Gelatin and low methoxyl pectin films containing probiotics: Film characterization and cell viability

Abstract

Three different probiotics (Lactobacillus plantarum, L. casei, and Saccharomyces boulardii) were incorporated in gelatin and low methoxyl pectin (LMP) films separately and their viability was monitored during storage at two different temperatures (4 and 25 °C). The results showed that the gelatin based-films had a more protective effect on the viability of the cells during the preparation and storage of the films. The number of viable probiotic cells decreased through the storage period of the films and a higher rate of reduction was observed at 25 °C. S. boulardii cells showed the lowest stability during the drying and storage of the films. The physical properties of the films were investigated. It was observed that the probiotics incorporation significantly increased the film opacity, yellow-blue value (b*), solubility in water but the red-green value (a*), tensile strength, moisture content of the films was reduced (p ≤ 0.05). DSC curves confirmed the difference in the glass transition and melting temperature for gelatin and LMP films. SEM showed a more uniform and compact structure for gelatin-based films. It can be concluded that both gelatin and LMP based-films are suitable for protecting and delivering LAB (>106 CFU/g) during 42 and 21 days of storage at 4 and 25 °C, respectively.