Study On Determination Of Crude Protein And Crude Fat Content Of Grain By Thermal Analysis

Thermal analysis is analysis and testing techniques for measuring the sample physicalproperties of the relationship with temperature and time. Thermal analysis technique hasmany advantages such as small sample size, simple sample preparation, environmentallyfriendly features. The testing methods have been used widely. In recent years, With thedevelopment of science and technology, especially the continuous innovation andimprovement of thermal analysis technology, the application field of thermal analysis of thedevelopment, research and application in food is more and more popular. In this paper, thenew method to determine the grain crude fat and crude protein content quickly and accuratelywas established.1. The crude fat decomposition characteristic temperature in corn is the range of310℃-350℃by thermal analysis Spectrum, then verified through infrared spectroscopy.Optimalexperimental conditions are as follows: heating rate is10℃/min, the filling sample is20mg, the particle size is80mesh. Measured the fat content and peak area of25corn samplesby the national standard method and the DTA method, The result shows that the correlationequation between fat content and the peak area of DTA curve is: y=8.366x-19.723，thecorrelation coefficient r=0.9858. Based on the result of the precision and accuracyexperiment, the result has no significant difference with the true value, The revised DTAmeasurement results in the allowable error range.2. The crude protein decomposition characteristic temperature in wheat is that the rangeof250℃-320℃, then verified by infrared spectroscopy. Optimal experimental conditionsare as follows: heating rate is10℃/min, the filling sample is20mg, the particle size is80mesh. Measured the protein content and peak area of25wheat samples by the nationalstandard method and the DTA method, The result shows that the correlation equation betweenprotein content and the peak area of DTA curve is: y=2.905x4.79，the correlation coefficient r=0.9901. The precision and accuracy experiment shows the accuracy of crude protein fromthe model derived is higher.3. Simultaneous determination of crude fat and crude protein content of soybeans. Thecrude fat and crude protein decomposition characteristic temperature in soybeans are in therange of250℃-320℃and340℃-430℃by thermal analysis spectrum, then validated byinfrared spectroscopythe. Optimal experimental conditions are as follows: heating rate is30℃/min, filling is15mg, the particle size is80mesh. Measured the protein content、fat contentand peak area of25soybean samples by the national standard method and the DTA method, The result shows that the correlation equation between protein content and the peak area ofDTA curve is: y=2.720x-51.17, the correlation coefficient r=0.9846, the correlationequation between fat content and the peak area of DTA curve is: y=5.724x-38.04, thecorrelation coefficient r=0.9807. Based on the result of the precision and accuracyexperiment, the result has no significant difference with the true value, The revised DTAmeasurement results in the allowable error range.Therefore,according to this method, under the same experimental conditions the proteincontent and fat content of cereal can be measured by peak area in the temperature range offeatures. This method is accurate, fast, and has a better practicability.