Undervalued Atlantic brown seaweed species (Cystoseira abies-marina and Zonaria tournefortii): influence of treatment on their nutritional and bioactive potential and bioaccessibility

Abstract

The brown seaweed species Cystoseira abies-marina and Zonaria tournefortii are abundant Atlantic resources that remain undervalued. This results from an insufficient knowledge of their nutrients' and bioactive potential. There is also uncertainty regarding the adequate culinary treatment of these seaweeds prior to their consumption. Thus, the current study evaluated the composition, bioactivity, and bioaccessibility of target compounds and bioactivities of these two species as a function of two treatments, simple rehydration and steaming, in comparison to sun-dried seaweed. The proportion of SFA, MUFA, and PUFA differed between species. C. abies-marina was richer in PUFA (30-31% vs 20-21%) and Z. tournefortii was richer in SFA (53-57% vs 46-47%). Main contributors to ω3 PUFA content were different in each species: alpha-linolenic acid in C. abies-marina, 4.5-5.1%, and eicosapentaenoic acid in Z. tournefortii, 5.8-6.7%. The sum of Mg and Ca contents in Z. tournefortii was two-fold the same sum in the other species. Furthermore, rehydration led to an elemental concentration reduction in most instances. The As content in C. abies-marina was very high, ranging between 295 ± 5 mg/kg dw and 369 ± 2 mg/kg dw, in rehydrated and steam-cooked seaweed, respectively. While aqueous extracts of C. abies-marina had the highest phenolic contents, 620-1280 mg GAE/100 g dw, aqueous extracts of Z. tournefortii contained 170-280 mg GAE/100 g dw. Regarding bioaccessibility, Mg, K, Ca, As, and Cd showed relatively high bioaccessibility levels and it was shown that only a limited part of the original antioxidant activity in both species is bioaccessible. Keywords Cystoseira abies-marina • Zonaria tournefortii • Proximate and elemental composition • Fatty acid profile • Bioactivity • Bioaccessibility Abbreviations AA Eq Ascorbic acid equivalent ABTS 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) DPPH 2,2-Diphenyl-1-picrylhydrazyl FAME Fatty acid methyl ester FRAP Ferric reducing antioxidant power GAE Gallic acid equivalent MUFA Monounsaturated fatty acid PUFA Polyunsaturated fatty acid SFA Saturated fatty acid Trolox Eq Trolox equivalent ω3 PUFA Omega-3 polyunsaturated fatty acid ω6 PUFA Omega-6 polyunsaturated fatty acid * C. Cardoso

The effect of drying on undervalued brown and red seaweed species: Bioactivity alterations

“…Antioxidant activity measured by FRAP is less frequent. Namely, the scarce results for T. abies-marina (Fonseca et al 2021) agree with the present study. The determined ABTS values are relatively similar to results found for other brown and red seaweeds (Campos et al 2019).…”

“…The DPPH assay indicated non-negligible antioxidant activity in the extracts of most species. There is some agreement with the relevant literature, for instance, in the case of the aqueous extracts of A. taxiformis (Regal et al 2020) and both types of extracts of T. abies-marina (Fonseca et al 2021). The other two species are less studied and there are no comparable results.…”

“…These values were lower than in extracts from A. taxiformis in our study. With respect to T. abies-marina and aqueous extracts, a starker divergence exists between literature, with Fonseca et al (2021) reporting an ABTS value of 43 AE 1 μmol Trolox Eq g À1 dw, and our ABTS assay results (no detected activity). There is also disagreement regarding the phenolic content, DPPH, and FRAP results, which were all higher in the aqueous extracts of sun-dried T. abies-marina studied by Fonseca et al (2021) (8.40 AE 0.60 mg GAE g À1 dw, 0.50 mg AE 0.01 AA Eq g À1 dw, and 113 AE 8 μmol Fe 2+ Eq g À1 dw, respectively).…”

Saccharina latissima Cultivated in Northern Norway: Reduction of Potentially Toxic Elements during Processing in Relation to Cultivation Depth

“…The same has been documented in a previous study using S. latissima from the Faroe Islands, to which both boiling (15 min) and fermentation were applied without significantly altering the lead content of the samples [15]. During a study of two lesser known brown algae, Cystoseira abies-marina and Zonaria tournefortii, no lead was found in the former species in the raw state nor after processing (<limit of quantification), whereas for the latter species, the lead content remained unchanged during rehydration in milli-Q water but increased significantly during steaming [63]. Contrary to this, the following study has documented loss of lead during processing.…”

Potential of the Ethyl Acetate Fraction of Padina boergesenii as a Natural UV Filter in Sunscreen Cream Formulation

“…Brown seaweed develops phloroglucinol-based polyphenols over time, which enhances its antioxidant activity against oxidative damage [ 17 ]. Antioxidant activity of brown seaweed such as Padina australis [ 18 ], Padina pavonica [ 19 ], Sargassum horneri [ 20 ], Sargassum angustifolium [ 21 ], Cystoseria myrica [ 21 ], Eisenia bicyclis [ 22 ], Kjellmaniella crassifolia [ 23 ], Alaria crassifolia [ 24 ], and Cystoseira hakodatensis [ 25 ] has been reported. Due to polyphenol compounds, brown seaweed has other biological activities such as antibacterial [ 26 ], antiviral [ 27 ], anti-cancer [ 28 ], anti-inflammatory [ 29 ], anti-allergic [ 30 ], and anti-aging [ 31 ].…”