Oufedjikh H, Mahrouz M, Amiot M J, Lacroix M
Faculty of Science Semlalia, Department of Chemistry, B.P. S 15, Marrakech, Morroco.
J Agric Food Chem. 2000 Feb;48(2):559-65. doi: 10.1021/jf9902402.
The influence of gamma-irradiation on the content of phenolic compounds was evaluated on Moroccan Citrus fruits (Citrus clementina Hort. ex. Tanaka) treated at a mean dose of 0.3 kGy and stored for 49 days at 3 degrees C. The results show that irradiation has enhanced the synthesis of total phenolic compounds and is correlated with phenylalanine ammonia-lyase activity (PAL) during storage. Accumulation of phenolic compounds in cells is demonstrated and may be explained by the enhancement of PAL activity. HPLC/UV (diode array detector) analysis demonstrated that hesperidin was the major flavanone and nobiletin and heptamethoxyflavone were the major polymethoxylated flavones. Hesperidin is also the major phenolic compound in clementines. Irradiation stimulates the biosynthesis of hesperidin after 14 days of storage, corresponding to the maximum of PAL activity. p-Coumaric acid was also identified, and its content was particularly high in irradiated fruits after 49 days of storage. Accumulation of flavonoids and p-coumaric acid could be related to a better resistance. The percentage of losses due to peel injury "pitting" during storage was between 1 and 5% after 49 days of storage. The connections between irradiation, enzyme activity, phenolic content, and peel injury are briefly discussed.
对平均剂量为0.3千戈瑞处理并在3摄氏度下储存49天的摩洛哥柑橘类水果（克莱门氏小柑橘，学名：Citrus clementina Hort. ex. Tanaka），评估了γ辐射对酚类化合物含量的影响。结果表明，辐射增强了总酚类化合物的合成，且与储存期间的苯丙氨酸解氨酶（PAL）活性相关。细胞中酚类化合物的积累得到证实，这可能是由于PAL活性增强所致。高效液相色谱/紫外（二极管阵列检测器）分析表明，橙皮苷是主要的黄烷酮，川陈皮素和七甲氧基黄酮是主要的多甲氧基黄酮。橙皮苷也是克莱门氏小柑橘中的主要酚类化合物。储存14天后，辐射刺激了橙皮苷的生物合成，这与PAL活性的最大值相对应。对香豆酸也被鉴定出来，在储存49天后，其在辐照水果中的含量特别高。黄酮类化合物和对香豆酸的积累可能与更好的抗性有关。储存49天后，因果皮损伤“麻点”造成的损失百分比在1%至5%之间。简要讨论了辐射、酶活性、酚类含量和果皮损伤之间的联系。
