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请不要在线翻译，谢谢~ 1.Oxidative Stability Index The OSI of the vegetable oils, fish oil, oil blends, SLs with added tocopherols and their controls are given in Table 3. Coconut oil had the highest oxidative stability in comparison to the other oils. This is due to the high content of saturated fatty acids in coconut oil, leading to a high resistance to oxidation. On the other hand, fish oil had the lowest OSI value (0.2 h at 110 C), and therefore the lowest resistance to oxidative deterioration. The low OSI value of fish oil is attributed to its high-unsaturated fatty acids content, especially the LCPUFAs. Although safflower and soybean oils, which contain high amounts of monounsaturated fatty acids (MUFAs) had lower OSI values than coconut oil, they also had better oxidative stability than fish oil (Table 3). The enzymatic interesterification reaction appeared to increase the susceptibility of the SLs to oxidation, as the OSI values of S1 and SFO decreased significantly from that of B1 and BFO (Table 3). Factors such as loss of tocopherols and phospholipids during the short-path distillation process might be associated with the low stability of S1 and SFO samples. However, the addition of tocopherols as an antioxidant to the SLs positively affected their oxidative stability. The OSI values of SIV and SFOV were significantly higher than those of S1and SFO (Table 3). Although antioxidant addition increased the oxidative stability of the SLs (Table 3), the presence of LCPUFAs also had an impact on the OSI values of these SLs, irrespective of their tocopherol content. The results in Table 3 show that the OSI values of SIV and SFOV at 110 C are more comparable to those of B1 and BFO, unlike the values of S1 and SFO at the same OSI temperature. 2.P-Anisidine Value The p-anisidine assay is used to quantify the carbonyl compounds present in oils as a means to determine the past history of the oil . The vegetable oils had very low PAV(Fig. 2), unlike fish oil, which had an initial P-AV greater than 1.0/g, and about 95% increase in this index after 72 h oxidation at 60 C. The oil blends both showed a P-AV less than 0.2 after 72 h of oxidation (Fig. 2). The high P-AV of fish oils is attributed to a high rate of secondary oxidation products formation, unlike in the vegetable oils and oil blends. Tocopherol addition as an antioxidant had a positive effect on the P-AV of the SLs throughout the accelerated oxidation period. Comparison of S1V and SFOV to B1, BFO, S1, and SFO shows that the tocopherol-fortified oils had lower P-AV (Fig. 2). This is expected due to the low formation of hydroperoxides in these fortified SLs. Since the peroxides have to be present before subsequent breakdown to secondary oxidation products, it follows that low hydroperoxide formation increased the oxidative stability of these oils. The SLs with added tocopherols had P-AV that are comparable to their respective starting oil blends. S1 and SFO on the other hand, had P-AV at 24 h that are comparable to P-AV values of the oil blends at 72 h of accelerated oxidation (Fig. 2). Fish oil, S1 and SFO had higher P-AV than other samples, which suggests low oxidative stability of these oils with respect to the other oils. |
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momo198548(金币+80, 翻译EPI+1): 非常感谢，很好很强大！ 2011-11-04 15:18:52
爱与雨下(金币+5): 2011-11-05 07:54:05
sltmac(金币+10): 2011-11-09 10:14:53
sltmac(金币+10): 2011-11-09 10:14:57
sltmac: 欢迎常来 2011-11-09 10:15:01
momo198548(金币+80, 翻译EPI+1): 非常感谢，很好很强大！ 2011-11-04 15:18:52
爱与雨下(金币+5): 2011-11-05 07:54:05
sltmac(金币+10): 2011-11-09 10:14:53
sltmac(金币+10): 2011-11-09 10:14:57
sltmac: 欢迎常来 2011-11-09 10:15:01
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1. 抗氧化稳定指数 蔬菜油、鱼油、油混合物、加入生育酚的SLs及其控制值见表3中的开放式系统互联参考模型（OSI）。相比其他油，椰子油的抗氧稳定性最高。椰子油中含有大量的饱和脂肪酸，因此有高抗氧化性。另外，鱼油的OSI值最低（110C,0.2h），因此其抗氧化性最低。鱼油的较低的OSI值要归因于它的不饱和脂肪酸含量高。虽然含有大量单一不饱和脂肪酸的红花油和大豆油的OSI值比椰子油的OSI值低，但他们的氧化稳定性仍然要高于鱼油（见表3）。 值得注意的是，随着OSI值从B1和BFO下降到S1和SFO，酶酯交换反应好像增加了SLs对氧化的敏感性（见表3）。短程蒸馏过程中，生育酚和磷脂的损失可能与S1和SFO样品的稳定性低有关。然而，增加的生育酚作为SLs的抗氧化剂必定会影响其氧化稳定性。SIV和SFOV的OSI值要远高于S1和SFO的OSI值（见表3）。虽然抗氧化剂添加剂增加了SLs的氧化稳定性（见表3），即使不考虑生育酚的含量，不饱和脂肪酸的存在仍然对这些SLs的OSI值有重要影响。表3结果显示，与相同温度下，S1和SFO的OSI值相比，SIV和SFOV在110C下的OSI值与B1和BFO的OSI值更接近。 2. 对氨基苯甲醚值（PAV） 对氨基苯甲醚的含量作为检测油的过去史的一种手段是用来定量现有油的羰基化合物的。不同于鱼油，蔬菜油的PAV非常低（见图表2），初始值大于1.0/g，在60℃氧化72小时后该值增加约95%。油混合物氧化72小时后PAV小于0.2（见图表2）. 不同于蔬菜油和混合油，鱼油的高PAV值是由于形成高比率的次级氧化产品，在整个加速氧化时期，生育酚添加剂作为一个抗氧化剂对SLs的PAV值产生积极地影响。比较S1V、SFOV、B1、BFO、S1、和SFO显示加入生育酚的油PAV值更低（见图表2）。这正如预期的是因为在这些强化后的SLs中形成的氢过氧化物低的缘故。因为过氧化物必须在接下来的衰减产生的次级氧化产品之前出现，于是乎低氢过氧化物的形成增加了这些油的稳定性。加入生育酚的SLs的PAV值与其各自起始油混合物的PAV值相当。另一方面，S1和SFO在24小时的PAV值与混合油在72小时加速氧化后的PAV值相当（见图表2）。鱼油、S1和SFO的PAV值高于其他样品的PAV值，这说明相对于其他油，这些油的抗氧化性更低。 |
2楼2011-11-04 14:25:47
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