Rehydration of dried rice noodles (DRN) is a time-consuming process and has a significant impact on the quality of the rice noodles. In this study, the relationship between rehydration conditions and moisture content was explored through the rehydration kinetics analysis, and the effect of rehydration temperature on the quality of DRN was investigated, and preservation methods were optimized for preservative to improve storage quality on rehydrated rice noodles (RRN). The results demonstrated that the rehydration process of DRN could be described using mathematical equation, and the fitted and predictable equations were obtained. RRN remained better in terms of cooking quality, texture, and the rate of rupture after optimizing rehydration conditions. When the concentrations of lactic acid, ε-polylysine, and sodium dehydroacetate were 25 ppm, 63 ppm, and 200 ppm, respectively, the initial aerobic plate count of RRN was the lowest, and the shelf-life was extended to 3 days. Though the E-nose and Loadings analysis, nitrogen oxides, and aromatic hydrocarbons, played an important role in differentiating the odor of RRN. Understanding the rehydration process helped to maintain the quality of RRN, and the optimization of the preservative is expected to be applied to increase the economic benefits in rice products-related enterprises.
Zhongyu Du,Siyu Duan,Mingfang Ma,Xiangyu Xu,Zhenquan Li,Lingdong Kong,Jun Liu
The rate constants of two redox reactions and in the critical solution of 2-butoxyethanol and water have been measured by using the UV spectrophotometry at the initial reaction stage. It was found that the rate constants at various temperatures for two reactions were well described by the Arrhenius equation in the noncritical region. The critical slowing down effect was detected in the critical region. The critical slowing down exponents were determined to be 0.044 ± 0.004 and 0.046 ± 0.005 for reactions and , respectively. The values of the critical slowing down exponents showed that only dynamic critical slowing down effect, and no thermodynamic singularity could be observed for the two reactions.
Step ladder-structured nitrocellulose (LNC) is a novel energetic binder prepared by chemically modifying nitrocellulose (NC) with the introduction of flexible polyethylene glycol (PEG-400) chain segments, with a regular structure and good performance of bonding. The step ladder-structured addresses critical limitations of NC-based propellants, including low-temperature brittleness and high sensitivity, while enhancing process safety. Although the structural, thermal, and other properties of LNC have been investigated in our previous research, there is a lack of systematic studies on the rheological properties during solution and gelatinization. The study of the relationship between the structural features and rheological properties of LNC is a key factor in guiding its gelatinization and improving the properties of LNC-based propellants. Steady-state rheology flow experiments revealed that LNC exhibited shear thinning in different solutions, which decreased with increasing concentration. It has desirable solubility and dispersion in N, N-dimethylformamide (DMF) solvent. The effect of solvents on the entanglement or orientation of LNC molecular chains may be reduced. These results can be quantitatively demonstrated using the Herschel-Bulkley model. Dynamic viscoelastic studies identified a critical point of concentration-frequency of 2.5 rad/s. This particular frequency point is a turning point in the law of the effect of concentration on the loss factor (tan δ ). For gelatinized systems, increasing the solvent content reduces the temperature sensitivity of the gelatinized materials. The viscosity-temperature correlation based on the Arrhenius equation allowed the optimization of the solvent content through the derived equilibrium relationship. These structure-rheological performance relationships establish basic guidelines for the precision gelatinization of LNC-based propellant, provide theoretical support for the replacement of conventional NC by LNC, and guide the gelatinization process to improve the performance of gun propellants.
危险品化学品经营许可证（带存储）