报告题目：Functionality study of kojic acid analogs as tyrosinase inhibitors and influence on anti-tyrosinase activity

主 讲 人 （一）：Ravithej Singh 博士后  

报告题目：Texture Modification and Characterisation of Food for Elderly Consumption

主 讲 人 （二）： Enrico Karsten Hadde  博士后

报告时间：2019年4月24日 （周三）10:00

报告地点：下沙校区食品学院257报告厅

报告（一）摘要：

Tyrosinase enzyme is a key and rate-limiting enzyme for melanogenesis, thus it has been considered an important target for developing therapeutic agents of melanogenesis. despite its enzyme inhibitory effect, kojic acid not attracted attention as potential tyrosinase inhibitor due to metabolic instability and low weak inhibitory properties. In an attempt to synthesise new tyrosinase inhibitors, we designed and synthesized two series of kojic acid analogs as tyrosinase inhibitors with strategic modifications of kojic acid. All the newly synthesized compounds were characterized by analytical methods such as NMR and mass spectrometry. After an initial screening of target compounds, inhibitory properties of most active compounds were further investigated to get insight on inhibitory effects on enzyme kinetics and mechanistic aspects.

报告（二）摘要：

Thickened fluids are commonly used in the medical management of individuals who have swallowing difficulty (known as dysphagia). However, it is not always easy to obtain the correct consistency of thickened fluids. Fluids that are too thin may result in pneumonia, while overthickened fluids may result in aspiration due to residue possibly inhaled from pharyngeal stasis. Recent studies show that understanding the rheological properties of thickened fluids is advantageous in designing better-controlled fluids. Whilst the rheological behaviour of thickened fluids in shear deformation has been studied by several authors, studies on the extensional behaviour are limited. This project had three main objectives: (a) to rheologically characterise thickened fluids in extensional deformation, (b) to evaluate the significance of extensional viscosity in bolus controlling during swallowing, (c) to develop and evaluate a methodology to measure cohesiveness of thickened fluids for dysphagia management. It was observed that for similar shear viscosity, the extensional viscosity of the fluid was dependent on the type of thickener. This suggests that by thickening fluid with different types of thickeners, the cohesiveness of the fluid may be very different even at the same shear viscosity. Moreover, higher extensional viscosity reduced the elongation of the bolus during swallowing, thus potentially reduces the risk of post-swallow residue due to bolus breakage. The cohesiveness of thickened fluids was sensory evaluated and correlated with different rheological parameters of thickened fluids. It was observed that the maximum extensional viscosity is the most-well correlated with the cohesive properties and thus could be used as a feasible indication of fluid cohesiveness. In addition, syringe extrusion flow behaviour technique was developed to measure the cohesiveness of flowable materials. This technique was highly correlated with the perceived cohesiveness from the sensory study and could be used as a standardised methodology of evaluating cohesiveness of semi-solid and liquid materials for industrial purposes. 

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