The effect of phospholipids on the oxidative decomposition of d-γ-tocopherol (γ-Toc) and the formation of its dimers during the thermal oxidation of trilaurin (Tri-La) and of trilinolein (Tri-Li) was examined. After triglycerides, in which γ-Toc and additives (phospholipids or their model compounds) dissolved, were oxidized with air at 180 for 10 h, residual γ-Toc and formed dimers were determined by HPLC. On the oxidation in Tri-La, little change of γ-Toc consumption was observed and the amount of formed 5- (γ-tocopheroxy) -γ-tocopherol (γ-TED) decreased by the addition of phospholipids (Table-1). When a small amount of phosphatidyl choline was added to Tri-Li, γ-Toc consumption greatly decreased, and a similar effect was observed also by the addition of phosphatidyl ethanolamine (Fig.-1). From this fact, it was assumed that nitrogenous base of phospholipid molecule is independent of the inhibitory effect of phospholipids on the thermal oxidation of γ-Toc. For clarifying the mechanism of the suppresssion of the thermal oxidation of γ-Toc with phospholipids, the following experiments were carried out : the oxidation of γ-Toc in Tri-Li containing tri-n-octylamine (TOA) as a model compound of nitrogenous base, or tri-n-butyl phosphate (TBP) as a model compound of phosphate ester. A large amount of TOA depressed the oxidation, but a small amount has little influence. On the other hand, γ-Toc consumption was remarkably reduced by the addition of a small amount of TBP (Fig.-4). The action of TBP is very similar to that of phospholipids. From the above results, it is considered that the functional group which suppresses the thermal oxidation of γ-Toc in Tri-Li is phosphate ester linkage. The dimers which formed during the thermal oxidation of γ-Toc in the presence of phospholipids were qualitatively the same as those in the absence of phospholipids. The amount of γ-TED increased to some extent, and the amounts of 5- (γ-tocopherol-5-yl) -γ-tocopherol and its atropisomer [γ-TBD (H) and γ-TBD (L)] were not influenced by the addition of phospholipids (Figs.-2 and 3). When TOA or TBP was added to Tri-Li, a little increase of the amount of γ-TED formed was observed, but the change of the amounts of γ-TBD (H) and γ-TBD (L) was less than that of γ-TED (Figs.-5 and 6). All of the examined additives depressed the thermal oxidation of Tri-Li (Fig.-1).
The oxidative decomposition of γ-γ-tocopherol (γ-Toc) and the formation of its dimers during the course of autoxidation of methyl laurate (Me-La) and methyl linoleate (Me-Li) under A.O.M. conditions were investigated. Twenty mililiters of fatty acid methyl esters, in which γ-Toc dissolved in the concentration of 0.5%, were oxidized by blowing in dry air at a flow rate of 2.33 ml/s in a glycerol bath controlled at 97.8 0.2°C. Five oxidation products were obtained from the reaction mixture in Me-Li by the chromatography on a silicic acid column eluted with hexane-diethyl ether mixtures (Fig.-4). Products [I], [II], and [III] were identified as the dimers of γ-Toc by means of UV absorption, IR absorption, NMR, and MS spectroscopy : the former one 5- (γ-tocopheroxy) -γ-tocopherol (γ-TED), and the latter two 5- (γ-tocopherol-5-yl) -γ-tocopherol [γ-TBD (H) and (L)] as the atropisomer each other. These three compounds were also confirmed by TLC and HPLC (Figs.-1 and 3). Products [N] and [V], which were formed especially in Me-Li, were red substances. The oxidative dimerization of γ-Toc during the course of autoxidation in Me-La and in Me-Li was followed by HPLC. The decomposition of γ-Toc was more rapid in Me-Li than in Me-La (Fig.-5). γ-TED was formed more abundantly than γ-TBD, especially in Me-Li (Fig.-6). Each amount of the dimers formed in Me-La reached maximum by the autoxidation for 2 h : on the other hand, that in Me-Li reached maximum by the autoxidation for 5 h (Figs.-6 and 7). The formation of the red substances from the dimers was caused by further oxidation in Me-Li.
In the preceding report, we proposed relative interfacial tension of cyclohexane solution of frying oils and fats as a new index which reflects thermal oxidation of frying oils and fats. In this paper, superiority or inferiority between the relative interfacial tension and several methods proposed previously for the rapid evaluation of deterioration degree of frying oils and fats was discussed. As a result, thiobarbituric acid value and acid value were concluded to be inappropriate indices because of the low correlation with glyceride dimer fraction content (γ=0.252, γ=0.555) and petroleum ether insoluble oxidized fatty acid content (γ=0.333, γ=0.575). Saponification color number showed relatively high correlation with glyceride dimer fraction content (γ=0.705) and petroleum ether insoluble oxidized fatty acid content (γ=0.872). Saponification color number <9.0 and frytest (by E. Merk) <color 3 was correspondent to petroleum ether insoluble oxidized fatty acid content <0.7%. However, one should take account of the fact that the colors of the frying oils and fats themselves exert influence upon saponification color number and frytest to same extent, and the measurement of these indices should be practiced as soon as possible before autoxidation proceed. Relative interfacial tension showed the highest correlation with glyceride dimer fraction content (γ=0.909) among these indices. This index was influenced scarcely by the addition of yolk to the frying oil, similarly to petroleum ether insoluble oxidized fatty acid content. As compared with this, foam spread distance was strongly influenced by the addition of yolk. In conclusion, measurment of relative interfacial tension, saponification color number and frytest should be considerd as an appropriate methods for the rapid evaluation of the formation of injurious products to health by thermal oxidation of frying oils and fats.
Fat components of cacao seeds differing in maturity and variety were investigated, measuring com positions of fatty acids and triglycerides, sterol composition and content, and contents of tocopherols in fats extracted from seeds ranging unripe to overripe, collected from three cultivars of cacao trees. Results obtained as follows : 1) On changes of fatty acid and triglyceride compositions during ripening, until full ripe, C18 and C54 slightly increased while C18 : 2 and C50 slightly decreased. But after that, a reverse tendency were observed. 2) Contents of total sterols and total tocopherols slightly decreased until full ripe. However, after that, they clearly increased, and particularly c-tocopherol content showed a remarkable increase. In sterol composition, from unripe to overripe, it seemed that stigmasterol slightly increased while sitosterol slightly decreased. 3) Fatty acid composition (C16, C18) in SriLanka cultivar, contents of total sterols and total tocopherols in Malaysia cultivar, and sterol composition (campe-, stigma-, sitosterol) in Uganda cultivar were some different from each other two cultivars. 4) Though indices for judgement of purity of cacao butter indicated previously, were changed during ripening, there were little differences of them among fats in full ripe seeds and near ripe ones.
In recent years addition compounds of lower alcohols with ethylene oxide (EO) and/or propylene oxide (PO) have exclusively been investigated and utilized as the principal constituents for a brake fluid in automobiles. In this work, it was attempted to determine the species of alcohols (methanol or ethanol) used as raw materials, the addition number of molecules of EO and PO, and their arrangement (EO-PO or PO-EO) in the block addition compound by mass spectrometry. It was verified by the analysis of the mass spectra that a cleavage of these compounds expressed as the formula -R-O-R-O-R- (R : -CH2-CH2- or -CH2-CH (CH3) -) occurred on the O-R linkage and a positive charge remained on the R fragment. s Based on these results, it was possible to identify the molecular structures by the consecutive procedure as follows. (1) The possible structures are determined by the molecular weight obtained from the mass spectra. (2) The distinction o alcohols, the number of molecules of EO and PO added and their arrangement are determined by the fragment peaks on the mass spectra.
The rheological characteristics for oil-water interfacial films prepared from oil phase consisting of milk fat (MF), monoglycerides (MG), and sorbitan esters (SE) and aqueous phase consisting of caseinate (CA) and water (W), as model protective films, were studied. All the interfacial films exhibited viscoelastic behavior. From the creep compliance-time curves for the oil-water interfacial films a mechanical model can be derived consisting of a unit of Maxwell Model in series with two units of Kelvin-Voigt Model (6 element model). Instantaneous elasticity (E0) and Newtonian viscosity (ηN) of the said films increased as the hydrocarbon chain length of the sorbitan esters (HCL) increased. From comparison of electrophoretic mobility vs HCL curves for O/W emulsions with the rheological characteristics vs HCL curves for the oil-water interfacial films, instantaneous elastic behavior, Newtonian viscous behavior and retarded viscoelastic behavior of the films might be related to HCL under coexistence of (MG+SE+CA), (MG+SE), (SE) respectively at the oil-water interface. Since the rate of oil globule coalescence for the O/W emulsions prepared from oil phase consisting of MF, MG, and SE, and aqueous phase consisting of CA and W decreased linearly as E0 increased, and the rate decreased drastically at the region where ηN was higher than ca. 25 104 surface P, the mechanical strength of those protective films covering oil droplets in O/W emulsions was suggested as being responsible for the stability of the O/W emulsions.
The JIS method for assessing the soil removal efficiency was used in this study in order to complement the Bandle test which is used as a practical method for assessing the efficiency of synthetic detergents for home laundry. In this study, sodium sulfate was used as the balance component in the JIS index detergent combination containing 17% sodium tripolyphosphate, and a comparative study was made on the soil removal efficiency of 6 different types of detergent powders for home laundry prepared by mixing reduced phosphates with substitutes, such as, zeolite and trisodium imidobissulfate (TSIS). As a result it was found that the removal efficiency was definitely lowered when the amount of phosphate was reduced only, however, when the amount of phosphate was substituted by Zeolite, the lowering of the removal efficiency was not so pronounced. When the whole amount of phosphate was replaced by zeolite, the removal efficiency of the detergent was lower than when phosphate alone was used, although the Zeolite containing detergent exhibited some removal ability. When half of the amount of phosphate was replaced by TSIS, the removal efficiency was very near that of JIS index detergent, however, it is thought that confirmation by the Bundle test is necessary.
The experiment on the decomposition of methyl oleate hydroperoxide (OMH) was carried out in methyl oleate, methyl linoleate, methyl laurate, decane, and dodecane. It is assumed that the decomposition of OMH is uni- and bi-molecular decomposition in solvents. The hydrocarbons hastened to decomposition of OMH than methyl esters of fatty acid. It seemed that the each methyl esters made only a few contribution to decomposition of OMH.
Isomerization between nerol and geraniol was accomplished by photoirradiation in the presence of thiols, its rate being accelerated by benzoyl peroxide. The isomerization also proceeds thermally at 75°C in the presence of both thiol and benzoyl peroxide.