Nutritional composition and antioxidant properties of Raphionacme Splendens (SCHL.) Tubers.
The potential of many different wild edible plants as food for nutritional and health benefits is well recognized by many studies [1, 2]. In many parts of Africa, especially in rural communities, the use of wild edible plants as food source is an integral part of the culture of indigenous people [3, 4, 5].
Tuber crops along with other staples are commonly consumed in most countries in the world. They have great potential for ensuring food security and have ability to withstand drought. Cassava, Irish potato and sweet potato provide 93% of the root and tuber crops used for direct human consumption in the world. They rank among the top 10 food crops that are consumed as the main supply of food energy or carbohydrates [6, 7, 8].
In general, the Sudanese food diet is essentially composed of cereals, milk, eggs, fruits, and vegetables . Cereal foods comprise about 49.8% of the total dietary energy supply while milk, eggs, and fish are about 16.9%, followed by sugar and sweets (10.1%) and roots and tubers (1.0%) . Abdalla and Leonhauser  reported that the farm households consume rarely vegetables and their consumption is mainly related to its availability in the village market and the income level of the household. The consumption of wild food is seasonal and usually gathered by children. Raphionacmesplendens Schl. subspecies splendens Flickr, locally known as Elfayo, is a wild root tuber belonging to the family Apocynaceae. R. splendens is an important water tuber used as a source of drinking water in the western part of Sudan especially in Kordofan region. The tubers are also used as a food reserve during times of famine or poor harvest. They are consumed raw as a staple and sometimes prepared as salad with onion. Sudan's flora is rich in wild plants which have good nutritional values. However, dietary utilization of non-domesticated plants has received very little attention in Sudan. To date, there is, to our knowledge, no available data on the food value of R. splendens tubers. Therefore, the present study aimed to analyze the nutritional composition and radical scavenging capacity of R. splendens tubers.
MATERIALS AND METHODS
Plants were collected from Southern-West Kordofan in July 2009, were identified and voucher specimens No. 1109KR6 was deposited in the Herbarium of Botany Department, Faculty of Science, University of Khartoum.
Preparation of samples and extracts
Tubers were washed with tap water after manually removing inedible parts, peeled, sliced and dried under shade at 30[degrees]C for two weeks to avoid direct loss of phytoconstituents from sunlight. All calculations were made on dry matter basis. Ethanolic extract was also prepared for total phenolic and antioxidant capacity determination. The ethanol extract was prepared by soaking 20g of ground sample in 200mL ethanol at ambient temperature for 6 hours. The extract was decanted, filtered and concentrated in a rotary evaporator to yield 1.8g.
Proximate analysis of the sample's moisture content, ash, ether extract and fibre content was done using the method reported by AOAC . Nitrogen was determined by the micro-Kjeldahl method reported by Pearson . Crude protein content was subsequently calculated by multiplying the nitrogen content by a factor of 6.25. Carbohydrate content was estimated by subtracting the sum of the weights of protein, fibre, ether extract and ash from the total dry matter. Gross energy was calculated based on the formula by Eknayake et al. : Gross energy (kJ/100g dry matter) = (crude protein x 16.7) + (crude lipid x 37.7) + (crude carbohydrates x 17.7).
Amino acids analysis
Amino acids composition of sample was measured as hydrolysate using an Amino Acid Analyzer (Sykam- S7130) based on high performance liquid chromatography technique . Sample hydrolysis was prepared following the method of Moore and Stein . Two hundred milligram of sample was taken into a hydrolysis tube. Five milliliters of 6 N HCl were added to the sample. The tube was tightly closed and incubated at 110[degrees]C for 24 hours. After incubation period, the solution was filtered and 200[micro]L of the filtrate were evaporated to dryness at 140[degrees]C for an hour. The hydrolysate was diluted with 1 mL of buffer (citrate buffer pH 2.2). Aliquot of 150[micro]L of sample hydrolysate was injected in cation separation column at 130[degrees]C. Ninhydrin solution and an eluent buffer (the buffer system composed of solvent A of pH 3.45 and solvent B of pH 10.85) were delivered simultaneously into a high temperature reactor coil (16m length) at a flow rate of 0.7mL/min. The buffer/ninhydrin mixture was heated at 130[degrees]C for 2min to accelerate chemical reaction of amino acid with ninhydrin. The products of the reaction mixture were detected at wavelength of 570nm (440nm for proline) on a dual channel photometer. The amino acids were identified by their retention time and wavelength ratio calculated from the areas of standards obtained from the integrator and expressed as mg/100g.
Minerals were analysed by dry-ashing 1g of the sample at 550[degrees]C in a furnace. The ash obtained was dissolved in 10% HCl, filtered through an acid-washed filter paper and made up to standard volume with de-ionised water. Sodium, potassium, calcium, magnesium, manganese, zinc, copper and iron contents were determined using atomic absorption spectrophotometry (Perkin Elmer A100, Tokyo, Japan). Phosphorus content was determined by employing the method reported using VanadoMolybdate and read on CECIL CE 3041 colorimeter .
Fatty acids profile
Fatty acids profile of total lipids was determined after trans-esterification with 14% boron trifluoride in methanol (1:1 v/v). Fatty acid methyl esters were analyzed by GCMS (QP 2010 Shimadzu GC-MS equipment, Shimadzu Corporation. Kyoto, Japan). Supelco equity 1 column with a film thickness of 30m x 0.25microns was used. The total flow rate was 24mL/min and column flow rate was 1mL/min. Ultra high purity Helium was used as the carrier gas with injector split ratio of 20: 1. The ion source and inter-phase temperatures were 200[degrees]C and 250[degrees]C respectively. The solvent cut time of 4min and detector gain was 0.70kv. A Wiley 229 library search was conducted on major peaks of the sample in order to identify the components of the sample. The relative percentage of each compound was also determined.
Determination of vitamin C
The modified method of Bahorun et al.  was used to determine the vitamin C content of tubers. Ten grams of sample was blended with 40mL of a solution of 3% metaphosphoric acid in 8% glacial acetic acid, pH 1.5, for 1min. The extract was then mechanically shaken for 15min in darkness and filtered through glass wool. After filtration the clear extract was stored at -40[degrees]C prior to analysis by the 2,6dichloroindophenol titrimetric method .
Determination of total phenolics
Total phenolic content in the ethanol extract of tubers was determined using modified Folin-Ciocalteu method . Ethanol extract was re-suspended in ethanol to make 50mg/mL stock solutions. An aliquot of the extract was mixed with 5mL FolinCiocalteu reagent (previously diluted with water at 1:10 v/v) and 4mL (75g/L) of sodium carbonate. The tube was vortexed for 15s and allowed to stand for 30min at 40[degrees]C for colour development. Absorbance was then measured at 765nm using the SHIMADZU UV-2550 UV-VS spectrophotometer. Total phenolic content was expressed as gallic acid equivalents (mg/100g) using the following equation based on the calibration curve: y = 0.0057x, [R.sup.2] = 0.9315, where x was the absorbance.
Antioxidant activity studies
DPPH radical-scavenging test
Antioxidant activity of the ethanol extract of tubers was estimated using DPPH in vitro method . Test sample was dissolved separately in methanol to get test solution of 1mg/mL and then different concentrations (1, 5, 10, 20, 40, 60, 80 and 100[micro]g/mL) were prepared by diluting with methanol. Assays were performed in 96-well, microtiter plates. One hundred and fourty microlitres ([micro]L) of 0.6x[10.sup.-6]mol/L DPPH was added to each well containing 70pL of sample. The mixture was shaken gently and left to stand for 30min in the dark at room temperature. The absorbance was measured spectrophotometrically at 517nm using a microtiter plate reader (Synergy HT Biotek, logiciel GEN5). Blank was done in the same way using methanol and sample without DPPH and control was done in the same way but using DPPH and methanol without sample. Ascorbic acid was used as an antioxidant standard compound. The ability to scavenge DPPH radical was calculated by the following equation:
DPPH radical scavenging activity (%) =
1- [([Abs.sub.sample] - [Abs.sub.blank])]/ ([Abs.sub.control])] x 100
[Abs.sub.sample] is the absorbance of DPPH radical + sample;
[Abs.sub.blank] is the absorbance of sample+ methanol;
[Abs.sub.control] is the absorbance of DPPH radical + methanol.
The [IC.sub.50] value was calculated from the linear regression of plots of concentration of the test sample against the mean percentage of the antioxidant activity. The [IC.sub.50] values obtained from the regression plots (Sigma PlotsR 2001, SPSS Science, Chicago, Il, USA) using Pearson's correlation coefficient had a good coefficient of correlation, ([R.sup.2]=0.998) .
ABTS radical-scavenging test
A second in vitro method was performed to estimate antioxidant potential of the ethanol extract: ABTS assay, based on the method of Re et al. . Test sample was dissolved in methanol to get test solution of 1 mg/mL. A series of extract solutions of different concentrations (1, 5, 10, 20, 40, 60, 80 and 100pg/mL) were prepared by diluting with methanol. The ABTS radical cation ([ABTS.sup.*+]) was produced by reacting 7mM stock solution of ABTS with 2.45mM potassium persulfate and allowing the mixture to stand in the dark at room temperature for 12h before use. The obtained [ABTS.sup.*+] solution was diluted with methanol to an absorbance of 0.700[+ or -]0.02 at 734nm. One hundred and ninety microlitre of [ABTS.sup.*+] solution was added to each well containing 10[micro]L of sample. The mixture was shaken gently and left to stand for 15min in the dark at room temperature. The absorbance was measured spectrophotometrically at 734nm using a microtiter plate reader (Synergy HT Biotek[R], logiciel GEN5). The [ABTS.sup.*+] scavenging capacity of the extract was compared with that of ascorbic acid and the percentage inhibition calculated as: ABTS radical scavenging activity (%) =
[([Abs.sub.control] - [Abs.sub.sample])]/ ([Abs.sup.control])] x 100
[Abs.sub.control] is the absorbance of [ABTS.sup.*+] (=0.700 [+ or -] 0.02);
[Abs.sub.sample] is the absorbance of sample + [ABTS.sup.*+.
The [IC.sub.50] value was calculated from the linear regression of plots of concentration of the test sample against the mean percentage of the antioxidant activity obtained from three replicate assays. The [IC.sub.50] values obtained from the regression plots (Sigma PlotsR 2001, SPSS Science) had a good coefficient of correlation, ([R.sup.2]=0.9926) .
All analyses were performed in triplicate and data reported as mean [+ or -] standard deviation (SD). Statistical analyses were performed for the analysis of the Pearson correlation coefficients with the Statistical Package for the Social Sciences (spssx/pc) software (SPSS, Chicago, IL).
The proximate composition of raw R. splendens tubers is given in Table 1. Results, which referred to (%) dry weight, showed that the tubers contained 3.2% protein content, 18% carbohydrate, 0.5% lipid, 2.4% crude fibre, 3.5% ash, 79.2% moisture and gross energy 101.7kJ/g.
Amino acids content
The composition and amount of amino acids in raw R. splendens tubers are presented in Table 2. The total amino acids of R. splendens tubers were 10776mg/100g and the total essential amino acids were 3040mg/100g. The most abundant essential amino acids were leucine (792mg/100g), isoleucine (712mg/100g) and threonine (536mg/100g). The roots contained an abundance of the non-essential amino acids, in decreasing order, aspartic acid (1960mg/100g), glutamic acid (1656mg/100g), alanine (1336mg/100g) and proline (1184mg/100g).
Mean values for mineral content of raw R. splendens tubers are presented in Table 3. Minerals were potassium (259mg/100g), calcium (183mg/100g), magnesium (64mg/100g), phosphorus (37mg/100g), copper (3.6mg/100g), manganese (2.4mg/100g), zinc (1.8mg/100g) and iron (1.2mg/100g).
Fatty acids composition
The fatty acids composition of raw R. splendens tubers was low, only 14 types are reported (Table 4). Total saturated fatty acids were 45.6% whereas, total unsaturated were 54.4%. Mono-unsaturated fatty acids and poly-unsaturated fatty acids accounted for 33.54% and 20.86%, respectively. Ratio of unsaturated fatty acid: saturated fatty acid (U:S) was 1.6. Oleic acid (32.56%) and palmitic acid (30.23%) represented the most abundant unsaturated and saturated fatty acids, respectively.
Antioxidant activity, vitamin C and total phenolic content
The antioxidant property of raw R. Splendens tubers was also investigated using the DPPH and ABTS assays (Table 5). The [IC.sub.50] value of the tubers against DPPH radicals was 0.987mg/mL and was 1.559mg/mL against ABTS radicals. Vitamin C content of the tubers was found to be 31.5mg/100 g and their total phenolic content was 60mg gallic acid equivalent (GAE) per 100g dry sample (Table 5).
A comparison of the proximate composition of this tuber and other tubers consumed in Africa (Table 1) indicated that this tuber has a relatively higher protein content (3.2%) than wild cassava (1.3%), potato (2.0%), sweet potato (1.6%) and comparable to that of wild yams (3.2%). Total carbohydrate was high (18%) but lower than that reported for wild cassava and sweet potato (27%) but comparable to those of potato and wild yam (19%). Lipid content was relatively low (0.5%) but was relatively high compared to wild cassava (0.0%), potato (0.1%), sweet potato (0.2%) and wild yams (0.1%). The crude fibre content was 2.4%, whereas, the ash content was 3.5%. These values were also relatively higher than those of the other root tubers listed in Table 1. Moreover, these results were also found to be higher than those reported for the root vegetable carrot which contained 1.0% protein, 8.8% carbohydrate, 0.2% lipid and 0.8% ash . The gross energy value was 101.7kj/g comparable to that reported for radish (94.0kj/g) .
Essential amino acids represented 28.2% of the total amino acids of R. splendens tubers. The most abundant essential amino acids were leucine representing 20.3% of RDA, isoleucine representing 35.6% of RDA and threonine representing 35.7% of RDA. Methionine (7.2% of RDA) and lysine (6.7% of RDA) were the limiting amino acids.
Macro-minerals like calcium and phosphorus play major structural roles and others like sodium and potassium function as electrolytes. Micro-minerals often serve as catalysts in enzyme reactions . Deficiency or excess of elements may cause a number of disorders. Raw R. splendens tubers appeared to be especially rich in calcium and magnesium representing 18.3% and 16% of RDI respectively. Copper and manganese were the predominant micro-nutrient elements and their levels exceeded the RDI. Other micro-nutrient elements were generally in low concentrations.
The fatty acids profile of raw R. splendens tubers resembles most edible oils where oleic acid and palmitic acid were the most predominant acids. The ratio of unsaturated fatty acid: saturated fatty acid (1.6) was similar to that of sweet potato and Dioscorea dumetorum but considerably lower than that of Irish potato [24, 25].
Results of the antioxidant property of R. splendens tubers showed that tubers have higher scavenging capacity than those reported for yam varieties ([IC.sub.50] value DPPH ranged from 1.7 to 14.800mg/mL) from Philippine and for potato varieties ([IC.sub.50] value dpph ranged from 41.815 to 58.195mg/mL) from Iran [25, 26]. Typical compounds that possess antioxidant activity have been characterized as vitamin C and phenolic compounds. In this study, the content of vitamin C of tubers of R. splendens was relatively in the range of cassava (15-45 mg/100g) and potato (12.4-27.8mg/100g) [27, 28]. The total phenolic content of the tubers was relatively low. Thus, tubers of R. splendens might be considered as good sources of natural antioxidants that could help in the prevention of cancer, inflammation and other diseases related to radical mechanisms.
The nutritional importance of dietary diversity is now widely recognized. Growing a range of local crops supplemented by wild-harvested species helps provide such diversity in the diet . Wild plants represent an important part of the diet for rural people in western Sudan. Their consumption provides them with most of their daily requirements of macro and micronutrients and in many cases they also have medicinal properties and form part of local health care systems. Results of nutritional composition of tubers of R. splendens suggest that, this plant could contribute greatly in alleviating malnutrition in Sudan.
Nutritionally, R. splendens tubers could successfully substitute and/or complement the domesticated tubers consumed in Sudan and could contribute greatly towards meeting human nutritional requirements for normal body growth. Moreover, the results of this study suggested that the tubers could have beneficial effect for food and/or nutraceutical application in the promotion of health.
Authors would like to acknowledge Mrs. Manal El Hakim (Botany Department, Faculty of Science, University of Khartoum) for the identification of the plants.
[1.] VanderJagt DC, Freiberger C, Vu HT, Mounkaila G, Glew RS and RH Glew The trypsin inhibitor content of 61 wild edible plant foods of Niger. Plant Food Hum Nutr. 2000; 55: 335-46.
[2.] Cook J, VanderJagt DC, Pastuszyn A, Mounkaila G, Glew RS, Milison M and RH Glew Nutrient and chemical composition of 13 wild edible plant foods of Niger. J. Food Compost. Anal. 2000; 13: 83-92.
[3.] Bussmann RW, Gilbreath GG, Solio J, Lutura M, Lutuluo R, Kunguru K, Wood N and SG Mathenge Plant use of the Maasai of Sekenani Valley, Maasai Mara Kenya. J. Ethnobiol. Ethnomed. 2006; 2: 22.
[4.] Grivetti LE and BM Ogle Value of traditional foods in meeting macro-and micronutrient needs: the wild plant connection. Nutr. Res. Rev. 2000; 13: 31-46.
[5.] Medley KE and HW Kalibo Ethnobotanical survey of 'wild' woody plant resources at Mount Kasigau, Kenya. J. E. Afr. Nat. Hist. 2007;96(2): 149-186.
[6.] Nweke F "New challenges in the cassava revolution in Nigeria and Ghana." EPTD Discussion Paper No. 118, Washington, DC, IFPRI 2004.
[7.] Phillips TP, Taylor DS, Sanni L and MO Akoroda A Cassava industrial revolution in Nigeria: The potential for a new industrial crop. IFAD/FAO/UN Rome 2004.
[8.] Scott G, Best R, Rosegrant MW and M Bokanga Roots and tubers in the global food system -A vision statement to the year 2020. CIAT-CIP-IFPRIIITA-IPGRI-CIP 2000; 45.
[9.] FAO. Nutrition country profile- Food and Nutrition Division--Republic of the Sudan 2005.
[10.] Abdalla S and I Leonha user Dietary food consumption patterns in Sudan. J. Agric. Sci. Rev. 2013; 2: 180-185.
[11.] AOAC (Association of Official Analytical Chemists) Official Methods of Analysis, Association of Official Analytical Chemists. 15th Ed. Gaithersburg, USA: AOAC Press 1990.
[12.] Pearson D Chemical Analysis of Foods. 7th Ed. Livingstone, London: Churchill, 1976; 7-11.
[13.] Eknayake S, Jansz ER and BN Nair Proximate composition, mineral and amino acid content of mature Canavalia gladiata seeds. Food Chem. 1999; 66:115-119.
[14.] Doka ID, El Tigani S and S Yagi Amino acid content, fatty acid profile and radical scavenging capacities of Coccinia grandis (L.) Voigt. fruits. Adv. J. FoodSci. Technol. 2014; 6: 1307-1312.
[15.] Moore S and WH Stein Methods in Enzymology, 6, New York: Academic Press 1963.
[16.] Bahorun T, Luximon-Ramma A, Crozier A and IO Aruoma Total phenol, flavonoid, proanthocyanidin and vitamin C levels and antioxidant activities of Mauritian vegetables. J. Sci. FoodAgr. 2004; 84: 1553-1561.
[17.] AOAC. Official Methods of Analysis, Association of Official Analytical Chemists. 16th Ed. Arlington, Virginia, USA: 1995.
[18.] Wolfe K, Wu X and KH Liu Antioxidant activity of apple peels. J. Agr. Food Chem. 2003; 15: 609-614.
[19.] Mensor LI, Menezes FS, Leitao GG, Reis AS, Santos DOS and SG Leitao Screening of Brazilian plants extracts for an antioxidant activity by the use of DPPH free radical method. Phytother. Res. 2001; 15: 127-130.
[20.] Re R, Pellegrini N, Proteggente A, Pannala A, Yang M and C Rice-Evans Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radical Bio. Med. 1999; 26: 1231-1237.
[21.] Hu E, Bartev SI and H Liu Conceptual design of a regenerative life support system containing crops and silk worms. Adv. Space Res. 2010; 45: 929-939.
[22.] Obadina AO and OB Oyewole Assessment of the antimicrobial potential of roselle juice (zobo) from different varieties of roselle calyx. J. Food Process. Preservation 2007; 31: 607-617.
[23.] ALozie YOO and MI Akpanabsatu Fatty acid composition of Dioscorea dumetorum (pax) varieties. AJFAND.2010; 10 (8): 2956-2966.
[24.] Opute FI and AU Osagie Fatty acid composition of total lipids from some tropical storage organs. J. Sc. Fd. Agric. 1978; 29: 959-962.
[25.] Djanna F, Cornago DF, Rumbaoa RGO and IM Geronimo Philippine Yam (Dioscorea spp.) Tubers Phenolic Content and Antioxidant Capacity. Philippine J. Sci. 2011; 140 (2): 145-152.
[26.] Hesam F, Balali GR and RT Tehrani Evaluation of antioxidant activity of three common potato (Solanum tuberosum) cultivars in Iran. AJP. 2012; 2 (2): 79-85.
[27.] Okigbo BN Nutritional implications of projects giving high priority to the production of staples of low nutritive quality. In the case for cassava (Manihot esculenta, Crantz) in the humid tropics of West Africa. FNB. 1980; 2: 1-10.
[28.] Gugala M and K Zarzecka Vitamin C content in potato tubers as influenced by insecticide application. Pol. J. Environ. Stud. 2012; 21 (4): 1101-1105.
[29.] WHO/FAO. Diet, nutrition and the prevention of chronic diseases, Report of a joint WHO/FAO expert consultation, Geneva, 28 January-1 February 2002, WHO Technical Report Series No. 916, Geneva, Switzerland 2003.
[30.] Leung WTW Food composition tables for use in Africa. Rome, FAO/Bethesda, Maryland, USA, United States department of health, education and welfare 1968.
[31.] IITA. (International Institute of Tropical Agriculture) Annual Report for 1881. Ibadan, Nigeria1982.
[32.] FAO. Report of Workshop on Production and Marketing constraints on Roots, Tubers and Plantain in Africa 1985.
[33.] FAO/WHO/UNU. Energy and protein requirements. Tech. Rep Series 724, World Health Organization, Geneva 2007.
Doka IG (1,2), El Tigani S (1), and S Yagi (1) *
Corresponding author's email: email@example.com
(1) Botany Department, Faculty of Science, University of Khartoum, P.O. Box 321, Khartoum, Sudan
(2) Botany Department, Faculty of Science, University of Kordofan, Kordofan, Sudan
Table 1: Proximate composition and nutritional data of Raphionacme splendens tubers Wild Parameters R. splendens Cassava (a) Potato (a) Protein (%) 3.2 [+ or -] 0.02 1.3 (a) 2.0 (a) Lipid (%) 0.5 [+ or -] 0.01 0.0 (a) 0.1 (a) Carbohydrate (%) 18 [+ or -] 0.07 27.6 (a) 19.0 (a) Dietary fibre (%) 2.4 [+ or -] 0.02 1-2 (b) 0.4 (a) Ash (%) 3.5 [+ or -] 0.02 1.1 (a) 1.0 (a) Moisture (%) 79.2 [+ or -] 0.6 58-81 (b) 50-81 (b) Gross energy value (kj/g) 101.7 149 (c) 110 Sweet Parameters potato (a) Wild Yam (a) Protein (%) 1.6 (a) 3.2 (a) Lipid (%) 0.2 (a) 0.1 (a) Carbohydrate (%) 27.5 (a) 19.0 (a) Dietary fibre (%) 1.0 (a) 0.8 (a) Ash (%) 0.9 (a) 1.1 (a) Moisture (%) 50-81 (b) 65-73 (b) Gross energy value (kj/g) 121 (c) 119 (c) Values are means ([+ or -] SD) of triplicate analysis and are expressed on a dry weight basis. Source: a, Food Composition Tables For Use In Africa b, IITA . c, FAO  Table 2: Amino acids profile of Raphionacme splendens tubers (dry weight basis, mg/100g) Adult R. splendens requirement/ Amino acids tubers day * Essential Thr 536 1500 Met 72 1000 Ile 712 2000 Leu 792 3900 Tyr + Phe 488 2500 Lys 200 3000 His 240 1000 Total 3040 Non-essential Asp 1960 Ser 432 Glu 1656 Gly 120 Ala 1336 Arg 1048 Pro 1184 Total 7736 Total aminoacids 10776 Values are means ([+ or -] S. D.) of triplicate analysis. * Source: FAO/WHO/UNU  Table 3: Mineral composition of Raphionacme splendens tubers (dry weight basis, mg/100g) Element Concentration (mg/100g) Potassium 259 [+ or -] 0.01 Calcium 183 [+ or -] 0.02 Phosphorus 37 [+ or -] 0.3 Copper 3.6 [+ or -] 0.01 Manganese 2.4 [+ or -] 0.02 Iron 1.2 [+ or -] 0.01 Zinc 1.8 [+ or -] 0.01 Values are means ([+ or -] SD) of triplicate analysis Table 4: Composition of fatty acids of Raphionacme splendens tubers Fatty acids % fatty acid Caproic acid C6:0 0.34 Undecanoic acid C11:0 ND Lauric acid C12:0 ND Tridecanoic acid C13:0 ND cis-9 Myristoleic acid (n-5) C14:1 ND Myristi acid C14:0 0.75 cis-10-Pentadecenoic acid C15:1 ND Pentadecanoic acid C15:0 1.65 cis-9 Palmitoleic acid (n-7) C16:1 0.98 Palmitic acid C16:0 30.23 cis-6,9,12y-Linolenic acid (n-6) C18:3 5.90 cis-9,12 Linoleic acid (n-6) C18:2 2.44 trans 9,12 Linolelaidic acid C18:2 11.16 Oleic acid (n-9) C18:1 32.56 Stearic acid C18:0 6.73 cis-3,8,11,14 Arachidonic acid (n-6) C20:4 1.38 Heneicosanoic acid C21:0 0.38 Behenic acid C22:0 0.41 Tricosanoic acid C23:0 5.11 Nervonic acid (n-9) C24:1 ND Total saturated fatty acids (TSFAs) 45.6 Total unsaturated fatty acids (TUSFAs) 54.4 Mono-unsaturated fatty acids (MUSFAs) 33.54 Poly-unsaturated fatty acids (PUSFAs) 20.86 Values are means([+ or -] S. D.) of triplicate analysis Table 5: Vitamin C, total phenolic content and antioxidant activity of Raphionacme splendens tubers Total phenolic Vitamin C content (mg/10 g) (mg GAE/100g) Tubers 31.5 [+ or -] 0.01 60 [+ or -] 0.02 Ascorbic acid [IC.sub.50] (mg/mL) DPPH ABTS Tubers 0.987 [+ or -] 0.01 1.559 [+ or -] 0.01 Ascorbic 0.027 [+ or -] 0.03 0.025 [+ or -] 0.02 acid Values are means( [+ or -] S. D.) of triplicate analysis
|Printer friendly Cite/link Email Feedback|
|Author:||Doka, Ibtisam; El Tigani, S.; Yagi, S.|
|Publication:||African Journal of Food, Agriculture, Nutrition and Development|
|Date:||Mar 1, 2016|
|Previous Article:||Assessing the determinants of tissue culture Banana adoption in Western Kenya.|
|Next Article:||Dr. Dorothy Anima Effa.|