Ultrasound-assisted osmotic dehydration pretreatment before pulsed fluidized bed microwave freeze-drying (PFBMFD) of Chinese yam. (June 2020)

• Record Type: Journal Article
• Authors: Li, Linlin; Zhang, Min; Wang, Weiqin
• Is Part Of: Food bioscience. Volume 35(2020)
• Publication Date: 2020-06
• Subjects: Ultrasound assisted osmotic dehydration -- Pulsed fluidized bed microwave freeze-drying -- Yams -- Dioscorea opposita Thunb; Food -- Biotechnology -- Periodicals; Food -- Research -- Periodicals; Aliments -- Biotecnologia -- Revistes; Aliments -- Investigació -- Revistes; Food -- Biotechnology; Food -- Research; Revistes electròniques; Periodicals; 664.005
• DOI: 10.1016/j.fbio.2020.100548
• Languages: English
• ISSNs: 2212-4292

Abstract

Abstract: The effect of ultrasound assisted osmotic dehydration (USOD) with 5% salt solution as the osmotic solution with pulsed fluidized bed microwave freeze-drying (PFBMFD) of Chinese yam ( Dioscorea opposita Thunb.) was studied. Yam cubes were subjected to osmotic dehydration with different ultrasonic power (1.52, 2.28 and 3.04 W/g) or without ultrasound for 10 min, and the mass transfer, water status and distribution, dielectric properties and microstructure were measured. The drying characteristics and quality attributes (color and total soluble polyphenols content, total flavones content and antioxidant capacity) of the pretreated and dried yams as well as texture, flavor and microstructure of dried yams were also studied. The USOD treatment increased the mass transfer, increased loss factor and made the water more mobile. Cell size increases were observed on the micrograph because of the application of higher ultrasonic power. Thus, the acceleration of drying and energy savings were achieved. The Page model was successfully fitted to the drying curves. Furthermore, PFBMFD dried yams with USOD pretreatment had good color and texture, reduced astringency and sourness, as well as improved antioxidant capacity when compared with fresh dried samples. Highlights: USOD pretreatment made the water of the yam tissue more mobile. Cell size was increased using USOD pretreatment. USOD pretreatment shortened the drying time and saved energy. PSMFD dried yams with USOD pretreatment showed better antioxidant capacity.