常温下MAP对核桃脂肪酸氧化的影响

目的]为核桃的科学贮藏提供技术参考。方法]以甘肃成县产核桃为试材,将带壳核桃分别放入30μm的紫色PVC袋、白色PVC袋和普通40μm聚乙烯塑料袋中进行自发气调贮藏,研究常温贮藏180 d期间核桃脂肪酸氧化的变化。结果]贮藏30 d时,PVC袋中的O2含量最低,CO2含量最高。贮藏期间,核桃的总脂肪含量、碘价均下降,酸价、过氧化值和皂化值均升高。30μm紫色PVC袋可以较好地抑制总脂肪降解。贮藏180 d时,30μm紫色PVC袋贮藏的核桃的酸价、过氧化值和皂化值均低于30μm白色PVC袋和40μm聚乙烯塑料袋,碘价则高于后2种袋。结论]MAP可以较好地抑制核桃脂肪酸氧化,有利于保持核桃的品质,其中30μm紫色PVC袋的贮藏效果最佳。

Effects of Modified Atmosphere Packaging(MAP)on Fatty Acid Oxidation of Walnut at Room-temperature

Objective] The aim was to provide the technical reference for scientific storage of walnuts.Method] Using walnuts produced in Cheng country in Gansu province as tested material,the unshelled walnuts were cased in 30 μm purple PVC bags,30 μm white PVC bags and general 40 μm polyethylene plastic bags,resp.for spontaneous storage at modified atmosphere and the fatty acid oxidation changes of walnuts for 180 d storage at room temperature were studied.Result] When walnut storage was for 30 d,the O2 content in PVC bags was lowest and the CO2 content was highest.During storage,the total fat content,iodine value all declined,and the peroxide value and saponification value all rose.The 30 μm purple PVC bags were effective to inhibit degradation of the total fat.The acid value,peroxide value and saponification value of walnuts cased in 30 μm purple PVC bags were lower than that cased in 30 μm white PVC bags and 40 μm polyethylene plastic bags,but the iodine value was opposite.Conclusion] MAP could inhibit the fatty acid oxidation of walnuts better and was preferable to maintain the quality of walnuts.The effect of storing walnuts cased in 30 μm purple was the best.