Characterization of (poly)phenolic compounds during the ripening and after domestic cooking of bananas and plantains

Several studies highlight the antioxidant, anti-ulcerogenic, antihypertensive, antidiabetic and anticancer action of Musa spp. caused by the presence of phenolic compounds. The aim of this study was to evaluate phenolic contents in bananas and plantains genotypes at the active germplasm bank (Embrapa Cassava & Tropical). Fruit in the ripening stages 2 (green), 5 (yellow) and 7 (yellow with black spots) from 20 genotypes were used for phenols analysis by HPLC. In addition, we analyzed two genotypes (cooking banana and plantain) regarding the retention of phenols after the thermal processing (boiling in water, microwaving and stir-frying). The average of total phenols varied from 74.64 to 506.12 mg GAE/100g (d.w.). The highest phenols quantity was verified in the ripe fruit, decreasing in the stage 7, probably due to processes of degradation, oxidation and/or isomerization of the compounds. The cooking bananas ‘Tiparot’ (stg 5: 658.80 mg EAG/100g) and ‘Pelipita’ (stg 2: 506.12 mg GAE/100g) and the dessert banana ‘Poovan’ (460.19 mg EAG/100g) presented the highest phenols values. ‘Ney Poovan’, ‘Tiparot’ and ‘Samurá B.’ showed the highest phenol acids (170.2, 190.3 and 113.6 µg/g, respectively) and flavonoids (149.0, 314.8 and 133.7 µg/g, respectively) contents. The dessert banana ‘Ney Poovan’ (stg. 5 and 7), the plantain Samurá B. (stg. 2) and the cooking banana Tiparot (stg. 5) were the genotypes with the highest levels of hydroxybenzoic acid (85.9, 72.3 and 58.2 μg/g). There was a high correlation of catechin and quercetin with antioxidant activity (e.g. FRAP: r = 0.92 and 0.85, respectively). The cooking with peel (boiling and micro-wave) and without peel (boiling) showed the highest total phenol contents. Despite the large retention (89%), boiled fruits of ‘D’Angola’ plantain without peel showed loss of hydroxybenzoic acid, differently from what is observed in 'Pelipita'. When we used peel during the cooking, there were more pronounced increases of the phenolic compounds in pulps, mainly phenolic acids (until 116.4%). All cooking methods using ‘Pelipita’ (cooking bananas) improved the bioavailability of phenolic compounds, resulting from inherent differences between genotypes (lower texture). We concluded that the highest total phenols contents are found in dessert bananas and cooking bananas, mainly in the ripe fruit. The presence of catechin, quercetin, gallic acid and hydroxycinnamic acid was confirmed. Catechin and quercetin were the compounds that presented a positive and significant correlation with the antioxidant activity. Some genotypes present high values of phenolic compounds, which is interesting for its promotion/incorporation in agricultural systems and biofortification programs. In addition, the thermal processing increases the functional and / or nutritional value of Musa spp., mainly boiling with water (fruit with peel), which should be preferred in domestic preparations, regardless of the used cultivar.

FAPESP (2016/00972-0, 2017/ 23488-0 and 2016/22665-2) and CNPq (305177/2015-0).