B-phycoerythrin of Porphyridium cruentum UTEX 161: A multifunctional active molecule for the development of biodegradable films

Abstract

In this study, films were developed combining gelatin-sodium alginate with an aqueous extract of B-phycoerythrin (B-PE) derived from Porphyridium cruentum (45, 67.5, and 90 µg/mL). Firstly, the production conditions of B-PE by the red microalgae were optimized using response surface methodology applied to culture medium composition prior to examining its antioxidant activities. The optimized process yielded a maximum amount of B-PE equal to 4.16 ± 0.24 % of dry matter using an F/2 culture medium supplemented with NaCl = 17 g/L; MgCl2·6H2O = 2.6 g/L and KH2PO4 = 0 g/L. B-PE extracts demonstrated in vitro antioxidant properties, as evidenced by its DPPH radical scavenging capacity, ABTS radical inhibition, and substantial reducing power. B-PE incorporation in gelatin-sodium alginate films resulted in a notable increase in the swelling index and water solubility, and a significant decrease in the moisture content. In addition, when added to gelatin-sodium alginate films, B-PE extracts enhanced ΔE* values and have positive influence on the crystallinity of the developed films as revealed by X‑ray diffraction analysis. Regarding microstructure, films incorporating B-PE extracts exhibited a homogenous structure with a slightly rough surface. Furthermore, these films demonstrated complete biodegradability after 10 days of burial in soil. The current investigation suggested that gelatin-sodium alginate films incorporating B-phycoerythrin obtained from Porphyridium cruentum UTEX 161 could be used as a promising colored functional packaging for food products.