辐照处理对薏仁米中脂肪酸的影响

Effects of irradiation on fatty acids composition in Coix seed

目的研究辐照剂量、温度和湿度等不同条件对薏仁米中储藏过程脂肪酸组成的影响。方法样品经提取后,经CP-SIL 88毛细管柱(100 m×0.2 mm, 0.25μm)分离,进样量为1μL,流速为6.3 mL/min,由气相色谱检测,采用面积归一化法进行相对定量分析。结果辐照处理会加速薏仁米中不饱和脂肪酸的氧化,且氧化速率和辐照剂量成正比。温度和湿度的都会影响对薏仁米储藏过程中脂肪酸的变化,高温和高湿度会加速薏仁米样品中不饱和脂肪酸的水解酸败,不利于薏仁米的储藏。薏仁米在储藏过程中会产生有害的反式脂肪酸,在辐照剂量大于3kGy,储藏温度大于45℃时,有利于反式脂肪酸C19:1-10t的产生,而辐照处理后样品长时间储藏时,则有利于反式脂肪酸C17:1-10t的产生。结论辐照处理、高湿度、高温都会加速薏仁米中不饱和脂肪酸的氧化,导致不饱和脂肪酸含量降低,产生有害的反式脂肪酸,不利于薏仁米的储藏。

Objective To investigate the effects of irradiation dose, temperature and humidity on fatty acid composition during storage in Coix seed. Methods After extraction, the samples were separated by a CP-SIL 88 capillary column(100 m×0.2 mm, 0.25 μm) with an injection volume of 1 L and the flow rate was 6.3 m L/min. The samples were detected by gas chromatography and the relative quantitative analysis was performed by area normalization method. Results The oxidation of unsaturated fatty acids in Coix seed was accelerated by irradiation treatment, and the oxidation rate was directly proportional to the radiation dose. The changes of fatty acids in the storage process of Coix seed were affected by both temperature and humidity, the hydrolysis and rancidity of unsaturated fatty acids in the samples of Coix seed were accelerated by high temperature and humidity, which were not conducive to the storage of Coix seed. Coix seed could produce harmful trans fatty acids during storage, when the radiation dose was greater than 3 k Gy and the storage temperature was greater than 45 ℃, it was beneficial to the production of trans-fatty acid C19:1-10 t, and when the sample was stored for a long time after irradiation, it was beneficial to the production of trans fatty acid C17:1-10 t. Conclusion Irradiation treatment, high humidity and high temperature will accelerate the oxidation of unsaturated fatty acids in Coix seed, resulting in the decrease of unsaturated fatty acid content and the production of harmful trans fatty acids, which is not conducive to the storage of Coix seed.