| After grain mildew or sprouting,all kinds of quality will be seriously deteriorated.These deteriorated grains will also affect the stability of normal grains during grain storage.Therefore,it is necessary to carry out strict detection in the grain storage link to avoid the deteriorated grains entering the grain pile.In this study,catalase activity was used as the only detection index to analyze the moldy and budding status of grain,in order to build a rapid detection technology of grain moldy and budding which can replace the existing conventional methods and meet the needs of the field application of grain storage and transportation.The preparation method of detection medium for rapid detection of grain mildew and sprouting was studied.The high-speed agitation washing process was selected to prepare the washing liquid for grain surface,which was used to detect the mildewed state of grain.Compared with the conventional method,the variation coefficient of the final test value of the high-speed stirring washing process is smaller,and the operation time can be shortened by 10?20 times.The optimum condition of the technology of preparing test solution for washing liquid on the surface of grain is to weigh 100 g grain into the mixing container,add 500 ml tap water directly,maintain the mixing speed of 2300(r·min-1)40 s,and filter out the grain through the filter screen,which is the grain mildew test solution.The high-speed crushing and homogenate extraction technology are selected for grain mutation detection.5g grain is weighed and put into the mixing container,200ml of water not more than 5?is added,the rotating speed is controlled at 18400(r·min-1),the comminuted grain is stirred for 2min,the suspension is centrifuged at 4500 rpm for 2min,and the supernatant of comminuted homogenate is taken as the grain mutation detection solution.The results showed that the detection stability of this method was high,and the detection value of the same moldy degree sample had no significant difference?P>0.05?.This test method was little affected by human factors of operators.Three operators with different proficiency tested the enzyme activity of the same food sample,and the test value did not show significant difference?P>0.05?.The correlation coefficients between the two methods and the detection values of different proportion of mildewed wheat were 0.99 and 0.97 respectively.Further comparison of the detection characteristics of several detection methods on the process of grain mildewing showed that the rapid detection method of enzyme activity was more sensitive,which could be 8-12 days ahead of time D.the moldy state of grain was found.The rapid detection technology of enzyme activity was used to detect the moldy correlation of different grain varieties and varieties.The results showed that the enzyme activity of the external washing solution of grain with normal quality was different among different varieties of wheat and rice,but it was lower than that of the significantly moldy grain.The enzyme activity of the external washing solution of three kinds of normal wheat was not more than 300 U/100 g.The enzyme activity values of three kinds of normal rice washing solution were all lower than 500 U/100g.When the grain is mildewed under the condition of high water content,the detection value of enzyme activity will increase significantly.The enzyme activity of wheat with 18%water content stored at30?for three days will increase 1000 times more than that of the original sample.In this paper,the rapid detection technology of enzyme activity was applied in large-scale grain depots.The samples of wheat and corn were collected in large-scale grain depots.The results showed that the enzyme activity of the external washing solution of wheat grain was lower than 300 U/100when the artificial counting method did not detect the moldy grain g.The enzyme activity of the external washing solution of corn grain was lower than 500 U/100 g;when the mildewed grain content was>0 and<2%,the enzyme activity of the external washing solution of corn grain exceeded 500 U/100 g;for the unqualified grain with mildewed grain content more than 2%,the enzyme activity of the external washing solution of corn grain exceeded 1000 U/100 g.The practical application results show that the rapid detection technology of grain mildew established in this project is suitable for the field use of grain storage.The results showed that although there were significant differences in the enzyme activities of different varieties of grain homogenate extracts,the enzyme activities of the three kinds of rice homogenate extracts with no signs of germination were less than 150 U/g,the enzyme activities of the ten kinds of wheat homogenate extracts were less than 400 U/g U/g.In the process of grain germination,the enzyme activity increased rapidly.The enzyme activity of wheat germinated for two days was 4.25 times higher than that of normal wheat.The rapid detection of catalase used in this experiment has a good correlation with the routine detection of a-amylase activity in grain germination.Compared with the detection of four samples,the correlation coefficient of the detection value is?0.96,but the detection of catalase used in this experiment is simple and fast,which can reduce the detection time by 5 times.It was found that the enzyme activity of the homogenate extract of not sprouted grains soaked in water for 3-15 hours could be increased by 9%-89%respectively.Further analysis of the effect of wheat bud drying and de-sprouting treatment on the enzyme activity detection of grain homogenate extract and the detection of germinating grains showed that the dry de-sprouting treatment would hide the signs of grain germination,and the content of grain germinating grains detected by artificial eyes would be significantly reduced,but the enzyme activity value detected by this technology was significantly higher than that of normal wheat,which indicated that the enzyme activity was rapidly detected The method has a better screening effect on the budding of grain. |
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