Enhancement of Haskap Vacuum Freeze-Drying Efficiency and Quality Attributes Using Cold Plasma Pretreatment

Vacuum freeze drying (VFD) has been widely used for drying berries, by combining with pretreatment technology, energy consumption and cost can be effectively reduced as well as product quality improved. However, the effect of cold plasma pretreatment (CPP) on the drying efficiency and quality characteristics of VFD haskap has not been investigated. In this study, an innovative drying technology, cold plasma pretreatment–assisted vacuum freeze drying, was applied to process haskap. The purpose of the present study was to explore the effect of different times of CPP (0–75 s) on VFD haskap performance. The results indicated that the application of CPP enhanced the effective diffusion rate and drying rate (27.68%) owing to pretreatment etching larger and more cracks in the microstructure, increasing cell membrane permeability (15.59%), and altering cell wall pectin composition. Midilli is the most recommended model for drying kinetics. CPP contributed to increased hydrophilicity (25.33%) and degraded enzymatic activity, thereby prompting the enhancement of polyphenols, anthocyanins, flavonoids, and antioxidant capacity. Besides, the physico-chemical properties were ameliorated, the possible mechanism for the enhanced drying rate and quality properties of VFD haskap by CPP was explained by chemometrics. Overall, CPP is a promising pretreatment technology for haskap VFD.