Stefania Contento

Malaxing temperature affects volatile and phenol composition as well as other analytical features of virgin olive oil

Three Italian olive varieties (Caroleo, Leccino and Dritta) were processed by centrifugation in the oil mill. The olive paste was kneaded at 20, 25, 30 and 35 °C. The results achieved revealed that the oil content in green volatiles from lipoxygenase pathway (including C 5 and C 6 compounds and especially unsaturated C 6 aldehydes) decreased progressively as the kneading temperature increased, dropping markedly at 35 °C. The content of phenols, o-diphenols and secoiridoids showed an opposite trend, but the temperature of 35 °C was critical also for them, as it was for the majority of the other components, analytical parameters and indices related to quality, typicality and genuineness. In general, an increasing kneading temperatures increased the release of oil constituents from the vegetable tissue. This factor also affected the oil extraction yields. The best overall results were achieved by malaxing the olive paste at 30 °C. In fact, this temperature level led to achieving both pleasant green virgin olive oils and satisfactory oil extraction outputs.

Lipochromes, vitamins, aromas and other components of virgin olive oil are affected by processing technology

Abstract A stone mill-integral decanter (SD) olive processing line was compared with a traditional stone mill-press (SP) line, a discontinuous method, that, if properly used, yields high-quality virgin olive oils. With “difficult olives” (not easy to process), the SD line yielded oils characterised by: (1) higher contents of pleasant volatiles, tocopherols, β-carotene, xanthophylls, chlorophylls, pheophytins and waxes; (2) higher values of the 1,2-diglycerides/1,3-diglycerides ratio, integral colour index and chroma; (3) lower contents of phenols, secoiridoids, unpleasant volatiles, aliphatic alcohols, triterpene alcohols and sterols; and (4) lower values of turbidity, brightness and oxidative stability. With “non-difficult olives” (easy to process), whose paste needed to be fluidised with lukewarm water, the SD line yielded oils showing higher contents of pleasant volatiles and tocopherols, lower contents of unpleasant volatiles and comparable contents of phenols and lipochromes. The content of organophosphorus pesticide residues did not depend on the processing method.

Bioactives and nutraceutical phytochemicals naturally occurring in virgin olive oil. The case study of the Nocellara del Belice Italian olive cultivar

This work reports on the composition and bionutritional value of organic virgin olive oil from the Nocellara del Belice variety, one cultivated in the olive areas of the Sicily region, Italy. Destoned oils obtained by processing olives with a destoning-based procedure were compared with conventional oils. This innovative technique, consisting in removing the stone from fruits prior to processing, strongly enhanced the already high-quality level of the conventional product. An in-depth analytical investigation from 2008 to 2010 showed how this innovative olive extraction process led to an excellent peculiar final product, mainly attributable to the improved biophenol and volatile composition, as well as higher concentrations of the lipophilic and vitamin antioxidants (tocopherols and tocotrienols). It had higher levels of oleocanthal (p-HPEA-EDA), a nutraceutical compound exerting actions against COX1 and COX2 (cycloxygenases). Its head-space aroma displayed new volatile phytomolecules and also had higher levels of green volatiles from the lipoxygenase (LOX)-pathway (one having as precursors the polyunsaturated fatty acids containing a cis–cis-1,4-pentadiene system). Among the other bioactives, we highlight its significant levels of trans-β-carotene and xanthophylls (lutein, violaxanthin, neoxanthin and other carotenoids). Its enhanced nutritional value was also attributable to the increased intensity of valuable tasting notes.

Concentrations of Bioactives and Functional Factors in Destoned Virgin Olive Oil. The Case Study of the Oil from Olivastra di Seggiano Cultivar

Abstract This work reports on the composition and bionutritional value of destoned (vs. whole) virgin olive oil from Olivastra di Seggiano cultivar, one having wild features, which is cultivated in olive areas of Tuscany Region, Italy. Removal of the stone from fruit before processing is an innovative technique that strongly enhanced the already high quality level of this oil variety. There was for this product marked interaction between genetic background and destoning. An in-depth analytical investigation from 2008 to 2010 showed how the innovated olive extraction process led to an improved product standing out for its peculiar features, related mainly to the improved biophenol and volatile composition, as well as to higher concentrations of the lipophilic and vitamin antioxidants (tocopherols and tocotrienols). It had slowly higher levels of oleocanthal ( p-HPEA-EDA ), which was found to be a nutraceutical factor. Its head-space aroma even displayed new volatile phytomolecules and also had higher levels of green volatiles from the LOX-pathway (having as precursors the polyunsaturated fatty acids containing a cis-cis- 1,4-pentadiene system). Among the other bioactives are to be highlighted the significant levels of trans- β-carotene and xanthophylls (lutein, violaxanthin, neoxanthin and other minor carotenoids), whose amount however was not higher with respect to reference oil. Its enhanced bionutritional value was confirmed by the increased intensity of valuable tasting notes, among which stood out the artichoke flavour. Finally it showed higher resistance to autoxidation and longer shelf-life