Effect of high hydrostatic pressure pretreatment on flavour and physicochemical properties of freeze‐dried carambola slices

Abstract

Summary Ripe carambolas are hard to store and transport, while freeze‐dried ones are easy to store. However, its long production time leads to higher costs. This study shows that high hydrostatic pressure (HHP) treatment could shorten the freeze‐drying time of carambola slices. After HHP treatment (25–250 MPa), the drying time of the fresh sample can be shortened by 33.3–44.4% and the distribution of water and pigment in tissues is much uniform. With the increment of the pressure, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and hydroxyl radical scavenging rate are increased. At 250 MPa, the total phenolic content (TPC) increased from 11.34 to 13.36 mg GAE g −1 , and the total flavonoid content (TFC) of the control sample was increased from 10.77 to 12.73 mg RE g −1 . Compared with the untreated sample, HHP treatment can enhance the flavour and shorten the freeze‐drying time. This work guides the application of HHP technology for drying food processing.