Preparation and digestive behavior of ferulic acid-bacterial cellulose/arabinoxylan complex with strong antioxidant activity.

Bacterial cellulose/arabinoxylan composite (BA) is widely used as plant cell wall analog for binding polyphenols to form antioxidant dietary fiber (ADF), which is a potential functional ingredient. This study aimed to utilize ferulic acid (FA) to prepare ADF (FA-BA complex) and investigate its functional properties and digestive behavior. Results showed that the FA-BA complex was successfully prepared, with FA content of 20.44 μg/mg and the crystallinity index of 87.56 %. The complex exhibited stronger DPPH and ABTS antioxidant activities than the FA-BA mixture. The in vitro digestion assay indicated that the complex underwent swelling, and 66.78 % of FA was released from the complex to become bioaccessible. The pH changes (oral-gastro-intestinal digestion), the presence of digestive enzymes, and the complex swelling did not significantly promote the release of FA, while the FA-BA interaction was the primary factor affecting FA release. The binding of FA and BA was mainly driven by hydrogen bonding. Moreover, the hydrogen bonding energy between FA and BA was weakened as digestion proceeded. The post-digestion complex retained a portion of FA and antioxidant activities. The study elucidates that the digestive behavior of the complex was influenced by the FA-BA interaction, which is crucial for its application in functional foods.