Comoros Union presents a considerable biodiversity of food resources that are neglected or still not valorised, as breadfruit. This study aimed to evaluating nutritional and nutraceutical traits of
In the Comoros Union, as in all the developing countries, malnutrition and food insecurity affect a very large percentage of the population [
Food insecurity in the Comoros Union is at a troubling level due to poverty. According to the Global Hunger Index 2011 report, the International Food Policy Research Institute (IFPRI) reported an increase in poverty of nearly 17%, placing the country 73rd of 81 countries surveyed. The IFPRI statistics reveal a troubling nutritional situation: 46% of the Comorians are undernourished, and children under 5 years of age have a mortality rate estimated at 10.4%, with 22% of cases being underweight deaths [
The country is bursting with a significant diversity of food resources, but they are naturally not exploited or neglected [
The breadfruit tree is known locally as “fouryapa.” Its cultivation is simple and does not require special efforts. As a plant that does not produce seed, it is only propagated vegetatively. Its cultivation is by suckers (root projections), root cuttings, or grafting of mature branches.
The breadfruit tree is a multipurpose species that provides food, medicine, building materials, and feed. Breadfruit is a versatile food, with different types of culinary preparations. At the mature stage, breadfruit can be steamed, baked, or fried [
This work aims at determining the chemical and nutritional potential of breadfruit of the Comoros Islands for its potential as a large-scale crop to guarantee both food security and the protection of biodiversity.
The study material consisted of two fruit samples of
Aerial view of sampling sites (village of Ouziouani in Grande Comore). A: sample P1; B: sample P2.
Sodium carbonate, Folin–Ciocalteu phenol reagent, sodium acetate, citric acid, potassium chloride, hydrochloric acid, iron(III) chloride hexahydrate, 2,4,6-tripyridyl-S-triazine, and 1,2-dihydrochloride-phenylenediamine (OPDA) were used for analyses. All polyphenolic and terpene standards, potassium dihydrogenphosphate, phosphoric acid, methanol, and HPLC-grade acetonitrile were purchased from Sigma-Aldrich (St. Louis, MO, USA). Acetic acid, ethanol, organic acids, and HPLC-grade formic acid were purchased from Fluka BioChemika (Buchs, Switzerland). The disodium salt of ethylenediaminetetraacetic acid was purchased from AMRESCO (Solon, OH, USA). Sodium fluoride was purchased from Riedel-de Haen (Seelze, Germany). Cetyltrimethylammonium bromide (cetrimide), ascorbic acid (AA), and dehydroascorbic acid (DHAA) were purchased from Extrasynthese (Genay, France). Milli-Q ultrapure water was purchased from Sartorius Stedim Biotech (Arium, Göttingen, Germany).
All the fruits were manually picked at the same maturity levels (full maturation stage: fruit suitable for fresh consumption by local population) from the plants based on selected qualitative parameters (firmness and total soluble solids), considering also literature and experience of the University researchers. Moreover, the appearance of the latex on the skin was considered. For each biological replication (
Different stages of breadfruit drying.
Pieces of 3-day sun-dried breadfruits were then divided into two portions: first one was grinded with a ceramic mortar and milled with an automatic grinder (sample name: powder/flour), while fruits of the other portion were reduced in size to 10 mm × 10 mm (sample name: small pieces). Two extraction methods were used to prepare methanol extracts. Extracts designated S and T were obtained from the methanolic solution of small pieces of dried breadfruit, and extracts designated S1 and T1 were obtained from the powder (flour) of dried breadfruit. The material for the extracts T and T1 came from site P1, while the extracts S and S1 came from site P2.
For each sample, 10 g of powder (flour) and 10 g of small pieces of dried fruits were macerated in 50 mL of methanolic solution (methanol: double-distilled water, 95 : 5 v/v, pH adjusted with 1.5 mL of 37% HCl, pH = 1.2) for 72 h using a magnetic stirrer for 5–10 min per day. The mixture was then filtered using a Whatman™ filter paper (185 mm diameter), after which the filtrate was stored. A second extraction was then repeated from the recovered sample with the same extraction solvent. The filtrate was recovered, mixed with the first filtrate (for a total of 100 mL), and then stored at 4°C until analysis.
The antioxidant capacity of breadfruit was assessed using a ferric reducing antioxidant power (FRAP) assay [
The Folin–Ciocalteu reagent consists of a mixture of phosphotungstic acid (H3PW12O40) and phosphomolybdic acid (H3PMo12O40) reduced by oxidising phenols in a mixture of blue oxides of tungsten and molybdenum [
Each analysis was carried out in triplicate. Two millilitres of each sample were centrifuged for 5 min at 12000 rpm and 4°C (ALC Multispeed PK 121R refrigerated centrifuge, Milan, Italy). Samples were then filtered through a C 18 cartridge (Sep-Pak C 18, Waters Corporation, Milford, MA, USA) that retained the polyphenolic compounds. The first elution was the extract for analysing the vitamin C (AA plus DHAA) content. The vitamin C analysis was carried out by adding 250
Four different chromatographic methods were used to analyse samples: two for polyphenols, one for terpene compounds, and one for organic acids. In all the methods, the separation of bioactive compounds was obtained on a Phenomenex Kinetex C18 column (4.6 × 150 mm, 5
UV spectra were recorded at 330 nm (for method A); 280 nm (for method B); 210, 220, 235, and 250 nm (for method C); and 214 nm (for method D).
The amount of nitrogen and crude protein was analysed using the Kjeldahl method (ISO 1871, 2009). Samples (1 g) and controls were mineralised at 420°C for 105 min. Distillation was performed using a Kjeltec™ 2200 system (Foss, Hillerød, Denmark) for 4 min. The protein content was calculated using a nitrogen-protein conversion factor of 6.25 [
Determination of the total lipids of dried breadfruit samples was carried out according to the Soxhlet method using petroleum ether as the extraction solvent. The sample was continuously extracted with boiling petroleum ether, which gradually dissolved the fat. The solvent containing the fat was returned to the flask by successive pouring caused by the siphoning effect in the lateral bend. Because only the solvent could evaporate again, the fat accumulated in the flask until the extraction was complete. Upon completion, the petroleum ether was evaporated, typically using a rotary evaporator, and the fat was weighed [
Ten grams of powder (flour) of dried breadfruit samples were suspended in 50 mL of 80% ethanolic solution followed by stirring for 15 min (at 30°C). The mixture was macerated overnight at room temperature. After 5 min of stirring, samples were filtered by Whatman 185 mm diameter paper, after which the filtrate was recovered in a test tube. A second extraction was repeated from the recovered samples. The mixture of the extractions constituted one sample for the analysis of sugars (100 mL).
HPLC analysis was carried out using a SphereClone NH2 column (4.6 × 250 mm, 5
Dietary fibre referred to indigestible materials measured by a standard method, such as the enzymatic-gravimetric method [
The contents of calcium, magnesium, potassium, and sodium were determined by atomic absorption spectrophotometry in an acetylene-air flame using a flame and graphite furnace atomic absorption spectrometer (PerkinElmer, PinAAcle 900T, Waltham, MA, USA). Reference solutions for each atom were prepared in standard solutions as a reference system in order to determine the quantity of each atom in samples previously mineralised by dry incineration (for Ca2+, Mg2+, K+, and Na+) or wet mineralisation (for Fe3+) at room pressure. In dry incineration, 3 g of the sample were homogenized and charred on a heating plate; the sample was then transferred to a stove and incinerated for 8 hours at a temperature of 380°C. The resulting ash was then solubilised in 65% HNO3 solution. In wet mineralisation, 2 g of the homogenized sample were added to a solution of 65% HNO3 : 64% HClO4 : 96% H2SO4 (24 : 24 : 1, v/v/v) and gradually warmed up (max 150–200°C) continuing until clarification. The wavelengths and relative widths were 422.7 nm and 0.7 nm for calcium, 285.2 nm and 0.7 nm for magnesium, 766.5 nm and 2.0 nm for potassium, and 589.6 nm and 0.7 nm for sodium, respectively. For phosphorus, the colorimetric method after dry mineralisation of the sample followed by solubilisation in HCl (6 N) and treatment with the molybdovanadate reagent was used. The optical density of the coloured solution was spectrophotometrically measured at 430 nm [
Student’s
All the methanolic extracts showed similar TPC values, ranging from 28.30 ± 3.71 to 29.69 ± 1.40 mgGAE/100 g of dried weight (DW) (Table
Total polyphenol content, antioxidant activity, and vitamin C of the different breadfruit extracts.
Material | Extract | TPC (mgGAE/100 gDW) | Antioxidant activity (mmol·Fe2+/kgDW) | Vitamin C (mg/100 gDW) |
---|---|---|---|---|
Small pieces | S | 28.90 ± 4.68 | 5.44 ± 0.35 | 6.32 ± 0.12 |
T | 28.30 ± 3.71 | 6.40 ± 1.02 | 6.25 ± 0.16 | |
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Flour | S1 | 29.26 ± 2.78 | 2.29 ± 0.32 | 35.30 ± 1.48 |
T1 | 29.69 ± 1.40 | 1.99 ± 0.33 | 35.40 ± 1.46 |
Samples T and T1 are from site P1, and samples S and S1 are from site P2. Values represent the mean of three measurements ± SD. SD = standard deviation. DW = dry weight of the plant material.
The ANOVA and Student’s
The
The vitamin C values of the different samples were reported in Table
The HPLC analysis of the different dried breadfruit samples showed that breadfruit may be a good source of phenolic constituents. The main identified phenolic groups were cinnamic acids, with a maximum of 51.88 ± 2.63 mg/100 gDW for chlorogenic acid and 3.21 ± 0.09 mg/100 gDW for caffeic acid; tannins, with 26.59 ±5.38 mg/100 gDW for castalagin and 15.99 ± 5.65 mg/100 gDW for vescalagin; benzoic acid, with 5.69 ± 0.08 mg/100 gDW for ellagic acid and 5.56 ± 0.04 mg/100 gDW for gallic acid; and catechins, with a maximum of 8.04 ± 0.44 mg/100 gDW for epicatechin (Tables
Cinnamic acid composition of the different breadfruit samples.
Materials | Extracts | Caffeic acid (mg/100 gDW) | Chlorogenic acid (mg/100 gDW) | Coumaric acid (mg/100 gDW) | Ferulic acid (mg/100 gDW) |
---|---|---|---|---|---|
Small pieces | S | 2.31 ± 1.26 | 30.27 ± 35.03 | n.q. | n.q. |
T | 2.49 ± 1.21 | 43.30 ± 3.93 | n.q. | n.d. | |
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Flour | S1 | 3.21 ± 0.09 | 51.88 ± 2.63 | n.d. | n.q. |
T1 | 2.65 ± 1.00 | 43.80 ± 5.43 | n.q. | n.d. |
Samples T and T1 are from site P1, and samples S and S1 are from site P2. Values represent the mean of three measurements ± SD. SD = standard deviation. DW = dry weight of the plant material. n.d. = not detected. n.q. = not quantified.
Benzoic acid, catechin, and tannin composition of breadfruit extracts.
Materials | Extracts | Ellagic acid (mg/100 gDW) | Gallic acid (mg/100 gDW) | Catechin (mg/100 gDW) | Epicatechin (mg/100 gDW) | Castalagin (mg/100 gDW) | Vescalagin (mg/100 gDW) |
---|---|---|---|---|---|---|---|
Piece | S | 5.25 ± 0.18 | 5.56 ± 0.04 | n.d. | 8.04 ± 0.44 | 26.59 ± 5.38 | 15.99 ± 5.65 |
T | 5.17 ± 0.36 | 5.46 ± 0.12 | n.q. | 7.76 ± 0.31 | 15.66 ± 5.42 | 13.53 ± 4.94 | |
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Flour | S1 | 5.43 ± 0.12 | 5.32 ± 0.42 | n.d. | 7.31 ± 1.38 | 26.33 ± 2.36 | 12.03 ± 4.29 |
T1 | 5.69 ± 0.08 | 5.23 ± 0.14 | n.q. | 6.96 ± 0.52 | 13.37 ± 5.17 | 5.79 ± 1.27 |
Samples T and T1 are from site P1, and samples S and S1 are from site P2. Values represent the mean of three measurements ± SD. SD = standard deviation. DW = dry weight of the plant material. n.d. = not detected. n.q. = not quantified.
Among the identified organic acids, quinic acid was the predominant acid among all dried breadfruit extracts in this study; quinic acid was followed by citric acid and traces of tartaric acid. Quinic acid levels in the samples ranged from 77.25 ± 6.04 (S1) to 32.55 ± 0.35 mg/100 g (T, P1) (Table
Organic acid composition of breadfruit samples.
Materials | Extracts | Citric acid (mg/100 gDW) | Malic acid (mg/100 gDW) | Oxalic acid (mg/100 gDW) | Quinic acid (mg/100 gDW) | Succinic acid (mg/100 gDW) | Tartaric acid (mg/100 gDW) |
---|---|---|---|---|---|---|---|
Small pieces | S | 3.41 ± 0.87 | n.d. | n.d. | 45.66 ± 6.09 | n.d. | 2.61 ± 1.75 |
T | 2.49 ± 1.31 | n.d. | n.q. | 32.55 ± 0.35 | n.d. | 1.77 ± 0.28 | |
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Flour | S1 | 6.53 ± 0.90 | n.d. | n.d. | 77.25 ± 6.04 | n.d. | n.d. |
T1 | 5.07 ± 0.77 | n.d. | n.q. | 48.86 ± 4.56 | n.d. | n.q. |
Samples T and T1 are from site P1, and samples S and S1 are from site P2. Values represent the mean of three measurements ± SD. SD = standard deviation. DW = dry weight of the plant material. n.d. = not detected. n.q. = not quantified.
Monoterpenes were among the major molecules identified in dried breadfruit. Different monoterpene compounds were detected: limonene, with a maximum of 247.91 ± 29.29 mg/100 gDW; phellandrene, with 56.67 ± 57.77 mg/100 gDW; and sabinene, with a maximum of 52.98 ± 1.08 mg/100 gDW (Table
Monoterpene composition of different breadfruit extracts.
Materials | Extracts | Limonene (mg/100 gDW) | Phellandrene (mg/100 gDW) | Sabinene (mg/100 gDW) |
|
Terpinolene (mg/100 gDW) |
---|---|---|---|---|---|---|
Small pieces | S | 247.91 ± 29.29 | 100.29 ± 5.87 | 41.33 ± 9.28 | n.d. | n.d. |
T | 235.21 ± 52.29 | 56.67 ± 5.77 | 37.24 ± 3.50 | n.q. | n.q | |
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Flour | S1 | 140.15 ± 24.46 | 20.16 ± 1.10 | 41.70 ± 10.09 | n.d. | n.d. |
T1 | 145.64 ± 40.78 | 44.63 ± 4.27 | 52.98 ± 1.08 | n.q. | n.q. |
Samples T and T1 are from site P1, and samples S and S1 are from site P2. Values represent the mean of three measurements ± SD. SD = standard deviation. DW = dry weight of the plant material. n.d. = not detected. n.q. = not quantified.
The protein composition of breadfruit is shown in Table
Macronutrient content of dried breadfruit flour samples.
Breadfruit flour | Protein (g/100 gDW) | Lipid (g/100 gDW) | Fibre (g/100 gDW) |
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P1 | 4.46 | 0.66 | 18.86 |
P2 | 4.42 | 0.68 | 20.12 |
Mean value | 4.44 | 0.77 | 19.49 |
DW = dry weight of the plant material.
The lipid content of breadfruit is summarised in Table
The values of raw fibre between the two flour samples are shown in Table
Simple sugars identified in the flour of dried breadfruit in decreasing order included glucose, sucrose, and fructose, and their mean values were 2.80 ± 0.52, 1.51 ± 0.25, and 0.34 ± 0.06 g/100 g (dried breadfruit flour), respectively (Table
Sugar content of dried breadfruits.
Sample | Fructose (g/100 gDW) | Glucose (g/100 gDW) | Sucrose (g/100 gDW) | Total sugars (g/100 gDW) |
---|---|---|---|---|
P1 | 0.35 ± 0.09 | 2.83 ± 0.40 | 0.90 ± 0.22 | 4.08 ± 0.71 |
P2 | 0.33 ± 0.04 | 2.76 ± 0.65 | 2.11 ± 0.28 | 5.20 ± 0.97 |
Mean value | 0.34 ± 0.06 | 2.80 ± 0.52 | 1.51 ± 0.25 | 4.64 ± 0.83 |
Values represent the mean of three measurements ± SD. SD = standard deviation. P1 = flour sample from site 1. P2 = flour sample from site 2. DW = dry weight of the plant material.
Glucose peak of the P1 sample and relative retention time (
Glucose peak of the P2 sample and relative retention time (
Fructose and sucrose peaks of the P1 sample, with fructose (
Fructose and sucrose peaks of the P2 sample, with fructose (
The results of the mineral composition of dried breadfruit flour are shown in Table
Mineral content in dried flour of breadfruit.
Flour | Calcium (mg/100 gDW) | Iron (mg/100 gDW) | Phosphorus (mg/100 gDW) | Magnesium (mg/100 gDW) | Chlorides (mg/100 gDW) | Potassium (mg/100 gDW) | Sodium (mg/100 gDW) |
---|---|---|---|---|---|---|---|
P1 | 678 | 1.05 | 76 | 32 | 0.46 | 1.174 | 12.7 |
P2 | 880 | 1.45 | 71 | 52 | 0.41 | 1.217 | 13.7 |
Mean value | 779 | 1.25 | 73.5 | 42 | 0.435 | 1.195 | 13.2 |
P1 = flour sample from site 1. P2 = flour sample from site 2.
The results of this study are important because they are derived from the first analytical study on breadfruit consumed by the Comorian population. The presented data provide information on the nutrition and health properties of breadfruit by the identification of the main biologically active molecules in breadfruit. Nutritionists and epidemiologists could use these data for the evaluation of food-health relationships among the Comorian population.
An earlier version of this work was presented as an abstract at the International Symposium on Survey of Uses of Plant Genetic Resources to the Benefit of Local Populations, 2017.
The authors have no conflicts of interest to declare.
This research was supported by the EGALE project “Gathering Universities for Quality in Education” (ACP-EU Cooperation Programme in Higher Education EDULINK II) (Contract no. FED/2013/320-117).