The present study aimed to characterize the nutraceutical properties and the antimicrobial effect of Moroccan
The Moroccan coast extends over 3500 km (2900 km for the Atlantic coast and 500 km for the Mediterranean coast). This ecosystem was recognized as vital and fragile but with a considerable ecological value. Despite increasing recognition of different foods and their safety, algae have received small interest in spite of their wide and abundant availability. Algae were one of the first life forms on Earth, and several thousand species existed [
All chemical reagents and solvents used were provided by Sigma-Aldrich (St. Louis, MO). Bacterial strains studied are in the form of batches by the American Type Culture Collection (ATCC), maintained by subculture on nutrient agar favorable to their growth, and obtained from the Fungus Collection Mycology Laboratory of the Forest Research Centre of Rabat, Morocco.
Protein, carbohydrates, lipids, fibers, ash, and micronutrient content were expressed on a microalga dry weight basis, and the results were presented in g/100 g. Analyses were carried out in three replicates. Ash content: it was determined by AACC [ Moisture: it was measured by drying at 80°C for 24 h, and the samples and their results were reported on a dry weight basis [ Crude protein (CP): it was quantified using the Kjeldahl method by the AOAC [ Crude fat (fat): it was determined using the Soxhlet method by the AACC [ Total fiber fractions: crude fiber (CF) was assessed according to the AOAC method [ Mineral composition: macroelements including K+ and Na+ contents were determined using a flame photometer, while Mg2+ and Ca2+ contents were determined using complexometric titration. On the contrary, phosphorus content was measured by using the acidified solution reaction of ammonium molybdate containing ascorbic acid and antimony [ Carbohydrates (CHO): they were quantified according to the method in [ Energy value (
Values were expressed in kcal/100 g.
The microbiological stability of the packaged sample was analyzed by measurement of total aerobic mesophilic flora (NF EN ISO 4833),
It was estimated by the Folin–Ciocalteu method [
It was assessed by applying the aluminum chloride colorimetric method according to the study in [
10 g of each powder sample was crushed in a solvent (MeOH) (1 L) for 48 h at 24°C in dark and stirred [
The radical-scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) test was used. Each test was repeated in triplicate. The procedure was followed as described by Lopes-Lutz [
The antioxidant activity of each sample was determined based on the inhibition curve and was expressed in terms of IC50.
The minimum inhibitory concentrations (MICs) of the methanolic extract were assayed according to the procedure described in [
Results were expressed as mean values ± standard deviation of three separate determinations.
Microalgae were considered an alternative source of protein, thanks to their high content of proteins [
Global nutritional analysis of
Elements | Percentage (%)b | Other micro/macroalgae |
---|---|---|
Moisturea (%) | 12.66 ± 1.7 | <9% [ |
Ash (%) | 14.56 ± 0.74 | 7.4–10.4% [ |
4–20% [ | ||
Protein (%) | 76.65 ± 0.15 | 60–71 [ |
6–71% [ | ||
3–47% [ | ||
Lipids (%) | 2.45 ± 0.82 | 6–13% [ |
>60% [ | ||
>5% [ | ||
CF (%) | 4.07 ± 1.42 | 1.36–7.73% [ |
Carbohydrates (%)c | 6.46 ± 0.32 | 15–25% [ |
10–27% [ | ||
20–68% [ | ||
Energy (kcal/100 g) | 436.18 ± 2.29 | ND |
The Moroccan strain studied contains a considerable amount of protein (76.65 ± 0.15%). This value was higher than that of various
Lipids represent one of the main sources of energy for human metabolic processes.
Microalga carbohydrates (e.g., starch, glucose, sugars, and other polysaccharides) normally generate energy and cellular structure. The carbohydrate content was about 6.46 ± 0.32%. This value was considerably lower than the carbohydrate concentration average of 15 to 25% reported previously for other
Algae were characterized by a higher ash content. The ash content for Moroccan samples was 14.56 ± 0.74%. This value was higher than that found previously in other
Moisture is an important factor for assessing the microalga quality. The dry matter content was 87.70 ± 1.85%. In fact, companies provide standards in their nutritional information and set the moisture standard below 9% [
The dietary fiber content of algae was of high nutritional importance. The present study was focused on the determination of crude fiber (CF, lignocellulose complex) and some polysaccharides of fibrous nature which would be identified further by future studies using highly sophisticated techniques. The cellulose and hemicellulose play an important role as structural components of the cell wall in algae [
Generally, algae were considered to have a high ash content, essential minerals, and trace elements required for human nutrition. Given the ash content in
Mineral composition of
Elements |
|
Other microalgae [ | |
---|---|---|---|
Minerals (mg/100 g dw) | P | 10088.33 ± 5766.88 | 1700–3000 |
Na | 14004 ± 397.55 | 7000–1100 | |
K | 2501.66 ± 4.22 | 600–1200 | |
Ca | 6000 ± 4.66 | 300–2100 | |
Mg | 100.33 ± 1.77 | 100–1100 | |
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Trace elements (mg/100 g dw) | Fe | 80.66 ± 1.77 | 100–700 |
Zn | 5 ± 0.66 | 23.9–370 | |
Cu | 1.22 ± 0.66 | 1.2–65 | |
Mn | 1.56 ± 0.11 | 3.7–59.2 |
The edible product was exposed to all contamination vectors. The microbial monitoring of marketed
Microbiological quality of edible
Pathogens | All aerobic mesophilic flora |
|
Total coliforms | Fecal coliforms | Sulfito-reducer bacteria | Yeasts and molds |
|
|
---|---|---|---|---|---|---|---|---|
Bacterial count | 208 | 93 | 26 | ND | ND | 14 | 4.15 | ND |
EU standard | 105 | Absent | Absent | No data | 104 | 104 | Absent | Absent |
WHO | No data | No data | No data | No data | 103 | No data | Absent |
EU, European Union [
Crosstalk between nutritional and physicochemical properties and bioactivities in the functional food
Total phenolic content (TPC) and total flavonoid content (TFC) of the methanolic extract of
A chromatographic separation method (HPLC-DAD/MS) was developed for simultaneous identification and quantification of phenolic acids and flavonoids in
Phenolic and flavonoid compounds determined in the
Phenolic acids |
|
Molecular formula | Molecular weight (M) | HPLC-ESI/MS ( | |
---|---|---|---|---|---|
RT (min) | [M-H] |
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Quinic acid | 844.17 ± 42.21 | C7H12O6 | 192.167 | 0.51 | 191.120 |
Citric acid | 64.06 ± 3.20 | C6H8O7 | 192.123 | 0.63 | 191.102 |
Pyrogallol | 0.42 ± 0.02 | C6H6O3 | 126.111 | 0.64 | 125.024 |
Succinic acid | 1122.88 ± 56.14 | C4H6O4 | 118.088 | 0.65 | 117.018 |
Gallic acid | 2.13 ± 0.11 | C7H6O5 | 170.022 | 0.66 | 168.90 |
Chlorogenic acid | 0.86 ± 0.04 | C16H18O9 | 354.311 | 0.83 | 353.202 |
3,4-Hydroxybenzoic acid | 687.07 ± 34.35 | C7H6O4 | 154.121 | 0.95 | 153.010 |
4-Hydroxybenzoic acid | 1.07 ± 0.05 | C7H6O3 | 138.122 | 1.30 | 137.050 |
Catechin | 584.53 ± 29.22 | C15H14O6 | 290.271 | 1.63 | 289.064 |
Vanillic acid | 16.24 ± 0.81 | C8H8O4 | 168.148 | 2.12 | 167.036 |
4-Hydroxycinnamic acid | 0.12 ± 0.01 | C9H8O3 | 164.160 | 2.21 | 163.042 |
Rutin | 0.93 ± 0.05 | C27H30O16 | 610.153 | 2.63 | 609.1 |
3-Hydroxycinnamic acid | 0.15 ± 0.01 | C9H8O3 | 164.160 | 2.98 | 163.042 |
Ferulic acid | 0.48 ± 0.02 | C10H10O4 | 194.186 | 3.12 | 193.050 |
Quercetin | 0.01 ± 0.00 | C15H10O7 | 302.238 | 3.48 | 301.000 |
2-Hydroxycinnamic acid | 0.31 ± 0.02 | C9H8O3 | 164.160 | 3.65 | 163.042 |
Salicylic acid | 0.08 ± 0.003 | C7H6O3 | 138.122 | 3.68 | 137.025 |
Rosmarinic acid | 0.18 ± 0.01 | C18H16O8 | 360.318 | 4.01 | 359.054 |
Resveratrol | 0.10 ± 0.005 | C14H12O3 | 228.247 | 5.83 | 227.072 |
Quercitrin | 0.04 ± 0.00 | C21H20O11 | 448.38 | 5.99 | 447.120 |
4-Hydroxycoumarin | ND | C9H8O3 | 164.160 | ND | 163.042 |
Aesculin | ND | C15H16O9 | 340.284 | ND | 339.072 |
Epigallocatechin gallate | ND | C22H18O11 | 458.375 | ND | 457.078 |
Esculetin | ND | C9H6O4 | 178.143 | ND | 177.018 |
Kaempferol | ND | C15H10O6 | 286.239 | ND | 285.040 |
Luteolin | ND | C15H10O6 | 286.239 | ND | 285.040 |
Malic acid | ND | C4H6O5 | 134.087 | ND | 133.014 |
Syringic acid | ND | C9H10O5 | 198.174 | ND | 197.045 |
3-Hydroxybenzoic acid | ND | C7H6O3 | 138.122 | ND | 137.025 |
Benzoic acid | ND | C7H6O2 | 122.123 | ND | 121.031 |
Caffeic acid | ND | C9H8O4 | 180.159 | ND | 179.035 |
Epicatechin | ND | C15H14O6 | 290.271 | ND | 289.064 |
Hesperetin | ND | C16H14O6 | 302.282 | ND | 301.015 |
Hesperidin | ND | C28H34O15 | 610.565 | ND | 609.172 |
Naringenin | ND | C15H12O5 | 272.256 | ND | 271.061 |
Naringin | ND | C27H32O14 | 580.539 | ND | 579.173 |
Pyrocatechol | ND | C6H6O2 | 110.112 | ND | 109.028 |
Sinapic acid | ND | C11H12O5 | 224.212 | ND | 223.061 |
Tannic acid | ND | C76H52O46 | 1701.206 | ND | 1700.080 |
ND: not detected.
The total antioxidant capacity (TAC) of the methanolic extract was determined using the DPPH radical-scavenging assay. The results are displayed in Figure
Percentage radical scavenging of the methanolic extract of
The DPPH radical-scavenging activity was generally quantified in terms of inhibition percentage of the preformed free radical by antioxidants and EC50 (concentration required to obtain a 50% antioxidant effect) [
The growth of pathogenic and contaminant microorganisms in food decreases the nutritional quality and increases food toxicity. The antimicrobial activity of the methanolic extract of
Inhibitory volumes and minimum inhibitory concentrations of the methanolic extract of
Concentration | 1/100 | 1/250 | 1/500 | 1/1000 | 1/2000 | 1/3000 | 1/5000 | Control |
---|---|---|---|---|---|---|---|---|
(mg/ml) | 0.001 | 0.0004 | 0.002 | 0.001 | 0.00005 | 0.000033 | 0.00002 | 0 |
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Given its chemical composition, rich nutritional value, and antimicrobial and antioxidant activities, the Moroccan
The data used to support the findings of this study are included within the article.
The authors declare that they have no conflicts of interest.
The authors are grateful to the National Center for Agricultural Research, a Research Unit on Agri-Food Technology and Quality (Rabat); University Center for Analysis, Expertise, Transfer of Technology and Incubation, University Ibn Tofaïl, Kénitra; Research Laboratory of Biotechnology and Biomolecule Engineering (ERBGB), Faculty of Science and Technology, Abdelmalek Essaadi University, Tangier; and Center of Forest Research, at Research Unit of Medicines and Microbiology, Rabat, Morocco, for the research facilities. The algal supplier “Spirulina-Berbère” (Morocco) is thanked for providing samples.