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In order to investigate the effects of different drying methods on the properties of porous starch. The present study used four drying methods, namely hot air drying (HD), spray drying (SPD), vacuum freeze drying (FD) and supercritical carbon dioxide drying (SCD) to prepare maize and kudzu porous starch. Findings indicated that the physicochemical properties (e.g., morphology, crystallinity, enthalpy value, porosity, surface area and water absorption capacity as well as dye absorption capacity, particle size) of porous starch were significantly affected by the drying method. Compared with other samples, SCD-treated porous starch exhibited the highest surface areas of the starch (2.943 and 3.139 m2/g corresponding to kudzu and maize, respectively), amylose content (22.02 % and 16.85 % corresponding to kudzu and maize, respectively), MB and NR absorption capacity (90.63 %, 100.26 % and 90.63 %, 100.26 %, corresponding to kudzu ad maize, respectively), and thermal stability, whereas HD-treated porous starch showed the highest water-absorption capacity (123.8 % and 131.31 % corresponding to kudzu and maize, respectively). The dye absorption of the maize and kudzu porous starch was positively correlated with surface area, according to Pearson's correlation analysis. Therefore, in this study, our aim was to explore the effects of different drying methods on the Structure and properties of porous starch, and provide reference for selecting the best drying method for its application in different fields.

Porous starch is a denatured starch product with high porosity, a large specific surface area, and strong adsorption. It is widely used in medicine, food, and chemical industries. Native starch includes types A, B, and C. In this study, the various starch materials, including potato maize, and kudzu starch, were used to prepare different crystal types of porous starch with α-amylase and glucoamylase. The structural and chemical characteristics of the porous starch were measured using Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry. The results showed that maize , potato and kudzu starches were typically A, B, and C types, respectively. Compared to the native starch, the three types of porous starch treated with α-amylase and Glucoamylase cause varying degrees of destruction of the surface of the starch. Moreover, investigating the reaction factors which are expected to affect the water adsorption capacity were studied systematically, including the mass ratio of α-amylase to glucoamylase (m α-amylase/m glucoamylase), the mass ratio of the total amount of enzymes to starch (m enzyme/m St), enzymatic reaction temperature, and enzymatic reaction time. The results suggested that A-type starch has higher enzymolysis efficiency than other types of starch and can be used to produce ideal cavity and pore-size starch granules with potential applications in many fields.

Radiation-induced skin injury (RISI) is a frequent and severe complication with a complex pathogenesis that often occurs during radiation therapy, nuclear incidents, and nuclear war, for which there is no effective treatment. Hyaluronan (HA) plays an overwhelming role in the skin, and it has been shown that UVB irradiation induces increased HA expression. Nevertheless, to the best of our knowledge, there has been no study regarding the biological correlation between RISI and HA degradation and its underlying mechanisms. Therefore, in our study, we investigated low-molecular-weight HA content using an enzyme-linked immunosorbent assay and changes in the expression of HA-related metabolic enzymes using real-time quantitative polymerase chain reaction and a Western blotting assay. The oxidative stress level of the RISI model was assessed using sodium dismutase, malondialdehyde, and reactive oxygen species assays. We demonstrated that low-molecular-weight HA content was significantly upregulated in skin tissues during the late phase of irradiation exposure in the RISI model and that HA-related metabolic enzymes, oxidative stress levels, the MEK5/ERK5 pathway, and inflammatory factors were consistent with changes in low-molecular-weight HA content. These findings prove that HA degradation is biologically relevant to RISI development and that the HA degradation mechanisms are related to HA-related metabolic enzymes, oxidative stress, and inflammatory factors. The MEK5/ERK5 pathway represents a potential mechanism of HA degradation. In conclusion, we aimed to investigate changes in HA content and preliminarily investigate the HA degradation mechanism in a RISI model under γ-ray irradiation, to consider HA as a new target for RISI and provide ideas for novel drug development.