and the oral cavity (tongue, upper palate) gradually increases. The changing trend of the curve is mainly affected by the viscosity of the milk tea sample. It is the main region affecting the smooth taste and the key region for judging the smooth taste of the milk tea. Therefore, the slope K2 at the inflection point of the curve in the mixed lubrication region is used as one of the key indicators for evaluating the smooth taste of the milk tea.

[0064] Hydrodynamic region: defined as the range of the curve after T2(logvR2, logμ2). The trend of the curve is affected by both viscosity and system stability, and has no obvious effect on the smooth taste. On the one hand, if the logarithm of the friction coefficient increases as the logarithm of the shear rate increases, it indicates that the hydrodynamic film has been fully formed in this milk tea, and at this time, the oral cavity (tongue, palate) of the sample contacts the hydrodynamic film. On the other hand, if the logarithm of the friction coefficient decreases to a smaller value as the logarithm of the shear rate increases, it indicates that the fluid structure of this milk tea has been damaged.

[0065] Based on the above model, the friction coefficient of the above four groups of different milk tea samples was analyzed with respect to the change in shear rate to construct an evaluation model for the smooth taste of milk tea based on oral tribology.

[0066] The curves of the friction coefficient of milk tea samples with different amounts of non-dairy creamer added varying with the shear rate are as Figure 2 shown. The k2 values of the curves of milk tea samples with seven different lipid contents are all less than 0. As the shear rate increases, the friction coefficient shows an obvious decreasing trend. Among them, the k2 value of the milk tea with the smoothest taste (non-dairy creamer content of 50 g) is -0.116. However, for the milk tea with a non-dairy creamer content of 100 g, k2 = -0.278, which is less than -0.232. The k2 value of this milk tea sample is twice that of the milk tea sample with the smoothest taste. This milk tea has a thick taste, a strong sense of retention, and poor smoothness. At the same time, the milk tea samples with 5 g and 20 g of non-dairy creamer added also have relatively low smoothness scores and poor smoothness, showing a bland taste, similar to that of tea water, without an obvious smooth taste. The obvious characteristic of their curves is vR2 > 40 mm / s; while for the 4 milk tea samples with higher sensory scores with 30 g, 40 g, 50 g, and 60 g of non-dairy creamer, the characteristic of their curves is that the k2 values are all greater than -0.232, and vR2 < 40 mm / s. These milk teas can all form a stable lubricating film in the oral cavity, so they have a smooth taste.

[0067] The curves of the friction coefficient of milk tea samples with different amounts of edible ice added varying with the shear rate are as Figure 3 shown. From the results of the smoothness score of the milk tea taste, it can be seen that the milk teas with 50 g and 200 g of edible ice added have higher sensory scores and a smooth taste. Their curve k2 values are both greater than -0.232, and vR2 < 40 mm / s, which conform to the curve characteristics of the smooth-tasting milk tea in the aforementioned non-dairy creamer addition amounts. The milk tea with 5 g of edible ice added has the lowest smoothness score for the milk tea taste, a thick taste, and the worst smoothness. The obvious characteristic of its curve is vR2 > 40 mm / s, which does not conform to the curve characteristics of the aforementioned smooth-tasting milk tea, and k2 > -0.0466, which is 1 / 5 of the k2 value of the milk tea with the smoothest taste. At this time, the formation of the lubricating film in the oral cavity of the milk tea is hindered, and the friction coefficient always remains at a relatively high value in the mixing zone, resulting in a thick and sticky taste.

[0068] The curves of the friction coefficient of milk tea samples with different sugar contents varying with the shear rate are as follows Figure 4 shown. From the sensory evaluation results of milk tea, it can be seen that the addition of syrup has the effect of improving the smooth taste. Compared with the sugar-free milk tea samples, the smoothness of the milk tea samples with added sugar is generally better. Among them, for the milk tea sample with a syrup addition of 9%, the tasters think that it is harmonious when entering the mouth, with a soft and smooth taste, having a creamy feeling but no lingering feeling. However, according to the data Figure 4 it can be seen that after the curve enters the mixed lubrication zone, the five different syrup addition amounts have no significant effect on the change of the friction coefficient of milk tea and there is no obvious pattern. We think this is because the syrup has no significant promoting or inhibiting effect on the formation of the emulsion during the production of milk tea and on the formation process of the lubricating film in the mouth. Therefore, we judge that the syrup addition amount is not the main factor affecting the smoothness of milk tea taste. The differences in the traditional sensory evaluation scores mainly come from the influence of the subjective factors of the sensory evaluators, especially the personal preference for sweetness, which leads to the improvement of the overall feeling of the milk tea samples, thus affecting the judgment of smoothness. Therefore, in the subsequent model establishment process of the present invention, the single factor of the syrup addition amount is removed, and the syrup addition amount with the highest smoothness score (9%) is selected in the mentioned milk tea production method, and on this basis, a milk tea smoothness evaluation model is established.

[0069] The curves of the friction coefficient of milk tea samples with different tea brewing times varying with the shear rate are as follows Figure 5 shown. From the sensory evaluation results of milk tea, it can be seen that the tea brewing time has no special contribution to the smoothness of milk tea taste. The milk tea samples prepared with different tea brewing times from 4 to 20 minutes are all relatively smooth, without obvious lingering feeling, and among them, the milk tea prepared with a tea brewing time of 8 minutes has the highest smoothness score. From Figure 5 it can be seen that after the curve enters the mixed lubrication zone, the milk tea samples with five different tea brewing times all show a downward trend, and the formation and thickening rates of the lubricating film are close and stable. Therefore, we judge that the tea brewing time is not the main factor affecting the smoothness of milk tea taste. The differences in the sensory evaluators' evaluation of the smoothness of milk tea samples with different tea brewing times mainly come from the degree of preference for the tea soup concentration itself, and the oral astringency caused by substances such as tea polyphenols. Therefore, in the subsequent model establishment process of the present invention, the single factor of the tea brewing time is removed, and the milk tea with the highest smoothness score (tea brewing time of 8 minutes) is selected in the mentioned milk tea production method as the final tea brewing time, and on this basis, a milk tea smoothness evaluation model is established.

[0070] 2. Construct a milk tea smooth taste evaluation model based on the determined influencing factors

[0071] As can be seen from the above, it is determined in this application that the key factors affecting the friction coefficient of milk tea are: the lipid content and ice content in the milk tea.

[0072] Therefore, based on the variation law of the friction coefficient of milk tea samples with different lipid contents and different ice contents as described above, the following evaluation model for the smooth taste of milk tea based on tribology is summarized: When the slope K2 at the inflection point of the mixed lubrication zone is between -0.232 and -0.0466, and at the same time vR2 < 40 mm / s, the taste is considered smooth; otherwise, the taste of the milk tea is considered not smooth. The specific analysis is as follows:

[0073] Calculate the slope k2 at the inflection point of the curve in the mixed lubrication zone, and judge whether the slope k2 of the milk tea sample in the mixed zone of the evaluation model is greater than -0.00466 and whether the friction coefficient shows a downward trend. If the slope k2 ≥ -0.0466, the formation of the lubricating film is blocked, the taste of the milk tea is thick, and the smoothness is poor; when k2 < -0.0466, when the curve enters the hydrodynamic lubrication zone, the shear rate vR2 corresponding to the turning point T2 ≥ 40 mm / s, indicating that the increase in the thickness of the lubricating film of the milk tea sample in the oral cavity is too slow, and the taste is more similar to pure water or tea, with poor smoothness; if vR2 < 40 mm / s when the curve enters the hydrodynamic lubrication zone and k2 ≤ -0.232, the taste of the milk tea is rough, with a sticky feeling and poor smoothness; when the curve k2 ∈ (-0.232, -0.0466) and vR2 < 40 mm / s, the taste is smooth.

[0074] Example 2

[0075] This example verifies the evaluation model for the smooth taste of milk tea constructed in Example 1. The specific method is as follows:

[0076] 1. Preparation of milk tea samples

[0077] Brew tea at a mass ratio of tea:100 °C water = 1:30 for 8 minutes, stir gently, filter and collect the tea soup. Wait for the tea soup to cool to 70 °C. Take two portions of 150 g of tea soup, add 10 g and 80 g of non-dairy creamer respectively, stir with a Bear egg beater at speed 1 for 2 minutes, add 13.5 g of syrup respectively, stir with a Bear blender at speed 1 for 30 seconds after adding the syrup, add 100 g of edible ice cubes respectively, stir manually for 30 seconds after adding the ice cubes, and transfer to a shaker and shake by hand for 10 seconds to obtain 2 kinds of milk tea with different non-dairy creamer contents.

[0078] Brew tea at a mass ratio of tea:100 °C water = 1:30 for 8 minutes, stir gently, filter and collect the tea soup. Wait for the tea soup to cool to 70 °C. Take two portions of 150 g of tea soup, add 50 g of non-dairy creamer, stir with a Bear egg beater at speed 1 for 2 minutes, add 13.5 g of syrup respectively, stir with a Bear blender at speed 1 for 30 seconds after adding the syrup, add 25 g and 150 g of edible ice cubes respectively, stir manually for 30 seconds after adding the ice cubes, and transfer to a shaker and shake by hand for 10 seconds to obtain 2 kinds of milk tea with different ice contents.

[0079] 2. Sensory Evaluation

[0080] Twenty-four volunteers were invited to conduct a sensory evaluation of the prepared milk tea according to the scoring criteria described in Table 1, score the smoothness, and count and calculate the smoothness scores of the four different milk tea samples. The smoothness scores of the milk tea samples with different contents of non-dairy creamer (10 g and 80 g) and different ice addition amounts (25 g and 150 g) were 10.11 points, 13.21 points, 13.52 points, and 16.25 points respectively. Among them, the milk tea with an ice addition amount of 150 g had the highest smoothness score in terms of taste.

[0081] 3. Rheometer Detection

[0082] Subsequently, a tribological measurement and analysis of the above four kinds of milk tea was carried out using a rheometer. Open the built-in software "HAAKE RheoWin Job Manager" of the rheometer, confirm the probe TR 13 at 45°, select the "tribology measuring" program, set the shear rate range: 0 - 300 mm / s, temperature: 37°C, zero the instrument, add the sample to 2 / 3 of the height of the accessory, click "continue" to start the measurement, and the measurement time is 6 minutes. Each measurement is repeated three times. The curves of the friction coefficients of the four milk tea samples changing with the shear rate are as Figure 6 shown.

[0083] 4. Result Analysis

[0084] According to Figure 6 the data calculation, the k2 value of the milk tea with an ice addition amount of 150 g was -0.170, and the vR2 value was 16 mm / s, both of which were close to the milk tea with the highest smoothness score in Example 2 (ice addition amount of 200 g), meeting the curve characteristics of the smooth-tasting milk tea in the above smoothness evaluation criteria. And the sensory evaluation results showed that its smoothness score was relatively high (16.25 points), which was consistent with the results of the smoothness evaluation model, so the verification was successful.

[0085] However, the k2 value of the milk tea sample with an ice addition amount of 25 g was -0.021, and the vR2 was 157 mm / s, which did not meet the curve characteristics of the smooth-tasting milk tea in the above smoothness evaluation criteria. At the same time, its smoothness score was 13.52 points, with a relatively low score, indicating that the sensory smoothness evaluation was consistent with the prediction results. The k2 values of the milk tea samples with 10 g and 80 g of non-dairy creamer were -0.228 and -0.258 respectively, and the vR2 values were 41 mm / s and 6 mm / s respectively. For the former, vR2 > 40 mm / s, and for the latter, k2 < -0.232, both of which did not meet the curve characteristics of the smooth-tasting milk tea in the smoothness evaluation criteria. Their smoothness scores were relatively low, 10.11 points and 13.21 points respectively, and the samples had a rough taste. The smoothness evaluations of both samples were consistent with the prediction results.

[0086] In summary, the milk tea smoothness evaluation model constructed by the present invention can correctly predict the taste smoothness of milk tea with different non-dairy creamer contents and ice addition amounts.

Claims

1. A method for constructing a smooth taste evaluation model of milk tea based on oral tribology, characterized in that, It includes the following steps: S1: Conduct a sensory evaluation on the milk tea sample and count the score of the smoothness of the milk tea sample; S2: Use a rheometer to detect the friction coefficient of the milk tea sample to obtain the changing trend of the friction coefficient of the milk tea sample with the shear rate; S3: Conduct a correlation analysis on the smoothness score of the milk tea sample in step S1 and the changing trend of the friction coefficient of the milk tea sample with the shear rate in step S2, and construct an evaluation criterion for the smoothness of milk tea based on oral tribology, that is, an evaluation model for the smooth taste of milk tea based on oral tribology; Step S2 further includes constructing an evaluation criterion model for the smoothness of the milk tea sample based on the changing trend between the friction coefficient and the shear rate of the milk tea sample: The standard model is a curve constructed with the logarithm of the shear rate as the abscissa and the logarithm of the friction coefficient as the ordinate; The standard model successively includes a boundary lubrication zone, a mixed lubrication zone, and a hydrodynamic lubrication zone; Calculate the slope K2 at the inflection point of the curve in the mixed lubrication zone, and the shear rate vR2 at the turning point between the mixed lubrication zone and the hydrodynamic lubrication zone, and numerically analyze whether the milk tea sample has a smooth taste based on K2 and vR2; Step S3 further includes determining the key components affecting the smooth taste of milk tea based on the smoothness score of the milk tea sample in step S1 and the smoothness evaluation criterion model in step S2, and analyzing the correlation between the slope K2 at the inflection point of the curve in the mixed lubrication zone corresponding to the key components and the shear rate vR2 at the turning point between the mixed lubrication zone and the hydrodynamic lubrication zone based on the key components, and constructing an evaluation model for the smooth taste of milk tea based on oral tribology.

2. The construction method according to claim 1, wherein In step S1, the milk tea sample is prepared by mixing tea water, non-dairy creamer, syrup, and ice cubes; The milk tea sample includes milk tea prepared with the addition amounts of non-dairy creamer and ice cubes as single-factor variables respectively.

3. The construction method according to claim 1, characterized in that, In step S1, the standards for the sensory evaluation of the milk tea sample are as follows: Coordinated when entering the mouth, soft and smooth in taste, with a creamy feeling but no sense of retention, scored 16 - 20 points; Relatively smooth in taste, without an obvious sense of retention, scored 11 - 15 points; Heavy in taste, with a strong sense of retention; or weak in taste, weak in creamy feeling, and poor in smoothness of taste, scored 6 - 10 points; Viscous in taste, with an extremely strong sense of retention and extremely weak fluidity; or tasteless in taste, more like the taste of tea water, without an obvious smooth taste, scored 1 - 5 points.

4. The construction method according to claim 1, wherein In step S2, during the process of using a rheometer to detect the friction coefficient of the milk tea sample, the detection temperature is set at 37°C; The shear rate range is 0 - 300 mm / s; The detection time is 6 minutes.

5. The construction method according to claim 4, wherein Each milk tea sample is repeatedly detected three times by the rheometer.

6. The construction method according to any one of claims 1 to 5, characterized in that, When the slope K2 at the inflection point of the mixed lubrication zone is between -0.232 and -0.0466, and at the same time vR2 < 40 mm / s, it is considered that the milk tea has a smooth taste, otherwise it is considered that the milk tea does not have a smooth taste.

7. Application of the construction method according to claim 6 in milk tea research and development.

8. A method for evaluating the smooth taste of milk tea, characterized in that, It includes the following steps: Use a rheometer to detect the friction coefficient of the milk tea sample to be tested, obtain the changing curve of the friction coefficient with the shear rate, and analyze whether the smoothness of the milk tea sample to be tested is poor or good according to the construction method described in claim 6.

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