THESIS
2016
xvii, 96 pages : illustrations (some color) ; 30 cm
Abstract
2-ACBs are uniquely formed when triglycerides-containing food products are exposed to ionizing radiation. Thus, 2-ACBs have been used as marker molecules to identify irradiated food. Most methods to determine 2-ACBs involve mass spectrometric detection after chromatographic separation. The spectrofluorometer is rarely used to determine 2-ACBs because these molecules do not fluoresce. In the first part of this study, we developed an ultra-performance liquid chromatography method with fluorescence detection (UPLC-FLD) to determine 2-ACBs. 2-ACBs were converted into fluorophores after reacting with 1-naphthalenyl hydrazine to facilitate their sensitive and selective detection using a fluorescence detector (FLD). Analysis of 2-ACBs using our developed UPLC–FLD method allows sensitive determ...[
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2-ACBs are uniquely formed when triglycerides-containing food products are exposed to ionizing radiation. Thus, 2-ACBs have been used as marker molecules to identify irradiated food. Most methods to determine 2-ACBs involve mass spectrometric detection after chromatographic separation. The spectrofluorometer is rarely used to determine 2-ACBs because these molecules do not fluoresce. In the first part of this study, we developed an ultra-performance liquid chromatography method with fluorescence detection (UPLC-FLD) to determine 2-ACBs. 2-ACBs were converted into fluorophores after reacting with 1-naphthalenyl hydrazine to facilitate their sensitive and selective detection using a fluorescence detector (FLD). Analysis of 2-ACBs using our developed UPLC–FLD method allows sensitive determination of 2-ACBs at a detection limit of 2 ng 2-ACBs per gram of fat (30 pg/injection), which is significantly lower than that of existing analytical methods. After validation for trueness and precision, the method was applied to γ-irradiated chicken samples to determine their 2-ACB content. Comparative studies employing liquid chromatography–tandem mass spectrometric method revealed no systematic difference between the two methods, thereby demonstrating that the proposed UPLC–FLD method can be suitably used to determine 2-ACBs in irradiated foodstuffs.
In the second part of the study, by using a spectrum of state-of-the-art analytical instruments, we present for the first time that the generation of 2-ACBs was also possible when fatty acids and triglycerides are exposed to a non-ionizing, short-wavelength ultraviolet (UV-C) light source. An irradiation dosage-dependent formation of 2-ACBs was also observed in UV-C irradiated fatty acids, triglycerides, corn oil, and pork samples. With UV-C irradiation becoming an increasingly common food treatment procedure, it is anticipated that the results from this study will alert food scientist and regulatory officials of a potential new source for 2-ACBs.
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