Synthesis and characterization of aloe vera-based edible film incorporated with shellac resin and hydrocolloids

Abstract

Aloe vera-based edible film usually has weak structure, thus it has low strength. Incorporation of shellac resin and gelatine/guar gum might create composite edible film with preferable properties. This research aimed to synthesis edible film of aloe vera gel that was incorporated with shellac resin and gelatine or and guar gum. The initial concentration of shellac resin was kept constant at 6% w/w; meanwhile the initial concentrations of gelatine were 4% and 6% w/w and of guar gum were 1% and 2% w/w. The ratio between SHGE/SHGG and aloe vera gel in the suspension (ALSHGE/ALSHGG) was 1:1. The suspension was kept in the fridge for 4 days and the film was prepared from this suspension at day 0, 2 and 4. The suspension was characterized in terms of its viscosity, sedimentation and microbial activity during storage. The film was characterized in terms of its thickness, solubility, moisture content and water vapor transmission rate (WVTR). The results showed that ALSHGE and ALSHGG suspension were pseudoplastic, depending on their concentrations, with sedimentation occurred in ALSHGG suspension after 4 days. Microbial growth in the suspension was inevitable in both concentrations of ALSHGG, but there was no microbial growth observed in both concentrations of ALSHGE. After 20 g of suspension was casted into film, ALSHGE4% and 6% resulted in thicker films, with lower moisture content, than ALSHGG1% and 2%. These could be the reason for high solubility of ALSHGG films. The WVTR of the films varied, independent of storage time of the suspension, with the least WVTR was observed in the film from ALSHGE.