Cabbage red with pH-sensitivity was added to tara gum film to prepare pH-sensing intelligent film. Effects of cabbage red on physicochemical and mechanical properties of film were initially studied and then application of the film in pasteurised milk system was investigated. Results showed that cabbage red did not affect the chemical composition of films, but led to the change in its crystalline structure. The addition of cabbage red could improve the flexibility of the film, its breaking elongation rate increased by 83.8 %, while the tensile strength decreased slightly. In addition, it was confirmed that the acidity value of the pasteurised milk was linearly related with the pH during the change of freshness, and it was found that the pH of simulated milk solution was linearly related with the chromaticity change of the cabbage red-tara gum film. And further detection of the real system of pasteurised milk freshness showed that the cabbage red-tara gum film could rapidly and accurately monitor the change of acidity during the change of its quality, which was suitable for application in monitoring the food freshness following with pH change.
Guangdong Chemical Industry