The effects of ripening and cooking method on mineral and proximate composition of plantain (Musa sp AAB cv. 'Agbagba') fruit pulp

In West and Central Africa, plantain fruits are eaten after cooking or after some other forms of processing. The cooking or processing method employed influences the biochemical and nutritional composition thereafter. In this study, the fruits of Falsehorn plantain (Musa sp. AAB, cv. 'Agbagba') at the green harvest stage, light green (more-green-than-yellow), yellowish green (more-yellow-than-green) and fully-ripe (yellow) stages of ripeness were analysed for nutritional composition after boiling, steaming or roasting, alongside the unprocessed (raw) fruits as the control. The fruits were analysed in triplicate samples for fat, protein, carbohydrate (CHO), dry matter content (DMC), beta-carotene (vitamin A precursor), ash, Fe, K and Zn contents in a 4 x 4 factorial in a completely randomized design (CRD). Results showed significant variations in the mineral and proximate composition of the fruits following natural ripening, and the cooking (processing) method employed. Ash, CHO and K contents of the fruits seemingly increased with ripeness, whereas fat, DMC, Fe and beta-carotene decreased particularly at full ripe state. Majority of the proximate and mineral constituents (fat, protein, CHO, DMC, vitamin A, Fe and K) were relatively higher at the light green and the greenish yellow (semi-ripe) stages. Similarly, ash, fat, protein, DMC, Fe and K were significantly (P < 0.05) higher in the roasted fruits, but steamed fruits had the highest concentration of beta-carotene. Except for CHO content, boiling significantly (P < 0.05) decreased most of the proximate and mineral contents of the fruits. It was observed that fruits roasted at the semi-ripe stages had the highest concentration of nutrients, and the CHO content in roasted fruits was correspondingly low. It is conclusive from this study that roasting followed by steam-cooking better conserved nutrients of plantain fruits, thus adjudged the best cooking methods. To optimize nutrients derivable from eating plantain fruits, roasting semi-ripe (light green or slight yellow stage) fruits was the best option.