Here, a rapid method for identifying adulterated Thai jasmine rice was developed using near-infrared spectroscopy combined with backward propagation (BP) neural network. Near-infrared spectra of pure and adulterated rice samples were pretreated by multiplicative scatter correction (MSC) and 48 characteristic wavelengths were selected by competitive adaptive reweighted sampling (CARS). Then, the optimal structure model for BP neural network algorithm was established using absorbance values at these wavelengths as the input layer neurons and Thai jasmine rice contents in samples as the output layer neurons, involving a single hidden layer, seven hidden layer neurons, logsig as the transfer function of hidden layer, tansig as the transfer function of output layer, trainlm as the training function, learngdm as the learning function of the network, and learning rate of 0.35. The model showed an excellent prediction performance with a root mean square error (RMSE) of 0.000830, correlation coefficient of the calibration set of 0.9929, correlation coefficient of the verification set of 0.9761, and correlation coefficient of the test set of 0.9755.

Three materials (agar, konjac glucomannan (KGM) and κ-carrageenan) were used to prepare ternary systems, i.e., sol-gels and their dried composites conditioned at varied relative humidity (RH) (33%, 54% and 75%). Combined methods, e.g., scanning electron microscopy, small-angle X-ray scattering, infrared spectroscopy (IR) and X-ray diffraction (XRD), were used to disclose how κ-carrageenan addition tailors the features of agar/KGM/κ-carrageenan ternary system. As affirmed by IR and XRD, the ternary systems with κ-carrageenan below 25% (agar/KGM/carrageenan, 50:25:25, m/m) displayed proper component interactions, which increased the sol-gel transition temperature and the hardness of obtained gels. For instance, the ternary composites could show hardness about 3 to 4 times higher than that for binary counterpart. These gels were dehydrated to acquire ternary composites. Compared to agar/KGM composite, the ternary composites showed fewer crystallites and nanoscale orders, and newly-formed nanoscale structures from chain assembly. Such multi-scale structures, for composites with κ-carrageenan below 25%, showed weaker changes with RH, as revealed by especially morphologic and crystalline features. Consequently, the ternary composites with less κ-carrageenan (below 25%) exhibited stabilized elongation at break and hydrophilicity at different RHs. This hints to us that agar/KGM/κ-carrageenan composite systems can display series applications with improved features, e.g., increased sol-gel transition point.