Vitamin E (tocopherols and tocotrienols) and γ-oryzanol are two minor constituents of rice bran oil (RBO) and are known to be potential bioactive compounds. The content of γ-oryzanol, a unique antioxidant found only in RBO, is a key factor in determining the retail price of the oil. Limitations of conventional HPLC columns for vitamin E and γ-oryzanol analysis are the alteration of these components and the time-consuming need for pretreatment of samples by saponification. High-performance size exclusion chromatography (HPSEC) equipped with a universal evaporative light scattering detector (ELSD) is a versatile tool for screening optimum mobile phase conditions because components of the sample can be separated and detected in the same run. In this work, the RBO components (triacylglycerol, tocopherols, tocotrienols, and γ-oryzanol) assessed on a single 100-Å Phenogel column using ethyl acetate/isooctane/acetic acid (30:70:0.1, v/v/v) as the mobile phase provided baseline separations (R s >1.5) with a total run time of 20 min. The HPSEC condition was then transferred to determine the content of tocopherols, tocotrienols, and γ-oryzanol in RBO products using a selective PDA detector. The limit of detection (LOD) and limit of quantification (LOQ) of α-tocopherol, α-tocotrienol, and γ-oryzanol were 0.34 and 1.03 μg/mL, 0.26 and 0.79 μg/mL and 2.04 and 6.17 μg/mL, respectively. This method was precise and accurate, with a percentage of relative standard deviation (%RSD) of the retention time of less than 0.21%. The intra-day and inter-day variations were 0.15-5.05% and 0.98-4.29% for vitamin E and γ-oryzanol, respectively. The recoveries of tocopherols, tocotrienols, and γ-oryzanol ranged between 90.75% and 107.98%. Thus, the developed HPSEC-ELSD-PDA method is a powerful analytical tool for determining the vitamin E and γ-oryzanol present in oil samples without requiring any sample pretreatment.
The objective of our study is to evaluate quality and thermo oxidative stability of soybean, palm olein, and canola oils and their blends. The binary blends of SO:POO and CO:POO were formulated in a ratio of 75:25 and ternary blend were prepared by blending CO:POO:SO in a ratio of 35:30:35. To monitor the thermal stability, pure oils and their blends were subjected to heating at 180°C for 4 hours. Heating process led to a substantial increase in free fatty acid (FFA), peroxide value (PV), p-anisidine value (p-AV), and saponification value (SV), while iodine value (IV) and oxidative stability index (OSI) were decreased. The principal component analysis (PCA) was also performed. The data indicated that three significant principal components have eigenvalue ˃ 1, which collectively constitute 98.8% of the total variance. PC1 contributed mainly with a total value of 50.1%, followed by PC2 (36.2%) and PC3 (12.5%). Results of the present study revealed that the binary and ternary blends exhibited greater oxidative stability than the pure oils. But, the ternary blend CO:POO:SO in a ratio of (35:30:35) was found to be better on the basis of stability and health point of view than other blends. Overall, our study demonstrated the utility of chemometric approaches for evaluating the quality and stability of vegetable oils and their blends, which can be helpful in the selection and optimization of oil blends for food applications.
Modifying the surface of nanodiamonds, which have antibacterial properties, with organic molecular chains enables biomolecular adsorption on a single particle layer on the water surface. For organo-modification, long-chain fatty acids act on the terminal hydroxyl groups present on the nanodiamond surface, and cytochrome C protein and trypsin enzyme are used as biomolecules. Cytochrome C and trypsin introduced into the subphase were electrostatically adsorbed onto the unmodified hydrophilic surface of the organo-modified nanodiamond monolayers on the water surface. The ampholyte protein is thought to exhibit Coulomb interactions with the positively charged unmodified nanodiamond surface. The protein adsorption was supported by morphological observations and spectroscopic properties; circular dichroism spectra suggested denaturation of the adsorbed proteins. However, the biopolymers could maintain their second-order structure even under a high-temperature environment, after being slightly denatured and adsorbed to the template. The nanodiamonds form excellent templates for structural retention in the atmosphere while yielding minor denaturation corresponding to the chirality of biomolecules upon adsorption.
Emulsification is an important technology in the field of cosmetics and household products. Emulsions are in non-equilibrium state; therefore, the products vary depending on the preparation process, and their state changes with time. Furthermore, it is known empirically that different types of oils have different emulsification properties (preparation and stability). For these reasons, the variables in emulsification research are numerous and complicated to analyze. As a result, many industrial applications have had to rely on empirical rules. In this study, emulsions with a lamellar liquid crystalline phase as an adsorption layer at the emulsion interface were investigated. The characteristics of O/W emulsions formed with the excess solvent phases (aqueous and oil phases) separated from the lamellar liquid crystalline phase were investigated based on the phase equilibrium of the ternary system.
As a result, it was found that by agitating the aqueous phase containing dispersed vesicles of emulsifier (polyether modified silicone) together with the oil phase, an emulsion with a uniform interfacial membrane of lamellar liquid crystalline phase could be obtained. The emulsions prepared by this method were found to have good stability against coalescence. The process of transformation from vesicles to the uniform liquid crystal interfacial membrane during the emulsification process was clarified by a freeze-fracture transmission electron micrograph and the calculation of interfacial membrane thickness based on precise particle size analysis. Furthermore, the emulsification properties of polyether-modified silicones were clarified using polar oils and silicone oils, which are a combination of high/low and low/high compatibility with hydrophilic (polyethylene glycol) and lipophilic (polydimethylsiloxane) groups of polyether modified silicone, respectively. It is expected that this research will lead to the evolution of various functionalities in products in the fields of cosmetics, household products, food, pharmaceuticals, paint and others.
The adsorption and lubrication of an amino acid-based surfactant at the solid/liquid interface were studied in the presence of calcium ions. The surfactant used here was disodium N-dodecanoylglutamate (C12Glu-2Na). The solid surface used in this study was hydrophobically modified to mimic the hydrophobicity of the skin surface. Quartz crystal microbalance with dissipation monitoring (QCM-D) measurements revealed that the anionic surfactant was adsorbed on the hydrophobically modified solid surface. The replacement of the surfactant solution with CaCl2 aqueous solution resulted in the desorption of the surfactant to some extent; however, a rigid and elastic adsorption film interacting with calcium ions remained on the solid surface. The adsorption film containing calcium ions lowered the kinetic friction coefficient in aqueous media. The insoluble calcium salt of the surfactant, dispersed in the solution phase, also contributed to lubrication. We expect that the usability of personal care products formulated using amino acid-based surfactants is relevant to such adsorption and lubrication properties.
Amino acid surfactants derived from animal/vegetable oils and amino acids have attracted growing interest in surfactant industry. The relationship between the molecular structures of natural building blocks and the performance of the derived surfactants has become a significant subject in their application. A series of serinate surfactants with different characteristic acyls were synthesized. The specific effect of the fatty acyl structures, namely, the hydrocarbon chain length, the number of C=C bonds, and hydroxyl substituent, on the foam properties and interfacial behaviors were revealed. The serinate surfactants with long fatty acyls showed better interfacial activity and were more closely arranged at the interface, thus improving the foam stability. But the long fatty acyls also decreased the water solubility, and lead to the decreased the foamability of N-stearyl serinate surfactant. The C=C bonds in the fatty acyl improved the water solubility of the surfactants. But multiple cis C=C bonds caused the bend of hydrocarbon chains, which was unfavorable for the close arrangement of surfactant molecules, thus leading to the decrease of the foam stability. The hydroxyl group in the ricinoleoyl decreased the intermolecular van der Waals interactions and hindered the close arrangement of ricinoleoyl serinate surfactant molecules, leading to the decrease of the foam stability.
The aim of this study was to present a facile protocol for preparation of both enantiomerically pure forms of (Z)-1,5-octadien-3-ol with lipases and to identify the stereochemistry of oyster alcohol from Crassostrea gigas. The asymmetric hydrolysis of (±)-(Z)-1,5-octadien-3-yl acetate with CHIRAZYME L-2 afforded the (R)-alcohol with ≧99% ee in 37.8% conversion. On the other hand, the first asymmetric acylation of the alkadienol with lipase PS recovered the (S)-alcohol with 79.5% ee in 47.8% conversion. Then, the second asymmetric acylation of the recovered (S)-alcohol with lipase PS gave the remaining (S)alcohol with ≧99% ee in 14.1% conversion. Thus, we have successfully prepared both enantiomerically pure forms of (Z)-1,5-octadien-3-ol with high ee (≧99%) separately. On the other hand, oyster alcohol in the extract from C. gigas was purified by silica gel column chromatography and the structure was confirmed by 1H- and 13C-nuclear magnetic resonance spectra. Furthermore, the stereochemistry of oyster alcohol was decided as the (R)-form from the specific rotation and its optical purities were determined as 20.45 ± 0.2% ee by a chiral gas chromatograph/mass spectrometry for the first time.