Nutritional And Phytochemical Evaluation Of Anchote (coccinia Abyssinica) (lam.) (cogn.) Accessions To Promote Its Contribution For Food Security And Medicinal Use

Anchote (Coccinia abyssinica (Lam.) (Cogn.)) is one of the important endemic cropsrnprincipally grown for its edible tuber throughout the south and southwestern parts ofrnEthiopia. Moreover, its newly growing leaves along with tendrils are served as vegetablernafter cooking; making Anchote a double crop. Being one of the underutilized vegetables, therernare few research efforts made to comprehensively characterize Anchote germplasm in respectrnto its nutritional composition, anti-nutritional factors, functional properties, phytochemicalrncomposition (qualitative and quantitative) as well as volatile organic compounds. The mainrnobjective of this study was, thus, to assess the nutritional profile and phytochemicalrnproperties of the edible parts of 44 Anchote accessions.rnSignificant variability was observed in nutrient composition and anti-nutrient content amongrnthe tested accessions and plant parts. Leaves were found to be rich in crude protein contentrn(8.96±0.01% - 35.42±0.05%) compared to tubers (5.82±0.00% - 13.72±0.10 %)of 100 g dryrnmatter. In contrast, tubers were found to be superior in utilizable carbohydratesrn(73.89±0.22% - 84.51±0.43%) of 100 g dry matter, and gross energy (349.14±0.10 -rn368.48±0.24) of Kcal/100g dry matter. Other proximate values documented include crude fatrn(0.24±0.05 - 0.75± 0.07% and 2.44±0.27- 4.68±0.84%); crude fiber (3.63±0.04-6.96±0.24%rnand 7.89±0.03 -13.05±0.08%) as well as total ash (4.63±0.31 - 6.83±0.02% and 10.74±0.04 -rn13.59±0.02%); in tubers and leaves of Anchote, respectively. Total amino acid content ofrnaccessions with high protein content ranged from 45.12 to 62.89 g/100g protein for tubersrnand 67.31 to 75.69 g/100g protein for leaves. Variations in mineral contents namely Sodium (Na), Phosphorus (P), Potassium (K), Calciumrn(Ca), Magnesium (Mg), Iron (Fe), Cooper (Cu), Zinc (Zn), Manganese (Mn) and Boronrn(B)were also recorded among accessions and plant parts. The Ca content of tuber rangedrnfrom 80.64–372.16 mg/ 100g and for leaf, it ranged from 64.10 –226.95mg/ 100g. The Ferncontent ranged from 0.39–2.92 mg/100g for tuber and 1.58 – 18.65mg/100g for leaf while Znrncontent of tuber ranged from 0.22–0.53mg/100g and 0.32 – 3.41mg/100g for leaf. The meanrnantinutritional contents of tuber samples were: phytate (131.10mg/100g), tanninrn(112.02mg/100g) and cyanide (13.08mg/kg). For leaves, the contents were phytate (250.30rnmg/100g), tannin (216.53 mg/100g) and cyanide (12.36 mg/kg). The levels of antinutrients inrnleaves were higher than in tubers. On the other hand, the levels of potentially toxic elementsrnsuch as Cd, As, and Pb were almost negligible, with mean concentration values of 0.86, 0.83rnand 7.05 ng/g, and 1.29, 2.62 and 13.53 ng/g in tubers and leaves, respectively. The meanrnmolar ratios for phytate: calcium, phytate: iron, phytate: zinc and phytate x calcium: zinc wasrn0.05 and 0.11, 3.81 and 4.31, 27.79 and 22.47 and 142.20 and 90.72 in tubers and leaves,rnrespectively.rnChemical composition and functional properties of leaf protein concentrate (LPC), tuber andrnleaf powder of Anchote were also analyzed. Heat coagulation at natural pH was used tornobtain the LPC from the aqueous fresh leaf extract. The mean crude protein content for LPCrnwas 47.46 g/100gand its mean total amino acid content was 99.64 g/100g protein. Lowestrnprotein solubility of Anchote LPC (11%) obtained in pH ranges of between 6 and 10 andrnhighest solubility (19%) recorded at pH 12. The result for in-vitro protein digestibility wasrn57.44±1.48 % for tuber powder, 49.46±1.68% for LPC and 40.92±0.54 % for leaf powder.rnLeaf powder revealed highest water (2.94 g/g) and oil (1.29 g/g) absorption capacities (WACrn& OAC), and lowest value of WAC (1.61 g/g) was observed in LPC. Emulsification reducedrnwith increase in protein concentration and increased with increase in pH in all testedrnsamples. The foaming capacity was highest in leaf powder followed by LPC.rnAnchote accessions were also tested for presence of some phytochemicals using qualitativernand quantitative methods. Qualitative test was done for 12 phytochemicals using extraction solvents Secondary metabolites including total phenols, total flavonoids, crude saponins and betacarotenernwere analyzed quantitatively. Positive results were observed during qualitativernscreening for five phytochemical compounds tested in tubers whereas only two tests werernpositive for leaves in all the seven solvent extracts. Water extract showed positive results forrn11 phytochemicals while n-butanol extract showed positive results for six tests for both tuberrnand leaf samples. The water extract of Anchote showed highest number of phytochemicals inrnboth tuber and leaf parts when compared to other solvent extracts. Anchote leaf had higherrntotal phenol and flavonoid contents followed by fruit and the least concentration of theserncompounds occurred in tuber for all the tested accessions. Leaf of Anchote contained thernhighest percentage of saponins (27.65%) compared to other parts. The β-carotene content ofrnAnchote leaf ranged from 25.90.03 to 35.20.16 in μg/g.rnAnchote leaf and tuber powder samples were extracted by simultaneous steam distillation andrnsolvent extraction (SDE) to determine volatile organic compounds. The extracts wererncharacterized by gas chromatography-mass spectrometry (GC/MS). Thirty volatilerncompounds from leaves and 15 compounds from tubers were identified with a yield of 770.57rnmg/kg and 4536.91 mg/kg, respectively.rnIn conclusion, the study showed that both the tuber and leaf parts of Anchote havernappreciable amount of different essential nutrients. Leaves have relatively higher nutrientrncomposition in all accessions compared to tubers, which provides a good scientific evidencernto diversify the consumption habit of indigenous people who are growing Anchote mainly forrnits tuber, the principal edible part of the crop. The different functional properties of AnchoternLPC also suggest its potential to be used as an ingredient in processed foods. Anchote is alsornrich in different phytochemicals and volatile organic compounds that make the plant arnpotential crop to be used in pharmaceuticals and food industries.

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