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A novel active food packaging film was developed by casting a corn starch/tea polyphenol (TP)-loaded porous starch (PS, obtained by enzymatic hydrolysis) film forming solution, with the latter helping to regulate the slow release of TP. Results showed that PS had a favorable TP adsorption capacity, and the casted films had a homogeneous distribution of the formulation components. Likewise, the active films had good mechanical properties, UV barrier properties, thermal stability, and excellent antioxidant properties. The slow release of TP from the films was sustained, which is a desired characteristic for extending the protection afforded by the active film to the food under consideration., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Due to the poor controlled release ability, bio-based materials are difficult for large scale application on controlled release fertilizers (CRFs). Starch-based polyol (SP) and castor oil (CO) were mutually modified, and a cross-linked polymer film was formed on the surface of urea by in-situ reaction, which improved the slow release ability of the bio-based material. The results showed that increasing the CO ratio reduced porosity of coating and prolonged the nitrogen (N) release period, while the SP changed the high-temperature wrinkle characteristics and regulated the early N release rate. The mutual modification achieved an ultra-long release period of bio-based CRUs for 7 months. The degradation rate during nine months of bio-based coatings (5.05 %) was significantly higher than that of petroleum-based (3.74 %), and the coating was non-toxic to rice seeds. Mutual modification provided a safe and effective solution for the preparation of bio-based CRFs with long-term controlled release capability., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The thermoplastic starch-vermiculite (VER) composite films were prepared by solution-casting technique in this study. First, the VER was used as the filler reinforcement for thermoplastic starch to enhance its properties. The modification of VER and the structure of films were investigated and characterized by X-ray diffraction and scanning electron microscope technology. Moreover, the Fourier transform infrared spectra confirmed that the VER particles formed strong hydrogen bond interactions with starch matrix. According to TGA, differential scanning calorimetry study, and water absorption testing, the starch-VER composite films exhibited better improvement properties than did the starch matrix. It provides information on the use of VER to reinforce the properties of starch-based materials. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

In this work, thermoplastic starch-clay composite films were prepared via solution casting method. The use of acid-modified clay including kaolinite (HKAO) and vermiculite (HVER) improved the thermal properties of starch matrix. The structure of films was investigated and characterized by XRD and SEM techniques. The results showed that the well-dispersed clay particles were distributed in the starch matrix. According to TGA, DSC study and water absorption testing, the films with acid-modified clay exhibited higher water resistance and thermal properties compared to those of films containing pristine clay. These results provide the important information with using acid as the clay modifier to obtain starch-based materials with higher performance. [ABSTRACT FROM AUTHOR]

Slow release active packaging films can realize the sustained release of active agents and prolong the shelf life of food. For this aim, a novel slow release active polyvinyl alcohol (PVA) film was developed by using solution casting method. With porous starch loaded with tea polyphenols (PSTP) as core material and maltodextrin (MD) as wall material, PSTP@MD microcapsules were prepared using freeze drying method and used as slow release carrier of tea polyphenols (TP) in the active films. The interactions between PSTP@MD microcapsules and PVA molecular chains were physical interactions. In addition, the relative crystallinity of the slow release active films was reduced to 23.74 %. The addition of PSTP@MD microcapsules can enhance the ductility of active films and reduce the water content and swelling degree of active films by 46.74 % and 54.38 %, respectively. Moreover, the thermal stability, water vapor and ultraviolet barrier properties of active films were promoted. The transparency and antioxidant activity of active films was high, and the radical scavenging activity of active films was 58 %. The encapsulation of TP with PSTP@MD microcapsules can realize the slow release of TP. The slow release active films had antioxidant activity and sustained release properties, which could be used as an active packaging film to extend the shelf life of food. [Display omitted] • Porous starch loaded with tea polyphenols (TP) was used to prepare microcapsules. • PVA and microcapsules were used to prepare active packaging film (PPMF). • Adding microcapsules can improve the ductility and thermal stability of film. • The water vapor and ultraviolet barrier properties of PPMF are enhanced. • The release of TP is sustained and the antioxidant activity of PPMF is good. [ABSTRACT FROM AUTHOR]