Dan Peng,Qi Zhou,Min Su,Shaoshuai Zheng,Shuli Xie,Jun Li
Low-field nuclear magnetic resonance (LF-NMR) combined with chemometrics was used for the rapidly and nondestructively quantitative determination of carbonyl value (CV) of frying oils during frying process. The quality indices of frying oils during frying process were analyzed as well as the changes of its LF-NMR signal, followed by exploring the correlation between the quality indices of frying oils and the relaxation-characteristic indices and investigating the influences of modeling data and preprocessing methods on the modeling performance. Based on the echo decay curves data of LF-NMR and the relaxation-characteristic indices data, the prediction model of CV was established by partial least square (PLS), principal component regression (PCR), multiple linear regression (MLR), and support vector machine regression (SVR). Results showed that there was a significant correlation between CV and relaxation-characteristic indices ( p < 0.01) with both modeling data and preprocessing methods affecting the model performance. The prediction performance of non-linear SVR model was significantly superior to that of linear modeling methods (PLS, PCR, and MLR). The best prediction model of CV was built using the SVR method based on echo decay curves data. The root mean square error of prediction and coefficient of determination were 2.599 mmol/kg and 0.9873, respectively.
Cao Qiongju,Du Hongying,Huang Yuan,Hu Yang,You Juan,Liu Ru,Xiong Shanbai,Manyande Anne
Grass carp ( Ctenopharyngodon idellus ) is a kind of freshwater fish which is rich in polyunsaturated fatty acids and easily exposed to lipid oxidation during refrigeration. The effect of chlorogenic acid (CGA) on lipid oxidation, protein oxidation, enzymatic activities, and color stability of grass carp muscle during chilled storage was investigated. The lipid oxidation was inhibited by CGA, as evidenced by lower thiobarbituric acid values, peroxide values, carbonyl valence, less free fatty acid content, and higher amount of unsaturated fatty acid compared to the control group. CGA also had a positive effect on the whiteness value and the stability of protein oxidation of fish samples. In addition, the inhibitory study of CGA on endogenous lipase and lipoxygenase activities of fish muscle can help to partly illustrate the mechanism that retains its freshness effect. The results indicate that CGA is a novel natural additive which can be used to inhibit lipid and protein oxidation and be applied in the storage of aquatic products or some similar fields.
危险品化学品经营许可证（带存储）