Kinetics of anthocyanin condensation reaction in model wine solution under pulsed light treatment.

The effects of Pulsed Light (PL) technology on the anthocyanin condensation reaction in model wine solutions were investigated. Model wine solutions containing malvidin-3-O-glucoside, cyanidin-3-O-glucoside, and delphinidin-3-O-glucoside were separately prepared with the presence of (-)-epicatechin and acetaldehyde. The solutions were subjected to PL treatment with 2, 4, and 8 J/cm2 energy and stored in 10 °C. The loss of anthocyanin during the treatment and the aging period fitted the first-order reaction model (R2 > 98 %). Delphinidin-3-O-glucoside suffered the highest loss, only 46 % remaining after 60 s treatment; the malvidin-3-O-glucoside showed the lower loss, 72 % remaining after 60 s treatment. Furthermore, the PL treatment significantly influenced the kinetics of anthocyanin loss. The results from LC ESI TOF/Q-TOF MS/MS analysis revealed that in the PL treated samples, more peaks eluted in the chromatogram assigned to anthocyanin ethyl-linked (-)-epicatechin products, suggesting that PL treatment led to the formation of new isomers of anthocyanin ethyl-linked (-)-epicatechin. The color characteristics of the model solutions were affected by the PL treatment and the formation of ethyl-linked products. For example, the ΔE* value for samples treated with 8 J/cm2 increased by 42.52, 55.73, and 45.61 % for malvidin-3-O-glucoside, cyanidin-3-O-glucoside, and delphinidin-3-O-glucoside respectively after 110 days.

Impact of Three Different Dehydration Methods on Nutritional Values and Sensory Quality of Dried Broccoli, Oranges, and Carrots.

Radiant Energy Vacuum (REV)-dried broccoli, oranges, and carrots prepared by the optimal drying protocols determined in this study were compared to the freeze-dried and air-dried samples based on the nutritional values before and after drying. An accelerated shelf-life study for REV-dried broccoli, oranges, and carrots was also conducted. For all the samples, REV drying significantly shortened the processing time. The REV-dried samples had much higher retention of the nutritional values (vitamin C, ß-carotene) compared to the conventional air-drying process, and the values were also competitive to those of the freeze-dried samples. Although freeze-drying resulted in the best rehydration property, the REV-dried samples still earned the highest scores in the sensory test. In the accelerated shelf-life study conducted on the REV-dried samples, the moisture content and water activity stayed at the same level, but the nutritional values showed a downward trend. The sensory properties fluctuated in the shelf-life but still gained positive feedback from the panelists. Moreover, the testing method for ß-carotene content was uniquely designed in this project and could be a semi-quantitative method to refer to.