Studies on the analysis of triglyceride (TG) by high-performance liquid chromatography (HPLC), the molecular species of TG in naturally occurring fats and oils, and the relationship between TG molecular species and rates of their oxidation were discussed and summarized. In the method of HPLC analysis of TG, partition number (PN) was designated by the following equation : PN=TC (Total carbon number) -2 × DB (Number of double bond). On the other hand, the equation, TCN (theoretical carbon number) =PN (ECN) -Σ13 Ui was also explained. Practical procedure for the calculation of molecular species in TG was indicated as to soybean oil, and then major molecular species of several plant and animal lipids TG were listed in order of major one. On these evaluation, triunsaturated type of TGs could be found among those major species. In the subject of oxidation, it waspointed out that the TG having unsaturated acyl linked at the 2-position of glycerol are more stable towards oxidation than those linked at the 1 (3) -position.
Using tocopherol as a natural antioxidant and citric acid and sodium pentapolyphosphate as synergists, the prevention of heat deterioration of frying oils was investigated. The addition of condensed phosphate, which chelates a trace amount of metal ions, to the refined palm oil containing tocopherol and citric acid caused the oxidative stability of the oil to increase by about twice as much. The synergistic effects o tocopherol, citric acid and sodium pentapolyphosphate in combination were also observed, on other edible fats and oils such as refined hydrogenated rapeseed oil, refined tallow and refined lard. The oxidative stabilities of these oils increased by about 2.0, 3.0, and 1.5 times, respectively, those in the absence of additions.
High performance liquid chromatography (HPLC) using gel permeation column was developed for the quantitative determination of saturated acylglycerols. It was possible to separate acylglycerols into their respective homologs within 20 min using Shim-pack HSG-15 H column (30 cm × 7.9 mm i.d.) under the following conditions : mobile phase, tetrahydrofuran; flow rate, 0.5mL/min; detector, refractive index detector. Mono-, di- and triacylglycerols in saturated acylglycerols were determined simultaneously using hexastearoyldipentaerythritol (HSDP) as the internal standard. This method had excellent reproducibility and was highly accurate. The determination of free glycerol and a relative response factor (RRF) method are also described. The present HPLC method was found quite very useful for the quality and process control of acylglycerol emulsifiers.
The effects of a polymeric stabilizer (Polyvinyl alcohol, PVA) and inorganic electrolytes (NaCl, HCl) on the stability of a liquid-liquid dispersion were studied to determine to what degree these chemicals contribute to dispersion stability. The sedimentation potentials and separation rates of styrene monomer droplets were measured in solutions of various concentrations of polyvinyl alcohol (PVA) and electrolyte so as to estimate dispersion stability. Dispersion stability increased with stabilizer concentration. Stability due to the polymeric stabilizer was enhanced between pH=4 and pH=9 with the addition of an inorganic electrolyte. The degree to which the polymeric stabilizer and electrolyte enhance dispersion stability is discussed on the basis of electric double layer and adsorbed polymeric layer theories.
Solution properties of anionic-amphoteric surfactant mixed system in aqueous solutions were studied in terms of surface tension, pH and pNa values, electric conductivity, heat of dissolution, and relative viscosity. This system was sodium dodecyl sulfate (SDS) -Nα, Nα-dimethyl-Nα-lauroyllysine (DMLL). When the mole fraction of DMLL was about 0.7, the cmc values of SDS mixed with DMLL were minimum and the pH values, heats of micelle formation, relative viscosities, and effective volumes maximum. The degree of ionic dissociation of mixed micelle (α) increased with the addition of amphoteric surfactant (DMLL) to SDS solution. Moreover, the values of α increased with increasing molar ratio of DMLL involved. The electric conductivities of the mixed surfactant solutions were dependent on the molar ratio of DMLL involved. It is considered that these phenomena are caused by hydrophilic interactions between SDS and DMLL molecules in mixed micelles.
The effects of alkyl chain length in a nonionic surfactant of the solution properties of anionic-nonionic mixed surfactant systems are described. The systems studied were sodium dodecyl sulfate (SDS) -alkyl polyoxyethylene ethers (CmPOE2O, m=6, 8, 10, 12, 14, 16, and 18). The degree of ionic dissociation of mixed micelle shows a minimum with an increase in the number of alkyl chains in the nonionic surfactant. As chain length increases, the electrical conductivities of the mixed surfactant solutions decrease, in spite of decreased activation energy for conduction. The radius of mixed micelle with the electric double layer is larger for a nonionic surfactant with longer alkyl chain length than one with short chain length. Two kinds of micelles (anionic surfactant rich and nonionic rich micelles) were found to form more easily with decreasing alkyl chain length in nonionic surfactants. Of particular significance is the fact that in a mixed system consisting of SDS and C6POE20 with extremely short alkyl chains, nonionic surfactant molecules may penetrate into the palisade of an SDS micelle.