Determinação do efeito antioxidante e da estabilidade espectroscópica da R-Ficoeritrina isolada da macroalga marinha Solieria filiformis (Kützing) P. W. Gabrielson e sua aplicação como corante natural vermelho em iogurte

Abstract

Color is an attribute with a great impact on the decision to consume an industrialized product. The industry uses a variety of dyes, mainly in foods and drugs intended for children. However, reports of allergenicity of artificial dyes have stimulated the search for new natural dyes, especially yellows and reds. Red marine seaweed biosynthesize a red accessory photosynthetic pigment (R-Phycoerythrin) with physicochemical and spectroscopic characteristics (absorbance and fluorescence) with wide biotechnological and industrial application. Given the above, the present work aimed to extract, purify and characterize the R-Phycoerythrin from the red seaweed Solieria filiformis, and to determine its antioxidant potential and its application as a natural dye in yogurt. Two purification methodologies were determined, reaching purity indices of 4.5 and 2.4, with a recovery of 14.28% and 37.69%, respectively. R-Phycoerythrin from S. filiformis (R-FESf) showed 60% of α-helix in its secondary structure, with good spectroscopic stability to heat (70 °C for 1 hour) and pH variation (5 to 11). The spectroscopic properties of R-FESf remained stable at temperatures of -20 °C and 4 °C when stored for 30 days. R-FESf, at a concentration of 500 μg/mL, reached high antioxidant capacity in three different methods, ABTS radical scavenging, 97.98 ± 0.52%, ferrous ion chelating capacity, 94.75 ± 1.86%, and DPPH radical scavenging, 79.04 ± 0.66%. Sensory analysis showed that RFESf when used as a natural red coloring in yogurts, obtained good acceptance and preference by consumers. Thus, two purification protocols were established for R-phycoerythrin from S. filiformis, with different levels of purity, which can be applied industrially, presenting a predominance of secondary structure in α-helix with high stability spectroscopic properties, and with a high power antioxidant. Furthermore, R-FESf may be a promising biomolecule to replace dyes used in the food industry.