Development of Packaging Film from Purple Heart (Tradescantia pallida) Anthocyanin for Fish Freshness Indicator

The pH sensitivity of anthocyanins enables their application as indicators of fish freshness, as spoilage is associated with an increase in pH due to the accumulation of volatile basic nitrogen compounds. Purple Heart (Tradescantia pallida) contain cyanidin-based anthocyanins as their primary pigment. In this study, different concentrations of Purple Heart anthocyanin extract (PHA) were incorporated into chitosan-cornstarch-based packaging films to evaluate their physical and chemical properties and to be applied as freshness indicators for tuna fillets. Five formulations with different concentrations of PHA (F0 - F4: 0 - 2 %) were evaluated for their physical properties (thickness, tensile strength, elongation, water vapor transmission rate (WVTR) and color) and chemical properties (antioxidant activity and total phenolic content). The concentration of PHA significantly influenced film thickness, elongation, and chemical properties (p < 0.05), while no significant effect was observed on tensile strength and WVTR (p > 0.05). Color analysis using a chromameter demonstrated that the film containing PHA was sensitive to pH changes. When applied to tuna fillets, the film exhibited a color shift from purple (fresh fish) to yellowish (spoiled fish), confirming its potential as a fish freshness indicator. HIGHLIGHTS Development of packaging film based on chitosan-corn starch with the addition of purple heart anthocyanin extract (Tradescantia pallida). Packaging film embedded with purple heart anthocyanin extract can be used as a freshness indicator for fish through visible color changes. Variation in the concentration of purple heart anthocyanin extract affects the physical and chemical properties of chitosan-corn starch film. GRAPHICAL ABSTRACT