Tropical fruits contribute substantially to human mineral intake, yet most nutritional studies focus narrowly on the edible flesh and overlook the mineral contribution of peels and seeds, fractions routinely discarded as waste. This study determined the mineral composition of the flesh, peel and, where applicable, seed fractions of four tropical fruits commonly consumed in Kenya: banana (Musa spp.), mango (Mangifera indica), pineapple (Ananas comosus) and watermelon (Citrullus lanatus). Twenty mature fruits of each species were sourced from retail markets in Eldoret, Uasin Gishu County, separated into their respective fractions, oven-dried, ground and analysed for potassium, zinc, calcium, magnesium and iron using Atomic Absorption Spectrophotometry following dry-ashing, in accordance with AOAC protocols. Potassium emerged as the dominant mineral across all samples, reaching its highest concentration in banana peel (66.84 mg/100g), while iron occurred at generally low concentrations throughout. Banana recorded the highest mean potassium (52.08 mg/100g) and zinc (9.80 mg/100g) content among the four fruits, whereas mango recorded the highest mean magnesium (9.85 mg/100g) and iron (4.73 mg/100g) content. Watermelon showed the lowest concentrations across most minerals examined. Across all four fruits, peel fractions consistently accumulated higher concentrations of potassium, zinc, calcium and magnesium than flesh, while seed fractions carried the highest iron content. One-way ANOVA revealed no statistically significant differences in mineral composition among the four fruit species (p = 0.1698) or among the three fruit fractions (p = 0.4623) at the 95% confidence level. These findings indicate that peel and seed fractions retain mineral concentrations comparable to, and in several cases exceeding, those of the edible flesh, positioning them as viable candidates for valorisation into flour, animal feed or nutraceutical products rather than continued disposal as agricultural waste.
Cite this paper
Riose, C. K. , Lagat, G. and Kipkemboi, P. (2026). Mineral Composition of Tropical Fruits: Banana (Musa spp.), Mango (Mangifera indica), Pineapple (Ananas comosus) and Watermelon (Citrullus lanatus). Open Access Library Journal, 13, e16038. doi: http://dx.doi.org/10.4236/oalib.1116038.
AlJuhaimi, F., Kulluk, D.A., Yılmaz, F.G., Ahmed, I.A.M., Özcan, M.M. and Albakry, Z. (2025) Quantitative Determination of Minerals and Toxic Elements Content in Tropical and Subtropical Fruits by Microwave-Assisted Digestion and ICP-OES. <i>Biological Trace Element Research</i>, 203, 1676-1684. <br>https://doi.org/10.1007/s12011-024-04265-7
Cosme, F., Pinto, T., Aires, A., Morais, M.C., Bacelar, E., Anjos, R., <i>et al</i>. (2022) Red Fruits Composition and Their Health Benefits—A Review. <i>Foods</i>, 11, Article 644. <br>https://doi.org/10.3390/foods11050644
Association of Official Analytical Chemists (AOAC) (1988) Official Method 975.03: Metals in Plants and Pet Foods. Atomic Absorption Spectrophotometric Method.
Tsado, A., Okoli, N., Jiya, A., Gana, D., Saidu, B., Zubairu, R., <i>et al</i>. (2021) Proximate, Minerals, and Amino Acid Compositions of Banana and Plantain Peels. <i>BIOMED Natural and Applied Science</i>, 1, 32-42.
Lebaka, V.R., Wee, Y., Ye, W. and Korivi, M. (2021) Nutritional Composition and Bioactive Compounds in Three Different Parts of Mango Fruit. <i>International Journal of Environmental Research and Public Health</i>, 18, Article 741. <br>https://doi.org/10.3390/ijerph18020741
Adeyemi, M., Bawa, M. and Muktar, B. (2018) Evaluation of the Effect of Calcium Carbide on Induce Ripening of Banana, Pawpaw and Mango Cultivated within Kaduna Metropolis, Nigeria. <i>Journal of the Chemical Society of Nigeria</i>, 43, 108-118.
Devy, N., Dwiastuti, M., Sugiyatno, A., Ashari, H., Endarto, O., Triwiratno, A., <i>et al</i>. (2022) The Fruit Peel Anatomy, Leaf Nutrient Content, and Fruit Quality of “Terigas” Mandarin in Relation to Fruit Cracking. <i>Emirates Journal of Food and Agriculture</i>, 34, 1072-1078.
Mutua, J.K., Imathiu, S. and Owino, W. (2017) Evaluation of the Proximate Composition, Antioxidant Potential, and Antimicrobial Activity of Mango Seed Kernel Extracts. <i>Food Science & Nutrition</i>, 5, 349-357. <br>https://doi.org/10.1002/fsn3.399
Pérez-Jiménez, J. and Saura-Calixto, F. (2018) Fruit Peels as Sources of Non-Extractable Polyphenols or Macromolecular Antioxidants: Analysis and Nutritional Implications. <i>Food Research International</i>, 111, 148-152. <br>https://doi.org/10.1016/j.foodres.2018.05.023
Wallace, T.C., Bailey, R.L., Blumberg, J.B., Burton-Freeman, B., Chen, C.O., Crowe-White, K.M., <i>et al</i>. (2020) Fruits, Vegetables, and Health: A Comprehensive Narrative, Umbrella Review of the Science and Recommendations for Enhanced Public Policy to Improve Intake. <i>Critical Reviews in Food Science and Nutrition</i>, 60, 2174-2211. <br>https://doi.org/10.1080/10408398.2019.1632258
Elegbede, J.A., Achoba, I.I. and Richard, H. (1995) Nutrient Composition of Mango (Mangnifera Indica) Seed Kernel from Nigeria. <i>Journal of Food Biochemistry</i>, 19, 391-398. <br>https://doi.org/10.1111/j.1745-4514.1995.tb00543.x
Peters, D., Ogbeifun, H. and Monanu, M. (2022) Nutrient Composition of Citrullus lanatus (Water Melon) Seeds. <i>International Journal of Research in Life Sciences</i>, 9, 37-48.
