New olive fruit processing method involving stone removal and dehydration: towards obtaining highly valuable products with zero waste generation

OLMO-GARCÍA, LUCÍA; MONASTERIO, ROMINA P.; SANCHEZ- ARÉVALO, CARMEN MARÍA; NZOBOUH-FOSSI, P.A.; FERNÁNDEZ-GUTIÉRREZ, ALBERTO; OLMO-PEINADO, JOSÉ MARÍA; CARRASCO-PANCORBO, ALEGRÍA

Granada

Otro; XVI Reunión del Grupo Regional Andaluz de la Sociedad Española de Química Analítica (GRASEQA 2018); 2018

Sociedad Española de Química Analítica

Virgin olive oil (VOO) is still produced using, essentially, the same principle implemented by Romans, which involves huge simultaneous waste generation (mainly olive pomace and mill wastewater). Over the last decades, the interest in looking for a cost-efficient, technically feasible and environmentally sound solution for the residues generated from olive oil industry has considerably increased. One of the innovative proposed strategies consists on performing a stone removal treatment from clean olives, followed by a dehydration process and a cold press. This procedure drives to two products: 1) an olive oil with numerous potential uses which could certainly meet the increasing demand for high-quality oils (with a very high content of bioactive compounds); and 2) a pulp pellet that can be converted into ?olive flour? by grinding and which is expected to contain high levels of fiber and bioactive compounds, fulfilling the criteria to act as a potential ingredient in functional food. Carrying out the chemical characterization of both products is essential to estimate its industrial viability and to check the advantages that the novel processing method could bring to the VOO industry.Thus, the main objective of the present work has been to accomplish the comprehensive qualitative and quantitative characterization of olive oil and olive flour from 15 different cultivars obtained by means of the described methodology (performing the dehydration step at four different temperatures: 35, 55, 75 and 100 ºC). To this end, a total of 75 olive oil samples (including ?conventional? VOOs to facilitate the comparison with the new ones) and 60 olive flour samples have been analyzed by applying a powerful LC-MS method capable of determining a wide number of molecules belonging to different chemical classes (phenolic compounds, pentacyclic trirterpenes and tocopherols) within the same run. Quinic acid, elenolic acid and its glucoside, luteolin, some isomers of oleuropein and ligstroside aglycones, decarboxymethyl oleuropein aglycone, three triterpenic acids (maslinic, betulinic and oleanolic) and three tocopherols (a, b and g-tocopherols) were detected, in general, in all the studied matrices; logically qualitative differences among the three kind of samples under study were pointed out too. In a further stage of the project, the quantitative data were studied (i) to compare the overall quantitative composition of the different matrices and (ii) to evaluate the influence of the dehydration temperature on the composition of the obtained oils and flours.