Maria Luisa Scarpati

Microcomponents of olive oil—III. Glucosides of 2(3,4-dihydroxy-phenyl)ethanol

Abstract The molecular structure of the microcomponents of olive fruit was investigated in order to evidence new molecules which could be transferred to the resulting oil and therefore be typical of olive oil. The three glucosides of 2(3,4-dihydroxy-phenyl)ethanol, 1 , 2 and 3 were isolated together with other glucosides previously identified in Olea europaea . Glucosides 1–3 were detected in the olive oil, there being always present a small quantity of water as an emulsion, together with the aglycone, the 2(3,4-dihydroxy-phenyl)ethanol. The presence of glucosides 1–3 is closely linked with the organoleptic characteristics and to the recognized antioxidant properties of olive oil..

Isolation of cornoside from olea europaea and its transformation into halleridone

Abstract Olea europaea contains, besides oleuropein, demethyloleuropein, verbascoside and ligstroside, cornoside which can be easily transformed into halleridone.

Olea europaea chemicals repellent toDacus oleae females

The egg dispersion strategy of the olive fruit flyDacus oleae, which is dependent on chemicals from the fruit, was investigated. In particular, the exact role ofo-diphenolic compounds, such as the typical olive glucosides, oleuropein and demethyloleuropein, and their derivatives was clarified. It appears that the strong chemotactile repulsive effect exerted by the water fraction of crushed olives is due mainly to (E)-2-hexenal. Several compounds, such asβ-3,4-dihydroxyphenylethanol and other oleuropein derivatives, which exert a strong chemotactile repulsion, were newly identified or confirmed either in fresh olive juice or in olive mill waste water. This result confirms that the small droplets of olive juice, regurgitated just after egg laying by theD. oleae female all around the oviposition hole, actually prevent other females from ovipositing on the same fruit.

Olea europaea Volatiles attractive and repellent to the olive fruit fly (Dacus oleae, Gmelin)

Comparative study of the headspace (HS) composition from olive leaves, olives of varying degrees of ripeness, and crushed olives revealed significant quantitative and qualitative differences. Three different methods were employed to test the effect of the substances identified on the behavior ofDacus oleae gravid females. Attractive/repellent features were tested by presenting the insects with olfactory choices of a water solution of the test chemicals examined, water (blank), and a highly attractive (control) solution of olive maceration water (MW). Toluene and ethylbenzene, present in leaf and half-ripe olive HIS proved attractive, while (E)-2-hexenal emitted by the crushed olives was found to be decidedly repellent. An oviposition stimulation/deterrence test was carried out on olives placed in proximity to test chemicals under examination in water solution, with olives from the same crop serving as control. In the oviposition testα-pinene, mostly emitted by the leaves and half-ripe olives, emerged clearly as an activant,p-xylene, myrcenone, ethylbenzene,n-octane ando-xylene as weak activants. (E)-2-hexenal and hexanal, both emitted by the crushed olives, displayed an oviposition deterrent effect. The highly repellent property of (E)-2-hexenal was again confirmed in this test.

Microcomponents of olive oil. Part II: Digalactosyldiacylglycerols from Olea europaea

Two galactolipids, 1 and 2, were isolated and identified both in olive fruits and in olive oil. They are characterized by a low polarity, despite the presence of a diglycosidic unit, giving, in water, micelles. Because of this characteristic, compounds 1 and 2 could be responsible for the stability of the light emulsion typical of freshly produced olive oil. The presence of hydrophilic ortho-diphenolic compounds enhances the antioxidant properties of this oil, particularly in the first period after the production. In addition, the functions present in 1 and 2 are susceptible to hydrolysis and may be easily modified in the alkaline treatment used for the olive oil refining process. For this reason, their presence in olive oil may be a very useful indication of the untreated food product.

Chemiotropic behavior of female olive fly (Bactrocera oleae GMEL.) onOlea europaea L

An interpretation is given of a number of observations on the chemiotropic behavior ofBactrocera oleae in connection with olive maceration water and the flys return to the olive groves after the first summer rains. To this end, the headspace of both maceration water and leaf leaching water, simulating rainfall, were examined. In both cases, the presence of ammonia, which is generally known to attract fruit flies (Diptera, Tephritidae), was detected and, for the first time, in addition to other compounds that are inert for the fly, the presence of styrene was also detected. This aromatic hydrocarbon was found to be a strong attractant. It is shown that both ammonia and styrene are products of the metabolism of microbial flora present on the olive and leaf surface.

Selective Formylation of Diphenols

Abstract An improved procedure for the regioselective formylation of ortho-and para-diphenols is described.

Synthesis of Models Related to Taspine

Abstract The synthesis of diphenylic compounds related to the alkaloid taspine 1 is reported.

The variability of composition of the volatile fraction of olive oil

Aroma of olive oil is a very complex mixture of components. Analysis of head space of a series of virgin olive oil samples indicate a great variability of volatile substances composition in olives and these data probably should be related to the story of olives after collecting.

The recovery of biophenols from wastewaters of olive oil production

In this article, the phenolic composition of wastewaters prepared from different cultivars of Olea europaea have been described. The main aim is the recovery of these compounds for technological utilization.