Pomace oil

Part I extraction solvents allowed for all uses according to good manufacturing practice propane, butane, ethyl acetate, ethanol, carbon dioxide, acetone (not for production of olive-pomace oil), nitrous oxide. 

Refined olive oil, including olive pomace oil E 307 a-tocopherol 200 mg F1... 

Ntsorankoua, H., Artaud, J. and Gueree, M. (1994) Triterpene alcohols in virgin olive oil and refined olive pomace oil. Ann. Falsif. Exp. Chim Toxicol., 87, 91—107. 

Olive-residue oil is an oil consisting of a blend of refined olive-pomace oil and virgin olive oils, except for virgin lampante oil. The oil has a free acidity, expressed as oleic acid, of not more than 1.5 g per 100 g and the characteristics correspond to those fixed for this category in Annex I to EC regulation 2568/91 and amendments. The oil is fit for consumption as is (Table 2.2). 

Studies on the chemical structure of olive wax esters have shown that the homologues present in olive-pomace oil are almost entirely esters of oleic acid with long chain alkanol constituting the homologous series C40, C42, C44, C46. Odd-chain esters identified in the oil were esters of oleic acid with C23, C25, C27 alcohols. Gas chromatography and mass spectrometry analysis has shown that each carbon chain of the esters in made up of a single isomer in which the acyl moiety is that of oleic acid (Bianchi el al., 1994). Thus, for example, ester C44 was found to be made up of the couple acid-alcohol Cl8 1 and C26, whereas other possible isomers such as C16 l-C28 were not detected. This is unusual if it is compared with the composition of epicuticular ester fractions of oil seeds for which, in cases studied, each ester chain was composed of several positional isomers of the ester group. 

Table 8.1 Descriptions and definitions of olive oils and olive-pomace oils...

Crude olive-pomace oil Oil obtained by treating olive pomace with solvents, excluding oil obtained by means of re-esterification and mixtures with other types of oil, and having the other characteristics laid down for this category. 

The definition of crude olive-pomace oil has been changed because this type of oil is now not only derived by solvent extraction of the olive pomace but also by physical extraction by means of a second centrifugation of the olive paste. The setting of limits for certain chemical criteria, aliphatic alcohols and wax, to differentiate lampante oil and second centrifugation oil, is currently under consideration. 

The new definitions and categories of olive oil, which are listed in Table 8.3, come into effect on 1 November 2003, with the exception of that for crude olive-pomace oil , which is effective from 1 November 2001. This allows producers time to adjust to the new system. 

Olive oil, virgin and refined, and refined olive-pomace oil... 

In addition to oil, the pulp and epicarp contain a variety of natural components soluble in the oil. As will be seen later, the oil is obtained from the olive by a variety of techniques, always physical, leaving a residue (pomace) that contains up to 8% oil, which is then extracted by solvent (usually hexane) and named pomace oil. 

Because of the behavior of the solvent, solvent-extracted oil contains more minor components at higher levels than those found in physically extracted oil. This provides the basis for designating pomace oil as a commercial product distinct from virgin oil (obtained only by mechanical means) or refined (lower grade) virgin oil mixed with virgin oil (olive oil, Riviera type). 

Olive-pomace oil the oil obtained by solvent extraction of olive-pomace and not including any oil obtained by a reesterification procedure or any mixture with other kinds of oils. (The various categories of olive-pomace oil are described below.)... 

A. Crude olive-pomace oil olive-pomace oil intended for refining to produce a product (as B, below) suitable for human consumption, or intended for technical purposes. 

B. Refined olive-pomace oil the oil obtained from cmde olive-pomace oil by refining methods that do not lead to alterations in the original triglyceride structure. 

C. Olive-pomace oil a blend of refined olive-pomace oil and virgin olive oil (any A, B, or C). In no case may this be called olive oil. ... 

The epicarp contains a number of components of relatively high polarity that are not removed by mechanical extraction and remain in the pomace. Removal of these components along with the oil by solvent extraction of the pomace accounts for the higher unsaponifiable content of olive-pomace oil. 

At the solvent extraction plant, the cake (pomace) containing up to 8% residual oil is dried in a rotary kiln before proceeding to the solvent extraction unit, usually a semicontinuous system (Figure 7). The extracted pomace oil is always refined. Spent cake is used as fuel or is separated into two fractions, the pulp (including skin) and the pit. In addition to use as fuel, the pit is occasionally used to produce fiberboard (23). 

Total Sterol Content. The gas liquid chromatographic method for sterol determination using an internal standard (cholestanol) is used to calculate the absolute (total) sterol content of an oil (68, 69). Gravimetric, enzymatic, colorimetric, and liquid chromatographic methods have also been reported (69). Limits (mg/100 g) are as follows (12) virgin olive oil, refined olive oil, and olive oil (mixture of refined and virgin) >100 crude olive-pomace oil >250 and refined ohve-pomace oil, olive oil and olive-pomace oil (mixture) >180. 

Wax Content. Olive oil fatty acid esters of straight chain alcohols (wax esters present in solvent extracted olive-pomace oil are isolated by column chromatography on silica gel (LC) and quantitated by GLC to determine if olive-pomace oil is present in olive oil (78). LC separation of the wax esters can be replaced with HPLC to automate the separation step and improve rehability and repeatabihty (79). Limits for content of C40 + C42 + C44 + C46 wax esters (mg/kg) are as follows (12) ... 

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