Abstract In this study, the effects of degradation on ascorbic acid (AA) in asparagus-lemon juice with different blending ratios were investigated during storage. The R2 values of the first-order kinetic model for predicting AA loss were 0.8216-0.9990, indicating that the model described well the degradation of AA in asparagus-lemon juice with different blending ratios. Response surface methodology (RSM) was applied to optimize the blending ratio of asparagus-lemon juice during storage. The optimum blending ratios that selected by the RSM were: 23%, 26%, 27%, 28% and 29% of diluted asparagus juice blended with 85% of diluted lemon juice, and the desirability were 0.820. The RSM correlation coefficients (R2) between experimental and model predicted values ranged from 0.6394 to 0.9975. Therefore, RSM and the first-order model may be effective tools to optimize the blending ratio of blended juice and AA degradation in juices.

A new Rhodamine B derivative RBMAB, namely 3-amino-N-(2-(3',6'-bis (diethylamino)-3-oxospiro[isoindoline-1,9'-xanthen]-2-yl)ethyl)benzamide, was designed, synthesized and structurally characterized to develop a chemosensor. The studies show that RBMAB exhibits high selectivity toward Fe3+ among many other metal cations in an ethanol-H2O (3:2, v/v, PBS buffer, 1.2 mmol L-1, pH 7.2) solution. It has a low detection limit of 0.021µm. Fluorescence microscopy experiments further demonstrate that RBMAB can be used as a fluorescent probe to detect Fe3+ in living cells.