Thermochemical Characterization of Eight Seaweed Species and Evaluation of Their Potential Use as an Alternative for Biofuel Production and Source of Bioactive Compounds.

Pascual Garcia-Perez,Franklin Chamorro,Catarina Lourenço-Lopes,Lucía Cassani,Jesus Simal-Gandara,Marta Barral-Martinez,Miguel A Prieto

doi:10.3390/ijms23042355

Abstract

Algae are underexplored resources in Western countries and novel approaches are needed to boost their industrial exploitation. In this work, eight edible seaweeds were subjected to their valorization in terms of nutritional characterization, thermochemical properties, and bioactive profile. Our results suggest that seaweeds present a rich nutritional profile, in which carbohydrates are present in high proportions, followed by a moderate protein composition and a valuable content of ω-3 polyunsaturated fatty acids. The thermochemical characterization of seaweeds showed that some macroalgae present a low ash content and high volatile matter and carbon fixation rates, being promising sources for alternative biofuel production. The bioactive profile of seaweeds was obtained from their phenolic and carotenoid content, together with the evaluation of their associated bioactivities. Among all the species analyzed, Porphyra purpurea presented a balanced composition in terms of carbohydrates and proteins and the best thermochemical profile. This species also showed moderate anti-inflammatory activity. Additionally, Himanthalia elongata extracts showed the highest contents of total phenolics and a moderate carotenoid content, which led to the highest rates of antioxidant activity. Overall, these results suggest that seaweeds can be used as food or functional ingredient to increase the nutritional quality of food formulations.

Highlights

Algae have traditionally been used as sea vegetables, animal feed, fertilizers, and exploited by the phycocolloids industry for the extraction of agar-agar, carrageenan, and alginate [1]
The protein protein content content of of the studied macroalgae ranged from 9.81 to 34.79 g/100 g DW and red algae obtained the the studied macroalgae ranged from 9.81 to 34.79 g/100 g DW and red algae obtained the highest values. These results are in line with Sanchez-Machado [14] who reported highest values. These results are in line with Sanchez-Machado [14] who reported that the highest protein content corresponded to Porphyra purpurea and Taboada [15] who that the highest protein content corresponded to Porphyra purpurea and Taboada [15] who found 33.2 g protein/100 g DW for that species [15]
These results show that U. pinnatifida is a promising source rich in ω3 fatty acids

Summary

Introduction

Algae have traditionally been used as sea vegetables, animal feed, fertilizers, and exploited by the phycocolloids industry for the extraction of agar-agar, carrageenan, and alginate [1]. 6 billion per year, with China, Japan, and South Korea being the main consumers [2], the worldwide algae production is still restricted to the cultivation of edible species and for the phycocolloids industry [3]. From a nutritional point of view, seaweeds are attractive for their high protein content (up to 47% of dry weight in red species), being comparable to meat and dry legumes. Their low-fat content is remarkable with a healthy ratio of fatty acids ω6/ω3, and high dietary fiber content, which can reach 50% of dry weight in brown species with soluble fiber as the predominant fraction [6]. Seaweeds present many functional properties, such as water retention capacity, oil holding capacity, swelling, etc, associated with their protein and dietary fiber content that supported their incorporation into farinaceous products (bread, noodles, pasta, cake, biscuit, cookies, etc. [6])

Methods

Discussion

Conclusion