This study aimed to examine the changes and correlations between fatty acids and volatile organic compounds in ready-to-eat fried loach (RTE-FL) over 10 days of storage by Schaal oven tests. The results showed that the peroxide value (POV) increased to 16.64 mg/100 g within first 4 days of storage and decreased over the next 6 days. The thiobarbituric acid reactive substances (TBARS) value increased gradually from 0.51 mg MDA/kg to 1.45 mg MDA/kg, while the sensory evaluation score showed the opposite trend. OPLS-DA combined with ROAV analysis revealed the 7 flavor substances with VIP ≥ 1 and ROAV ≥ 1 were identified as key differential flavor compounds. Furthermore, γ-linolenic acid (C18:3n6), linoleic acid (C18:2n6c), arachidonic acid (C20:1), pentadecenoic acid (C15:1), heneicosanoic acid (C21:0) and palmitic acid (C16:0) were significantly correlated with substances with rancid and pungent odors such as Hexanal-D (ROAV=29.29-62.09), Butanal-D (ROAV=15.95-35.59), 2-methyl propanal (ROAV=332.53-411.37), and 2-methylbutanal-D (ROAV=69.67-204.73). These findings provide valuable insights into flavor changes in RTE-FL during storage.

This study evaluated the incorporation of linoleic acid (LA) into canola oil (CO) through enzymatic interesterification reactions aided by microwave irradiation and catalyzed by TL IM lipase enzyme (sn-1,3). To optimize the process and identify the best reaction conditions, an experimental design utilizing a central composite experiment was implemented to analyze the effects of time (1.5-3.5 h), the reactant ratio LA:CO (0.3:1) and temperature (50-75°C). The linoleic acid (LA) extract was obtained from grapeseeds through extraction and purification techniques. Under optimal conditions (73°C, 48 min and an LA:CO ratio of 1.2), a 69.80% incorporation of linoleic acid was achieved. Moreover, the reactant ratio emerged as the most crucial factor shaping the outcome of the reaction, underscoring its vital role in achieving optimal results. The quality analysis of the crude oil, obtained as a reaction product, revealed a variation in the saponification index (177.5 ± 0.7 mg KOH/g), with respect to the starting substrates, indicating modifications in its composition. This value is higher than the saponification index reported for canola oil (172.82 ± 1.92 mg KOH/g) but lower than that of grapeseed oil (184.56 ± 0.45 mg KOH/g). This variation may be attributed to differences in fatty acid composition; specifically, the crude oil contains a lower proportion of long-chain fatty acids compared to canola oil. This study emphasizes the potential of grapeseeds as a sustainable source of polyunsaturated fatty acids (PUFA). Additionally, the use of microwave irradiation has proven to be a viable alternative to traditional methods by reducing reaction times, minimizing energy consumption and increasing yield percentages. These advancements support green chemistry, the circular economy and the creation of value-added products that can benefit various industries.

We studied the adsorption and lubrication of cationic surfactants on silica in the presence of 1-hexadecanol (C16OH). The surfactants employed in this study were quaternary ammonium salts with different alkyl chain lengths (alkyltrimethylammonium chloride, CnTAC, where n is the alkyl chain length of 14, 16, and 18). The mixing of CnTAC, C16OH, and water generally yields the structure of “α-form hydrated crystals” or the structural unit of “lamellar gel networks” at appropriate compositions. In these structures, the alkyl chains of CnTAC and C16OH are packed in the hexagonal arrangement within lamellar bilayers. Quartz crystal microbalance with dissipation monitoring technique suggested that the adsorbed vesicular aggregates of CnTAC and C16OH flattened on the silica surface. The larger vesicular aggregates formed a viscosity-dominant thicker adsorption film in the initial stage, and then experienced the flattening more significantly to yield an elasticity-dominant thin film. At a given size of the vesicular aggregates, the alkyl chain length of CnTAC did not make large impact on the adsorption in their steady state. The adsorption film achieved excellent lubricity, being irrespective on the size of the vesicular aggregates and the alkyl chain length of CnTAC. We anticipate that these findings will be useful in formulating “α-gels” in various personal care applications.

To investigate glycerol effect on the microstructure and rheology of lyotropic liquid crystals formed in sucrose laurate/glycerol/water systems, a series of pseudo-ternary surfactant system are prepared and investigated. SWAXS data confirms the presence of hexagonal liquid crystal phase (H₁ phase) as the predominant phase in sucrose laurate/water systems with a medium-to-high surfactant concentration. These changes in SAXS pattern demonstrate that glycerol incorporation into aqueous phase in sucrose laurate/water system would reduce the long-range positional ordering of cylindrical micelles in H₁ phase, even results in a transformation of H₁ phase to other disordered phases. Moreover, the effect gradually diminishes with growing surfactant content but still remains in these systems. However, The WAXS profiles indicate that the short-range order of hexagonal liquid crystals is also affected by the glycerol addition. These conclusions are corroborated by polarized light microscope observations and subsequent rheological tests. Variable-temperature SWAXS experiments show that glycerol incorporation significantly reduces the critical temperature where a drastic decrease in the long-range positional ordering of the H₁ phase occurs. Steady shear rheology confirms that glycerol incorporation leads to a decrease in the structural ordering of H₁ phase. Dynamic frequency sweep experiments indicate the strength or stiffness of the liquid crystals decrease with the addition of glycerol. However, these effects become less pronounced with the increase of surfactant content.

We investigated the dynamics of surface tension in binary nonionic surfactant mixtures in aqueous solutions using a custom-made sessile bubble tensiometer. When the bubble surface is initially saturated with tetraethyleneglycol monooctylether (C8E4), adding a second surfactant, octyl-β-D-maltopyranoside (OM), to the adsorbed film results in a straightforward, gradual decrease in surface tension. Conversely, if the surfactants are introduced in reverse order, the surface tension exhibits an overshoot or oscillation over time, depending on the relative concentrations of C8E4 and OM. This pattern mirrors those previously observed in C8E4 - dodecyltrimethylammonium bromide (DTAB) and tetradecyltrimethylammonium bromide (TTAB) - DTAB systems. The surface tension overshoot and oscillation phenomena are explained by the differences in the critical micelle concentrations (i.e., surface activity) of the surfactants. We also analyzed the observed surface tension behaviors using the theory developed for the adsorption kinetics of higher alcohols on lipid-insoluble monolayers. Comparing our findings with those in lipid-insoluble monolayers, it was suggested that the elasticity of the initially formed adsorbed film is another crucial factor in determining whether surface tension oscillation or overshoot occurs.

Fish oil contains not only major fatty acids with double bonds at the n-3, n-6, n-7, and n-9 positions but also those with a double bond at the n-1 position, such as 6,9,12,15-hexadecatetraenoic acid (C16:4 n-1; HDTA). However, intracellular bioconversion and metabolic fate of n-1 polyunsaturated fatty acids (PUFA) remain unclear. Therefore, in this study, we aimed to assess the intracellular bioconversion and metabolic fate of HDTA and its metabolite, 8,11,14,17- octadecatetraenoic acid (C18:4 n-1; ODTA), using HepG2 cells. Based on the results of cell viability and cytotoxicity assays for HDTA and ODTA, the concentration of each fatty acid supplemented in the experiments was set at 10 μM. HepG2 cell culture with HDTA revealed C20:4 n-1 as a new HDTA metabolite, along with previously reported ODTA. Our findings suggest that the HDTA taken up by HepG2 cells undergoes elongation to form ODTA and C20:4 n-1. Following supplementation with HDTA, ODTA, and 5,8,11,14,17-eicosapentaenoic acid (C20:5 n-3; EPA), fatty acids disappeared from the culture medium within 24 h. Notably, the total relative level of HDTA and its metabolites, including ODTA and C20:4 n-1 in HDTA- and ODTA-supplemented cells were significantly lower than the total relative level of EPA and its metabolites, including 7,10,13,16,19-docosapentaenoic acid (C22:5 n-3), C24:6 n-3, and 4,7,10,13,16,19-docosahexaenoic acid (C22:6 n-3) in the EPA-supplemented cells. Except for a portion that was intracellularly elongated, most HDTA was taken up by HepG2 cells and may undergo rapid fatty acid β-oxidation. However, RNA-sequencing and real-time polymerase chain reaction analysis revealed no significant changes in fatty acid β-oxidation–related gene expression levels in HDTA-supplemented cells. Collectively, these results provide novel insights into the intracellular bioconversion mechanisms and metabolic fate of HDTA and ODTA in HepG2 cells, suggesting that the metabolic fate of n-1 PUFA is distinct from that of common PUFA.

Given the global challenge of drug-resistant pathogens, essential oils would be new pharmacological supplements for antibacterial action with low toxicity and low or no resistance. This study investigated the physical properties, chemical profile and antimicrobial activity of native essential oils to develop antibiotic alternatives. Specifically, essential oils were extracted from Dendranthema indicum, Orixa japonica, Chamaecyparis pisifera var. filifera, Peucedanum japonicum, and Pinus strobus using hydrodistillation. The antimicrobial activity of essential oils against Staphylococcus aureus and Klebsiella pneumonia was assessed by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The essential oils from D. indicum with blue colour showed lower b* values (3.21±0.78) than other species (14.94±0.51-15.84±0.78). D. indicum oil showed the highest values in relative density (0.920±0.000g/mL) and refractive index (1.493±0.000nD²⁰) among the other oils. These results might be attributed to the major component of camphor in oils, known for its high density and refractive index. C. pisifera had the highest oil yield (4.01±0.17% DW) among the other species (0.36 ± 0.13-0.78±0.18% DW). Both C. pisifera and P. japonicum oils were rich in monoterpenes (81.09-91.06%), such as 3-carene (34.28%) and β-pinene (47.37%). Yet, the other oils were abundant in sesquiterpenes (13.82-36.45%). For example, the major components of D. indicum oils were germacrene-D (16.56%), followed by caryophyllene (9.20%). D. indicum and O. japonica oils were particularly effective in inhibiting both bacterial growths (MIC:0.5-1.5% and MBC:4-8%), whereas the other essential oils might require higher concentrations for bactericidal effects (MIC:1-3% and MBC:3- ≥ 12%). The strong antibacterial effect of D. indicum and O. japonica oils might be attributed to the major components of camphor (23.05%) and linalool (10.92%), respectively. Therefore, D. indicum and O. japonica essential oils would exhibit strong antibacterial activity, highlighting a potential antimicrobial agent in food and health industrial resources.

This study investigates the effects of microwave radiation on Euglena gracilis (Euglena) during brief exposure periods, as well as the subsequent enhancement of growth under different conditions. The growth patterns of Euglena in these environments were systematically analyzed. Additionally, the study examined whether the growth rate of microwave-irradiated heterotrophic cultures of Euglena could be improved with 24-hour or shorter light exposure, which is an important factor in the industrial production of this organism. Results indicated that a 1-minute pulse of microwave radiation caused a twofold increase in growth compared to the control, even under autotrophic culture conditions without added CO₂. Furthermore, there was a significant 2.6-fold increase in growth when daily light exposure was reduced from 24 to 10 hours.