Sanyal Bhaskar, Sajilata M G, Chatterjee Suchandra, Singhal Rekha S, Variyar Prasad S, Kamat M Y, Sharma Arun
Food Technology Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.
J Agric Food Chem. 2008 Oct 8;56(19):8987-91. doi: 10.1021/jf8016089. Epub 2008 Sep 4.
Cashew nut samples were irradiated at gamma-radiation doses of 0.25, 0.5, 0.75, and 1 kGy, the permissible dose range for insect disinfestation of food commodities. A weak and short-lived triplet (g = 2.004 and hfcc = 30 G) along with an anisotropic signal (g perpendicular = 2.0069 and g parallel = 2.000) were produced immediately after irradiation. These signals were assigned to that of cellulose and CO 2 (-) radicals. However, the irradiated samples showed a dose-dependent increase of the central line (g = 2.0045 +/- 0.0002). The nature of the free radicals formed during conventional processing such as thermal treatment was investigated and showed an increase in intensity of the central line (g = 2.0045) similar to that of irradiation. Characteristics of the free radicals were studied by their relaxation and thermal behaviors. The present work explores the possibility to identify irradiated cashew nuts from nonirradiated ones by the thermal behaviors of the radicals beyond the period, when the characteristic electron paramagnetic resonance spectral lines of the cellulose free radicals have essentially disappeared. In addition, this study for the first time reports that relaxation behavior of the radicals could be a useful tool to distinguish between roasted and irradiated cashew nuts.
腰果样品在0.25、0.5、0.75和1千戈瑞的伽马辐射剂量下进行辐照，这是食品商品昆虫除害的允许剂量范围。辐照后立即产生了一个微弱且短暂的三重态（g = 2.004，超精细耦合常数hfcc = 30高斯）以及一个各向异性信号（垂直g值 = 2.0069，平行g值 = 2.000）。这些信号被归因于纤维素和CO₂⁻自由基的信号。然而，辐照后的样品显示中心线（g = 2.0045 ± 0.0002）呈剂量依赖性增加。对常规加工（如热处理）过程中形成的自由基的性质进行了研究，结果表明中心线（g = 2.0045）的强度增加，与辐照后的情况类似。通过自由基的弛豫和热行为研究了其特性。本研究探讨了在纤维素自由基的特征电子顺磁共振谱线基本消失后的这段时间之外，通过自由基的热行为来区分辐照腰果和未辐照腰果的可能性。此外，本研究首次报道自由基的弛豫行为可能是区分烘焙腰果和辐照腰果的有用工具。
