Impact of storage conditions on the structure and functionality of starch/polyvinyl alcohol films containing Lycium ruthenicum anthocyanins

• The homogeneity and crystallinity of films increased during storage. • Films showed color changes and decreased light barrier property during storage. • The elongation at break of films significantly increased during storage. • The antioxidant activity and pH-sensitivity of films decreased during storage. • Storage temperature and time significantly influenced the stability of films. We prepared intelligent and active packaging films by using cassava starch, polyvinyl alcohol (PVA) and Lycium ruthenicum anthocyanins. The impact of storage conditions as temperature (4, 20 and 35 °C), light (with or without light) and time (1, 2, 3 and 5 months) on the structure and functionality of the films were investigated. Results showed the cross-section of the films gradually became uniform with the increase of storage time and temperature. Meanwhile, the degradation products of anthocyanins formed strong intermolecular interactions with films matrix, resulting in increased crystallinity of the films. The initial purple color of the films gradually faded and turned green or yellow at the fifth month. UV–vis spectroscopy confirmed anthocyanins in the films gradually degraded during film storage. The films stored at 35 °C degraded much faster than those stored at 4 and 20 °C. The mechanical property of the films gradually increased, however, the antioxidant activity and pH-sensitivity of the films gradually decreased during film storage. The films stored at 4 °C preserved good antioxidant activity and pH-sensitivity for three months. Our results suggested that storage time and temperature were key factors affecting the structure and functionality of the films.