Abstract: Background and Objective: Mangrove plants are known sources of food and medicinal ingredients. Mangroves in Lubuk-Kertang, Pulau-Sembilan, Langkat and North Sumatra, Indonesia have great biodiversity. The study purposed to evaluate nutritional parameters based on antioxidant content and elemental analysis (micronutrients and macronutrients) in 15 true and associated mangrove species in Lubuk Kertang and Pulau Sembilan mangrove forests of North Sumatra, Indonesia. Materials and Methods: Determining each bioprospection parameter based on nutrients, antioxidants and analysis elements (macronutrients and micronutrients) in fine fifteen mangrove fruits with three individual repetitions: A. auriculiformis, B. asiatica, C. equisetifolia, H. tiliaceus, L. littorea, L. racemosa, M. candidum, M. citrifolia, N. Fruticans, P. odoratissima, P. pinnata, S. hydrophyllacea, S. portulacastrum, S. jamaicensis and T. catappa. Each mangrove fruit was then labelled, stored in an icebox and taken to the laboratory. The data are presented as Mean±SD, using one-way analysis of variance (ANOVA), followed by pairwise comparisons using Fisher's Least Significant Difference (LSD), with the value of p<0.05 as a significant limit. Results: The seventh nutritional parameter showed that A. auriculiformis had the highest protein content, P. pinnata had the highest fat content and P. odoratissima was the highest in two parameters (total sugar and non-reducing sugar). M. citrifolia provided the highest reducing sugar parameters of which B. asiatica and L. littorea were the highest for one parameter (moisture content and ash content). The highest antioxidant content of P. odoratissima as ascorbic acid. The highest beta-carotene was in M. candidum. The highest phenolic acid was in B. asiatica. The highest macronutrients varied among mangrove fruit species, sodium in L. racemosa, potassium in N. fruticans and calcium in S. jamaicensis. Further, the analysis of the highest microelements in iron was done in S. Portulacastrum and Manganese and copper in H. tiliaceus. Conclusion: This study showed that mangrove fruit has good prospecting value for antioxidants and-nutrients and is an alternative food source too for coastal communities.
INTRODUCTION
Mangroves are defined as halophytic woody plant communities along tropical and subtropical coastlines1. According to another study2, mangroves are divided into major mangroves and minor mangroves, while other species found around the mangrove ecosystem are known as associated mangroves3.
Mangroves are biochemically unique plants, due to their diverse secondary metabolite content4. Some types of mangroves can be used as food and medicine5. Producers of carbohydrates, o-methyl-inositol, sugars, iridoid glycosides, free amino acids, pheromones, gibberellins, phorbol, esters, heterocyclic oxygen, sulfur compounds, fats, free fatty acids6. In addition, the leaves and roots of plants also contain polyphenolic compounds, minerals, vitamins and amino acids7.
Mangroves in Lubuk Kertang, Langkat and North Sumatra, Indonesia have the highest plant diversity: where found 15 true mangrove species8, while 26 species of associated mangrove were found in Pulau Sembilan9. Bioprospecting is defined as the exploration of bioresource materials and their conversion into derivative products that help conserve and utilize mangrove forests in a sustainable manner, such that it has little impact on natural regeneration and provides alternative food sources8. The use of mangroves for bioprospecting can serve as a food resource, as fruit and leaves can be used as a source of food and nutrition10 and as food and beverage like taffy, syrup, salad, cake and chip11.
The sustainable use of mangrove fruits will have little impact on natural regeneration and its role as an alternative food source. It also minimizes the conversion of mangroves to other land uses by providing coastal communities with an excellent alternative income source.
Bioprospecting was known to yield bioresource materials to produce commercially valuable, useful mangrove products and towards sustainable management of the mangrove ecosystem in Lubuk Kertang and Pulau Sembilan, North Sumatera, Indonesia. Many studies have examined the efficacy and usefulness of consuming mangrove products, but information about the antioxidant potential and nutritional value of North Sumatran mangroves is still lacking, though antioxidants play an important role in plant adaptation to abiotic and biotic stresses12. This study aimed to evaluate nutritional parameters based on bioprospection, antioxidant content and elemental analysis (micronutrients and macronutrients) in 15 true and associated mangrove species in Lubuk Kertang and Pulau Sembilan mangrove forests of North Sumatra, Indonesia.
MATERIALS AND METHODS
Study site: The research was conducted for seven months, namely from September, 2020 to April, 2021. Lubuk Kertang is located at Langkat Regency, Berandan Barat district, bounded on the East by Malacca Strait and South by Perlis district and Pangkalan Batu (4°03' LU and 98°16 16'00. 19" BT). Pulau Sembilan is located at Langkat Regency, Pangkalan Susu district and bounded on the East by Malacca Strait, South by Pangkalan Susu, West by Teluk Arun, and North by Pulau Kampai Strait (04° 08' 39.13'' N and 98°13' 55.38'' E). Another study8 found 15 species of mangrove families in Lubuk Kertang and 26 species of associated mangrove in Pulau Sembilan9. Knowing that the mangroves in this area have high diversity, the local community works as fishermen, catching fish, crabs and prawns close together in the mangrove plants. The local community in this village can take advantage of the mangrove fruits as a potential source of food and medicine.
Sampling and mangrove fruit preparation: Fifteen selected mangrove fruits were selected, consisting first of four major mangrove fruits: Lumnitzera littorea (Jack.), (Combretaceae), Lumnitzera racemosa Willd (Combretaceae), Nypa fruticans (Thunb.) Wurmb. (Araceae), Scyphiphora hydrophyllacea Gaertn. F. (Rubiaceae). Eleven others from associated mangroves namely, Barringtonia asiatica (L.), Kutz (Lecythidaceae), Pandanus odoratatissima (L.) F. (Pandanaceae), Stachytarpheta jamaicensis (L.) Vahl (Verbenaceae), Casuarina equisetifolia L (Casuarinaceae), Melastoma candidum (D.) Don (Melastomaceae), Morinda citrifolia L. (Rubiceae), Sesuvium portulacastrum L. (Alzoaceae), Terminalia catappa L. (Combretaceae), Acacia auriculiformis (A.) Cun. ex-benth. (Mimosoidae), Hibiscus tiliaceus L. (Malvaceae) and Pongamia pinnata (L.) Pierre. (Leguminosae) were collected on September-October, 2020. The flow chart of the implementation of bioprospecting and functional food from selected mangrove fruits is described in Fig. 1.
These mangrove species produce fruits at approximately the same time. B. asiatica, M. citrifolia, T. catappa and H. tiliaceus were found on the banks and along with the river mouth in Lubuk Kertang. P. odoratatissima was found along the mangrove coast, while C. equisetifolia, A. auriculiformis, S. jamaicensis, M. candidum, S. hydrophyllacea, S. portulacastrum, P. pinata, N. fruticans, L. racemosa and L. littorea were found mostly along the upstream estuary.
| Fig. 1: | Flow chart of bioprospecting functional food from selected mangrove fruits |
Three individuals were taken from each mangrove species. Mangrove fruit in decent condition and without damage was then collected for further analysis. Each mangrove fruit was then labelled, stored in an icebox and taken to the Tjut Nyak Dhien University Research Laboratory for antioxidant analysis, to the Medan Research and Industrial Standardization Institute for nutrient content analysis, and the Socfindo Laboratory Medan for elemental analysis (macronutrients and macronutrients). Upon arrival at the laboratory, some samples were separated for drying and others were analyzed in a fresh condition. All samples were dried in an oven for 3 days at 100°C and used for elemental analysis.
Total protein etraction and estimation: Approximately 500 mg of mangrove fruit samples were put into a 100 mL flask using the Kjeldahl Semi micro Method, adding 2 g of the selen mixture and 25 mL of concentrated H2SO4 and heated on a hotplate until it boiled and the solution became clear greenish (about 2 hrs). It was allowed to cool, diluted and put into a 100 mL volumetric flask, aligning to the line mark. The 5 mL of the solution was put in a Pipette and placed in a distiller and 5 mL of 30% NaOH and a few drops of PP indicator were added. The samples were distilled for about 10 min in a container using 10 mL of 2% boric acid solution. The tip of the cooler was rinsed with distilled water, Titar with 0.01 N HCl solution. Blank determination was performed.
Fat content extraction and estimation: The fat content of the mangrove fruit was extracted using the direct extraction method with the Soxhlet tool. Two gram of the fruit sample was weighed and put it in a paper sleeve lined with cotton. The paper sleeve containing the sample was plugged with cotton, heated in the oven at a temperature of not more than 80°C for 1 h and put in a Soxhlet connected to a fat flask containing boiling stones that had been dried and had known weight. The contents were extracted with hexane or another fat solvent for approximately 6 hrs. Hexane was distilled and the fat extract dried in a drying oven at 105°C, cooled and weighed. This drying was repeated until a constant weight was reached.
Total sugar extraction and estimation: The total sugar content of 15 mangroves was ascertained through the Luff Schoorl method. The 50 mL Pipette was filtered into a 100 mL flask. Twenty-five mL of 25% HCl was added and the contents hydrolysed. This was followed by the addition of 40% NaOH indicator PP until it turned pink. Aquadest was added and the contents were shaken up to 12 times. Ten mL was Pipetted into a 500 mL Erlenmeyer, 15 mL of aquadest and add 25 mL of Luff's solution were added, following by the addition of the boiling stones. After boiling for 10 min, the contents were allowed to cool. Ten mL of 20% HCl and 25 mL of 25% H2SO4 were added. The 0.1 N Na2S2O3 solution was titrated twice until the colour changed to rice white.
Reducing sugar extraction and estimation: Reducing sugar was calculated in fifteen mangroves using the Luff Schoorl method. Take 10 mL of the filter and put it in a 500 mL Erlenmeyer. Fifteen mL of aquadest was added to 25 mL of Luff's solution, with boiling stones, heated for 10 min and cooled. The 25 mL of 25% H2SO4 and Ten mL of 20% Hcl were added titrated with 0.1 N Na2S2O3 and titrated again until the colour changed to rice white.
Non-Reducing sugar estimation and extraction: Non-reducing sugars were quantified using subtracting amounts to reduce the sugar from the total sugar.
Proximate analysis: Fifteen mangrove fruit extracts (5 g) were weighed and used to measure the moisture content using a moisture analyzer MX-50 (A and D Company Ltd.) at 115°C. An empty, clean evaporated dish was heated for 1 h to the furnace of muffle at 600°C to determine the amount of ash content of eight mangrove fruits13. The resulted ash was then cooled and stored in a desiccator and weighed as W1. As much as 1 g of each fruits samples was stored in an evaporating dish (W2). The sample was burned for 6 hrs in a furnace of muffle at 550°C till charred. Grey-white ash will produce when all organic matters of the sample were oxidized. The evaporated cooling dish was described in weighed (W3). The percent ash calculation was determined using the formula:
| (1) |
The weight ash difference = W3 - W1.
Where:
| W1 = | Weight of the empty evaporated dish |
| W2 = | The initial sample weight |
| W3 = | Final weight of the evaporating dish and initial weight of the sample from the furnace |
Estimation and extraction of ascorbic acid content: Ascorbic acid content was measured based on the literature13 with some modifications. Mangrove fruit was extracted with 0.5% oxalic acid solvent, 10 mL of the filtrate was filtered and 1 mL of 500 g mL–1 Potassium Permanganate (KMnO4) reagent was added, homogenized. The absorption at λ maximum 525.5 nm was measured immediately (UV/Vis UV-1800 Spectrophotometer). The concentration of ascorbic acid was calculated using the linear regression equation of the calibration curve14. Each measurement was repeated thrice and the ascorbic acid content was calculated using a standard curve and expressed as mg/100 g fresh weight.
Carotenoids content extraction and estimation: Total carotenoids content was counted by using sample compared with the standard of β-carotene15. Approximately 0.5 g of sample powder from each mangrove fruit was weighed and homogenized with 80% acetone. The volume of the solution was then brought to 50 mL and centrifuged at 5,000 rpm for 20 min until the supernatant became transparent. The supernatant was taken and absorbance was measured at 645 and 663 nm (UV/Vis-1280 Spectrophotometer).
Total phenolic content analysis: The total phenolic content was measured based on the literature16. Mangrove fruit was extracted with distilled water and then filtered. A total of 100.1 of the filtrate was added with 100.1 of Folin-Ciocalteu reagent (1:1) and 1 mL of 7.5% Na2CO3 into a test tube. The mixture was homogenized with a vortex and allowed to stand for 120 min. Then 3.8 mL of Aqua pro-injection was added and the absorbance was measured at a wavelength of 727.5 nm (UV/Vis UV-1800 Spectrophotometer). Each measurement was repeated thrice and the result was expressed as mg gallic acid equivalent (GAE)/100 g fresh weight16.
Macronutrient analysis: Macronutrients such as sodium (Na), potassium (K) and calcium (Ca) from fifteen mangroves were analyzed17. About 0.5 g finely powdered samples of each mangrove fruit were digested using 30% H2O2 and HNO3 concentrated. Digested samples were used for Na, K and Ca analysis using a PFP7 flame photometer (Jenway, Staffordshire, UK). Each sample was measured in three trials.
Micronutrient analysis: Micronutrients were analysed in fifteen mangroves17. Approximately 0.5 g of finely ground mangrove fruits were wet digested using concentrated HNO3 and 30% H2O2 . The digested samples were then analyzed for Iron (Fe), Manganese (Mn), Copper (Cu) concentrated using flame atomic absorption spectrophotometer, processed in distilled water were processed as described above and used for a new solution. Each sample was measured in three trials.
Statistical analysis: The data are presented as Mean±Standard Deviation (SD) values for given and observation number, n = 3. The mean of nutritional, antioxidants, macronutrients and micronutrients (element analysis) values was calculated and statistically compared among mangrove fruits using one-way analysis of variance (ANOVA), followed by pairwise comparisons using Fisher's Least Significant Difference (LSD), with the value of p<0.05 as a significant limit. All statistical comparisons were calculated using the SPSS version 21 program.
RESULTS
Nutritional and proximal analysis: Comparative evaluation of the nutritional potential of fifteen selected mangroves, namely A. auriculiformis, B. asiatica, C. equisetofolia, H. tiliaceus, L. littorea, L. racemosa, M. candidum, M. citrifolia, N. fruticans, P. odoratissima, P. pinnata, S. hydrophyllacea, S. portulacastrum, S. jamaicensis and T. caappa was performed with various parameters such as protein, water content, total sugar, reducing sugar, non-reducing sugar and ash content.
| Table 1: Comparative results of nutritional parameters from mangrove fruits in Lubuk Kertang and Pulau Sembilan, Sumatera Utara Indonesia | |||||||
| Nutritional parameters from mangrove fruits | |||||||
| Species | Protein (mg g–1) | Fat (mg g–1) | Total sugar (mg g–1) | Reducing sugar (mg g–1) | Non-reducing sugar (mg g–1) | Moisture (%) | Ash (%) |
| A. auriculiformis | 43.88±0.09a | 8.77±0.26b | 1.02±0.06i | 0.01±0.00g | 1.02±0.06hi | 62.18±0.81hij | 1.53±0.01e |
| B. asiatica | 17.49±0.07g | 1.17±0.20i | 5.72±0.35f | 1.61±0.08e | 4.10±0.41d | 93.13±0.11a | 0.61±0.01i |
| C. equisetifolia | 20.21±0.09f | 5.48±0.16f | 3.16±0.23g | 0.60±0.09f | 2.55±0.33efg | 55.91±0.20k | 0.29±0.01j |
| H. tiliaceus | 32.06±0.16b | 1.96±0.09h | 2.14±0.06h | 0.01±0.00g | 2.14±0.06fgh | 63.91±3.23h | 1.56±0.01e |
| L. littorea | 17.34±0.12g | 8.16±0.17c | 3.33±0.07g | 0.01±0.00g | 3.33±0.07de | 59.28±1.05jk | 3.41±0.01a |
| L. racemosa | 17.48±0.16g | 4.33±0.10g | 5.67±0.16f | 2.85±0.11d | 2.82±0.05ef | 73.36±2.19ef | 3.01±0.01b |
| M. candidum | 3.07±0.22k | 4.59±0.06g | 2.59±0.34gh | 0.01±0.00g | 2.59±0.34efg | 74.58±1.09def | 1.72±0.01d |
| M. citrifolia | 16.74±0.09h | 6.50±0.13e | 19.58±0.16b | 18.23±0.08a | 1.34±0.10hi | 86.30±0.14b | 0.63±0.01i |
| N. fruticans | 20.66±0.47f | 4.38±0.08g | 6.76±0.03e | 5.15±0.14b | 1.61±0.13ghi | 77.89±0.93cd | 1.72±0.02d |
| P. odoratatissima | 8.73±0.21j | 7.09±0.14d | 23.43±0.71a | 5.18±0.25b | 18.24±0.93a | 59.66±0.84ijk | 1.28±0.01g |
| P. pinnata | 29.46±0.09c | 26.45±0.16a | 1.06±0.01i | 0.01±0.00g | 1.06±0.01hi | 69.06±1.54g | 1.43±0.01f |
| S. hydrophyllacea | 14.36±0.19i | 8.51±0.08bc | 16.36±0.51c | 1.58±0.34e | 14.77±0.83c | 63.68±0.66hi | 2.02±0.01c |
| S. portulacstrum | 22.01±0.13e | 7.25±0.14d | 16.62±0.10c | 0.01±0.00g | 16.62±0.10b | 80.98±1.12c | 3.37±0.01a |
| S. jamaicensis | 23.01±0.08d | 6.54±0.11e | 8.51±0.27d | 4.25±0.13c | 4.25±0.13d | 76.51±1.15de | 1.39±0.01f |
| T. catappa | 23.43±0.10d | 8.52±0.09bc | 1.02±0.09i | 0.01±0.00g | 1.02±0.09i | 71.30±2.04fg | 1.07±0.01h |
Data are expressed as Mean±SD (n = 3), means by the same superscript were not significantly different from each other (p<0.05) by Fisher’s LSD |
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| Table 2: Comparative results of antioxidant parameters from mangrove fruits in Lubuk Kertang and Pulau Sembilan, Sumatera Utara Indonesia | |||
| Antioxidant contents from mangrove fruits | |||
| Species | Ascorbic acid (mg/100 g) |
Beta carotene (mg/100 g) |
Phenolic acid (mg/100 g) |
| A. auriculiformis | 8.21±1.50cd |
16.85±0.86b |
23.53±1.62cd |
| B. asiatica | 14.35±0.51ab |
10.10±0.84defg |
103.69±8.95a |
| C. equisetifolia | 15.33±1.15ab |
6.11±0.86efgh |
34.53±1.69b |
| H. tiliaceus | 16.28±0.17a |
5.92±0.47fgh |
0.98±0.22f |
| L. littorea | 16.03±0.10a |
8.16±0.15defgh |
16.15±3.42de |
| L. racemosa | 16.47±0.52a |
11.21±1.60cde |
31.92±9.69bc |
| M. candidum | 5.85±3.21d |
22.44±0.42a |
30.93±2.00bc |
| M. citrifolia | 15.83±0.63a |
15.76±5.72bc |
7.36±0.65ef |
| N. fruticans | 15.51±0.48a |
6.57±2.04efgh |
1.61±0.70f |
| P. odoratatissima | 17.16±2.58a |
3.73±0.27h |
2.66±0.43f |
| P. pinnata | 13.66±1.06ab |
4.98±0.23gh |
22.72±0.54cd |
| S. hydrophyllacea | 15.08±0.14ab |
10.84±0.42cdef |
6.41±0.52ef |
| S. portulacastrum | 11.32±1.16bc |
7.28±1.49defgh |
4.63±0.27f |
| S. jamaicensis | 14.79±0.27ab |
11.04±0.21cdef |
5.20±0.70ef |
| T. catappa | 14.54±1.81ab |
11.92±0.45bcd |
32.05±1.58bc |
Data are expressed as Mean±SD (n = 3-6), means by the same superscript were not significantly different from each other (p< 0.05) by Fisher’s LSD |
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The protein content in A. auriculiformis fruit (43.88 mg g–1) was the highest compared to other fruits, with the lowest content being that of M. candidum (3.07 mg g–1) in Table 1.
P. pinnata showed the highest fat content (26.45 mg g–1), followed by A. auriculiformis (8.77 mg g–1), while the lowest value was found in B. asiatica (1.17 mg g–1). Similarly, P. odoratissima (23.43 mg g–1) had the highest total sugar content significantly among other fruits (Table 1). The highest reducing sugar content was found in the fruit of M. citrifolia (18.23 mg g–1) and the lowest in the fruit of A. auriculiformis, H. tiliaceus, L. littorea, M. candidum, P. pinnata, S. portulacastrum and T. catappa. (0.01 mg g–1).
P. odoratatissima was found to have the highest non- reducing sugar (18.24 mg g–1) compared to other mangrove fruits, while the fruit of B. asiatica significantly had the highest water content (93.13%) and L. littorea (3.41%) the highest ash content (Table 1).
Antioxidant analysis: To evaluate the nutritional adequacy of selected mangrove fruits, the results of ascorbic acid, beta-carotene and total phenol were subjected to an additional antioxidant analysis. The highest ascorbic acid content was found significantly in P. odoratissima (17.16 mg/100 g), followed by L. racemosa (16.47 mg/100 g), H. tiliaceus (16.28 mg/100 g) and L. littorea (16.03 mg/100 g), with the lowest ascorbic acid content in M. candidum (5.85 mg/100 g) in Table 2.
| Table 3: Comparative results of macronutrients from mangrove fruits in Lubuk Kertang and Pulau Sembilan, Sumatera Utara, Indonesia | |||
| Macronutrients from fruits of mangrove (mg/100 g) | |||
| Species | Sodium (Na) | Potassium (K) | Calcium (Ca) |
| A. auriculiformis | 146.66±25.16bc | 1373.33±37.85efg | 270±0.00efg |
| B. asiatica | 43.33±5.77e | 1983.33±41.63bcde | 190±26.45efg |
| C. equisetifolia | 43.33±5.77e | 280±10.00h | 586.67±15.27cd |
| H. tiliaceus | 20±0.00e | 1743.33±57.73bcde | 816.67±40.41c |
| L. littorea | 623.33±51.31abcde | 1506.67±25.16defg | 1066.67±11.54b |
| L. racemosa | 1113.33±45.09a | 2266.67±41.63bcd | 1173.33±23.09ab |
| M. candidum | 10±0.00e | 760±103.92gh | 780±182.48c |
| M. citrifolia | 70±0.00de | 2523.33±55.07b | 383.33±5.77de |
| N. fruticans | 916.66±30.55ab | 3546.67±843.46a | 110±0.00fg |
| P. odoratatissima | 126.66±5.77cde | 2340±45.82bcd | 320±20.00ef |
| P. pinnata | 116.66±5.77cde | 1736.67±58.59bcde | 253.33±23.09efg |
| S. hydrophyllacea | 706.66±11.54abcd | 1626.67±11.54cdef | 136.67±20.81fg |
| S. portulacastrum | 1066.66±228.54a | 2380±45.82bc | 430±0.00de |
| S. jamaicensis | 720±615.06abc | 1900±633.79bcde | 1416.67±249.86a |
| T. catappa | 116.66±30.55cde | 816.67±217.79fgh | 63.33±11.54g |
Data are expressed as Mean±SD (n = 3), means by the same superscript were not significantly different from each other (p< 0.05) with Fisher’s LSD |
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| Table 4: Comparative results of micronutrients from mangrove fruits in Lubuk Kertang and Pulau Sembilan, Sumatera Utara Indonesia | |||
| Macronutrients from fruits of mangrove (mg/100 g) | |||
| Species | Iron (Fe) |
Manganese (Mn) |
Copper (Cu) |
| A. auriculiformis | 8.77±6.01ab |
0.87±0.15ef |
0.12±0.02ef |
| B. asiatica | 7.46±3.29ab |
0.44±0.14ef |
0.36±0.04cd |
| C. equisetifolia | 7.07±2.34ab |
2.04±0.05de |
0.01±0.00f |
| H. tiliaceus | 6.74± 0.58ab |
19.95±1.97a |
0.73±0.05a |
| L. littorea | 3.33±0.63b |
1.09±0.16def |
0.26±0.01de |
| L. racemosa | 5.91±0.68b |
0.50±0.06ef |
0.42±0.04bcd |
| M. candidum | 7.16±5.97ab |
7.75±0.74c |
0.35±0.15cd |
| M. citrifolia | 6.54±1.73b |
0.84±0.05ef |
0.01±0.00f |
| N. fruticans | 11.03±7.48ab |
13.34±0.35b |
0.01±0.00f |
| P. odoratatissima | 5.16±1.93b |
0.01±0.00f |
0.02±0.01f |
| P. pinnata | 8.71± 2.28ab |
1.20± 0.12def |
0.44±0.16bcd |
| S. hydrophyllacea | 5.32±0.27b |
0.10±0.06f |
0.61±0.03ab |
| S. portulacastrum | 16.52±0.53a |
2.67±0.17d |
0.01±0.00f |
| S. jamaicensis | 6.83±1.30ab |
0.47±0.11ef |
0.47±0.07bc |
| T. catappa | 5.37±1.66b |
0.01±0.00f |
0.26±0.01de |
Data are expressed as Mean±SD (n = 3), means by the same superscript were not significantly different from each other (p<0.05) with Fisher’s LSD |
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Elemental analysis: The highest sodium content was in L. racemosa (1113.33 mg/100 g), while the minimum amount was found in M. candidum (10 mg/100 g). The highest Potassium content was significant in N. fruticans (3546.67 mg/100 g) and C. equisetofolia (280 mg/100 g) indicating lower potassium content. Similarly, the highest calcium content was in S. jamaicensis (1416.67 mg/100 g) and the lowest in T. catappa (63.33 mg/100 g) in Table 3. The maximum iron content was shown in S. portulacastrum (16.52 mg/100 g), while the lowest was in L. littorea (3.33 mg/100 g). The H. tiliaceus was recorded as having the highest manganese content (19.95 mg/100 g), while P. odoratissima and T. catappa showed the lowest yields (0,001 mg g–1), respectively). Among the fifteen mangroves studied, the maximum copper content was found in H. tiliaceus fruits (0.73 mg/100 g) in Table 4.
DISCUSSION
The contents of nutrients, antioxidants macronutrients and micronutrients (element content) from mangrove fruits in Lubuk Kertang Village and Pulau Sembilan, North Sumatera, Indonesia were analyzed. Among them, A. auriculiformis and P. odoratissima were promising sources of nutrition and antioxidants. Mangroves are known to have various metabolites that are antibacterial and antifungal18, antifeedant19 and antiplasmodial20.
Antioxidants produced by the mangrove plant A. auriculiformis were identified as essential compounds for humans and beneficial for animal health6. Among these is the role of phenolics that can be used from A. auriculiformis as an antioxidant supplement formulation preparation21. The seeds of the acacia plant have considerable amounts of protein and nutritionists have shown great interest in assessing the protein quality and functionality of this protein-rich plant22. Two new glucosides named proacaciaside I and II which show anti-filarial activity was detected in A. auriculiformis mangrove fruit22.
These results indicate the potential for mangrove fruits in Lubuk Kertang Village and Pulau Sembilan. These types of mangrove fruits play an important role in the food security and nutrition of rural communities in general and particularly in coastal communities23. Mangroves are rich in the nutrients required by the surrounding community and many are not known by rural communities, such that common fruit cultivars are less well known and thus inaccessible to them.
Therefore, exploration of the types of edible mangrove fruit that are less known to the public is very necessary, considering the increasing human population and diminishing natural resources. Although mangroves are rich in nutrients and antioxidants, many urban communities are still not familiar with them, and information is still limited, with their nutritional aspects and values scarce or insufficient. Edible mangrove fruit is a natural source of antioxidants. For example, N. fruticans was found to produce high yields of sugar saps, and it was further found to be fermented to ethanol in high yields, also as competitive as sugarcane and cone, based on the development of natural potential24. Flour from Nipah fruit had low-fat content and high crude fibre content and promising substitute for ordinary flours such as wheat rice especially for producing high fibre food25.
This study showed that P. odoratissima fruit is a potential source of vitamin C or ascorbic acid. Vitamin C acts as a strong antioxidant that can protect cells from cancer-causing agents, and in particular, can increase the body's absorption of calcium (a mineral for the growth of teeth and bones) and iron from other foods26. The B. asiatica fruit showed the highest phenolic acid content. Phenolic compounds are important for products, possessing many health benefits such as antioxidant, anticarcinogenic and antimicrobial properties27.
The nutritional content, as antioxidants, macronutrients and micronutrients were selected from mangrove fruits in Lubuk Kertang dan Pulau Sembilan, North Sumatera, Indonesia was described. Among them N. fruticans, P. pinnata and P. odoratatissima were promising sources for nutritional values and antioxidants content. This study nutritional values were almost similar values with the previous studies28-30. This study provided much higher value than that reported in Carita, Banten31 for protein content in P. pinnata.
The highest protein content in the fruits of Acacia spp. in this study was supported by a previous document in A. tortilis31 but was higher than the protein content determined for A. colei and A. tumida32. Furthermore, the protein and moisture value in T. catappa and M. citrifolia was similar to those plants reported33,34. The results indicated that Acacia seed, T. catappa and M. citrifolia can be included in food formulations as a source of protein. Such as fruit consumption for Acacia spp., supporting food resources for Lubuk Kertang and Pulau Sembilan communities.
CONCLUSION
Bioprospection of fifteen mangrove plants, namely A. auriculiformis, B. asiatica, C. equisetofolia, H. tiliaceus, L. littorea, L. racemosa, M. candidum, M. citrifolia, N. fruticans, P. odoratissima, P. pinnata, S. hydrophyllacea, S. portulacstrum, S. jamaicensis and T. catappa has been discussed in this study. Species A. auriculiformis had the highest protein content of 43.88 mg g–1. Further, P. pinnata species had the highest fat content of 26.45 mg g–1. The total sugar content (23.43 mg g–1), non-reducing sugar (18.24 mg g–1) and ascorbic acid from P. odoratissima species were the highest, followed by the maximum phenolic acid content identified in B. asiatica (103.69 mg g–1). The highest content of beta carotene compounds was in M. candidum 22.44 mg/100 g. From the results of the study, it is expected that these mangrove species provide potential as antioxidants, bio-nutrients and food alternatives.
SIGNIFICANCE STATEMENT
The study found that there was mangroves fruit that has good prospecting value for antioxidants and bio-nutrients and is an alternative food source too for coastal communities. This finding is expected to help researchers to find mangrove fruits provide food resources for Lubuk Kertang and Pulau Sembilan coastal communities. Thus the new finding may be considered as an alternative of food resources except conventional food resources to support coastal communities' food sources in the adjacent mangrove ecosystem.
ACKNOWLEDGMENT
This work was supported by the Ministry of Education, Culture, Research and Technology of the Republic of Indonesia through the World-Class Research Program 2021 (No. 214/SP2H/AMD/LT/DRPM/2020).