The utilization of solid carbon dioxide in the extraction of extra-virgin olive oil
VOO/EVOO yield and quality as a function of extraction conditions adopted
ANGELA ZINNAI, FRANCESCA VENTURI*, CHIARA SANMARTIN, ISABELLA TAGLIERI, GIANPAOLO ANDRICH
*Corresponding author
University of Pisa, Department of Agriculture, Food and Environment (DAFE),
Via del Borghetto 80, 56124 Pisa, Italy
Abstract
The impact of the addition of solid CO2 on olive oil (EVOO/VOO) production in terms of extraction yield and chemical quality was studied at pilot scale in an industrial oil-press in two different crop seasons. The addition of CO2,s to the fruits induces the intracellular water freezing and the consequent laceration of cellular membranes could induce the diffusion of many cellular compounds. In the experimental conditions adopted, the addition of the cryogen to the olives during pre-milling phase greatly increased the extraction yield (ranging from ≈ 1 to ≈ 21 %), with respect to the related control. Furthermore, the use of solid CO2 had no negative effects on chemical composition of the olive oil, maintaining the highest quality according to EU legal standards showed by control. Therefore, the utilization of solid CO2 as cryogen could be an appropriate technology to improve olive oil yield and quality and increase its shelf-life.
INTRODUCTION
In recent years, the Mediterranean diet has become increasingly popular, gaining widespread attention among the nutrition and research communities (1-2) and their unreplaceable element in this dietary style is extra virgin olive oil (EVOO). For these reasons, extra-virgin olive oil (EVOO) is characterized as one of the highest economic values for vegetable oils, being the main dietary fat in the Mediterranean countries (3-6)
One of the most important industrial handicaps of VOO and EVOO production is the low efficiency of current extraction techniques (7). Nowadays, several studies have pointed out the importance of the different virgin olive oil processing stages on the extraction yield as well as the minor composition found in the final product and the most used solution in oil mil for improve extraction is increase malaxation time and/or temperature (3,7-8).
Although the important research effort devoted to find innovative mild techniques to enhance VOO and EVOO production (7,9-11), at industrial level the entire virgin olive oil (VOO) process has changed very little over the last twenty years (3).
The addition o ...
