Determination of Stigmastadien Content Analysis

Thermal treatments applied during the refining processes of vegetable oils can cause the formation of significant amounts of hydrocarbons. Of the resulting hydrocarbons, stigmata-3,5-diene, a steroidal compound derived from b-sitosterol by dehydration, is the most abundant.

The process of determining the stigmatadiene content helps to identify heat-treated oils and detect small amounts of refined oil. The procedure for determining the stigmatadiene content in vegetable oils involves the isolation of the unsaponifiable matter in the oil and its fractionation on a column of silica gel.

Pressure in extra virgin olive oil. and no measurable amounts of stigmatadiene are produced in centrifugation processes. It may occur in amounts of 0.01 mg/kg. Due to the high temperatures applied in raw olive residue oils or drying of raw olive residues, around 0.2 – 3 mg/kg stigmastadien may be formed.

Often during refining processes, high temperatures are applied during the bleaching and deodorization stages and stigmatadiene may form. During these processes, stigmastadien can be measured between 1-29 mg/kg in commercial refined vegetable oils, although it varies depending on the conditions.