Polar Lipids of Commercial Ulva spp. of Different Origins: Profiling and Relevance for Seaweed Valorization

Abstract

Macroalgae of the genus Ulva have long been used as human food. Local environmental conditions, among other factors, can have an impact on their nutrient and phytochemical composition, as well as on the value of the seaweed for food and non-food applications. This study is the first to initiate a comparison between commercial Ulva spp. from different European origins, France (FR, wild-harvested Ulva spp.), and Portugal (PT, farm-raised Ulva rigida), in terms of proximate composition, esterified fatty acids (FA), and polar lipids. The ash content was higher in PT samples, while FR samples had higher levels of proteins, lipids, and carbohydrates and other compounds. The profile of esterified FA, as well as FA-containing polar lipids at the class and species levels were also significantly different. The FR samples showed about three-fold higher amount of n-3 polyunsaturated FA, while PT samples showed two-fold higher content of monounsaturated FA. Quantification of glycolipids and phospholipids revealed, respectively, two-fold and three-fold higher levels in PT samples. Despite the differences found, the polar lipids identified in both batches included some lipid species with recognized bioactivity, valuing Ulva biomass with functional properties, increasing their added value, and promoting new applications, namely in nutraceutical and food markets.

Assessment of Arabian Gulf Seaweeds from Kuwait as Sources of Nutritionally Important Polyunsaturated Fatty Acids (PUFAs)

“…In this study, the PUFA/SFA values were in accordance with the nutritional guidelines only for Ulva species (0.57-0.80). However, much higher PUFA/SFA values (≥0.4) have been reported for species of the genera Ulva, Codium, Sargassum, and Padina in previous reports [4,14,15,24,25,34,43,46,49]. The low PUFA/SFA ratio in our study may be due the warm environment of the Arabian Gulf, in agreement with the reports that seaweeds of temperate regions tend to feature a higher degree of unsaturation in their fatty acid composition [46,59,62,68].…”

“…Overall, a substantial variation was observed in the individual FA contents of the same and related species of the same genus among all green, red, and brown seaweeds in our study, which is also reflected in the literature from different regions of the world [4,24,39,45,47,48,52]. These variations are due to species-specific variations, different geographical locations, and environmental factors (temperature, light, salinity, nutrients) [25,28,30,46,59]. Thus, it becomes necessary to screen different seaweeds (both wild and cultivated) from different regions for their FA contents and to monitor them across different seasons to determine the suitable period of harvest for seaweed valorization.…”

“…The effect of different seasons or other environmental factors on FA composition of seaweeds were not studied in the present study but will be an objective of our future research. Additionally, there can be variations in FA contents of same or related species in literature due to different extraction and derivatization methods employed by researchers [25,60], but it is beyond the scope of this study to compare such FA variations.…”

“…Among LC-PUFAs, n3 PUFAs are of immense clinical and nutritional importance since a balance of n6 and n3 PUFAs is critical for the prevention of chronic diseases including cardiovascular diseases, colon and breast cancers, neurodegenerative and inflammatory diseases, and is also crucial for infant brain development [18][19][20][21][22][23]. Numerous seaweeds have been recognized to have health-promoting effects reflected in their nutritional indices such as n6/n3 PUFA ratio (0.1:1-3:1), as well as an atherogenic index (AI) and thromogenic index (TI) of both less than one [2,4,11,14,24,25], underlining their potential utilization in nutritional and functional food formulations. AI signifies the relationship between the sum of pro-atherogenic saturated fatty acids (SFAs) such as 12:0, 14:0, and 16:0 and anti-atherogenic unsaturated fatty acids (UFAs) [23,26].…”

“…The taxon-specific understanding of FA profiles of seaweeds is necessary for selecting appropriate seaweed taxa for their valorization as human food, animal feed, or development of other nutraceutical, pharmaceutical, and cosmeceutical products [4,14]. Therefore, it is not surprising that numerous seaweeds have been studied from different parts of the world for their fatty acids and this dataset is continuously growing [15,25,[28][29][30]; still, the absolute number of seaweeds studied is low considering the overall seaweed diversity, with approximately 10,000 species been reported worldwide [31].…”