| China is the largest country in the world for rice production and consumption.Rice is the main food in people's daily life,With the rapid economic development and the continuous improvement of material living conditions of our country,people also have higher and higher requirements for the taste quality of rice,but if people want to eat delicious,nutritious,healthy and safe rice,choosing a high-quality rice variety is an essential part.Jilin Province,as a major province in grain production,has many varieties of rice,so how to screen out high-quality rice is a crucial issue.And no matter how good the quality of the rice variety is,if there is not a good cooking process and method,it will not be able to produce good-tasting rice,so the cooking process of rice is also an important factor affecting the quality of rice.Therefore,based on the principle of "cooking good rice and choosing good rice ",this paper designs the orthogonal experiment scheme of variable power change time,and uses rice cooker to cook rice to find out a kind of cooking rice with good taste,good taste and low energy consumption.Then,10 kinds of Jilin rice were cooked according to this cooking process,and the cooked rice was subjected to sensory evaluation,texture analyzer measurement,food taste analyzer measurement,cooking characteristics measurement and low-field nuclear magnetic resonance analyzer measurement.Finally,the correlation analysis was performed based on the rheometer measurement indicators G '(Elastic modulus),G "(Viscous modulus)and G" / G'(Loss factor,tan?),cooking characteristics measurement indicators(expansion rate and water absorption rate),and the different forms of water(combined water,non-flowable water and free water)measured by low-field nuclear magnetic resonance equipment and sensory evaluation indicators,and establish a regression equation to predict and evaluate the taste quality of rice.The main research contents of this paper are as follows:(1)Design of variable parameter orthogonal test schemeElectric rice cookers with a rated voltage of 220 V and a rated power of 200 W are used to cook rice at different constant powers.Experiments have found that cooking rice with different constant power requires different time,so the process of cooking rice will be affected by power and time.In this paper,based on the rated voltage and rated power of the rice cooker,the cooking time is 13.80 min and the rated power is 200 W.Each test scheme is divided into three stages,so the time of each stage is 4.60 min,and the power is designed to change up and down based on 200 W.(2)Determination of the best method for cooking rice with variable power and timeOrthogonal experiment was designed to cook rice with variable power and time,and sensory evaluation,taste measurement,texture measurement and low-field nuclear magnetic resonance measurement of cooked rice were performed,then use the range method to analyze the taste meter and texture meter indicators,and combine energy consumption and sensory evaluation during cooking rice,finally,the best experimental scheme was determined as the fifth group: the power gradient was-100,that is,the power was 300-200-100(W);the time gradient was 4,that is,the time was 0.6-4.6-8.6(min).Based on the subjective evaluation results(sensory evaluation and food taste meter evaluation)and texture analyzer evaluation results,this paper compares and analyzes the effects of power gradients of-100,0,and 100 on rice food taste meter evaluation,this is,the effect of gradually decreasing power,constant power,and increasing power on cooking rice on the evaluation of rice taste meter.The results show that the texture analyzer palatability and food taste indicator and sensory score of the rice cooker cooked with variable power are ranked by power gradient-100> power gradient 100> power gradient 0,therefore,with the power of the cooked rice gradually decreases during the process of cooking the rice,the appearance,taste,comprehensive score and sensory score of the cooked rice are better than the gradually increasing power,that is to say,the rice cooked with high power and then gradually converted to low power(that is,"xian wu hou wen")is better than the rice that is cooked with low power and gradually converted to high power(that is,"xain wen hou wu ").(3)Determination of taste quality of different varieties of Jilin riceUsing the determined best experimental scheme to cook ten different varieties of Jilin rice,the cooked rice was subjected to a sensory evaluation,a taste meter measurement,a texture analyzer measurement,a cooking characteristic measurement,and a low-field nuclear magnetic resonance measurement.The results showed that there were significant genetic differences among sensory scores,taste meter indicators,texture meter indicators,cooking characteristics indicators,and relaxation time of different varieties,and there is a significant correlation between most indicators and sensory indicators.For japonica and indica rice,the hardness value,hardness / viscosity value of japonica rice is lower than that of indica rice;the appearance score,taste score and comprehensive evaluation of japonica rice are larger than that of indica rice;the final water absorption and expansion rate of japonica rice are higher than indica rice.However,the water absorption of indica rice is higher than that of japonica rice in the soaking stage.For japonica rice,it is more obvious to use the hardness / viscosity index,taste index and expansion rate index to evaluate the discrimination;for indica rice,it is obvious to use the chewability index,appearance index and water absorption index to evaluate the discrimination of indica rice.(4)Evaluation method of rice taste quality testTen different varieties of rice were cooked,the cooked rice was measured by rheometer,cooking characteristics and low-field nuclear magnetic resonance.The results showed that the rheometer indicators G '(Elastic modulus),G "(Viscous modulus)and G" / G'(Loss factor,tan?),and cooking characteristics indicators were genetically different between different varieties,and there was a significant correlation with the sensory evaluation indicators.Therefore,regression equations were established through rheometer indicators,cooking characteristics indicators,and sensory evaluation indicators to predict and evaluate the taste quality of rice;For different forms of water(combined water,non-flowable water,and free water),although the water forms of different varieties are significantly different,there is no significant correlation between the different forms of water and sensory evaluation.Therefore,it is impossible to establish a regression equation with sensory indicators to predict and evaluate the taste quality of rice.It can be seen from the correlation analysis of subjective indicators(sensory evaluation indicators and taste meter indicators)and objective indicators(texture meter indicators and rheometer indicators),significant correlations between sensory viscosity,sensory elasticity,soft hardness,and sensory scores in the sensory evaluation indicators,hardness,viscosity,and hardness / viscosity in texture and rheometer indicators,as well as G '(Elastic modulus),G "(Viscous modulus)and G" / G'(Loss factor,tan?);There is a significant correlation between the indicators of the taste meter and the viscosity and hardness / viscosity of the texture meter,but the correlations with the indicators of the rheometer are not significant.Therefore,this article mainly analyzes the correlation between sensory evaluation and objective indicators in subjective indicators,and uses the objective indicators that are significantly related to sensory indicators as the final evaluation indicators. |
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