Characterization of a sodium alginate–carboxymethylcellulose film incorporated with cinnamaldehyde, and its application for preservation of almond paste

Almond paste is a valuable traditional product that quickly deteriorates due to oxidative rancidity and microbiological spoilage. This study involved the enhancement of sodium alginate (SA)- and carboxymethylcellulose (CMC)-based edible films with varying concentrations of cinnamaldehyde (CN: 0.1%, 0.2%, and 0.3% w/v) to prolong the shelf life of almond paste. With the increase in CN concentration, the films showed higher opacity (1.64 ± 0.05 A/mm–29.58 ± 0.19 A/mm) and allowed a higher permeability to water vapor (0.18 ± 0.01 g·mm/(m²·h·kPa)–0.44 ± 0.03 g·mm/(m²·h·kPa)). Furthermore, CN enhanced the antibacterial efficacy of the films against food pathogens. On the other hand, sensory evaluations of almond paste samples showed that the coating with films containing 0.2% CN was preferable to the other coatings. The coated samples indicated an inhibition in total mesophilic aerobic count from 3.39 log colony-forming unit (CFU)/g to 2.87 log CFU/g and a decrease in peroxide value from 6.46 milli-equivalent (meq) O2/kg to 5.76 meq O2/kg after 15 days of storage at 25°C. The results suggest that SA–CMC film enriched with CN may be useful in preserving foods with high lipid content.