Effect of boiling on phenolic profiles determined using HPLC/ESI-LTQ-Orbitrap-MS, physico-chemical parameters of six plantain banana cultivars (Musa sp)
The effect of boiling on pulp and peel phenolic profiles of five plantain cultivars and the plantain hybrid F568 was evaluated using high-performance liquid chromatography/electrospray ionisation-linear trap quadrupole-Orbitrap-mass spectrometry (HPLC/ESI-LTQ-Orbitrap-MS) and HPLC-diode array detector (DAD) analysis on sample extracts obtained by a solid/liquid extraction. Total soluble solids, pH, water, and total ash contents were also determined. After boiling the whole fruit, total phenolics decreased considerably in the peel (34.3% on average), whereas no significant change was observed in the pulp after boiling with or without peel. With regards to individual phenolic compounds, all the peel flavonols decreased except for myricetin-deoxyhexose-hexoside, with maximum losses of 61.3% and 59.8% of kaempferol-3-O-rutinoside and rutin, respectively, for the cultivar Red Yade. In both pulp and peel, ferulic acid was apparently released from its conjugated forms after boiling, with increases of 63.7% after boiling with peel and of 33.2% after boiling without peel in the pulp of the cultivar Moto Ebanga. Changes in water and total ash contents also suggested a protective effect of the peel. Finally, the principal component analysis revealed that peel total ash content and pH were strongly correlated to the decrease in phenolics.