Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), José Antonio Novais 10, 28040 Madrid, Spain.
Institute of Food Science, Technology and Nutrition (ICTAN-CSIC), José Antonio Novais 10, 28040 Madrid, Spain.
Food Res Int. 2017 Oct;100(Pt 1):541-550. doi: 10.1016/j.foodres.2017.07.052. Epub 2017 Jul 24.
The effect of two-step and five-step acetone washing of soybean lecithin (SL) on compositional properties of partially purified phosphatidylcholines (PW2 and PW5) was studied. Trace amounts of protein were detected in SL, PW2 and PW5, with a predominance of glutamic acid and aspartic acid. Increasing the number of acetone washing steps significantly reduced the total content of γ-, δ- and α-tocopherol. Similar reductions (≈90%) of neutral lipids were found in both PW2 and PW5, but the removal of free fatty acids was higher in PW5 than in PW2 (78% vs. 71%). Linoleic acid was the main constituent in both the neutral lipids and the phospholipid fractions of SL, PW2 and PW5, accounting for around 53-59% of total fatty acids; however, a considerable amount of it was removed by increasing the number of washing steps. All phospholipid classes were mostly concentrated in the first two-step washing of lecithin. Further washing increased the concentration of phosphatidylcholine (PC) in PW5, as compared to PW2. Glycerol-containing liposomes from PW2 and PW5 were produced using two different-intensity sonication procedures (method A: 120W, 5min; method B: 30W, 2min) using a probe-type sonicator (100mL volume suspension). Liposomes of soy lecithin and liposomes of PW5 without glycerol were also obtained by using strong sonication (method A). The liposomal dispersion with the highest purification and the stronger sonication was clearly distinguished from the others, both in particle size and in zeta potential. DSC results showed noticeable interference of glycerol in the membrane structure, but minimal changes in particle size and surface charge.
研究了两步和五步丙酮洗涤大豆卵磷脂（SL）对部分纯化磷脂酰胆碱（PW2 和 PW5）组成特性的影响。SL、PW2 和 PW5 中检测到痕量蛋白质，以谷氨酸和天冬氨酸为主。增加丙酮洗涤步骤的数量会显著降低γ-、δ-和α-生育酚的总含量。在 PW2 和 PW5 中均发现中性脂质相似的降低（≈90%），但 PW5 中游离脂肪酸的去除率高于 PW2（78%对 71%）。亚油酸是 SL、PW2 和 PW5 中中性脂质和磷脂部分的主要成分，占总脂肪酸的 53-59%左右；然而，通过增加洗涤步骤的数量，大量亚油酸被去除。所有磷脂类主要集中在卵磷脂的前两步洗涤中。与 PW2 相比，进一步洗涤增加了 PW5 中磷脂酰胆碱（PC）的浓度。使用探针式超声仪（100mL 体积悬浮液），通过两种不同强度的超声处理程序（方法 A：120W，5min；方法 B：30W，2min），从 PW2 和 PW5 制备含有甘油的脂质体。还通过强烈的超声处理（方法 A）获得了不含甘油的 PW5 脂质体和大豆卵磷脂脂质体。具有最高纯度和更强超声的脂质体分散体在粒径和 ζ 电位方面明显不同于其他分散体。DSC 结果表明，甘油对膜结构有明显的干扰，但粒径和表面电荷的变化最小。
