Yoichiro Totani

Preparation of polyunsaturated phospholipids by lipase-catalyzed transesterification

AbstractTransesterifications were investigated to determine a means for preparing polyunsaturated phospholipids simply from soy phospholipid, sardine oil, and two kinds of microbial lipases originating fromCandida cylindracea andRhizopus delemar.The optimum reaction conditions forCandida cylindracea lipase were: 4 g of sardine oil, 10 mL of water, 0.7 g of lipase, 10 mL of hexane, 48 hr of reaction time at 37°C for 3 g of soy phospholipid, for which the transesterification ratio reached approximately 45%. Recovery of phospholipid was low, because hydrolysis also occurred under these reaction conditions. However, hydrolysis could be suppressed by using glycerine instead of water, and the recovery of phospholipid increased to 47%, although the transesterification ratio was reduced to 32%. Rhizopus delemar lipase has 1,3-specificity for triglycerides, and the transesterification ratio was approximately 37% in the 1-position of phospholipid. The resulting phospholipid was rich in polyunsaturated fatty acids and linoleic acid, while the total percentage of polyunsaturated fatty acids incorporated was 18.4%. Therefore, polyunsaturated phospholipids can be prepared easily by transesterification of soy phospholipid with fish oil by means of commercial lipases.

Increased levels of lipid peroxides in aged rat brain as revealed by direct assay of peroxide values

Lipid peroxide concentrations in brain tissues of young and aged rats were determined by a direct method for measuring peroxide values. Three different brain regions were analyzed for lipid peroxides. The peroxide levels increased in all three regions of aged as compared to those of young rats, while lipid peroxides in plasma appeared to be stable along with age. Lipid peroxides in cerebrum and cerebellum increased 1.6-2.0 times in aged brains compared with young ones, and about 3-fold in the brain stem. Increased levels of lipid peroxides in aged brains seem not merely due to increased pools of precursor polyene fatty acids, but rather due to altered protection systems for lipid peroxidase formation.

A highly sensitive method for the micro-determination of lipid hydroperoxides by potentiometry

A modified method for peroxide value (POV) determination of lipids was developed through the application of potentiometry to conventional POV tests such as the official method of the Japan Oil Chemists’ Society (JOCS). The new method permits a simple and reliable determination of low hydroperoxide levels in the initial stages of lipid autoxidation when only very small amounts of sample are available, even when those levels are measured on less than 10 mg of lipid. Using the present method, hydroperoxide levels as low as 20 nanoequivalents (neq) were determined with reasonable precision. This method is applicable to all lipids tested including oils and fats, free fatty acids, phospholipids, glycolipids and cholesterol esters.

Quantitative analysis of cyclopentadiene compounds

Abstract and SummaryA quantitative color reaction of cyclopentadiene was examined when cyclopentadiene was contained in a mixture of benzene, 1,3-cyclohexadiene, cyclohexene, cyclohexane, cyclopentene, or cyclopentane. It was found that cyclopentadiene could be determined in the following manner. A sample was weighed to 1.38 x 10-5 mole in a test tube, while a mixture of 10 ml ethyl alcohol plus 4 ml sulfuric acid was cooled in an ice bath. The mixture was poured into the test tube and the tube was heated in a water bath at 95 C for 30 sec followed by immediate cooling. Then the absorbance at 580 nm was measured and the content of cyclopentadiene was calculated with a calibration curve. The color reaction was tested with ethyl linoleate cyclic monomer (11 cm), ethyl linolenate cyclic monomer (mem), and photoisomerized tung oil fatty acid ethyl ester cyclic monomer (βcm), which were prepared from each purified fatty acid or from photo-isomerized tung oil by cyclization with sodium hydroxide. It was found that cyclopentadiene compounds were formed from ethyl linolenate, but not from ethyl linoleate or from β-eleostearate, which was a main component of photo-isomerized tung oil.

Tetrabutyrate on the Autoxidation of Oils and Fats

脂肪酸エステルの自動酸化に対するB2酪酸エステル添加の影響について究明した。(1) 魚油またはアマニ油脂肪酸メチルエステルに, 1.4×10-3mole/kgまたは1.4×10-2mole/kg添加した場合においては, 過酸化物生成最高値は添加しないものに比べて低下した。(2) 自動酸化させて, ある程度の過酸化物をもった脂肪酸エステルに, 1.4×10-3mole/kg, 1.4×10-2mole/kg, 1.4×10-1mole/kg程度添加した場合は, 添加量に比例して過酸化物価の低下が見られた。(3) 自動酸化した脂肪酸エステルはその有する活性な酸素によって, B2酪酸エステルを酸化分解させると同時に, 自身も分解するものと考察する。

Studies on the Lipid in Skin and Liver of Seborrhea-ratst

白ネズミにオレイルオレエート, スクアレン, スクアランを, 10%または15%基礎飼料に混合投与してセボレアを発生させた。1) オレイルオレエートを与えてセボレアを発生した白ネズミの表皮エーテル抽出物 (皮下脂肪をも含む), 肝臓エーテル抽出物について, 化学的性状測定, TLC, IR, GLC分析を行なったところオレイルオレエートの存在を確認した。とくに, 上記エーテル抽出物のメタノール不溶部にオレイルオレエートが良く分離される。2) オレイルオレエートを与えてセボレアを発生した白ネズミに対して, その投与を中止しエチルリノレート投与にかえて飼育したところ, 次第にセボレア症状を回復した。セボレアは体組織に悪い影響を与えず, 代謝が不良であることによるものと推察される。3) スクアレンを与えてセポレアを発生した白ネズミの体表面から分泌したエーテル抽出物には, スクアレンが含まれることが認められた。4) スクアランを与えてセボレアを発生した白ネズミに対してその投与を中止し, 市販の固型飼料に切換えたところ, セボレア症状の回復をみた。

Oxidative Deterioration of Commercial Foods Containing Oils and Fats

市販の油脂含有食品として即席ラーメン (31種), ポテトチップス (14種), 揚げせんべい (14種), バターピーナッツ (10種), クラッカー (15種), ドーナッツ (10種), かりん糖 (6種), 計100種について, その酸化変性の状態を調べた。試料から抽出した油脂の過酸化物価, ヨウ素価, 酸価を測定した結果を総合して考察すると下記のようである。(1) 過酸化物価についてみると, 100種中30meq/kg以下のもの91種, 30.1meq/kg以上のものはバターピーナッツに多く (10種中7種), その最高は95.7meq/kgであった。(2) 酸価は0.1～3.4の間にあり, 1.0以下のもの59種, 2.0以下のもの82種であり, 揚げせんべいとドーナッツに高いものが多かった。(3) 今回の各試料の過酸化物価, 他の報告にみられる試料の過酸化物価, 既報の白ネズミによる動物実験の結果を総合して考察し, 油脂含有食品中の油脂の過酸化物価は30meq/kgあたりにその限度をおくのが適当であろうとも考える。