阅读说明：本技术 一种基于模拟口腔咀嚼评价米饭品质的方法 (Method for evaluating quality of rice based on simulated oral chewing ) 是由 刘国栋 魏海燕 张洪程 张超 黄帅 陈有成 张海鹏 邢志鹏 陈英龙 崔培媛 章思 于 2020-05-14 设计创作，主要内容包括：本发明公开了一种基于模拟口腔咀嚼评价米饭品质的方法,属于食品测量技术领域。本发明方法基于挤压装置,通过模拟口腔咀嚼环境,根据“咀嚼”过程中力和还原糖含量的变化,分析米饭的口感,能够实时动态监测,客观评价米饭质地和滋味,且评价结果更加准确、全面,具有非常好的市场前景。(The invention discloses a method for evaluating rice quality based on simulated oral chewing, and belongs to the technical field of food measurement. The method is based on the extrusion device, analyzes the taste of the rice according to the force and the content change of the reducing sugar in the chewing process by simulating the chewing environment of the oral cavity, can dynamically monitor in real time and objectively evaluate the texture and the taste of the rice, has more accurate and comprehensive evaluation results, and has very good market prospect.)

1. A method for evaluating the quality of rice, which is characterized by comprising the following steps:

(1) preparing artificial simulated saliva in advance, wherein 20-40U of low-temperature amylase is contained in every 3-4mL of artificial simulated saliva;

(2) placing 25-30g of rice in an extrusion device, adding 3-4mL of artificial simulated saliva obtained in the step (1) at room temperature, and circularly extruding for 40-60 times;

(3) after extrusion, inactivating enzyme, and then measuring the content of reducing sugar in the extruded cooked rice; meanwhile, work done in the cyclic reciprocating extrusion process is calculated based on the extrusion force in the cyclic reciprocating extrusion process;

(4) and (4) evaluating the taste of the cooked rice according to the work done in the cyclic reciprocating extrusion process obtained in the step (3) and the content of reducing sugar in the cooked rice after extrusion.

2. The method of claim 1, wherein the method of preparing artificial simulated saliva comprises the steps of:

(A) adding 0.3-0.5g of sodium chloride, 0.3-0.5g of potassium chloride, 0.7-0.9g of calcium chloride, 0.7-0.9g of sodium dihydrogen phosphate, 0.005-0.01g of sodium sulfide, 0.5-1.5g of urea and 0.05-0.1g of guar gum into 1L of water, and adjusting the pH to 6.8-7 by adopting sodium hydroxide to obtain a mixed solution;

(B) weighing 3-4mL of mixed liquor obtained in the step (A), adding 20-40U of low-temperature amylase, and uniformly mixing to obtain the artificial simulated saliva.

3. The method of claim 1, wherein work W performed by the nth extrusion in the cyclic reciprocating extrusion process_n＝∫F_n×s_n＝w_A×EXP(-n/n_A)+w_B×EXP(-n/n_B)+C_n(ii) a Wherein n is the number of times of the cyclic reciprocating extrusion; w_nDoing work in the nth extrusion process; f_nThe extrusion force in the nth extrusion process; s_nThe movement distance of the extrusion force in the nth extrusion process is shown; w is a_A、w_BRespectively representing the energy lost by the breakable structure and the non-breakable structure in the rice in each extrusion process; n is_A、n_BRespectively representing the attenuation rate constants of the breakable structure and the unbreakable structure in the rice to do work in each extrusion process; c_nFitting constants for the nth extrusion run.

4. A method according to claim 3, characterized by cycling the work W performed during the reciprocal extrusion_{General assembly}＝W₁+W₂+W₃+W₄+…W_n(ii) a n is the number of times of the cyclic reciprocating extrusion.

5. The method according to claim 1, wherein said reducing sugar content is determined colorimetrically using 3, 5-dinitrosalicylic acid.

6. The method according to claim 1, wherein in the step (4), the chewiness of the cooked rice is evaluated by using work done during the cyclic reciprocating extrusion, and the digestibility of the cooked rice is evaluated by using the content of reducing sugar in the extruded cooked rice.

7. The method of claim 6, wherein when the work done during the cyclic reciprocating extrusion is less than 35J, the chewiness of the rice is weak, etc.; when the work in the process of circularly reciprocating extrusion is not less than 35J and not more than 40J, the chewiness of the rice is medium; when the work done in the cyclic reciprocating extrusion process is higher than 40J, the chewiness of the rice is strong, etc.

8. The method according to claim 6, wherein when the reducing sugar content is less than 70mg/g of rice, the digestibility of the rice is difficult, etc.; the digestibility of the cooked rice is moderate when the content of reducing sugar is not less than 70mg/g and not more than 75 mg/g; when the content of reducing sugar is more than 75mg/g, the digestibility of the cooked rice is easy, etc.

9. The method according to claim 1, wherein the discrimination of the evaluation method is verified using known different types of rice.

10. The method of claim 1, wherein the accuracy of the evaluation method is verified using human true taste tests.

Technical Field

The invention relates to a method for evaluating rice quality based on simulated oral chewing, and belongs to the technical field of food measurement.

Background

Rice is one of three staple grains in the world, about half of the world population uses rice as staple food, and the proportion is closer to 2/3 in east Asia, southeast Asia and south Asia countries. China is the largest rice producing country and consuming country and is an essential staple food for daily life of residents in China. At present, with the improvement of grain high-yield technology and the reduction of the consumption of staple food by everyone, the problem of 'fullness' of residents is solved. However, with the development of economy and the improvement of the living standard of residents, the consumption concept of residents gradually changes from 'full' to 'good', so that rice with 'good taste' is increasingly paid attention by consumers and researchers, and is certainly to become an important development direction of the rice consumption market.

At present, the most important means for evaluating the mouthfeel of rice by researchers is artificial sensory evaluation. The specific operation is that volunteers with tissue experience score the indexes of hardness, viscosity, cold rice retrogradation and the like of the rice, and the taste of the rice is evaluated according to the scores. However, the evaluation method is time-consuming and labor-consuming, the evaluation result is obviously influenced by personal preference, living habits, dietary culture and the like of testers, and the evaluation method has strong subjectivity, large fluctuation of the evaluation result, poor stability and low reliability. In addition, researchers also adopt single indexes such as amylose content, protein content and rice paste viscosity to evaluate the taste of the rice, related results have great limitation, and the real taste of the rice is difficult to accurately reflect. In recent years, with the development of food measuring techniques, texture meters are gradually used by researchers to evaluate the texture of cooked rice. However, the current research methods adopted by researchers, including the "three-grain" method and the "rice cake" method, require measurement after the rice is sufficiently cooled to obtain stable measurement results, and the measurement methods cannot dynamically analyze the chewing process of the mouth and provide information about the digestion of the rice during the chewing process of the mouth, and the obtained evaluation results are different from the real taste of the rice.

Disclosure of Invention

In order to solve the problems, the invention provides a method which can simulate the oral chewing of rice, dynamically analyze the texture and digestion of the rice in the chewing process and more accurately and comprehensively evaluate the taste of the rice.

The invention has strong professional requirements and large subjective factor influence aiming at the current method for evaluating the taste of rice by manual taste; the invention aims to provide a method for more accurately and comprehensively simulating the mouth chewing of rice, which is used for evaluating the mouth feeling of the rice. The method is based on a texture analyzer extrusion device, the mouth feeling of rice is analyzed according to the variation of strength and reducing sugar content in the chewing process by simulating the chewing environment of the mouth of a person, so that the result is closer to the real situation and is more objective and accurate.

In order to achieve the purpose, the invention adopts the following technical scheme:

the method for evaluating the quality of the rice comprises the following steps:

(1) preparing artificial simulated saliva in advance, wherein 20-40U of low-temperature amylase is contained in every 3-4mL of artificial simulated saliva;

(2) placing 25-30g of rice in an extrusion device, adding 3-4mL of artificial simulated saliva obtained in the step (1) at room temperature, and circularly extruding for 40-60 times;

(3) after extrusion, inactivating enzyme, and then measuring the content of reducing sugar in the extruded cooked rice; meanwhile, work done in the cyclic reciprocating extrusion process is calculated based on the extrusion force in the cyclic reciprocating extrusion process;

(4) and (4) evaluating the taste of the cooked rice according to the work done in the cyclic reciprocating extrusion process obtained in the step (3) and the content of reducing sugar in the cooked rice after extrusion.

In one embodiment of the present invention, the method for preparing artificial simulated saliva includes the following steps:

(A) adding 0.3-0.5g of sodium chloride, 0.3-0.5g of potassium chloride, 0.7-0.9g of calcium chloride, 0.7-0.9g of sodium dihydrogen phosphate, 0.005-0.01g of sodium sulfide, 0.5-1.5g of urea and 0.05-0.1g of guar gum into 1L of water, and adjusting the pH to 6.8-7 by adopting sodium hydroxide to obtain a mixed solution;

(B) weighing 3-4mL of mixed liquor obtained in the step (A), adding 20-40U of low-temperature amylase, and uniformly mixing to obtain the artificial simulated saliva.

In one embodiment of the present invention, the work W of the n-th extrusion in the cyclic reciprocating extrusion process_n＝∫F_n×s_n＝w_A×EXP(-n/n_A)+w_B×EXP(-n/n_B)+C_n(ii) a Wherein n is the number of times of the cyclic reciprocating extrusion; w_nDoing work in the nth extrusion process; f_nThe extrusion force in the nth extrusion process; s_nThe movement distance of the extrusion force in the nth extrusion process is shown; w is a_A、w_BRespectively representing the energy lost by the breakable structure and the non-breakable structure in the rice in each extrusion process; n is_A、n_BRespectively representing the attenuation rate constants of the breakable structure and the unbreakable structure in the rice to do work in each extrusion process; c_nFitting constants for the nth extrusion run.

In one embodiment of the invention, the work W performed during said cyclic back and forth extrusion is characterized in that_{General assembly}＝W₁+W₂+W₃+W₄+…W_n(ii) a n is the number of times of the cyclic reciprocating extrusion.

In one embodiment of the invention, the reducing sugar content is determined using a 3, 5-dinitrosalicylic acid colorimetric method.

In one embodiment of the present invention, in the step (4), the chewiness of the cooked rice is evaluated using the work done during the cyclic reciprocating extrusion, and the digestibility of the cooked rice is evaluated using the content of reducing sugar in the cooked rice after extrusion.

Based on the simulated oral chewing method of the present invention, the evaluation criteria of the rice taste are shown in table 1:

TABLE 1 evaluation of Rice taste ratings

In one embodiment of the present invention, when the work done during the cyclic reciprocating extrusion is less than 35J, the chewiness of the rice is weak, etc.; when the work in the process of circularly reciprocating extrusion is not less than 35J and not more than 40J, the chewiness of the rice is medium; when the work done in the cyclic reciprocating extrusion process is higher than 40J, the chewiness of the rice is strong, etc.

In one embodiment of the present invention, when the reducing sugar content is less than 70mg/g of rice, the digestibility of the rice is difficult, etc.; the digestibility of the cooked rice is moderate when the content of reducing sugar is not less than 70mg/g and not more than 75 mg/g; when the content of reducing sugar is more than 75mg/g, the digestibility of the cooked rice is easy, etc.

A method for simulating oral chewing of rice specifically comprises the following steps:

step 1: adding 0.3-0.5g of sodium chloride, 0.3-0.5g of potassium chloride, 0.7-0.9g of calcium chloride, 0.7-0.9g of sodium dihydrogen phosphate, 0.005-0.01g of sodium sulfide, 0.5-1.5g of urea and 0.05-0.1g of guar gum into 1L of water, and adjusting the pH value to 6.8-7 by adopting sodium hydroxide to prepare artificial simulated saliva;

step 2: measuring 3-4mL of the artificial simulated saliva prepared in the step 1, adding 0.01-0.02g of low-temperature amylase (2000U/g), and fully mixing and dissolving;

and step 3: accurately weighing 25-30g of rice, placing into an extrusion device, and controlling the temperature to be 37 ℃;

and 4, step 4: adding the artificial simulated saliva prepared in the step 2 into the extrusion device in the step 3, circularly and repeatedly extruding for 20-30 times, and simulating oral chewing;

and 5: inactivating enzyme of the extruded cooked rice, and measuring reducing sugar content (C)_RMg/g rice); the content of reducing sugar is measured by a 3, 5-dinitrosalicylic acid (DNS) colorimetric method, and the method is accurate and convenient;

step 6: simulating the content of reducing sugar after chewing according to the work (W) done by the extrusion force (F) in the reciprocating extrusion process; the mouthfeel of the rice was evaluated.

In one embodiment of the present invention, the discrimination of the evaluation method is verified using known different types of rice.

In one embodiment of the invention, the accuracy of the evaluation method is verified by using a human real taste experiment.

Compared with the existing method for evaluating the mouthfeel of the rice, the method provided by the invention has the following obvious advantages and progresses:

(1) the determination conditions of the invention can reflect the chewing environment of people more truly, and the obtained result is objective and accurate, has high truth and strong reference. The similarity degree between the simulated oral chewing and the real oral chewing reaches more than 90 percent.

(2) The invention can realize dynamic analysis of the mouthfeel of the rice in the chewing process and can obtain detailed simulation data of the rice from the mouth to before swallowing.

(3) The invention can simultaneously obtain the force change and the digestibility data of the whole process of the rice chewing, and the obtained result can more comprehensively and deeply evaluate the taste of the rice.

Drawings

FIG. 1 is a graph showing the variation of the forces applied during the simulated chewing process of the oral cavity by glutinous rice, soft rice and ordinary rice;

FIG. 2 is a graph showing the work doing and fitting of glutinous rice, soft rice and ordinary rice in the process of simulating chewing in the oral cavity.

Detailed Description

The invention discloses a method for evaluating the taste of rice based on simulated oral chewing. The person skilled in the art can use the contents of the patent for reference, and make appropriate parameter modification to establish a similar evaluation method. It is expressly intended that all such substitutions and modifications are included in the present disclosure. The feasibility of the method of the invention is verified by the specific embodiments, and related personnel can realize or expand the application range of the invention by making appropriate changes or combinations according to the patent.

The process of determining the content of reducing sugar by using a DNS method comprises the following steps: after simulating the chewing in the oral cavity, the rice is firstly inactivated in boiling water, then is uniformly dispersed, and is added into a volumetric flask in a constant volume mode. 1.5mL of sample is measured and added into a 25mL colorimetric tube, and then 1mL of deionized water and 2mL of DNS reagent are added and mixed uniformly. After boiling water heating for 5 minutes, it was quickly transferred to ice water for cooling. Then, the volume is determined to be 25mL, the mixture is uniformly mixed, and the absorbance value is measured at 540 nm. And (3) calculating the content of reducing sugar by taking anhydrous glucose as a standard substance.