Fabrication Of Butterfly Pea Flower Anthocyanin-Incorporated Colorimetric Indicator Film Based On Gelatin/Pectin For Monitoring Fish Freshness

Abstract

Novel visual intelligent pH-indicator film was prepared from the eggshell membrane- gelatin, pectin, and anthocyanin pigment from butterfly pea flower (BP) (Clitoria ternatea). It was used as a real-time pH indicator for predicting food freshness. Eggshells are useful biowaste, gelatin has been extracted from the eggshell membrane and was used for fabricating the film. The Anthocyanin content of BP extract was 198.3 mg g⁻¹. The film's surface morphology and chemical nature were estimated using a Scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray diffraction technique. The film was pH responsive and exhibited color variation ranging from shades of red, purple, blue, green, and yellow at different pH (1-13). The applicability of the developed pH- indicator film was studied on fresh Tilapia fish by monitoring its deterioration for a specific time period. The film showed a visible color change after seven days of storage at 4ºC from dark blue, bluish-grey to olive, and deep green. Change in the total volatile basic nitrogen (TVB-N) content and pH change had an effect on the color response of the film. The findings demonstrated that the fabricated pH indicator film proved to be pH sensitive and could be used to monitor fish freshness.