赋形剂对冻干西番莲果粉理化特性及抗氧化活性的影响

Effects of Excipients on the Physicochemical Properties and Antioxidant Activity of Freeze-dried Passion Fruit Powder

摘要:

针对西番莲果浆在真空冷冻干燥过程中物料营养物质损失及终产品易吸湿潮解等技术难点，通过添加赋型剂麦芽糊精(MD)、阿拉伯胶(AG)、乳清分离蛋白(WPI)和大豆分离蛋白(SPI)，研究西番莲果粉在制备过程中吸湿性、水分含量、维生素C保留率、DPPH自由基清除率的变化规律，并对果粉的玻璃化转变温度和形貌特点进行分析。研究表明，添加麦芽糊精使得果粉的玻璃化转变温度从62.30 ℃增加到89.87 ℃，并有效降低其吸湿性至10.69%；添加阿拉伯胶（15%）可以有效降低果粉终产品的水分含量，从4.15%降低至1.56%；而添加乳清分离蛋白使得果粉的维生素C保留率由54.16%提高至91.85%，DPPH自由基清除率由36.81%提高至61.89%。添加赋形剂有助于西番莲果浆在冻干过程中保持疏松多孔结构，且在果粉的表面可能形成类似包覆层的保护膜或类似微胶囊的包埋结构，防止果粉中的糖类结块粘连，保护产品的品质。

Abstract:

During the vacuum freeze-drying of passion fruit pulp, the technical difficulties faced include nutrient loss and that the end products easily become hygroscopic and deliquescent. In order to solve the aforementioned issues, the changes in the pattern of hygroscopicity, moisture content, vitamin C retention rate, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity of the fruit powder, in the process of preparation, were studied by adding excipients-maltodextrin (MD), gum Arabic (AG), whey protein isolate (WPI), and soy protein isolates (SPI). Additionally, the glass transition temperature and morphological characteristics of the fruit powder were analyzed. The results showed that the addition of maltodextrin increased the glass transition temperature of fruit powder from 62.30 to 89.87 ℃, and effectively decreased its hygroscopicity to 10.69%. The addition of gum Arabic (15%) could effectively reduce the moisture content of the final product of fruit powder from 4.15 to 1.56% and increase the retention rate of vitamin C of fruit powder from 54.16 to 91.85%. And its DPPH radical scavenging rate was increased from 36.81 to 61.89% by the addition of whey protein isolate. The addition of excipients could help to maintain the porous structure of passion fruit pulp during the process of freeze-drying. Furthermore, a protective film similar to the cladding layer or an embedding structure similar to microcapsules were formed on the surface of the fruit powder to prevent the sticking and agglomeration of the carbohydrates in fruit powder, thereby protecting the quality of the product.