Analysis of γ-Irradiated Melon, Pumpkin, and Sunflower Seeds by Electron Paramagnetic Resonance Spectroscopy and Gas Chromatography−Mass Spectrometry

• Published in: Journal of agricultural and food chemistry Vol. 54; no. 19; pp. 7159 - 7166
• Main Authors: Sin, Della W. M, Wong, Yiu Chung, Yao, Wai Yin
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 20.09.2006
• Subjects: Biological and medical sciences; Cucurbita - chemistry; Cucurbita - radiation effects; Cucurbitaceae - chemistry; Cucurbitaceae - radiation effects; electron paramagnetic resonance spectroscopy; Electron Spin Resonance Spectroscopy; food composition; Food industries; Food Irradiation; food quality; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; gamma radiation; Gamma Rays; gas chromatography; Gas Chromatography-Mass Spectrometry; General aspects; Helianthus - radiation effects; irradiation dose; mass spectrometry; melon seed; melons; Methods of analysis, processing and quality control, regulation, standards; pumpkin seed; seeds; Seeds - chemistry; Seeds - radiation effects; snack foods; sunflower seed; Sunflower seed; Oilseed; Vegetables; Fruit; Pumpkin; EPR; GC-MS; Gas chromatography; Analysis method; detection of irradiated seeds; Warehousing; Food preservation; Control method; Electron paramagnetic resonance; Detection; Mass spectrometry; Melon; Alkylcyclobutanones; storage influence
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf061349u

Seeds of melon (Citrullus lanatus var. sp.), pumpkin (Cucurbita moschata), and sunflower (Heliantus annus) were γ-irradiated at 1, 3, 5, and 10 kGy and analyzed by electron paramagnetic resonance (EPR) and gas chromatography−mass spectrometry (GC-MS) according to EN1787:2000 and EN1785:2003, respectively. Distinguishable triplet signals due to the presence of induced cellulose radicals were found at 2.0010−2.0047 g in the EPR spectra. The γ-irradiated radiolytic markers of 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) were identified in all irradiated seed samples. Both the free radicals and the alkylcyclobutanones were found to increase with irradiation dose. In general, linear relationships between the amount of radicals and irradiation dosage could be established. Studies at an ambient temperature (20−25 °C) in a humidity-controlled environment showed a complete disappearance of the cellulosic peaks for irradiated samples upon 60 days of storage. Such instability behavior was considered to render the usefulness of using EPR alone in the determination of irradiated seed samples. On the other hand, 2-DCB and 2-TCB were also found to decompose rapidly (>85% loss after 120 days of storage), but the radiolytic markers remained quantifiable after 120 days of postirradiation storage. These results suggest that GC-MS is a versatile and complimentary technique for the confirmation of irradiation treatment to seeds. Keywords: Alkylcyclobutanones; detection of irradiated seeds; EPR; GC-MS; storage influence