2025 Volume 74 Issue 3 Pages 275-285
The influence of calcium chloride (2% (w/v), 3% (w/v), 4% (w/v) or 5% (w/v)) as crosslinker on the performance of sodium alginate (SA) and anthocyanin extracted from black wolfberry (BWA) based films was observed. The results showed that after CaCl2 treatment, the elongation at break reduced, but the water resistance, thermal stability, and tensile strength of SA/BWA films were significantly improved and they increased with the increase of CaCl2 concentration. In which, 5%-CaCl2 treatment endowed the films with optimal performance, which was specifically manifested by a decrease in the swelling ratio from complete dissolution to 163.4% within 60 minutes, water content from 24.9% to 13.1%, water vapor permeation (WVP) from 6.1 g·cm–1·cm–2·s–1·Pa–1·10–12 to 1.6 g·cm–1·cm–2·s–1· Pa–1·10–12, and an increase in water contact angle from 2.19° to 43.85°, tensile strength from 0.76 MPa to 13.15 MPa. Interestingly, CaCl2 treatment slightly weakened the antioxidant activity (p < 0.05) but also had around 80% of DPPH radical scavenging rate and improved the visual color change of the film to pH. The films treated by 5%-CaCl2 monitored the freshness of pork well. Therefore, comparing with traditional SA-based films, the CaCl2 treated SA/BWA film is a better candidate for active and intelligent packaging application.
