Vc@SeNPs抗氧化活性评价及其对鲜切苹果品质的影响

Evaluation of antioxidant activity of Vc@SeNPs and its effect on thequality of fresh-cut apples

为开发既能补充人体微量元素硒,又能保持鲜切苹果优良品质的果蔬保鲜剂,以抗坏血酸(Vc)还原亚硒酸钠制得Vc修饰纳米硒(Vc modified nano selenium,Vc@SeNPs),采用紫外-可见光谱、傅里叶变换红外光谱、透射电镜对其进行表征,通过体外抗氧化指标,及鲜切苹果褐变、失重率、平均散失率和总酚含量的测定,初步评价Vc@SeNPs对鲜切苹果品质的影响。结果表明,Vc@SeNPs分散均匀,呈球形形貌,平均粒径为64.80 nm;具有较好的清除羟自由基(·OH),超氧阴离子自由基(O2^-·),1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基的能力;其IC50分别为0.10、0.24和0.50 mg/mL,且还原力强于Vc。在保持鲜切苹果感官价值及品质方面,Vc@SeNPs效果优于Vc。其中10 g/L Vc@SeNPs对延缓鲜切苹果褐变的效果最佳,50 g/L Vc@SeNPs能有效防止鲜切苹果多酚氧化,降低水分散失,而蒸馏水组褐变迅速,水分大量散失,多酚严重氧化。因此,Vc@SeNPs有望成为新型果蔬保鲜剂。

The objective of this work was to develop fruit and vegetable preservatives that can supplement human selenium nutrients and maintain the excellent quality of fresh-cut apples.Firstly,ascorbic acid(Vc)was used as the reducing agent and surface modifier in the formation of Vc modified nano-selenium(Vc@SeNPs).Then,the morphology and chemical composition of the nanoparticles was characterized using UV-Vis,Fourier transform infrared spectroscopy(FT-IR),and transmission electron microscope(TEM).Subsequently,the antioxidant capacity of Vc@SeNPs was evaluated by in vitro free radical scavenging indicators,and the effect of Vc@SeNPs on the quality of fresh-cut apples at room temperature(25℃)was also examined.The results showed that Vc@SeNPs has uniformly dispersed with spherical morphology and an average particle size of 64.80 nm.The antioxidant results showed that Vc@SeNPs has antioxidant activity.The IC50 of hydroxyl,superoxide and DPPH free radicals scavenging ability is 0.10,0.24,and 0.50 mg/mL,respectively.Moreover,the reducing power of Vc@SeNPs is stronger than Vc.In maintaining the sensory value and quality of fresh-cut apples,Vc@SeNPs treatment is better than Vc.10 g/L Vc@SeNPs has the best effect on delaying the browning of fresh-cut apples;50 g/L Vc@SeNPs could effectively prevent the oxidation of polyphenols and reduce the water loss in fresh-cut apples.However,in the distilled water group,fresh-cut apples browned rapidly with a large amount of water loss and severe polyphenols oxidation.Hence,Vc@SeNPs is expected to be a new fruit and vegetable preservative.