Synergistic microwave enzymatic immersion pretreatment of apple slices: Effects on mass transfer, enzyme activity, and digestive bioaccessibility.

Herein, we identified an optimal parameter combination for microwave-assisted cellulase immersion (MA-CI) based on the retention of water-soluble bioactive compounds and the extent of cell wall enzymatic hydrolysis. MA-CI showed cell wall remodeling and improved mass transfer, while MA9-2CI30 produced a more uniform pore network, facilitating moisture migration and limiting nutrient loss. Based on these results, the effects of penetrative microwave blanching (PMB) on the physicochemical properties and water migration of apple slices pretreated with MA-CI were examined. Results revealed that PMB effectively suppressed enzyme activities and reduced bioactive losses. Under MA9-2CI30P8, polyphenol oxidase and peroxidase activities decreased by 93.0% and 85.0%, respectively. In vitro digestion showed faster and larger release of phenolics and flavonoids, with their cumulative levels 53.2% and 24.3% higher than the control. These findings indicate that the synergism between MA-CI and PMB under MA9-2CI30P8 mitigates the quality deterioration of functional compounds while enhancing their digestive release.