Papers by Author: Yong Fu Tang

Abstract: A Box-Behnken experimental design and response surface methodology (RSM) was employed to optimize the parameters of ultrasonic extraction of phenolics from longan seed based on the single-factor experiments. The effects of extraction temperature, methanol concentration and extraction time on the extraction yield of phenolics from longan seed were investigated. The major parameter influencing the extraction was the extraction temperature. In this experiment, the maximal extraction yield of phenolics was obtained with 5.931 ± 0.016% (n = 3) at extraction temperature 82°C, methanol concentration 50% and extraction time 41 min. Under optimal conditions, the activity predicted by the model agreed well with experimental data.

Abstract: The ultrasonic technology was applied to optimize the processing parameters of extraction of flavonoids from litchi seed using the response surface methodology. The Box–Behnken design was used to analyze the effect of independent variables including extraction temperature (X₁), methanol concentration (X₂) and extraction time (X₃) on the yield of total flavonoids as the dependent variable(Y). The analysis of variance (ANOVA) indicated that three independent variables, their quadratic terms and interaction terms showed a significant effect on yield of total flavonoids (YTF) except the interaction between X₁ and X₂. A mathematical model with high determination coefficient was constructed, according to which the optimal extraction conditions were determined as follows: extraction temperature 70°C, methanol concentration 68%, extraction time 70 min. Under the above-mentioned condition, the experimental value of YTF was 3.55 g catechin equivalent per 100 g of dry (g CE/100 g ), which agreed with the predicted value perfectly, demonstrating the response surface model was suitable in optimizing the extraction of flavonoids from litchi seed.

Abstract: Optimization conditions for ultrasonic extraction of phenolics from litchi seed were studied using response surface methodology. A Box–Behnken design (BBD) was applied to determine the effects of extraction temperature, methanol concentration and extraction time on yield of phenolics. Then a quadratic regression model was developed and found to be statistically significant by examining its adequacy. According to the model, the maximum yield of phenolics was obtained at the theoretical extraction conditions described as follows: extraction temperature 90°C, methanol concentration 59% and extraction time 70 min. Under this condition, the experimental value was 5.48 ± 0.03% (n = 3) with gallic acid as the equivalent, which agreed with the predicted value (5.52%) closely.

Abstract: A new cellulose graft copolymer was synthesized by the homogeneous graft polymerization in ionic liquid. The methyl methacrylate was successfully grafted onto the bagasse cellulose in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) as a homogenous media. The obtained copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscope (SEM). The results of thermal analysis curves exhibited two separated pyrolysis with cellulose and the grafted pMMA. Moreover, the homogenous reaction media applied can be carried out in completely recycled ionic liquid, and the modified cellulose has a potential value for oil absorbent.

Abstract: Bagasse is an abundant agricultural byproduct. The use of bagasse has generated much interest due to its low cost, possibility of environmental protection and use of locally available renewable resources. In this paper, cellulose was dissolved in the ionic liquid （1-butyl-3-methylimidazolium chloride） and regenerated in water. FT-IR and SEM were used to characterize the structure of the original and regenerated cellulose. It was found that the treatment of the original cellulose in the ionic liquid significantly degraded the cellulose and completely destroyed the cellulose crystals. Despite many studies of the chemical modification of cellulose published around the world in this area, only a few have been investigated about the regeneration of sugarcane bagasse. Theoretical basis was established for further research on the application of the regenerated cellulose in material science.