Development of zein edible films containing different catechin/cyclodextrin metal-organic frameworks: Physicochemical characterization, antioxidant stability and release behavior

Catechin (CA) is a natural polyphenol with antioxidant activity. However, it is difficult to maintain stability and easy to release rapidly in active films. Novel zein edible films containing nano-sized CA/α-, β-, γ-cyclodextrin-metal-organic frameworks (CD-MOFs) were developed, and their physicochemical properties, antioxidant stability and release behavior were characterized. FT-IR revealed the CA/CD-MOFs and film matrix formed intermolecular hydrogen bonding interactions. XRD analysis detected that the film matrix was successfully embedded by CA/CD-MOFs. With the incorporation of CA/CD-MOFs, the microstructure of zein film was more compact, and significantly improved the water resistance, barrier and mechanical properties of zein film. Zein film containing CA/β-CD-MOFs showed good physical properties because of good compatibility of the CA/β-CD-MOFs with zein. Compared with zein film containing free CA, zein-CA/CD-MOFs films still have higher antioxidant capacity after 80 days of storage. Since CA was encapsulated into the porous structure of CD-MOFs by intermolecular force, the release of CA from zein films was controlled. These results suggest that the developed nanoedible films have potential application value as food packaging, which can be directly in contact with foods, and the longer active ingredient availability can effectively extend the food shelf life.