Preparation of bioactive gelatin film using semi-refined pectin reclaimed from blueberry juice pomace: Creating an oxidation and light barrier for food packaging

Semi-refined blueberry pectin (SBP) was extracted from the waste following blueberry juice processing. SBP and gelatin (Gel) were used as the base formulation for the preparation of a composite packaging film (SBP/Gel film), while Gel film, SBP film, apple pectin (AP) film, and an AP and Gel composite film (AP/Gel film) were prepared for comparison. The physicochemical properties, microscopic morphology and antioxidant activity of the prepared films were analyzed. The tensile strength and thermal stability of the SBP/Gel film were improved in comparison with the control films, and the moisture content, hygroscopicity and water vapor permeability were reduced when SBP was incorporated into the gelatin film formulation. Scanning electron microscopy verified the compatibility between SBP and Gel in the SBP/Gel film. Fourier-transform infrared spectroscopy showed that SBP changed the secondary structure of the Gel through non-covalent bonds in the SBP/Gel film. Compared with the AP/Gel and Gel films, the light barrier properties and antioxidant activities of the SBP/Gel film were enhanced significantly. When the SBP/Gel composite film was used to package olive oil or lutein, the SBP/Gel film could retard the oxidation of olive oil and delay the photodegradation of lutein, respectively.