Evaluation of Minerals, Reducing Sugar, Resistant Starch and Polyphenol Oxidase Activities of Selected Banana variety of Ethiopia BY

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Addis Ababa University


Banana cultivation is considered one of the most important agricultural activities of economic and social importance in Ethiopia. The objective of this work was to investigate minerals, reducing sugar, resistant starch and polyphenol oxidase activities of fi veselected banana varieties, these are giant cavendish,butuza,robusta,poyo and williamsofEthiopia. Banana fruits were collected, dried, ground and ashed. The mineral elements potassium(K), Iron (Fe) and zinc(Zn) were analyzed. Their composition was found to be 0.627 - 1.047 mg!IOOg for iron, 0.217 - 0.307 mg! IOOg for zinc and 287.171 - 355.271 mg! I OOg for potassium inripe banana fruits. Bananas are considered a good source of K in the diet, and the data obtained herein support these assertions. Zn and Fe are other minerals of nutritional importance in bananas and this study has shown that their average values are adequate to support its nutritive value at ripening stages.The RS content of banana were between 52.2 - 61.4 g! IOOg that containing the highest amount of RS, banana has a higher RS content the highest value comingfrompoyo fo llowed by Giant Cavendish.For reducing sugar, the sample extract was filtered through the two layers of cloths and reextracted in hot 80% alcohols. using 2 to 3 ml of alcohol per gm of sample and tested by Fehling's solution. The precipitate and color change of the sample were calculated by titration method and Polyphenol oxidase has been shown to be responsible for browning reactions and discoloration in banana fruit. Polyphenol oxidase was indirectly iso lated. The activity of the enzyme was evaluated using Hallberg and Halthen's algorithm method. Banana PPO catalyzes oxidation of both various substrates with catechol being the most readily oxidized substrate. The optimum pH of the enzyme was between pH 6 and 7 for all cultivars. Banana polyphenol oxidase was active towards catechol but not withgalloyl.The result obtained in this study showed that banana fruits can be a potential source of mineral elements supplement in the diet especially for k, and good source of resistant starch and reducing sugar. Key words: Banana, mineral,reducing sugar, resistant starch and polyphenol oxidase



Banana, mineral, reducing sugar, reducing sugar, polyphenol oxidase