Study On The Change Of Storage Quality And Shelf-life Prediction Of Matcha

Matcha tea is susceptible to oxidative deterioration during storage and transportation.At present,there are many related literatures on the processing technology of matcha,and there are few reports on the change of storage quality and shelf life prediction of matcha.This paper first studies the change law of sensory and physicochemical properties of matcha under different environmental factors and temperatures,and conducts a multivariate analysis of quality effects.Then,it uses accelerated destructive tests to determine the changes in matcha quality indicators.Combine the Q10 model to build a suitable shelf life prediction model to explore the impact of temperature changes on the quality of matcha.The research contents and results of the paper are as follows:(1)Place matcha under high temperature,high humidity and light conditions,and study the effects of individual environmental factors on the sensory quality and physical and chemical components of matcha storage.The experimental results show that with the extension of storage time,the total chlorophyll,chlorophyll a,chlorophyll b,L value,b value,EGC,EC,EGCG,ECG,total catechins and senses of matcha under high temperature and high humidity conditions The scores have decreased,and the a value has continued to increase.Under the light conditions,the b value has decreased,while the L value and a value have increased.The three different environmental factors are compared and analyzed.The effect of light on the storage quality of matcha The largest,followed by high temperature,the impact of high humidity environment is the smallest.In a multivariate analysis of the effects of high temperature and high humidity on the quality of matcha tea,the correlation analysis results showed that sensory scores were related to tea polyphenols,phenol-amino ratio,CAF,EGCG,EGC,ECG,EC,total catechins,and total chlorophyll.The correlation between the amount,chlorophyll a,chlorophyll b,L value,a value,b / a reached a significant level;the results of principal component analysis showed that under high temperature and high humidity conditions,the characteristics of the first two components of each If the value is greater than 1,the cumulative contribution ratesreach 97.955% and 98.129%,respectively.The first two principal components can be used instead of the above 15 indicators to evaluate and judge the quality of matcha.The final regression equations for the quality score are: Y = 5.276 X1 + 44.674(Y is the sensory score,X1 is the total chlorophyll),Y =-2.728 X1 + 7.426X2 + 42.394(Y is the sensory score,X1 is a value,and X2 is phenol-amino ratio).(2)In the experiment of the influence of different storage temperature on the quality of matcha,the change laws of sensory and physical and chemical characteristics of matcha at different storage temperatures of normal temperature,30? and 40? were studied.The experimental results showed that the a value of matcha rose gradually with the prolonged storage time,along with the ascorbic acid,the total amount of chlorophyll,the chlorophyll a,the chlorophyll b,L value,b value,b/a value and sensory score gradually decreased.Correlation analysis results showed that the sensory scores were between CAF,EGCG,EGC,ECG,EC,total catechins,ascorbic acid content,total chlorophyll,chlorophyll a,chlorophyll b,L value,b value,and b/a.The correlation relationship reached a significant level,while the correlation with the a value was negative.The results of principal component analysis showed that for normal temperature and 30?,the characteristic values of the first three components were greater than 1,and the cumulative contribution rates reached96.606% and 94.742%,respectively,while the characteristics of the first two principal components at 40? If the value is greater than 1,the cumulative contribution rate reaches 92.921%.At the same time,the relationship between sensory evaluation and physical and chemical indexes of matcha at different storage temperatures was studied.The final regression equations of quality scores at room temperature,30?,and 40 ? were: Y =-5.846X1 + 8.226X2 + 23.174(Y is sensory score,X1 is a value,X2 is chlorophyll b),Y = 9.205X1 + 33.813(Y is sensory score,X1 is chlorophyll a),Y =20.629X1 + 33.878(Y is sensory score,X1 is chlorophyll b).(3)Analyze the physical and chemical data and sensory scores obtained in the accelerated destructive test of Matcha.The Person correlation analysis shows that the correlation between chlorophyll and sensory scores is high,and the correlation reaches a very significant level.Key factors for prediction model of matcha qualitychange and shelf life dynamics.The chlorophyll was fitted with zero-order and first-order chemical kinetic models at 30? and 40?,and it was found that the change rule of chlorophyll in matcha leaves conformed to the first-order chemical reaction kinetic model.Therefore,the Arrhenius equation combined with the Q10 model was used to obtain chlorophyll EA = 54656.37 KJ / mol,k0 = exp(14.788),and Q10 value of 1.99 at the temperature range of 301-313 K(Kelvin).According to the physical and chemical indexes and sensory scores of matcha,the shelf-life analysis value and the chlorophyll kinetic model of matcha are used to obtain the Q10 shelf-life prediction model: SL = 150 * 1.99(313-T)/ 10,where: T is(303-313K)Storage temperature in temperature range,K.The matcha was stored at 310 K,and the model was verified with actual shelf-life measured values.The results showed that the relative error between the true value and the predicted value was within 10%,indicating that the model was reliable.