Impact of green extraction methods on the structural, morphological, physico-mechanical, and thermal properties of alginate films of Sargassum ilicifolium

In the present study, the alginate was extracted from Sargassum ilicifolium using conventional (CON), enzyme (Alcalase), ultrasound (UAE), and Alcalase-ultrasound (ALUAE) methods. Subsequently, the extracted alginates were used for the preparation of edible and biodegradable films. Results demonstrated that the application of different green extraction methods decreased the molecular weight (M-w) of extracted alginates compared to the CON method, which among them the UAE-extracted alginate had the lowest M-w. Green methods applied to alginate extraction also showed significant effects on different properties of alginate films. In this regard, films that are prepared from alginate with lower M-w (UAE-extracted ones) showed lower water vapor permeability (WVP) and light transmittance as well as higher tensile strength (TS) values. Conversely, the highest WVP and lowest TS were measured for films prepared from ALUAE-extracted alginate. These results are consistent with the SEM micrograph. Novelty impact statement Alginate is a polysaccharide with various applications in different industries. This polysaccharide is extracted using the conventional method (CON). Finding a greener and faster method is preferred by the industry. In the current study, alginate of Sargassum ilicifolium was extracted using different green extraction methods further to CON. The impact of green methods on the properties of films produced from extracted alginate was investigated for the first time. The results showed that the green extraction methods led to films with different properties and among them, the films produced from ultrasound-extracted alginate showed the lowest WVP and highest TS.

Automated summary

In this study, alginate was extracted from Sargassum ilicifolium using different green extraction methods, and the extracted alginate was used to prepare films with different properties. Results showed that ultrasound-extracted alginate had the lowest molecular weight, and the films prepared from it exhibited lower water vapor permeability and higher tensile strength.