This study shows the effects of blanching, citric acid addition, and drying temperature on the freeze-drying kinetics, l-ascorbic acid content, colour, and antioxidant activity of freeze-dried pepper. The process was performed at 20 °C, 40 °C, and 60 °C and with a constant pressure in a drying chamber at 63 Pa. The samples of pepper were pulped before drying. Blanching of pepper reduced the drying time to approximately 30%. The shortest drying time (about 290 min) was found for blanched pepper that was freeze-dried at 60 °C, whereas the samples of pepper freeze-dried at 20 °C and without blanching required the longest drying time (about 900 min). The kinetics of freeze-drying of pepper pulp are best described by using the Page model. The addition of citric acid increased the redness and yellowness of dried pepper, whereas an increase in drying temperature caused a decrease in the total phenolics content, antioxidant activity, and colour coordinates of all samples. The highest l-ascorbic acid content was found in unblanched pepper and when the temperature of drying did not exceed 40 °C. Water blanching pretreatment had the most negative effect on total phenolics content and antioxidant activity of dried pepper.

本研究表明热烫上冷冻干燥动力学，柠檬酸此外，和干燥温度的影响，升-冷冻干燥胡椒的抗坏血酸含量，颜色和抗氧化活性。该过程在20°C，40°C和60°C且在63 Pa的干燥室中恒压下进行。在干燥之前将胡椒样品制成纸浆。胡椒粉的漂白将干燥时间减少到大约30％。对于在60°C冷冻干燥的变白胡椒，发现最短的干燥时间（约290分钟），而在20°C且未变白的情况下冷冻干燥的胡椒样品需要最长的干燥时间（约900分钟）。使用Page模型可以最好地描述胡椒纸浆冷冻干燥的动力学。柠檬酸的添加增加了干胡椒的红色和黄色，而干燥温度的升高导致所有样品中总酚含量，抗氧化活性和色坐标的降低。在未漂白的胡椒中和干燥温度不超过40°C时发现1-抗坏血酸含量。水烫预处理对干胡椒中的总酚含量和抗氧化活性影响最大。