Effect of electron-beam irradiation on cholesterol oxide formation in different ready-to-eat foods

Determination of free cholesterol oxide products in food samples by gas chromatography and accelerated solvent extraction: influence of electron-beam irradiation on cholesterol oxide formation

“…Sample treatment has been described in a previous work; essentially, the e‐beam radiation source operated at 10 MeV and radiation doses absorbed by the samples were 1, 2, 4, 6 and 8 kGy at about 90 kGy min −1 .…”

“…The residue was dissolved in 6 mL of hexane by vortex shaking and the clean‐up was carried out using double cartridges (silica‐amino propyl). The hexane COP extract was passed through a silica cartridge following the procedure given by Lozada‐Castro et al , then, the acetone extract obtained was evaporated and the new residue was resolved in 3 mL of hexane/ethyl acetate (90:10, v/v) and it was passed through an amino propyl cartridge following the procedure given by Petron et al …”

“…COP content has been determined by using different analytical techniques, high‐performance liquid chromatography (HPLC) and gas chromatography (GC) being the most widely employed for the analysis of COPs in food. Although some COPs can be detected by HPLC with ultraviolet detection (UV), their sensitivity is not very high, so GC is preferred because it has higher detection sensitivity, identifications are easier by mass spectrometry (MS) and peak capacity is also higher than for HPLC, although a derivatisation reaction is required. Silylation is often used, Tri‐Sil being a useful reagent.…”

Sample preparation: A critical step in the analysis of cholesterol oxidation products

“…However, the application of direct saponification in more complex matrices may be unsuitable (Busch & King, 2009). Lozada-Castro et al (2011 observed that direct saponification, which was applied on cooked ham, produced emulsions that were difficult to handle.…”

“…Artifacts are COPs that are formed under analytical conditions, either due to cholesterol oxidation or due to the conversion of pre-existing COPs to others (Busch & King, 2009). The best known example is the degradation of 7-keto to cholesta-3,5-dien-7-one in alkaline medium (Lozada-Castro et al, 2011). Some authors in order to limit artifact generation, recommended the use of antioxidants, such as butylated hydroxytoluene (BHT), during sample preparation (Janoszka, 2010;Nam, Du, Jo, & Ahn, 2001).…”