Total Polyphenols, Total Flavonoids, Condensed Tannins, and Antioxidant Activity of Borassus aethiopum (Arecaceae) ripe fruits’ Peels, and Peel-Pulps, Dried at Different Temperatures

Abstract

Aims: To measure their possible beneficial contributions on the rabbits’ health, Borassus aethiopum ripe fruits’ peels and combined peel-pulp were dried at 60, 65, 70 and 75oC. Place and Duration of Study: On January and February 2023, Borassus aethiopum ripe fruits were collected within the graduate school of agronomy at the National Polytechnic Institute Felix Houphouët Boigny in Yamoussoukro, Côte d’Ivoire. Methodology: The unspoiled fruits were peeled. One sample was composed of peels without the pulps, and a second was composed of peel and pulp combined. Following, they were dried during 5 days in ovens. Then, the products were crushed, and sieved. Thereafter, the products were extracted with distilled water through maceration and decoction for 1 hour. Afterwards, total phenols (TP), total flavonoids (TF), condensed tannins (TC) contents, and antioxidant activity (AOA) were assessed. Results: The best extracts were obtained through decoction. Moreover, the peels presented the highest TP extract for 0.082+/-0.001 mg GAE/g at 70oC. Whereas the lowest TP extract was observed in the combined peel-pulp dried at 70oC for 0.067+/-0.001 mg GAE/g. However, concerning the TF, the peel-pulp dried at 75oC gave the best extracts through maceration, for 0.0450+/-0.007 mg QE/g. Globally, results revealed that the peels contain higher flavonoid contents than the combined peel-pulp. Regarding AOA, the extracts had much higher free radical scavenging capacity in the peels than in the combined peel-pulp parts. The highest antioxidant activity was observed with the peels dried at 70oC for 6.653+/-0.075 μmol TE/g, while the lowest value was observed with the combined peel-pulp dried at 70oC for 1.996+/-0.075 μmol TE/g. With condensed tannins, the best output was obtained with the peel dried at 60oC for 0.468+/-0.003 µg CatE/g. Conclusion: Borassus aethiopum ripe fruits’ parts can be dried between 65 and 70oC. So, they could be good sources of fibres and phytochemicals for rabbits’ diets.