Comparisons of rice taste and starch physicochemical properties in superior and inferior grains of rice with different taste value.

The difference in grain yield between superior grains (SG) on the upper part and inferior grains (IG) on the lower part of the same panicle was widely reported. To date, variations in rice taste quality between SG and IG and the related starch physicochemical properties remained poorly understood. Here, rice cultivars with different taste quality (NT, normal taste; GT, good taste) were grown to investigate the mechanism underlying taste difference between SG and IG and the correlation between cooked rice taste and starch properties. In this study, the taste value of GT rice was 32.2% higher than that of NT rice across the cultivars. The GT rice comprised a series of typical taste qualities of larger stickiness, smaller hardness, lower apparent amylose content (AAC), and lower protein content (PC). The taste quality differed among rice grains on the same panicle; SG achieved 21.9% and 17.0% higher taste value than IG in GT rice and NT rice, respectively. The higher taste value in SG was owing to the larger stickiness and lower PC. Meanwhile, SG of GT rice achieved the lowest PC (8.2%) and gluten content (5.6%), which might indicate a better health value. Additionally, larger and smoother granules, more fa (DP < 12), lower crystallinity, and larger 1045/1022 cm-1 ratios were found in SG starch compared to IG starch. These led to a weaker swelling power and lower gelatinization enthalpy in SG starch, while gelatinization temperature and retrogression enthalpy were the opposite. Moreover, SG starch exhibited higher storage modulus, loss modulus, slowly digestible starch contents, and resistant starch contents than IG. Our results revealed a great difference in taste quality between SG and IG in rice. The larger and smoother starch granules and shorter chain length could increase the ordered structure of starch, thus improving swelling power, gelatinization properties, and rheological characteristics and facilitating better taste quality of SG over IG. Besides, the lower PC (especially gluten content), higher slowly digestible starch, and higher resistant starch content indicated a more promising health value of SG in the food industry.

Optimization of surface enhanced Raman scattering performance based on Ag nanoparticle-modified vanadium-titanium nanorods with tunable nanogaps.

The combination of new noble metal nanomaterials and surface enhanced Raman scattering (SERS) technology has become a new strategy to solve the problem of low sensitivity in the detection of traditional Chinese medicine. In this work, taking natural cicada wing (C.w.) as a template, by optimizing the magnetron sputtering experimental parameters for the growth of Ag nanoparticles (NPs) on vanadium-titanium (V-Ti) nanorods, the nanogaps between the nanorods were effectively regulated and the Raman signal intensity of the Ag15/V-Ti20/C.w. substrate was improved. The proposed homogeneous nanostructure exhibited high SERS activity through the synergistic effect of the electromagnetic enhancement mechanism at the nanogaps between the Ag NPs modified V-Ti nanorods. The analytical enhancement factor (AEF) value was as high as 1.819 × 108, and the limit of detection (LOD) was 1 × 10-11 M for R6G. The large-scale distribution of regular electromagnetic enhancement "hot spots" ensured the good reproducibility with the relative standard deviation (RSD) value less than 7.31%. More importantly, the active compound of Artemisinin corresponded the pharmacological effect of Artemisia annua was screened out by SERS technology, and achieved a LOD of 0.01 mg/l. This reliable preparation technology was practically applicable to produce SERS-active substrates in detection of pharmacodynamic substance in traditional Chinese medicine.

Transfer coefficients for evaporation of a system with a Lennard-Jones long-range spline potential.

Surface transfer coefficients are determined by nonequilibrium molecular dynamics simulations for a Lennard-Jones fluid with a long-range spline potential. In earlier work [A. Røsjorde, J. Colloid Interface Sci. 240, 355 (2001); J. Xu, ibid. 299, 452 (2006)], using a short-range Lennard-Jones spline potential, it was found that the resistivity coefficients to heat and mass transfer agreed rather well with the values predicted by kinetic theory. For the long-range Lennard-Jones spline potential considered in this paper we find significant discrepancies from the values predicted by kinetic theory. In particular the coupling coefficient, and as a consequence the heat of transfer on the vapor side of the surface are much larger. Thermodynamic data for the liquid-vapor equilibrium confirmed the law of corresponding states for the surface, when it is described as an autonomous system. The importance of these findings for modelling phase transitions is discussed.

Scaling behavior for the pressure and energy of shearing fluids.

Recent simulation work has established that the widely accepted mode-coupling theory for the strain rate dependence of the pressure and energy of simple fluids under shear (i.e., energy and pressure are functions of strain rate to the power 3 / 2) is observed in the vicinity of the triple point. Away from the triple point, the scaling exponent of the strain rate was seen to be closer to 2 than 3 / 2, suggesting a possible analytic behavior. In this paper, we accurately determine the scaling exponent behavior for a Lennard-Jones fluid in the dense fliud region and find that it varies continuously between approximately 1.2 and approximately 2 as a function of density and temperature, thus confirming its nonanalyticity. We furthermore find that the behavior is characterized by a simple linear function of density and temperature.