Effects of purple passion fruit peel extracts on characteristics of Pouteria campechiana seed starch films and the application in discernible detection of shrimp freshness

In this work, the film-forming potential of Pouteria campechiana seed starch (PCSS) and the effects of purple passion fruit (Passiflora edulis) peel extracts (PPPAEs) on the properties of films were examined for the first time. The structural analyses showed that PPPAEs had great compatibility with PCSS without altering the chemical structure of PCSS films. The addition of PPPAEs meaningfully enhanced the ultraviolet–visible light barrier properties. The mechanical properties of the PCSS films were also remarkably influenced due to the introduction of PPPAEs, as confirmed by the increased elongation at break and decreased tensile strength. Moreover, the introduction of PPPAEs endowed the PCSS films with great antioxidant properties, as well as noticeable color change when subjected to the ammonia environment and pH alternation. The PCSS/9 PPPAEs films were utilized to monitor shrimp freshness, and obvious color changes from light pinkish brown to green could be observed as shrimp freshness was reduced during storage. The PCSS-based films presented great biodegradability, as confirmed by the test result that all systems have wholly integrated into the soil and nearly disappeared after 14 days of burial. In summary, PPPAEs were capable of bestowing PCSS films with desirable properties, and the fabricated PCSS/PPPAEs composite films could potentially be used for the visible detection of the freshness of meat and aquatic products rich in proteins.