Polyphenolic Content and Radical Scavenging Activities of the Peel, Pulp and Seed of Avocado (Persea americana Mill.) Grown in Tanzania

Authors

  • Ibrahim Juma Department of Food Science and Technology, University of Dar es Salaam, P. O. Box 35134, Dar es Salaam, Tanzania
  • Jan-Eric Englund Department of Biosystems and Technology, Swedish University of Agricultural Sciences, P. O. Box 190, 23422 Lomma, Sweden
  • Rodomiro Ortiz Department of Biosystems and Technology, Swedish University of Agricultural Sciences, P. O. Box 190, 23422 Lomma, Sweden
  • Mulatu Geleta Department of Biosystems and Technology, Swedish University of Agricultural Sciences, P. O. Box 190, 23422 Lomma, Sweden
  • Donatha D. Tibuhwa Department of Molecular Biology and Biotechnology, University of Dar es Salaam, P. O. Box 35179, Dar es Salaam, Tanzania
  • Anders S. Carlsson Department of Plant Breeding, Swedish University of Agricultural Sciences, P. O. Box 190, 23422 Lomma, Sweden
  • Agnes Nyomora St. Augustine University of Tanzania, P. O. Box 307, Mwanza, Tanzania
  • Moneim Fatih Department of Plant Breeding, Swedish University of Agricultural Sciences, P. O. Box 190, 23422 Lomma, Sweden
  • Helena Persson Hovmalm Department of Plant Breeding, Swedish University of Agricultural Sciences, P. O. Box 190, 23422 Lomma, Sweden

DOI:

https://doi.org/10.4314/tjs.v49i1.20

Abstract

Avocado is a healthy fruit and the consumption is continuously growing worldwide. The fruit contains polyphenolic compounds with antioxidant effects. Globally, research has been devoted to exploring the fruit quality, especially compounds with antioxidant effects, from different avocado-growing sites. However, the fruit quality of the Tanzanian avocado has so far not been investigated. In this study, the contents of polyphenols in peel, pulp and seed of avocados sampled in south-western Tanzania are described. The levels of total polyphenolic and flavonoid contents were measured, and antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The total polyphenolic content was highest in the seed and lowest in the peel (424 and 200 mg GAE/100 g DW, respectively). As for the total flavonoid content, the pulp had the highest value of 36.98 mg RE/100 g DW, while the seed had the lowest value of 32.54 mg RE/100 g DW. The overall average half maximal effective concentration (EC50) values in decreasing order, corresponding to an increasing antiradical activity, were 4.90 (peel), 3.63 (seed) and 3.24 µg/mL (pulp). The seed and peel possessed high levels of total polyphenolic and flavonoid content, thus demonstrating substantial antioxidant capacity. Seed and peel can potentially be processed and included in the diet to provide inexpensive antioxidant ingredients of natural origin. Consumption of the seed will not only improve human health but also reduce the environmental pollution, as many thousand tonnes of avocado seeds are produced in Tanzania per year; a huge amount currently remains as waste.

Keywords:  Flavonoid contents; Free radicals; EC50; Polyphenolic content

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Published

2023-03-31

Issue

Vol. 49 No. 1 (2023)

Section

Articles