The influence of different technological co-adjuvants on the quality and yield of virgin olive oil using response surfaces methodology

Abstract

Response surface methodology was employed to evaluate the effects of two technological co-adjuvants in virgin olive oil extraction from the Hojiblanca olive variety with a low ripening index: the addition of talc during the malaxation of the olive paste step, water addition during the same step and olive paste storage over a small period of time. Ranges of operation were established as follows: talc addition, 0-2 % (w/w); water addition, 0-20 % (w/w); and storage time, 0-36 h. Mathematical models and statistical analyses (ANOVA) were performed in order to evaluate the effects of theses factors on oil yield and quality of olive oils obtained. Using a confidence level of 95 %, oil yield, acidity, peroxide index, K270 and Chlorophyll contents, models are significant. The addition of talc is more effective in improving oil yield and paste storage is also useful to improve oil yield although a loss of oil quality is observed; but all the olive oil obtained may be characterized as extra virgin olive oil according to the regulations of the European Union.

Keywords

• coadjuvants
• response surfaces
• talc
• virgin olive oil