Macrocystis pyrifera sulfated fucans oligosaccharides by hydrothermal microwave process: extraction and chemical and biological characterization

Abstract

Brown seaweeds are natural resource with relevance to be explored due to the high quantity of added of high value compounds to be applied in food, cosmetic and pharmaceutical industries. Sulfated fucans oligosaccharides (SFO) from brown algae are bioactive compounds with antioxidant, anticoagulant, antimicrobial and prebiotic potential however the regular methods of extraction are regularly long time consumption and or non-green technologies. The aims of this work were the study the extraction of SFO of Mexican macroalgae Macrocystis pyrifera by hydrothermal microwave extraction HMAE and to characterize the SFO by chromatographic, antioxidant and prebiotic methods. HMAE experimental design were evaluated under three variables: temperature (160, 180 and 200 °C), power (800, 1400 y 1600 W) and time extraction time (1, 5.5 and 10 min), only under hydrothermal conditions. Chemical characterization of SFO treatments were analyzed by spectrophotometric methods, gas chromatography and FT-IR. SFO molecular weight was determined by size exclusion chromatography. The antioxidant activity was evaluated by DPPH, ABTS and FRAP and the prebiotic potential of Lactobacillus and Streptococcus strains. In this study, the results of the physicochemical characterization were similar to those reported in the literature, with 23% and 34% of total sugars content and minerals, respectively. The hydrothermal extraction MAE was optimized at 3.32 min, 171.9 °C and 1313.3 W as extraction conditions with a SFO yield of 9.7% with 12.2 % of total sugars and 16.9 %. The monomeric composition showed that fucose and galactose were sugars with highest concentrations in most treatments. Molecular weights ranges between 0.3 to 47 kDa and the range of 10 KDa showed the highest concentration of SFO with a maximum value of 18 mg/g SFO. The prebiotic greater potential was presented with Lactobacillus acidophilus, while the maximum DPPH inhibition was 69.29 in extract and 19.38 in precipitate. This work allows the valorization of unexplored Mexican seaweed by the optimization of bioactive SFO extraction process by hydrothermal green-technology and low time consumption. The Macrocystis pyrifera SFO showed a high antioxidant and prebiotic potential.