High Pressure‐Enhanced Infusion in Fresh and Frozen‐Thawed Cranberries: A Comparative Study. Issue 1 (10th February 2015) - Mahadevan, S.
Abstract: High‐pressure processing (HPP) has been shown to enhance and accelerate infusion of molecules compared with osmosis‐driven diffusion. The primary cause for enhanced HPP infusion is attributed to cell membrane permeabilization. This study tests the validity of this commonly accepted mechanism by conducting HPP (100 MPa–551 MPa) infusion of quercetin into cranberries. Two systems used in this study were fresh cranberries, cells of which are intact, and frozen‐thawed cranberries, cells of which are permeabilized during freeze‐thaw process. Results showed that while fresh and frozen‐thawed cranberries had similar cell membrane permeability after HPP, twice as much quercetin was infused into fresh cranberries as compared with frozen‐thawed cranberries. If cell membrane permeability were the only cause of infusion, the amount of quercetin infused into cranberries in both systems should have been same. These results suggest that enhanced infusion caused by HPP is not just caused by cell permeabilization alone. Practical Applications: Conventional diffusion based mass transport methods, currently used in the food industry for infusion, are slow processes. In order to accelerate the mass transport, this research investigated the potential of HPP to enhance and accelerate infusion in cranberries. The present study was focused on the comparison of infusion during HPP using fresh cranberries, cells of which were intact and frozen‐thawed cranberries, cells of which were permeabilized (with ruptured cell membranes) by freeze‐thaw process. Results showing increased infusion in fresh cranberries and similar cell permeability in both fresh and frozen‐thawed cranberries suggested that enhanced infusion during HPP was not caused only by cell permeabilization. This research opens new avenues for investigating additional mass transport mechanisms occurring during HPP, which will help develop accurate predictive mass transport models for HPP infusion processes.