Influence of iron redox state on black ripe olive processing.

The results presented in this study suggest that the formation of ferric ions during the colour fixation step of black ripe olives must be avoided to obtain darker olives. Consequently, the initial pH of the ferrous gluconate solution must be corrected to avoid oxidation of the ferrous to ferric cations during the fixation step. This study will contribute to the improvement of the colour fixation step of black ripe olive processing. © 2018 Society of Chemical Industry.