Colour response and release kinetics of Anthocyanin incorporated in sweet potato-based films

Ahmad Kamal, Ain Syafiqah (2021) Colour response and release kinetics of Anthocyanin incorporated in sweet potato-based films. [Project Paper] (Submitted)

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Abstract

Anthocyanin is a natural additive used in the pH indicator biopolymer films for smart packaging applications to monitor the quality and freshness of food products and at the same time to prevent food waste. However, due to the solubility nature of anthocyanin, migration of anthocyanin from packaging to food may occur. Hence, the migration of anthocyanin needs to be studied. ln this study, purple sweet potato starch (SPS) and sweet potato peel (SPP) based indicator films were solvent cast at different loadings of commercial anthocyanin (ANT) (O%, 1%, 1.5% & 2% w/v) to study the colour response of the SPS and SPS/SPP (6:4 ratio) films containing anthocyanin and to investigate the migration and release kinetics of anthocyanin. The SPS/ANT and SPS/SPP/ANT films were immersed in different pH buffer solutions ranging from pH 1 to pH 12 to evaluate the colour response of the films. Colour changes of the SPS/ANT and SPS/SPP/ANT films were studied on direct food contact using chicken meat and cherry tomato samples for 2 days at room temperature. To examine the migration of anthocyanin from the SPS/ANT and SPS/SPP/ANT films, water, 3% acetic acid, 50% ethanol, and 95% ethanol(v/v) were used as food simulants. The kinetic of colour changes of anthocyanin in 3% (v/v) acetic acid solution was studied for the SPS and SPS/SPP films with 1.5% ANT at 80°C, 25°C, 400°C, and 50°C. The concentration of anthocyanin migrated was determined based on the absorbance value measured at wavelength 520 nm by using UV - VIS spectrophotometer. In this study, both of the SPS/ANT and SPS/SPP/ANT films demonstrated colour changes ranging from bright red at pH 1.0 to pH 4.0, purple at pH 5.0 to pH 8.0, blue at pH 9.0 to pH 10.0, and green at pH 11.0 to pH 12.0 when immersed at different pH. As well as when both films were tested in direct contact with the chicken meat and cherry tomato, the films have changed their colour to blueish-green colour on the second day indicating pH towards alkaline. The anthocyanin was discovered to be migrated faster in the 3% acetic acid than in water, 50% ethanol, and 95% ethanol solutions. The results revealed that the SPS/SPP/ANT film released anthocyanin faster than the SPS/ANT film as the SPS/SPP/ANT film showed greater diffusion coefficient in each case. From this study, the diffusion of anthocyanin from SPS/ANT films was discovered to have required higher activation energy which is 134.76 kJ/mol compared to SPS/SPP/ANT films as the activation energy was recorded at 130.87 kJ/mol. In conclusion, the release kinetics of anthocyanin from the SPS/ANT and SPS/SPP/ANT films followed the first-order kinetic model and diffusion model and both films show good potential to be developed as pH indicator packaging.

Item Type:	Project Paper
Subjects:	Q Science > QD Chemistry
Faculty:	Faculty of Engineering
Depositing User:	Ms. AZLINA ZAINAL ABIDIN
Date Deposited:	09 Apr 2026 02:30
Last Modified:	09 Apr 2026 02:30
URI:	http://psaspb.upm.edu.my/id/eprint/2758

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