Effects of Storage and Cooking on the lodine Content in lodized Salt and Study on Monitoring lodine Content in Iodized Salt

In order to ensure that the intake of iodine from iodized salt is adequate, the effects of cooking, storage and iedination on iodine content in iodized salt have been studied. For moni toring the analytical Performance, a qoality control exawhnation was also undertaken. The loss of iodine was greater when salt was stored in plastic bag than in glass bottle. The loss was greater in fortified salt stored at 37℃ and under 76% humidity than in that at 20 ~ 25℃ and under lower humidity. The retention of iodine varied with the kind of has and also was influenced by the water content of cooked food. In general, the retention of iodine during cooking varied considerably (from 36. 6% to 86. 1 % ). The iodine concentration in salts varied greater from 3.0 to 100.3 mg/kg in salt for markets, and from 0 to 90.0 mg/kg in salts for households. 48. 3 % of samples from markets were found to be in compliance with national standards (30 ~ 50 mg/kg), and 72.0% of samples from households were in compliance with national standartl (20 ~ 50 mg/kg). Analytical data collected from 8 of the cooperative laheratories foran analytical reference material showed a 95% codridence interval of the population mean for both precision and accuracy, falling within X± 2SD and passing quality control exdrination

Monitoring model for predicting maize grain moisture at the filling stage using NIRS and a small sample size

The change in the maize moisture content during different growth stages is an important indicator to evaluate the growth status of maize.In particular,the moisture content during the grain-filling stage reflects the grain quality and maturity and it can also be used as an important indicator for breeding and seed selection.At present,the drying method is usually used to calculate the moisture content and the dehydration rate at the grain-filling stage,however,it requires large sample size and long test time.In order to monitor the change in the moisture content at the maize grain-filling stage using small sample set,the Bootstrap re-sampling strategy-sample set partitioning based on joint x-y distances-partial least squares(Bootstrap-SPXY-PLS)moisture content monitoring model and near-infrared spectroscopy for small sample sizes of 10,20,and 50 were used.To improve the prediction accuracy of the model,the optimal number of factors of the model was determined and the comprehensive evaluation thresholds RVP(coefficient of determination(R^(2)),the root mean square error of cross-validation(RMSECV)and the root mean square error of prediction(RMSEP))was proposed for sub-model screening.The model exhibited a good performance for predicting the moisture content of the maize grain at the filling stage for small sample set.For the sample sizes of 20 and 50,the R^(2) values were greater than 0.99.The average deviations of the predicted and reference values of the model were 0.1078%,0.057%,and 0.0918%,respectively.Therefore,the model was effective for monitoring the moisture content at the grain-filling stage for a small sample size.The method is also suitable for the quantitative analysis of different concentrations using near-infrared spectroscopy and small sample size.