Fan Xuetong, Sokorai Kimberly J B
US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038, USA.
J Food Prot. 2002 Nov;65(11):1760-5. doi: 10.4315/0362-028x-65.11.1760.
A study was conducted to investigate the effects of various doses of irradiation on the quality of fresh-cut iceberg lettuce and to determine a suitable maximum dose. Fresh-cut iceberg lettuce packaged in film bags was exposed to 0, 1, 2, 3, and 4 kGy of gamma radiation and stored at 3 degrees C for 14 days. CO2 levels were higher and O2 levels were lower in packages containing irradiated lettuce than in those containing nonirradiated lettuce for most of the storage period. Comparison with nonirradiated lettuce indicated that total ascorbic acid (ascorbic acid plus dehydroascorbic acid) content and firmness were not significantly influenced by irradiation at 1 or 2 kGy. The overall visual appearance was best for lettuce irradiated at 1 or 2 kGy. This improved quality may be related to the high CO2 and low O2 levels observed for the irradiated samples. Electrolyte leakage for lettuce increased with higher radiation doses and was correlated (R2 = 0.99) with a soggy appearance. The leakage for lettuce irradiated at > or = 2 kGy was significantly more extensive than that for nonirradiated lettuce. The irradiation of fresh-cut lettuce in modified atmosphere packages at doses of 1 kGy and perhaps 2 kGy for safety enhancement and quality improvement is feasible.
开展了一项研究，以调查不同剂量辐照对鲜切生菜品质的影响，并确定合适的最大剂量。将包装在薄膜袋中的鲜切生菜暴露于0、1、2、3和4千戈瑞的伽马辐射下，并在3摄氏度下储存14天。在大部分储存期内，含有辐照生菜的包装中的二氧化碳水平较高，氧气水平较低。与未辐照生菜相比，1或2千戈瑞的辐照对总抗坏血酸（抗坏血酸加脱氢抗坏血酸）含量和硬度没有显著影响。1或2千戈瑞辐照的生菜总体视觉外观最佳。这种品质的改善可能与辐照样品中观察到的高二氧化碳和低氧气水平有关。生菜的电解质渗漏随着辐射剂量的增加而增加，并且与软塌外观相关（R2 = 0.99）。2千戈瑞及以上辐照的生菜的渗漏明显比未辐照生菜更严重。在气调包装中对鲜切生菜进行1千戈瑞甚至2千戈瑞的辐照以提高安全性和改善品质是可行的。
