Development of intelligent films based on jackfruit seed starch/polyvinyl alcohol incorporated with purple sweet potato peel anthocynanin as an indicator.

Here, starch was extracted from jackfruit seeds using three different methods: acid extraction, distilled water extraction, and alkaline extraction. The extracted jackfruit seed starch (JSS) was subsequently utilized as a biopolymer for the fabrication of food packaging films. The results confirmed that all extracted starches exhibited similar shapes, A-type crystalline structures, and granule sizes (4-16 μm). The distilled water extraction method yielded up to 48 % starch with 92 % purity. Biodegradable films were developed using polyvinyl alcohol (PVA), JSS extracted by the distilled water method, and anthocyanin-rich extract from purple sweet potato peel (PSP). The PSP extract demonstrated good compatibility with the JSS/PVA matrix. The addition of PSP anthocyanin slightly increased the JSS/PVA film thickness (0.218-0.352 mm) and declined tensile strength (3.41-2.89 MPa). This could be attributed to the interference of PSP anthocyanin with intermolecular interactions between JSS and PVA that alters the internal spatial arrangement of the JSS/PVA polymer matrix. The JSS/PVA/PSP exhibited a pronounced color change from reddish to yellow in a wide pH range (pH 1-13). For a practical application, JSS/PVA/PSP showed good performance in monitoring shrimp freshness during storage. These findings suggest that the JSS/PVA/PSP film is an intelligent indicator for food packaging.