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momo198548

新蟲(chóng) (小有名氣)

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[求助] 求高手文獻(xiàn)翻譯

1.Free Fatty Acid Value
The FFA values were low (<1%) for all samplesthroughout the 72 h accelerated oxidation period at 60 C. There was no significant difference in the FFA content of
safflower and soybean oils during the oxidation period, though coconut oil had the lowest value, and fish oil the highest (Data not shown). The high FFA value of fish oil is due to its higher concentration of polyunsaturated fatty acids, and therefore increased susceptibility to oxidation in comparison to the other oils. The SLs had higher FFA values than their starting materials, with SFO and SFOV having higher values than their counterparts (S1 and S1V) due to their fish oil content. However, the higher initial FFA values (>0.1%) of the SLs in comparison to the vegetable oils and oil blends may have been as a result of increased FFA production during the enzymatic interesterification process. The short-path distillation step resulted
in a 0.3–0.4% residual FFA concentration in the SLs. Similar residual values were reported by Nielsen et al. where about 0.3% FFA remained after the distillation
process.
2.Peroxide Value
The PV of the oils are presented in Fig. 1. Coconut oil had the lowest initial (<0.1 mequiv/1,000 g) and final (\0.2 mequiv/1,000 g) values (Fig. 1). Coconut oil also
had the lowest increase in PV throughout the accelerated oxidation period, which is due to its lower unsaturated fatty acid content in contrast to the other oils. The initial PV of fish oil was about 50% higher than that of the other oils. High initial PV value signifies a high production of primary oxidation products, which leads to faster progression of oxidation. Fish oil had the highest increase in PV because of high LCPUFAs and low antioxidant contents (Fig. 1). The SLs had a lower initial PV in comparison to the oil blends. This may be as a result of the enzyme reaction
process, which increased the saturation of the lipids and also in part to the distillation process, which decreased the FFA, and other volatile contents of the SLs. Akoh and Moussata reported the stabilization of SLs to oxidative deterioration by incorporation of saturated medium chain fatty acid (caprylic). SFO had higher PV than S1 (Fig. 1) throughout the accelerated oxidation period because of its
higher LCPUFAs content in comparison to S1. Comparison of SFO with SFOV shows significantly lower values for the SL with added tocopherol. A similar result was obtained when S1 and S1V were compared, whereby S1V has a lower PV than S1 (Fig. 1). The PV of S1V and SFOV in comparison to that of S1 and SFO shows the effect of tocopherol addition on the oxidative stability of the SLs. The PV were quite similar for the SLs with added tocopherols, irrespective of their LCPUFA content.

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alvarohao

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【答案】應(yīng)助回帖

★ ★
愛(ài)與雨下(金幣+2): 2011-11-04 19:41:31
momo198548(金幣+50, 翻譯EPI+1): 很強(qiáng)大，謝謝 2011-11-06 19:46:16

1. 游離脂肪酸（FFA）值
在整個(gè)60攝氏度72小時(shí)的加速氧化期間，所有樣本的FFA值都比較低（<1%）。紅花油和豆油在氧化期間的FFA含量沒(méi)有顯著的不同，盡管椰子油的含量最低，而魚(yú)油的含量最高（未列出數(shù)據(jù)）。魚(yú)油中的FFA值之所以最高，是因?yàn)楹休^高濃度的多元不飽和脂肪酸，所以相對(duì)于其它油類更容易受到氧化的影響。根據(jù)它們的魚(yú)油含量，SL要比其原材料含有更高的FFA值，SFO和SFOV也高于其相應(yīng)的部分（S1和S1V）。但是，相對(duì)于植物油和調(diào)和油，SL含有較高初始FFA值（>0.1%）的原因很可能是在酶法酯交換過(guò)程中FFA產(chǎn)量增加的結(jié)果。短程蒸餾步驟導(dǎo)致在SL中產(chǎn)生FFA 0.3-0.4%的殘余濃度。Nielsen等報(bào)道過(guò)類似的殘余值，指出在蒸餾過(guò)程之后，大約有0.3%的FFA殘余。
2. 過(guò)氧化值（PV）
圖1顯示了各種油的過(guò)氧化值。椰子油的初值（<0.1 mequiv/1,000 g）和終值（\0.2 mequiv/1,000 g）最低（圖1）。而且在加速氧化時(shí)期，椰子油的PV增量也是最低的，這是因?yàn)樗牟伙柡椭舅岷勘绕渌鸵�。魚(yú)油的初始過(guò)氧化值要比其它油高出約50%。較高的初始過(guò)氧化值意味著初級(jí)氧化產(chǎn)物的產(chǎn)量較高，這將導(dǎo)致氧化進(jìn)程的加快。魚(yú)油之所以擁有最高的PV增量，是因?yàn)楹休^高的長(zhǎng)鏈多不飽和脂肪酸（LCPUFA）和較低的抗氧化劑含量（圖1）。SL的初始過(guò)氧化值低于調(diào)和油的原因是酶反應(yīng)過(guò)程的結(jié)果，酶反應(yīng)會(huì)增加油脂的飽和度，另外部分原因是由于蒸餾過(guò)程，這一過(guò)程會(huì)減小SL中FFA及其它揮發(fā)物的含量。Akoh和Moussata曾報(bào)道，通過(guò)中鏈飽和脂肪酸（羊脂酸）的加入，SL對(duì)氧化變質(zhì)具有一定的穩(wěn)定性。在整個(gè)加速氧化時(shí)期，SFO的過(guò)氧化值要高于S1（圖1），這是因?yàn)�，與S1相比，其長(zhǎng)鏈多不飽和脂肪酸（LCPUFA）的含量較高。將SFO與SFOV比較之后，可以看出添加有生育酚的SL的過(guò)氧化值明顯較低。比較S1和S1V之后，也有相似的結(jié)果，其中S1V的過(guò)氧化值要低于S1的（圖1）。S1V和SFOV的PV與S1和SFO的PV的比較結(jié)果表明了生育酚的添加對(duì)SL氧化穩(wěn)定性的效果。不論它們的LCPUFA含量如何，添加有生育酚的SL具有非常相似的過(guò)氧化值。

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求?創(chuàng)新，勵(lì)志圖?姡?

2樓2011-11-04 18:21:43