Determination of Edible Fat Refining by HPLC of Δ 3, 5‐Steradienes

Abstract

Steradienes are formed during fat refining by dehydration of sterols. For their determination a simple cleanup and a specific HPLC method are described. The excess of other lipids is removed by chromatography on a silica gel column using petroleum ether as an eluant. After concentrating, the eluate is separated on a reversed phase column with acetonitrileher!. butylmethyl ether using UV-detection at 235 nm. The conditions are so specific, that virtually only peaks of steradienes appear in the last part of the chromatograms. Their areas are summed up and the total content is calculated by using cholestadicne as external standard. The last peak representing stigmastadiene can be calculated separately as well.

Stigmastadiene and specific extitntion (270 nm) to evaluate the presence of refined oils in virgin olive oil commercialized in Brazil

“…Samples A and B had very high amounts of stigmastadiene. These values are similar to the values described in the literature for refined pomace olive oils (PIIRONEN et al, 2000;GROB;ARTHO;MARIANI, 1992;CERT et al, 1994;SCHULTE, 1994).…”

“…Olive oil samples E, H, and J contained 26.4, 24.9 and 41.7 mg kg -1 , respectively, indicating the presence of refined olive oil, which was expected given that this category of olive oil (a blend of virgin and refined olive oil) (PIIRONEN et al, 2000;GROB;ARTHO;MARIANI, 1992;CERT et al, 1994;SCHULTE, 1994). The extra virgin olive oil samples A, B, G, and I had very high levels of stigmastadiene and very high readings for E 270 (Table 1).…”

“…Neither the typical production of any oil (virgin olive oil or crude vegetable oils) nor long-term storage has been shown to produce measurable amounts of stigmastadiene (PIIRONEN et al, 2000;GROB;ARTHO;MARIANI, 1992;CERT et al, 1994;SCHULTE, 1994).…”

Analytical platforms to assess the authenticity of cocoa butter

“…Thus, the presence of steradienes is a good indicator whether an oil has been processed or is native. The compounds can easily be determined by GLC [83] or by HPLC [84]. Steradiene analysis was applied with success to chocolate to indicate the presence of refined vegetable fats in chocolate [85].…”

Membrane-based simultaneous degumming and deacidification of vegetable oils

“…In addition, all the refining operations subject oils to high temperatures; consequently, quantitative and qualitative changes inevitably take place especially in components responsible of quality. High temperatures seem to be the most harmful parameter, which is responsible of hydrolytic, oxidative, and polymerisation alterations (Cert, Lanzon, Carelli, Albi, & Amelotti, 1994;Schulte, 1995). Structural changes are also related to the heating especially during bleaching (Schulte, 1995) and deodorisation (Cert et al, 1994).…”