The isolation, structure elucidation, biological activities, total synthesis, and biosynthesis of the marine prostanoids such as clavulones, chlorovulones and punaglandins are described. These marine prostanoids have unique structural features and show strong antileukemic activities. Owing to their biosynthetic route which is different from those of the mammalian prostaglandins, the marine prostanoids are recognized as a new series of arachidonic acid cascade.
Soy lysolecithin, an excellent emulsifier for food, has been prepared by pancreatic phospholipase A2-catalyzed hydrolysis of soy lecithin. The emulsion with soy lysolecithin is stable in various conditions, for example high temperature, acidic solution and high salt concentration. Soy lysolecithin is also a good solubilizer. The interaction between soy lysolecithin and protein is very strong.
Silicone oil (SO) greatly increases the thermal oxidative stability of frying oils at high temperature. Our previous paper indicated SO to be concentrated both on the oil-air interface and oil-vessel interface. To clarify the mechanism by which SO on the oil-air interface suppresses the thermal deterioration of frying oil, the following experiments were carried out. 1) The temperature of the air-oil interface was measured by a surface thermometer while heating the frying oil and was usually lower than that of the bulk in the fryer. The difference in temperatures of surface and bulk was considerable in oil with SO than in that without it. It thus appears that SO effectively slows down the convection current of frying oil. 2) Soybean oil, MCT and their mixtures were heated at 180°C and the degree of oil deterioration was estimated in terms of viscosity and carbonyl value in each case. The degree of deterioration was essentially the same for each oil. Same experiment with fish oil, MCT and their mixtures gave basically the same results.
Reactions of geraniol with TBHP in the presence of several metal oxides such as SiO2, TiO2, WO3, and V2O5 were carried out. V2O5 showed the high catalytic activity in epoxidation reactions. Allylic alcohols such as nerol, cinnamyl alcohol, trans, trans-farnesol, 1-hexen-3-ol, 1-octen-3-ol, (-) -carveol, and (±) -trans-p-menth-6-ene-2, 8-diol were also successfully epoxidized. No epoxidation took place on using geranyl acetate, citral, or cinnamyl acetate.
The pyrolysis behavior of sucrose esters of fatty acids having different carbon numbers of acyl group and degrees of esterification was investigated by programmed thermogravimetry (TG). The thermostability of the sucrose esters was also evaluated from the initial temperature of weight reduction in programmed TG and decomposition time from the initial to 5% weight reduction on isothermal TG. 1) In the programmed TG of the sucrose esters, the initial temperature of the weight reduction increased with the number of carbons of the acyl group and decrease in the degree of esterification. Each sucrose ester showed unique pyrolysis behavior. 2) In the isothermal TG, the thermostability of the sucrose monoacyl esters showed no relation to the number of carbons of the acyl group, and thermostability increased in the order of C14<C12<C18<C16. An examination of the thermostability of sucrose esters differing in degree of esterification indicated the monoacyl esters to possess greater thermostability than di- and triacyl esters below 180°C. The triacyl esters, however, showed more thermostability than mono- and diacyl esters above 180°C. However, the thermostability of sucrose penta- and heptaacyl esters was markedly less than that of mono-, di- and triacylesters at any temperature.
Bovine serum albumin hydrolyzates (BSA-H) were prepared by the hydrolysis of BSA with pepsin, trypsin, chymotrypsin, or the combinations of these enzymes. In the presence of BSA-H, linoleic acid was oxidized in an ethanol-phosphate buffer (pH 7.0) system at 60°C in the dark, and the extent of lipid oxidation was measured by the ferric thiocyanate method. The antioxidative activity of BSA-H depended on the degree of hydrolysis but not on the particular enzyme or enzyme combination used. The antioxidative activity of BSA-H, however, was not as strong as ordinary antioxidants such as butylhydroxyanisol, butylhydroxytoluene, α-tocopherol or sodium ascorbate. BSA-H used with each antioxidant considerably enhanced in each case antioxidative activity, thus indicating BSA-H to be a useful synergists. BSA-H prepared with pepsin was separated into several peaks by Sephadex G-25 chromatography, and a particular group, comprised of relatively high molecular weight polypeptides, showed strong synergistic effect with each antioxidant.