Synthesis, characterization, and suitability of cocoyam starch-banana peels nanocomposite film for locust beans packaging

Abstract

Background: Packaging of locust beans is done to prevent deterioration and promote its shelf-life. This research was carried out to develop and evaluate a cocoyam starch-banana peels nanocomposite film for locust beans packaging. The film was prepared by gelatinizing a mixture of 0.36 g banana peels nanoparticles (~ 1.14–1.64 nm), 18 g cocoyam starch, and 18 ml glycerol in 300 ml distilled water at 90 °C. The thermal, structural, mechanical and barrier properties of the film were determined using standard procedures. A 100 g of the locust beans condiment was packaged using the film and compared with packaging in a low-density polyethylene (LDPE) at 5.16–7.58 pH and 16.67–11.50% moisture ranges. Results: Results indicate approx. 3% weight loss with an increase in temperature (≤ 250 °C). The heat of decomposition in the process was 4.64 J/g, which depended on the transition temperature. Also, the film has high stiffness and creep along the line of topography in the atomic force imaging. The material permeates more to CO₂ (27%) and H₂ (67%) but has a low O₂ (4%) and N₂ (1%) gas permeabilities. The size of particles in the film was in the range of 3.52–3.92 nm, which is distributed across its matrix to create the pores needed to balance the gases in the micro-atmosphere. The microbial load of the locust beans decreased with pH and increased with moisture, but this was generally lower compared to those packaged in the LDPE at p < 0.05. Conclusions: The film was a better packaging material than the LDPE since it recorded lower counts of the microbes throughout the storage. Thus, the nanocomposite film was effective in controlling the microbial growth of the locust beans irrespective of the sample moisture and pH over the 30 days packaging duration.