Seasonal Variability of the Biochemical Composition and Antioxidant Properties of Fucus spiralis at Two Azorean Islands

Abstract

This study evaluates, for the first time, the seasonal (winter and summer) and geographical (São Miguel–SMG and Santa Maria–SMA Islands) variability of Fucus spiralis (Fs) biochemical composition (dry weight basis) and antioxidant properties. Protein and carbohydrates presented higher values in Fs-SMGwinter, lipids, total dietary fiber, and energy value in Fs-SMAsummer, and ash and soluble dietary fiber/insoluble dietary fiber ratio in Fs-SMAwinter. The fatty acid (FA) profiles showed a lower SFA in Fs-SMGsummer, whereas MUFA and PUFA presented higher values in Fs-SMGsummer and Fs-SMGwinter, respectively. Excellent dietary ratios of n6/n3 PUFA and hypocholesterolemic/hypercholesterolemic FA were found, with lower values in Fs-SMAwinter and higher in Fs-SMGsummer, respectively. The highest total phenolics was found in Fs-SMAsummer acetone:water extract and total flavonoids showed the higher value in Fs-SMGwinter methanol extract. The best free radical-scavenging activity was observed in the Fs-SMAwinter methanol (EC50 = 0.045 mg/mL) and acetone:water (EC50 = 0.059 mg/mL) extracts. The ferric-reducing antioxidant power showed the best results in Fs-SMAwinter methanol extract (EC50 = 0.016 mg/mL) and Fs-SMAsummer acetone:water extract (EC50 = 0.017 mg/mL). The best ferrous ion-chelating activity was found in Fs-SMGwinter acetone:water extract. Overall, results revealed that F. spiralis nutritional and functional bioactivity values have geographical and seasonal variations and that its regular consumption may add benefits to human health.

Bioaccessibility of Antioxidants and Fatty Acids from Fucus Spiralis

“…The F. spiralis protein content of 12.73 ± 1.38% DW is within the ranges described for brown algae (3%-15% of DW) [25,26]. However, Paiva and co-workers reported lower values for F. spiralis collected in Azores islands (Portugal) (4.14% and 8.25%) for samples collected in the same time of the year, which might explain this variation [27]. Nevertheless, protein content varies with seawater temperature, salinity, nutrients, and geographical location [25,27].…”

“…However, Paiva and co-workers reported lower values for F. spiralis collected in Azores islands (Portugal) (4.14% and 8.25%) for samples collected in the same time of the year, which might explain this variation [27]. Nevertheless, protein content varies with seawater temperature, salinity, nutrients, and geographical location [25,27]. Moreover, this protein content is also comparable to that of some grains like oats (13.4%), wheat (13.8%) and is higher than that of corn (9.4%) and rice (7.1%) [28].…”

A critical review of analytical methods used for the chemical characterisation and quantification of phlorotannin compounds in brown seaweeds

“…Due to the number of processing and extraction variables, it is impossible to conclude whether the differences in the phenolic contents are a result of these or due to seasonal or locational differences. Seasonality is an issue in these studies as it is well known that seaweeds produce different TPC values dependent on the time of year . The way the phenolic content is expressed can also cause issues because many different units are recorded in the literature, which also makes phenolic content difficult to compare between studies.…”

“…Seasonality is an issue in these studies as it is well known that seaweeds produce different TPC values dependent on the time of year. 7,36,53 The way the phenolic content is expressed can also cause issues because many different units are recorded in the literature, which also makes phenolic content difficult to compare between studies. For example, Table 2 shows phenolic content of seaweeds expressed in caffeic acid, gallic acid and phloroglucinol equivalents (CAE, GAE, PGE respectively), these can all then be expressed as % content, mg/g, PGE/100 g. Given these discrepancies it is difficult to make direct comparisons of studies in the literature.…”

Determining the content of macronutrients in berry sauces using a method of IR-spectroscopy

“…However, it should be noted that currently most developments that use algae as food additives belong sition of carbohydrates and proteins. Table 1 gives the content of the main macronutrients in algal raw materials [18][19][20]. Among the berry raw materials are wild blueberries and cranberries, as well as the cultivated sea buckthorn berries.…”