Optimization of total polyphenol extraction and flavonoid screening by mass spectrometry in mango (Mangifera indica L.) waste from Peru

Abstract

This research aims to optimize the extraction yield of total phenolic compounds (TPC) and quantify flavonoids by mass spectrometry in peel and kernel of mango (Mangifera indica L.), varieties: Edward, Kent, Haden, and Criollo from the department of Lambayeque, Peru, which resulted in eight samples. Mango peels and kernels were manually separated, frozen at -20 °C, freeze-dried, and ground (300 μm). For the extraction, the Central Composite Design was applied with the factors of ethanolic solution, time, and sample/volume ratio. The extracts determined TPCs by Folin-Ciocalteu and UV-Vis spectrophotometry expressed as gallic acid equivalent. Optimization was performed by the desirability function; Quercetin was also quantified by liquid chromatography-mass spectrometry (m/z). The highest yield of TPC content for Criollo mango kernel was obtained with 67.99% ethanolic solution, 89.94 min, and 0.343 g sample/10 mL ethanolic solution with R2 of 0.8966, and for Edward mango peel with 73.996% ethanolic solution, 58.5 min, and 0.432 g sample/10 mL ethanolic solution with R2 of 0.8020. For peel, the methanolic extract from Criollo mango peel had the highest Quercetin value at (23.28 ± 2.35 mg QE/100 g) (p < 0.05), and for kernels, in both extractions (ethanolic and methanolic), the four varieties did not present differences (p > 0.05).

Keywords:
kernel; peel; desirability; polyphenols; Quercetin; spectrometry; untargeted metabolomic