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Journal of Food Science and Technology logoLink to Journal of Food Science and Technology
. 2011 Jan 29;49(6):774–780. doi: 10.1007/s13197-010-0220-0

Evaluation of the proximate, fatty acid and mineral composition of representative green, brown and red seaweeds from the Persian Gulf of Iran as potential food and feed resources

Kiuomars Rohani-Ghadikolaei 1,2,✉, Eessa Abdulalian 2, Wing-Keong Ng 1
PMCID: PMC3550831  PMID: 24293698

Abstract

The proximate, fatty acid and mineral composition were determined for green (Ulva lactuca and Enteromorpha intestinalis), brown (Sargassum ilicifolium and Colpomenia sinuosa) and red (Hypnea valentiae and Gracilaria corticata) seaweeds collected from the Persian Gulf of Iran. Results showed that the seaweeds were high in carbohydrate (31.8–59.1%, dry weight) and ash (12.4–29.9%) but low in lipid content (1.5–3.6%). The protein content of red or green seaweeds was significantly higher (p < 0.05) compared to brown seaweeds. The fatty acid composition of various seaweed lipids varied considerably with 51.9–67.4% of saturates, 22.0–32.9% of monoenes and 9.2–19.1% of polyunsaturated fatty acids (PUFA). E. intestinalis contained the highest total n-3 PUFA content with the lowest n-6/n-3 ratio. Persian Gulf seaweeds contained higher concentrations of all the minerals examined (K, Mg, Fe, Mn, Cu, Zn and Co) compared to terrestrial vegetables. Seaweeds could potentially be used as a food or feed additive in Iran.

Keywords: Fatty acids, Minerals, Persian Gulf, Proximate composition, Seaweed

Introduction

Seaweeds have been used as food, animal feeds, fertilizer and as sources of traditional medicine in many Asian civilizations since ancient times. Seaweeds are excellent dietary sources of vitamins, proteins, carbohydrates, trace minerals and other bioactive compounds (Kumar et al. 2008). In order to fully exploit the nutritional value of seaweeds, several studies on the biochemical and nutritional composition of various seaweeds collected from different parts of the world have been conducted (Rupérez 2002; McDermid and Stuercke 2003; Ortiz et al. 2006; Marsham et al. 2007; Chakraborty and Santra 2008; Matanjun et al. 2009). The biochemical composition of marine seaweeds is generally known to be highly influenced by geographical location and local environmental conditions.

In Iran, there is currently great interest to develop commercial seaweed farming to harness seaweeds with economical value as food, feed and fuel bio-resources. A number of surveys have recently been conducted to identify and map the distribution of Iranian coastal seaweeds. The dominant seaweeds found in Iran belong to the genus Phaeophyta (Sargassum spp., Padina spp., Colpomenia sp., and Cystoseira spp.), Chlorophyta (Caulerpa spp., Ulva spp. and Enteromorpha spp.) and Rhodophyta (Gracilaria spp. and Hypnea spp.) (Rohani and Hossaini 2005; Rohani et al. 2007). Considering the great potential for the extensive culture of seaweeds along the coastal waters of the Persian Gulf, an initial essential step would be to determine the chemical composition of these indigenous seaweeds to ascertain their potential as a food and feed source, as well as potential industrial applications based on agar, alginate and carrageenans from seaweed processing. As far as we know, there is currently no published data on the chemical composition of seaweeds from the Persian Gulf of Iran. In the present study, the proximate, fatty acid and mineral composition as well as the chlorophyll-a content of representative green, brown and red seaweeds collected from the Persian Gulf was determined.

Materials and methods

Sample collection and preparation

In total, six seaweeds, two green [Ulva lactuca (Linnaeus) and Enteromorpha intestinalis (Linnaeus) Nees], two brown [Colpomenia sinuosa (Endlicher) Derbès & Solier and Sargassum ilicifolium (Turner) C. Agardh], and two red [Gracilaria corticata (J. Agardh) J. Agardh and Hypnea valentiae (Turner) Montagne] were collected from the northern coast of the Persian Gulf of Iran for analyses in the present study. Immediately after collection, the seaweed samples were cleaned and washed with seawater to remove sand, debris, epiphytes and other extraneous matter attached to the thalli and transported to the laboratory. In the laboratory, the samples were sorted and then thoroughly cleaned by rinsing with distilled water. The cleaned seaweed samples were then freeze-dried (ZirBus VaCo 5, Germany). After reaching constant weight, the dried samples were ground (for 5 min) into a fine powder using a coffee grinder and passed through a 0.5 mm sieve before being stored in dark labeled glass jars in a refrigerator at 4°C until chemical analysis. All chemical analysis of seaweed samples was carried out in triplicates.

Proximate composition analysis

The moisture content (%) of seaweeds was determined by drying 2 g of samples in a thermo regulated incubator (Memert 40050ip20, Germany) at 105°C until constant weight (AOAC 1997). Moisture absorption (%) was determined by subtracting of freeze-dried from oven-dried seaweed sample. Ash content was determined by heating the samples for 4 h in a muffle furnace (Asan Godaz, Iran) at 500°C (AOAC 1997). Total carbohydrate was estimated by following the method used by Dubois et al. (1956) with glycogen used as standard. Total protein was determined with the method used by Lowry et al. (1951). Total crude lipid was determined gravimetrically by the Bligh and Dyer (1959) method.

Fatty acid analysis

Total lipid was extracted from 2 g of dried seaweed sample using the Bligh and Dyer (1959) procedure. The sample was extracted three times with chloroform: methanol (2:1, v/v; containing BHT 0.1 mg/100 g), purified using the method of Folch et al. (1957), and methylated and transesterified with boron trifluoride in methanol (AOAC 1997). A known amount of heneicosanoic acid (C21:0) was added as an internal standard (Sigma-Aldrich, USA). The resultant fatty acid methyl esters (FAME) samples were then resolved and analyzed by using a gas-liquid chromatograph (GC-SRI 8610C, USA) equipped with a fused silica capillary column Omega-wax 320 (60 m × 0.25 mm, I.D., 0.25 μm film; Sigma-Aldrich, USA), and a flame ionization detector (FID) as previously described in Ng et al. (2003).

Chlorophyll-a

A common pigment, chlorophyll-a, was extracted using 90% acetone. Ten ml 90% acetone was added to a centrifuge tube containing 10 mg of well-powdered seaweed sample, wrapped with aluminum foil and kept overnight in the refrigerator. Samples were then centrifuged (Universal Tlettich, Germany) at 3000 rpm for 5 min and the supernatant transferred to a new tube. The amount of chlorophyll-a was determined calorimetrically by a spectrophotometer (Cecil Spectro, England) using the method described by Strickland and Parsons (1989).

Mineral analysis

For the determination of mineral elements (Fe, Mg, Mn, K, Cu, Zn and Co), samples were dissolved in 1 M HNO3 and H2O2 before being digested by a microwave (Mileston, Ethos 1, Italy). The concentration of the elements in the dried seaweed samples were determined by means of an atomic absorption spectrometer (FS95, Thermo, England) equipped with a hollow cathode lamp according to the method described in MOOPAM (1989). The seaweed mineral concentrations were quantified from calibration curves of the respective standard elements. All chemicals used were of trace element analytical grade (Merck, Germany).

Statistical analysis

Data were analyzed with SPSS 16.0 software using parametric tests. One-way ANOVA was used to compare the means of chemical composition data determined for the three groups of seaweeds. When differences were found, Duncan multiple comparison test was used, and differences were considered significant at p < 0.05.

Results and discussion

The protein, lipid, carbohydrate, ash, moisture and chlorophyll-a content of the six different species from three different genera of seaweeds collected from the coastal waters of the Persian Gulf are shown in Table 1. The mean protein content of both the red and green seaweeds (with the exception of E. intestinalis) were significantly higher (p < 0.05) compared to the brown seaweeds. G. corticata had the highest protein content (19.3%, dry weight basis) and S. ilicifolium the lowest (8.9%). Burtin (2003) reported that the protein content in brown seaweeds are generally lower (ranging from 5 to 15% of dry weight) compared to red and green seaweeds (ranging from 10 to 30%). Similar range of protein content in seaweeds was also reported by Chakraborty and Santra (2008) and Manivannan et al. (2009).

Table 1.

Proximate composition (% dry weight of sample) and chlorophyll-a (mg/g dry weight) of representative green, brown and red seaweeds collected from the Persian Gulf of Iran a

Composition Green seaweed Brown seaweed Red seaweed
U. lactuca E. intestinalis S. ilicifolium C. sinuosa H. valentiae G. corticata
Protein 17.1 ± 1.59a 10.5 ± 1.02b 8.9 ± 0.94b 9.2 ± 1.78b 16.5 ± 2.78a 19.3 ± 2.19a
Crud lipid 3.6 ± 0.42a 2.9 ± 0.25ab 2.0 ± 0.20c 1.5 ± 0.29c 2.8 ± 0.67b 1.8 ± 0.46c
Carbohydrate 59.1 ± 0.37a 35.5 ± 2.83c 32.9 ± 1.08c 32.1 ± 1.75c 31.8 ± 1.34c 43.0 ± 5.58b
Ash 12.4 ± 1.05c 22.4 ± 1.46b 29.9 ± 2.73a 28.1 ± 0.86a 21.8 ± 0.69b 23.1 ± 0.53b
Moisture b 6.8 ± 0.24c 10.6 ± 0.50ab 10.4 ± 0.33ab 11.5 ± 0.20a 10.8 ± 0.35ab 9.2 ± 0.15b
Moisture absorption c 0.2 ± 0.05c 8.5 ± 0.80a 8.0 ± 0.64a 5.3 ± 0.75ab 6.5 ± 0.60ab 2.1 ± 0.30b
Chlorophyll-a 3.5 ± 0.60c 5.6 ± 0.46bc 13.3 ± 0.83a 12.1 ± 0.30a 6.1 ± 0.26bc 7.5 ± 0.35b
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aData are mean values of triplicate samples ± SD. Different superscript letters in the same row indicate significant differences (p < 0.05)

bexpressed as percentage of oven-dried sample

cexpressed as percentage of freeze-dried minus oven-dried sample

Seaweeds are relatively low in lipid (1–5% of dry weight) (Burtin 2003; Polat and Ozogul 2008). In the present study, the highest crude lipid content was observed in U. lactuca (3.6%) and E. intestinalis (2.9%), while the lowest content was found in C. sinuosa (1.5%) and G. corticata (1.8%). These results are comparably lower than those reported by Chakraborty and Santra (2008) for E. intestinalis (7.1%) and U. lactuca (4.4%), but higher than those estimated by Ortiz et al. (2006) for U. lactuca (0.3%). In the present study, the crude lipid content of green seaweeds was found to be generally significantly higher compared to both the red and brown seaweeds.

Carbohydrates were the major component in the proximate composition of all the seaweeds examined in the present study. The carbohydrate content ranged from 31.8% in H. valentiae to 59.1% in U. lactuca. The carbohydrate content in U. lactuca and G. corticata were both significantly higher compared to the other seaweeds. These results are comparatively higher than those reported by Chakraborty and Santra (2008) for U. lactuca (35.3%), and by Manivannan et al. (2008a) for H. valentiae (23.6%), but similar to those obtained by Ortiz et al. (2006) for U. lactuca (61.5%). Similar range of carbohydrate content was previously reported by Burtin (2003) and Matanjun et al. (2009) for various seaweeds.

In this study, the highest ash content was observed in the brown seaweed S. ilicifolium (29.9%), while the lowest was observed in U. lactuca (12.4%). Ash content in brown seaweeds was significantly higher compared to that determined in both the red and green seaweeds. The range of ash content determined in the present study was similar to that reported by Rupérez (2002) and Matanjun et al. (2009) but slightly lower than those reported by Renaud and Luong-Van (2006).

Despite undergoing the same drying and sample processing method, the observed differences in the moisture content of the freeze-dried seaweed samples may indicate that the powdered samples have different abilities to absorb atmospheric moisture during storage. The range of moisture content observed among the various seaweed samples varied from 6.8% (in U. lactuca powder) to 11.5% (in C. sinuosa powder). The higher and lower moisture absorption were observed for E. intestinalis (8.5%) and U. lactuca (0.2%), respectively. Moisture content is an important criterion in determining the shelf-life and quality of processed seaweed meals as high moisture may hasten the growth of microorganisms.

As previously mentioned, apart from species specific differences, geographical location and local environmental conditions can influence the proximate composition of seaweeds (McDermid and Stuercke 2003; Ortiz et al. 2006; Renaud and Luong-Van 2006; Marsham et al. 2007; Chakraborty and Santra 2008; Matanjun et al. 2009). The present study is the first published data on the proximate composition of representative green, brown and red seaweeds collected from the unique marine aquatic environment found in the Persian Gulf.

The chlorophyll-a content (mg/g dry weight) of brown seaweeds; S. ilicifolium (13.3 mg/g) and C. sinuosa (12.1 mg/g), were found to contain the highest content of chlorophyll-a, while the lowest content was observed in U. lactuca (3.5 mg/g) with both the brown seaweed showing significantly higher content compared to all the other seaweeds examined. The chlorophyll-a content in the green algae (U. lactuca and E. intestinalis) from the Persian Gulf was considerably higher than that reported by Chakraborty and Santra (2008) for the same species (2.1 and 1.7 mg/g, respectively) collected from the Indian Sunderbans area.

The fatty acid composition of the different seaweeds in the present study varied considerably with 51.9–67.4% of saturated fatty acids (SFA), 22.0–32.9% of monounsaturated fatty acids (MUFA) and 9.2–19.1% of polyunsaturated fatty acids (PUFA) (Table 2). Among the SFA, myristic acid (C14:0; 4.5–12.4%) and palmitic acid (C16:0; 38.0–59.8%) were the predominant fatty acids. As for MUFA, palmitoleic acid (C16:1n-7; 3.7–10.6%) and oleic acid (C18:1n-9; 3.5–28.6%) were the predominant fatty acids. The most abundant PUFA was linolenic acid (C18:3n-3; 0.3–8.4%). Similarly, Matanjun et al. (2009) and Polat and Ozogul (2008) reported that palmitic acid and oleic acid were the major fatty acids found in the seaweeds that they examined.

Table 2.

Fatty acid composition (% total fatty acids) of representative green, brown and red seaweeds collected from the Persian Gulf of Irana

Fatty acids Green seaweed Brown seaweed Red seaweed
U. lactuca E. intestinalis S. ilicifolium C. sinuosa H. valentiae G. corticat
C14:0 7.6 ± 1.83b 4.7 ± 0.77c 4.8 ± 0.75c 12.4 ± 1.33a 4.5 ± 0.64c 6.0 ± 1.52b
C16:0 50.7 ± 4.28b 38.9 ± 2.62c 46.1 ± 2.80b 38.0 ± 1.42c 59.8 ± 1.09a 43.6 ± 3.14b
C18:0 2.8 ± 0.71bc 15.0 ± 2.85a 1.9 ± 0.46bc 0.2 ± 0.01c 2.1 ± 0.37bc 2.2 ± 0.72bc
C20:0 0.8 ± 0.63 0.5 ± 0.07 0.6 ± 0.05 1.0 ± 0.05 0.4 ± 0.01 0.4 ± 0.06
C22:0 3.8 ± 1.05a 0.9 ± 0.28c 1.0 ± 0.07c 0.5 ± 0.06c 0.4 ± 0.06c 2.4 ± 0.72b
C24:0 0.6 ± 0.16bc 0.3 ± 0.02cd 0.9 ± 0.08b 0.1 ± 0.02d 0.2 ± 0.01d 1.0 ± 0.24a
Total SFA b 66.3 ± 3.68a 60.6 ± 3.04ab 55.2 ± 3.33b 51.9 ± 2.08b 67.4 ± 0.31a 58.7 ± 3.75ab
C14:1n-5 0.9 ± 0.36a ND ND 0.1 ± 0.07b 0.9 ± 0.08a 0.2 ± 0.04b
C16:1n-7 10.6 ± 1.83a 7.9 ± 2.35b 8.2 ± 0.64ab 3.7 ± 0.69c 8.5 ± 0.14ab 6.9 ± 0.40b
C18:1n-7 ND 6.2 ± 1.85a ND 0.4 ± 0.08c 3.1 ± 0.41b 0.7 ± 0.33c
C18:1n-9 11.5 ± 2.24cd 9.5 ± 1.19d 18.8 ± 2.16b 28.6 ± 2.30a 3.5 ± 0.28e 13.8 ± 3.30c
C20:1n-9 0.4 ± 0.02bc 0.5 ± 0.09b 0.2 ± 0.13c ND 6.8 ± 0.42a 0.2 ± 0.07bc
C22:1n-9 ND 0.4 ± 0.23b ND 0.1 ± 0.02c 0.7 ± 0.18a 0.2 ± 0.03bc
C24:1n-9 0.5 ± 0.28a 0.4 ± 0.04ab 0.1 ± 0.13c ND 0.2 ± 0.08bc ND
Total MUFA b 23.8 ± 3.13b 24.8 ± 2.02ab 27.5 ± 2.58ab 32.9 ± 1.60a 23.6 ± 0.68b 22.0 ± 3.65b
C18:3n-3 2.5 ± 0.80c 8.4 ± 0.37a 5.9 ± 0.72b 1.8 ± 0.28cd 0.3 ± 0.12d 7.7 ± 1.88a
C20:3n-3 ND 1.3 ± 0.82a 0.2 ± 0.03b 0.2 ± 0.06b 0.5 ± 0.02b ND
C20:5n-3 (EPA) b 1.3 ± 0.53bc 0.3 ± 0.08e 1.9 ± 0.22b 5.4 ± 0.86a 1.0 ± 0.04cd ND
C22:6n-3 (DHA) b 1.1 ± 0.30a ND 0.2 ± 0.11c 0.2 ± 0.07c 0.7 ± 0.13b ND
C18:2n-6 3.5 ± 1.26c 0.9 ± 0.30d 7.9 ± 0.42a 3.1 ± 0.24c 0.4 ± 0.07d 6.0 ± 0.20b
C20:2n-6 0.5 ± 0.14c 1.2 ± 0.46b 0.3 ± 0.11c 3.9 ± 0.53a 0.7 ± 0.17c 0.2 ± 0.03c
C20:4n-6 (AA) b 1.1 ± 0.46c 2.7 ± 0.53b 1.0 ± 0.12c 0.4 ± 0.04c 5.4 ± 0.42a 5.2 ± 0.88a
Total PUFA b 9.8 ± 1.20d 14.8 ± 0.74c 17.4 ± 0.68b 15.3 ± 0.75c 9.2 ± 0.80d 19.1 ± 2.86a
Total n-3 PUFA 4.8 ± 0.83c 9.8 ± 0.60a 8.2 ± 1.08b 7.7 ± 0.69b 2.5 ± 0.42d 7.8 ± 1.74b
Total n-6 PUFA 5.1 ± 1.14d 4.8 ± 0.75d 9.2 ± 0.44b 7.6 ± 0.68c 6.7 ± 0.53c 11.2 ± 0.70a
n-6/n-3 1.1 0.5 1.1 1.0 2.7 1.4
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aData are mean values of triplicate samples ± SD. Different superscript letters in row indicate significant differences in mean (p < 0.05)

bSFA, MUFA, EPA, DHA, AA and PUFA, represent saturated, monounsaturated, eicosapentaenoic, docosahexaenoic, arachidonic and polyunsaturated fatty acids, respectively

ND indicates not detectable fatty acid

Of the six seaweeds species investigated, H. valentiae (67.4%) and U. lactuca (66.3%) had the highest relative concentrations of SFA in their total lipid content of which more than half consisted of palmitic acid (Table 2). The brown seaweed species C. sinuosa (32.9%) and S. ilicifolium (27.5%) had the highest relative concentrations of MUFA, consisting mainly of oleic acid. The red seaweed, G. corticata, had the highest content of PUFA at 19.1% of total fatty acids. In general, the SFA and MUFA content of the green algae U. lactuca and E. intestinalis determined in the present study were relatively higher than those reported for the same species by Chakraborty and Santra (2008), but determined PUFA content was lower in the present study. The SFA content observed in the present study was comparatively higher than previously reported for brown and red seaweed species (Polat and Ozogul 2008). The seaweed MUFA content determined in the present study was lower than those reported by Durmaz et al. (2008) for red algae. In contrast to the present study, Terasaki et al. (2009) reported that PUFA constituted the most abundant fatty acid class in brown seaweeds collected off the coast of Hakodate in Japan.

The health-beneficial eicosapentaenoic acid (EPA; C20:5n-3) was found in all seaweed species except G. corticata, with 5.4% of total fatty acids as the highest concentration found in C. sinuosa. The EPA content (0.3%) of E. intestinalis observed in the present study was lower than that reported by Chakraborty and Santra (2008) for the same species (2.90%). Docosahexaenoic acid (DHA; C22:6n-3), another physiologically important long-chain PUFA, was found in low concentrations in all seaweeds (ranging from trace to 1.1%). Arachidonic acid (AA; C20:4n-6) content ranged from 0.4–5.4% in the six seaweeds. The DHA and AA results in the present study were higher than those reported by Matanjun et al. (2009) where the DHA content was below the detection limit (<0.1% of total fatty acids), while AA content was 0.6%. Terasaki et al. (2009) reported relatively high concentrations of AA (11.6–14.8%) and EPA (9.7–12.0%) in Sargassum spp., despite not detecting any DHA in their lipid extracts. Variation in the PUFA concentration and profile of different seaweeds have been reported to be mainly dependent on the local water temperature from which the seaweeds were collected with temperature species containing higher levels of fatty acids with longer-chain and higher degree of unsaturation compared to tropical species (Bhaskar et al. 2004). Consumption of long-chain omega-3 PUFA are known to be beneficial to human health (Ruxton et al. 2005) and together with a low dietary n-6/n-3 ratio, are fundamental for a diet with cardio-protective benefits. In the present study, the green seaweed, E. intestinalis, contained the highest total n-3 PUFA content with the lowest n-6/n-3 ratio among the seaweeds examined.

The mineral composition of the three groups of seaweed is shown in Table 3. Most of the seaweeds evaluated in the present study exhibited high amounts of potassium, magnesium and iron, but low concentrations of copper and cobalt, similar to values reported by Krishnaiah et al. (2008), but relatively higher than those reported by Rupérez (2002). Among the seven minerals determined, potassium content was the highest for all seaweeds (range 515.6–876.6 mg/100 g) but this was comparably lower than those reported in seaweeds examined by Matanjun et al. (2009) (8371.2–13155.2 mg/100 g). Higher potassium concentrations were found in the brown and red seaweeds as compared to the green seaweeds of the Persian Gulf.

Table 3.

Selected mineral composition (mg/100 g dry weight of sample) of representative green, brown and red seaweeds collected from the Persian Gulf of Iran, as compared to some vegetablesa

Treatments Inline graphic Minerals
Iron Potassium Magnesium Manganese Zinc Cobalt Copper
U. lactuca 46.4 ± 1.53c 515.6 ± 35.68d 79.1 ± 2.66a 1.5 ± 0.26b 1.6 ± 0.28c 0.07 ± 0.02d 0.34 ± 0.08bc
E. intestinalis 25.4 ± 2.75d 589.3 ± 43.52c 61.7 ± 5.82b 1.3 ± 0.21b 2.1 ± 0.07b 0.24 ± 0.03c 0.43 ± 0.08ab
S. ilicifolium 58.9 ± 9.26b 876.6 ± 15.85a 81.7 ± 6.90a 1.6 ± 0.08b 2.2 ± 0.11b 0.75 ± 0.09a 0.28 ± 0.04c
C. sinuosa 45.2 ± 2.20c 728.5 ± 50.14b 78.1 ± 1.53a 1.5 ± 0.03b 1.9 ± 0.08bc 0.43 ± 0.03b 0.51 ± 0.06a
H. valentiae 80.3 ± 9.08a 746.0 ± 40.82b 38.7 ± 1.68c 3.7 ± 0.31a 3.1 ± 0.21a 0.45 ± 0.02b 0.39 ± 0.04bc
G. corticata 85.0 ± 5.13a 713.0 ± 46.50b 18.3 ± 1.37d 3.3 ± 0.25a 3.2 ± 0.36a 0.81 ± 0.18a 0.33 ± 0.07bc
Lactuca sativab 0.9 194 13 0.3 0.2 ND 0.03
Spinacia oleraceab 2.7 558 79 0.9 0.5 ND 0.13
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aData are mean values of triplicate samples ± SD. Different superscript letters in the same column indicate significant differences in mean (p < 0.05)

bCommon vegetables (USDA 2010)

ND = not detectable

Magnesium content in both brown and green seaweeds was significantly higher than in the red seaweeds (p < 0.05). These results are higher than those determined by Manivannan et al. (2008b) in U. lactuca (17.5 mg/100 g) and H. valentiae (4.0 mg/100 g), and compatible to those estimated by Matanjun et al. (2009). The highest concentration of manganese was recorded from the red seaweed, H. valentiae (3.7 mg/100 g) followed by G. corticata (3.3 mg/100 g) while the lowest level was found in E. intestinalis (1.3 mg/100 g). The zinc content of the red seaweeds examined in the present study was significantly higher compared to the brown and green seaweeds; the values determined was also higher than the results reported by McDermid and Stuercke (2003).

The red seaweeds contain significantly higher levels of iron compared to that found in both the green and brown seaweeds (Table 3). The highest and lowest level of copper was found in the brown algae C. sinuosa (0.51 mg/100 g) and S. ilicifolium (0.28 mg/100 g), respectively, and this was significantly different. The iron and copper content determined for seaweeds in this study were higher than those reported by McDermid and Stuercke (2003) in other seaweed species of the same genus. The green seaweeds contained the lowest cobalt concentrations compared to both the brown and red seaweeds.

Seaweeds are able to selectively absorb minerals from the surrounding seawater and accumulate them in their thalli (Azmat et al. 2006). For this reason, their mineral composition and concentration are species and location specific. Edible brown and red seaweeds could be consumed as a food supplement to help fulfill the recommended daily intake of essential minerals and trace elements (Rupérez 2002). The present data showed that the seaweeds collected from the Persian Gulf generally contained higher concentrations of all the minerals examined compared to common vegetables such as lettuce (Lactuca sativa) and spinach (Spinacia oleracea) (Table 3). Potassium and magnesium content in the examined seaweeds were comparable or higher compared to that found in spinach (with the exception of Mg in red seaweeds) while content of the other minerals (Fe, Zn, Mn and Cu) in seaweeds were comparatively higher compared to that found in lettuce and spinach.

Chemical analysis of the seaweeds collected from the Persian Gulf of Iran showed that they were nutritionally rich in terms of protein (red and green seaweeds), carbohydrates (especially green seaweeds), lipids (in particular green seaweeds with higher content of n-3 PUFA) and essential minerals. Therefore, these seaweeds could potentially be used, after processing, as a food or feed additive in Iran. The present study is the first report on the biochemical composition of seaweeds from the Persian Gulf and further studies are needed on the nutritional and toxicological aspects of seaweed utilization as food and feed resources for human and animal consumption, respectively.

Acknowledgments

The authors would like to thank the Iranian Fisheries Research Organization (IFRO) for providing financial support and the Persian Gulf and Oman Sea Ecological Research Institute (PGOSERI) for their technical support. The authors are grateful to K.S. Lee for his editorial assistance.

References

  1. Official methods of analysis. 16. Arlington, VA, USA: Association of Official Analytical Chemists, AOAC International; 1997. [Google Scholar]
  2. Azmat R, Hayat A, Khanum T, Talat R, Uddin F. The inhabitation of bean plant metabolism by Cd metal and Atrazine III: effects of seaweed Codium Iyengaria on metal, herbicide toxicity and rhizosphere of the soil. Biotechnol. 2006;5:85–89. doi: 10.3923/biotech.2006.85.89. [DOI] [Google Scholar]
  3. Bhaskar N, Miyashita K, Hosokawa M. Comparative evaluation of fatty acid composition of different Sargassum (Fucales, Phaeophyta) species harvested from temperate and tropical waters. J Aqua Food Pro Technol. 2004;13:53–70. doi: 10.1300/J030v13n04_05. [DOI] [Google Scholar]
  4. Bligh EG, Dyer WJ. A rapid method of total lipid extraction and purification. Can J Biochem Physiol. 1959;37:911–917. doi: 10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
  5. Burtin P. Nutritional value of seaweeds. Electron J Environ Agric Food Chem. 2003;2:498–503. [Google Scholar]
  6. Chakraborty S, Santra SC. Biochemical composition of eight benthic algae collected from Sunderban. Indian J Mar Sci. 2008;37:329–332. [Google Scholar]
  7. Dubois M, Gilles KA, Hamilton JK, Rebers PA, Smith F. Colorimetric method for the determination of sugars and related substances. Analytical Chem. 1956;18:350–356. doi: 10.1021/ac60111a017. [DOI] [Google Scholar]
  8. Durmaz Y, Duyar HA, Gökpinar S, Taskaya L, Öğretmen YO, Bandarra NM, Nunes ML. Fatty Acids, α-tocopherol and total pigment contents of Cystoseira spp., Ulva spp. and Zostera spp. from Sinop Bay (Turkey) Int J Natural Enger Sci. 2008;2:111–114. [Google Scholar]
  9. Folch AJ, Less M, Sloan-Stanley GH. A simple method for isolation and purification of total lipids from animal tissues. J Biolo Chem. 1957;226:497–509. [PubMed] [Google Scholar]
  10. Krishnaiah D, Sarbatly R, Prasad DMR, Bono A. Mineral content of some seaweeds from Sabah’s South China Sea. Asian J Sci Res. 2008;1:166–170. doi: 10.3923/ajsr.2008.166.170. [DOI] [Google Scholar]
  11. Kumar CS, Ganesan P, Suresh PV, Bhaskar N. Seaweeds as a source of nutritionally beneficial compounds—A review. J Food Sci Technol. 2008;45:1–13. [Google Scholar]
  12. Lowry OH, Rosebrough NJ, Farr AL, Randall RJ. Protein measurement with the Folin phenol reagent. J Biolo Chem. 1951;193:265–275. [PubMed] [Google Scholar]
  13. Manivannan K, Thirumaran G, Devi GK, Hemalatha A, Anantharaman P. Biochemical composition of seaweeds from Mandapam Coastal regions along Southeast Coast of India. Am-Euras J Bot. 2008;1:32–37. [Google Scholar]
  14. Manivannan K, Devi GK, Thirumaran G, Anantharaman P. Mineral composition of marine macroalgae from Mandapam Coastal regions; Southeast Coast of India. Am-Euras J Bot. 2008;1:58–67. [Google Scholar]
  15. Manivannan K, Thirumaran G, Devi GK, Anantharaman P, Balasubramanian T. Proximate composition of different group of seaweeds from Vedalai Coastal waters (Gulf of Mannar): Southeast Coast of India. Middle-East J Sci Res. 2009;4:72–77. [Google Scholar]
  16. Marsham S, Scott GW, Tobin ML. Comparison of nutritive chemistry of a range of temperate seaweeds. Food Chem. 2007;100:1331–1336. doi: 10.1016/j.foodchem.2005.11.029. [DOI] [Google Scholar]
  17. Matanjun P, Mohamed S, Mustapha NM, Muhammad K. Nutrient content of tropical edible seaweeds, Eucheuma cottonii, Caulerpa lentillifera and Sargassum polycystum. J Appl Phycol. 2009;21:75–80. doi: 10.1007/s10811-008-9326-4. [DOI] [Google Scholar]
  18. McDermid KJ, Stuercke B. Nutritional composition of edible Hawaiian seaweeds. J Appl Phycol. 2003;15:513–524. doi: 10.1023/B:JAPH.0000004345.31686.7f. [DOI] [Google Scholar]
  19. Manual of oceanographic and pollutant analysis methods. 2. Kuwait: The Regional Organization for the Protection of the Marine Environment (ROPME); 1989. [Google Scholar]
  20. Ng WK, Lim PK, Boey PL. Dietary lipid and palm oil source affects growth, fatty acid composition and muscle α-tocopherol concentration of African catfish, Clarias gariepinus. Aquaculture. 2003;215:229–243. doi: 10.1016/S0044-8486(02)00067-4. [DOI] [Google Scholar]
  21. Ortiz J, Romero N, Robert P, Araya J, Lopez-Hernández J, Bozzo C, Navarrete E, Osorio A, Rios A. Dietary fiber, amino acid, fatty acid and tocopherol contents of the edible seaweeds Ulva lactuca and Durvillaea antarctica. Food Chem. 2006;99:98–104. doi: 10.1016/j.foodchem.2005.07.027. [DOI] [Google Scholar]
  22. Polat S, Ozogul Y. Biochemical composition of some red and brown macro-algae from the Northeastern Mediterranean Sea. Int J Food Sci Nutr. 2008;59:566–572. doi: 10.1080/09637480701446524. [DOI] [PubMed] [Google Scholar]
  23. Renaud SM, Luong-Van JT. Seasonal variation in the chemical composition of tropical Australian marine macroalgae. J Appl Phycol. 2006;18:381–387. doi: 10.1007/s10811-006-9034-x. [DOI] [Google Scholar]
  24. Rohani K, Hossaini MR. A survey on distribution and biomass estimation of two species of Brown algae (Colpomenia sinuosa and Iyengaria stellata) in the Persian Gulf of Iran. Iranian Sci Fis J. 2005;13:55–64. [Google Scholar]
  25. Rohani K, Rajabi I, Rameshi H, Behzadi S, Dehghani R, Tamadoni S, Hossaini MR. Study on distribution and biomass estimation of seaweeds in Hormozgan coastal waters and some of Persian Gulf Islands. Iranian Sci Fis J. 2007;15:59–68. [Google Scholar]
  26. Rupérez P. Mineral content of edible marine seaweeds. Food Chem. 2002;79:23–26. doi: 10.1016/S0308-8146(02)00171-1. [DOI] [Google Scholar]
  27. Ruxton CHS, Calder PC, Reed SC, Simpson MJA. The impact of long-chain n-3 polyunsaturated fatty acids on human health. Nutr Res Reviews. 2005;18:113–129. doi: 10.1079/NRR200497. [DOI] [PubMed] [Google Scholar]
  28. Strickland JDH, Parsons TR. Discussion of spectrophotometric determination of marine plant pigments with revised equations for ascertaining chlorophylls and carotenoids. J Mar Res. 1989;21:155–163. [Google Scholar]
  29. Terasaki M, Hirose A, Narayan B, Baba Y, Kawagoe C, Yasui H, Saga N, Hosokawa M, Miyashita K. Evaluation of recoverable functional lipid components of several brown seaweeds (Phaeophyta) from Japan with special reference to fucoxanthin and fucosterol contents. J Phycol. 2009;45:974–980. doi: 10.1111/j.1529-8817.2009.00706.x. [DOI] [PubMed] [Google Scholar]
  30. USDA National Nutrient Database for Standard Reference. Agricultural research service, nutrient data laboratory. United State Department of Agriculture. [Cited 2010 Jan 14]. Available from: http://www.ars.usda.gov/ba/bhnrc/ndl

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