High Oxidative Stability Research Articles

Algae-based antioxidant containing selenium yeast (Economase®) enhanced the growth performance, oxidative stability, and meat quality of broiler chickens.

ObjectiveAn experiment was conducted to determine the effect of algae-based antioxidant containing Se yeast (EconomasE®) on the growth performance, visceral organ weight, meat quality, and oxidative stability of broiler chickens.MethodsNine hundred sixty, day-old male broiler chickens (Cobb, 43.97±0.55 g) were divided into three dietary treatments and allocated into 12 deep litter pens in a completely randomized design giving 4 replicate cages for each treatment. Three dietary treatments were: i) control (CON, basal diet with sufficient nutrient), ii) vitamin E (VitE, basal diet supplemented with 100 IU VitE), and iii) Algae-based antioxidant containing Se yeast (EcoE, basal diet supplemented with 0.2% algae-based antioxidant containing Se yeast: EconomasE®). Maize soybean meal based basal diets were formulated to meet or exceed the nutrition requirement for broiler chickens. Chickens were fed ad-libitum experimental diets during the 42 days experiment period. On days 21 and 42, body weight and feed intake were measured to calculate the feed conversion ratio of the chickens. Intestine and visceral organs were measured together with meat quality and oxidative stability on days 14 and 42.ResultsChickens fed with EcoE showed improved (p<0.05) growth performance, meat quality, and higher (p<0.05) oxidative stability compared to the chicken fed on CON. Moreover, broiler chickens fed with EcoE showed similar (p<0.05) growth performance with better (p<0.05) meat quality and higher oxidative stability compared to the broiler chickens fed VitE (p<0.05).ConclusionThe algae-based antioxidant containing Se yeast can be supplemented into commercial broiler diets as a substitution of VitE while maintaining growth performance with enhancing meat quality and oxidative stability of the broiler chickens.

Valorization of Pinus halepensis Mill. seed oil: Physicochemical characteristics, bioactive compounds, and antioxidant activity as affected by location and extraction method

In this study, physicochemical characteristics, phytochemical compositions, and antioxidant activities of Pinus halepensis Mill. seed oils (PHSO) from two geographical origins (Algeria and Turkey) and obtained through two different extraction processes (cold pressing and solvent extraction) were determined. PHSO were majorly consisted of linoleic and oleic acids. Cold pressing yielded oils with lower peroxide and totox values, higher tocopherols contents (309.42–318.04 mg/100 g), higher DPPH-radical scavenging activities (25.33–26.94 mM TE/kg), and reducing capacity values (301.30–329.94 mg GAE/kg). The solvent-extracted oils contained more phytosterols (5,683.25–5,964.20 mg/kg), particularly β-sitosterol and campesterol. Phenolic compounds of PHSO were identified by HPLC-DAD for the first time in this study. More phenolic compounds were detected in solvent-extracted oils. Turkish PHSO were richer in individual phenolics (18,928.92 μg/100 g) than the Algerian variety (2,821.01 μg/100 g). Different extraction techniques and geographical origins led to differences in physicochemical and phytochemical attributes of PHSO. Novelty impact statement This study revealed that extraction technique (cold-pressing, solvent extraction) and geographical seed origin (Algeria, Turkey) influenced the Pinus halepensis Mill. seed oils (PHSO) composition. PHSO are rich in fatty acids, sterols, and tocopherols majorly linoleic acid, γ-tocopherol, and β-sitosterol which were detected for first time for the cold pressed oils. This is the first report on phenolics compounds of these oils, mainly luteolin. The high oxidative stability and good antioxidant activities of PHSO promote their exploitation in food, cosmetics, and pharmaceuticals uses.

Mechanochemical Synthesis and Structure of Lithium Tetrahaloaluminates, LiAlX4 (X = Cl, Br, I): A Family of Li-Ion Conducting Ternary Halides.

State-of-the-art oxides and sulfides with high Li-ion conductivity and good electrochemical stability are among the most promising candidates for solid-state electrolytes in secondary batteries. Yet emerging halides offer promising alternatives because of their intrinsic low Li+ migration energy barriers, high electrochemical oxidative stability, and beneficial mechanical properties. Mechanochemical synthesis has enabled the characterization of LiAlX4 compounds to be extended and the iodide, LiAlI4, to be synthesized for the first time (monoclinic P21/c, Z = 4; a = 8.0846(1) Å; b = 7.4369(1) Å; c = 14.8890(2) Å; β = 93.0457(8)°). Of the tetrahaloaluminates, LiAlBr4 exhibited the highest ionic conductivity at room temperature (0.033 mS cm–1), while LiAlCl4 showed a conductivity of 0.17 mS cm–1 at 333 K, coupled with the highest thermal and oxidative stability. Modeling of the diffusion pathways suggests that the Li-ion transport mechanism in each tetrahaloaluminate is closely related and mediated by both halide polarizability and concerted complex anion motions.

Potential oil resources from underutilized seeds of Sterculia foetida, L. - Quality assessment and chemical profiling with other edible vegetable oils based on fatty acid composition, oxidative stability, antioxidant activity and cytotoxicity

Vegetable oils are integral part in production of manufactured food both in domestic and industrial scale. Vegetable oil market is increasing upward with a CAGR of 3.25% during the forecast period (2019–2024) all around the world. Therefore, it is necessary to find alternative sources of vegetable oil to fulfil the scarcity in the market. Seeds of Sterculia foetida, L. yielded considerable amount of oil (58.7 g/100g) as compared to other vegetable oils (such as sunflower, ground nut, mustard, soybean). Fatty acids composition of all the five tested oils showed that total fatty acid as well as unsaturated fatty acid percentage is higher in Sterculia seed oil. Proximate and mineral composition analysis suggested that Sterculia oil is a good source of protein, lipids, macro and micronutrients. Lowest TOTOX value (2.67) and higher iodine value (132–144) indicated its higher oxidative stability and presence of greater number of unsaturated bands in the fatty acid moieties which is also beneficial for human health. Sterculia oil exhibited lower IC50 values in DPPH (825.73 μg/ml), and NO (111.98 μg/ml) radical scavenging assays. In case of ABTS radical scavenging activity, no significant differences were observed in groundnut, mustard, sterculia and soybean except sunflower. Sterculia oil did not exhibit any cytotoxic effect on both normal and cancerous cell lines even at concentrations of 40 μg/ml as evident from MTT assay. Thus, seed oil of Sterculia foetida may be a cost-effective and viable source of safe nutritious edible oils to combat the present market demand.

Study of Causes of Plastic Pipe Failures

It has been observed that critical failures and loss of function occur in a shorter period than specified service life during operation of polypropylene pipes in hot water systems. The paper analyzes the failure causes of polypropylene pipes in closed loop hot water systems, and provides recommendations for increasing their service life. It has been established that the primary factors responsible for ageing and failure of polypropylene pipes during operation are medium temperature, stress due to internal pressure, water composition. It has been observed that a combined influence of the above mentioned factors provides a synergistic effect. We developed the recommendations for increasing a pipe service life, including close monitoring and recording of energy carrier temperature and pressure; changes in specifications for propylene pipes, including the recommendation for using random propylene pipe grades with high thermal oxidation stability in hot water systems.

Lauric fats from the Brazilian Amazon: babassu and murumuru

Babassu and murumuru palms are both sources of lauric acid. Due to their high oxidative stability and well-defined melting points, fats from both plants are widely used in the cosmetic industry and in the preparation of specialty fats for confectionery, ice cream, margarines, and cocoa butter substitutes. This article reviews the composition and physicochemical properties of these exotic fats.

Carbon Nanotubes Doped Poly (arylene) Ether Copolymerised Multiblock Based Proton Exchange Composite Membranes for Fuel Cell Application

The article reports the synthesis of nanophase-separated multiblock poly(arylene ether ketone sulfone) copolymers. A series of hydrophobic oligomers end-capped with decafluorobiphenyl (DFBP) group was reacted with disulphonated poly(arylene ether ketone) copolymer containing 4, 4′-bis (4-hydroxyphenyl) valeric acid moieties to synthesize multiblock copolymer. The copolymers were characterized using 1H-NMR, 13C-NMR, 19F-NMR spectroscopy and Gel Permeation Chromatography. The membranes with high dimensional and thermal stability were obtained through solution casting method. The multiblock copolymers were crosslinked with 6F-bisphenol-A (6F-BPA) based novolac epoxy resin. The functionalized multi-walled carbon nanotubes (f-MWCNTs), in 0.5, 0.7, and 0.9 wt.%, were also incorporated into the polymer matrix in order to prepare nanocomposite membranes. Polymer nanocomposite membranes showed high oxidative stability, and proton conductivity. The surface morphology and composition of polymer nanocomposite membranes were studied using field emission-scanning electron microscopic (FE-SEM), and high-resolution transmission electron microscopic (HR-TEM) techniques. The fuel cell related parameters such as water uptake, proton conductivity, ion exchange capacity, oxidative stability, and methanol permeability were also evaluated. The thermal performance and mechanical behavior of the synthesized polymer nanocomposite membranes were also studied. The nanocomposite membranes showed better fuel cell performance as compared to the pristine membranes.

An overlooked issue for high-voltage Li-ion batteries: Suppressing the intercalation of anions into conductive carbon

Summary High-voltage Li-ion batteries have been extensively studied to increase energy density of batteries. However, their cycling stability has remained poor, despite various strategies being proposed to overcome the issues of high-potential cathodes, such as electrolyte oxidation and transition metal dissolution. Herein, we report anion intercalation into the cathode conductive carbon as an overlooked yet critical issue. We propose a concentrated sulfolane (SL)-based electrolyte that prevents anion intercalation via two mechanisms: (1) by offering a high activation barrier to intercalation via its strong anion-Li+ interaction and (2) by forming a sulfur-containing, anion-blocking SL-derived interphase. This electrolyte, used with graphitized acetylene black, which is oxidatively stable but usually susceptible to anion intercalation, enables the stable operation of a Li2CoPO4F/graphite full cell (cut-off voltage = 5.2 V), with 93% capacity retention after 1,000 cycles and an average Coulombic efficiency of ≥99.9%. This is a pivotal strategy to enhance the reversibility of >5 V Li-ion batteries on a commercial level.

Flaxseed oil and palm olein blend to improve omega-6: omega-3 ratio.

The objective of the study was to develop the oil blend with improved omega-6 to omega-3 fatty acid ratio (ω-6:ω-3) with good oxidative and thermal stability. Flaxseed oil and palm olein were selected for the blending. Flaxseed oil is rich in anti-inflammatory omega-3 fatty acid (ω-3 FA)but isoxidatively very unstable. Palm olein has low omega-6 fatty acid content and high thermal and oxidative stability. Blends containing various percent (v/v) of flaxseed oil and palm olein were prepared. Oxidative and thermal stability was determined by analyzing peroxide value, acid value, smoke point, % free fatty acids, para-Anisidine and TOTOX values. Nutritive quality was confirmed by determining fatty acid composition. Nine month storage stability of the blend containing highest flaxseed oil percentage was assessed in terms of peroxide and acid value and fatty acid composition. The biological effects were studied in THP-1 cell line as the effect on cell survival, FA uptake and inflammatory markers. The data indicates that, blending improved ω-6:ω-3 ratio. Oxidative and thermal stability study, and nine month storage stability study suggested that palm olein imparted stability to the blend. Fatty acid profiles of the cells treated with these blends showed uptake of Alpha Linolenic Acid (ω-3 FA). These blends lowered inflammatory TNFα level without affecting cell survival. Thus, blending of flaxseed oil with palm olein may result in better health benefits owing to their improved nutritional and stability properties.

Trans- Free Fat Spread Produced from Rice Bran Oil and Rice Bran Oil Shortening Blends

The objective of this study was to produce trans-free fat spread from rice bran oil and rice bran oil shortening blends to replace partially hydrogenated fats which contain high levels of trans fatty acids. The W/O emulsion of rice bran oil spread was prepared from blending of rice bran oil and rice bran oil shortening with the mass ratio of 40: 60 using PGPR as an emulsifier. Physicochemical properties, fatty acid compositions, thermal behaviors, micronutrients, sensory attributes and oxidative stability of rice bran oil spread were investigated and compared with commercial spread products. Results showed that physicochemical properties of the rice bran oil spread were similar to the commercial spread (B2). Trans fatty acids contents of the rice bran oil spread (0.2% TFAs) were much lower than the commercial spread (F2) produced from partially hydrogenated fat (4.9% TFAs). Thermal behaviors and SFC profile indicated good physical properties and spreadability of the rice bran oil spread which were comparable to the commercial spreads. Micronutrients in the rice bran oil spread were greater than those of commercial spread products. The rice bran oil spread had the highest overall preference scores compared to the two commercial fat spreads. In addition, the rice bran oil spread exhibited high oxidative stability. This study demonstrated that rice bran oil and rice bran oil shortening blends can be used as an alternative source of partially and fully hydrogenated fats as well as tropical oils to produce trans-free fat spreads with desirable properties.

A Review of Emerging Dual‐Ion Batteries: Fundamentals and Recent Advances

AbstractDual‐ion batteries (DIBs), based on the working mechanism involving the storage of cations and anions separately in the anode and cathode during the charging/discharging process, are of great interest beyond lithium‐ion batteries (LIBs) in high‐efficiency energy storage due to the merits of high working voltage, material availability, as well as low cost and excellent safety. Despite the progress achieved, the practical applications of DIBs are still hindered by negative issues, such as limited capacity and cyclic stability, which triggers the development of suitable electrode materials with highly reversible capacities, and corresponding electrolytes with high oxidative stability as well as sufficient reaction kinetics of active ions. Herein, in this article, a systematic and comprehensive review of fundamentals and recent advances in current DIBs with subcategories of cathode materials, anode materials, and electrolytes are presented. In particular, their energy storage mechanisms, as well as their respective features, are dissected. Furthermore, some strategies and perspectives are proposed for facilitating the further development of DIBs in the future.

Boronic acid with high oxidative stability and utility in biological contexts

Despite their desirable attributes, boronic acids have had a minimal impact in biological contexts. A significant problem has been their oxidative instability. At physiological pH, phenylboronic acid and its boronate esters are oxidized by reactive oxygen species at rates comparable to those of thiols. After considering the mechanism and kinetics of the oxidation reaction, we reasoned that diminishing electron density on boron could enhance oxidative stability. We found that a boralactone, in which a carboxyl group serves as an intramolecular ligand for the boron, increases stability by 104-fold. Computational analyses revealed that the resistance to oxidation arises from diminished stabilization of the p orbital of boron that develops in the rate-limiting transition state of the oxidation reaction. Like simple boronic acids and boronate esters, a boralactone binds covalently and reversibly to 1,2-diols such as those in saccharides. The kinetic stability of its complexes is, however, at least 20-fold greater. A boralactone also binds covalently to a serine side chain in a protein. These attributes confer unprecedented utility upon boralactones in the realms of chemical biology and medicinal chemistry.

Impact of variety and extraction process on physico-chemical and sensory characteristics of virgin olive oil

Abstract The aim of this study was to evaluate the effects of variety and extraction system on the physico-chemical and sensorial characteristics of olive oils produced from three dominant varieties of Algeria (Azeradj, Chemlal and Sigoise). The olive oils were extracted by three different processes (pressure system, two-phase centrifugation and traditional process). Physicochemical parameters including free acidity, peroxide value, absorbance in ultra violet (K232, K270, ΔK) and sensory evaluation were studied. The results show that free acidity, peroxyde value and K270 were influenced by the extraction system and variety. Olive oils obtained from the two phases centrifugation and Chemlal cultivar were characterized by higher oxidative stability. Sensory characteristics of olive oils were mainly influenced by the variety and extraction system. Olive oils obtained from the two phases centrifugation, traditional cold process and Sigoise variety were characterized by the lower mean values of negative attributes.

Application of Caseinate Modified with Maillard Reaction for Improving Physicochemical Properties of High Load Flaxseed Oil Microcapsules

AbstractHigh‐load flaxseed oil microcapsule is prepared with the Maillard reaction products (MRPs) of sodium caseinate and isomaltooligosaccharide as wall material. It is found that the emulsifying activity index and emulsion stability index of MRPs are increased by 31.32% and 34.11% respectively at the appropriate degree of graft (26.30%) compared with the mixture of sodium caseinate and isomaltooligosaccharide. Smaller droplet size and lower polydispersity index can be achieved in the flaxseed oil emulsions coated by MRPs, due to the change of sodium caseinate molecular weight and spatial structure. The microencapsulation efficiency of the microcapsules coated by MRPs is highly improved up to 98.22% at oil load of 58.43%, compared with the control group. Furthermore, MRPs as coating material can protect flaxseed oil against lipid oxidation at 50 °C for 4 weeks. More importantly, the smooth, round, and compact external surface structures of microcapsule powder support its physical necessity for industrial usage. Due to its high microencapsulation efficiency and good oxidation stability, MRPs formed with sodium caseinate and isomaltooligosaccharide show great application potential in preparing high load oil microcapsule.Practical Applications: Findings in this research could be utilized for developing microencapsulation loaded with higher concentration of flaxseed oil, a rich source of α‐linoleic acid and lignans. Application of MRPs (Maillard reaction products) formed through interaction between sodium caseinate and isomaltooligosaccharide by heating improved both its physicochemical properties and oxidative stability. It is a novel approach for developing microcapsule with higher percentages of oils with better oxidative stability.

Effects of Storage on Quality Traits of Sausages Made with Chicken Breast Meat Affected by Wooden Breast

Simple SummaryStudies of the meat quality of modern birds and their respective myopathies are important to clarify the influence of these on the meat quality of the animals. The constant genetic evolution that birds have undergone is the most plausible cause for the onset of Wooden Breast Myopathy. The processing of byproducts, such as sausages, represents an alternative to avoid the losses that this myopathy generates to the poultry industry due to discards of chickens affected by different degrees of wooden breast myopathy. The aim of this study was to examine the effects of storage on the quality of sausages made with breast from chickens affected by wooden breast myopathy (WBM). Breast samples from male broilers slaughtered at 48 days old were used. Normal (absence of myopathy), moderate degree (hardness only in one region of the breast) and severe degree samples (hardness over the entire length of the breast) were processed into sausages and evaluated prior to storage and after being vacuum-packed and stored for 7, 14, 21 and 28 days at 4 °C. There was a decrease (p < 0.001) in pH and an increase (p < 0.001) in cooking weight loss in samples of sausages, regardless of the myopathy, after 28 days of storage. Sausages produced with chicken breast samples affected by wooden breast myopathy presented higher (p < 0.0001) moisture concentration (72% for the severe degree) and higher (p = 0.0224) protein concentration (17.27% and 17.36%, respectively, for the moderate and severe degrees) than sausages made of normal samples (70.72% and 14.32%, respectively). The results indicate that sausages produced with meat from birds moderately and severely affected by the myopathy show higher oxidative stability. Fresh sausages produced with breast meat from birds affected by wooden breast syndrome may be stored (4 °C) for up to 28 days without exhibiting the characteristic rancid taste and smell. In sensory analysis, no differences were observed between the formulations, which suggests that the consumers approved the samples regardless of the disease severity in the meat used for the making of the sausages. The current results show that chicken meat affected by wooden breast myopathy can be used for producing fresh sausages in the industry.

Stepwise-incremental physicochemical factors induced acclimation and tolerance in oleaginous microalgae to crucial outdoor stresses and improved properties as biodiesel feedstocks

Stress-tolerant oleaginous microalgae are promising for economical outdoor cultivation and biofuel production. This study aimed to induce acclimation and adaptive evolution of oleaginous Scenedesmus sp. SPP to tolerate crucial outdoor stresses by stepwise increasing of physicochemical factors: salinity, light intensity and temperature. The acclimatized strains showed better growth and accumulated 20–30% higher contents of lipids and chlorophylls. The adaptive-evolved strain showed greater tolerance to culture stresses by giving > 2-fold higher biomass under nitrogen rich and accumulating > 1.5-fold higher lipid content under nitrogen starvation compared to the parental strain. Moreover, stepwise increasing of multi-stresses successfully induced the multi-tolerance of the adaptive-evolved strain and gave the highest lipid content of 44.1 ± 1.5%. The extracted lipids from acclimatized/evolved strains show improved prospect fuel properties in terms of high cetane number and oxidative stability. These results show the effectiveness of stepwise-incremental physicochemical factors to intensify potential of microalgae for outdoor cultivation and as biodiesel feedstocks.

Physicochemical properties and stability of pumpkin seed oil as affected by different extraction methods and species

The present work evaluated the influence of extraction method and species on the physicochemical properties, oxidative stability, fatty acid profiles, and rheological behaviour of pumpkin seed oils. The seeds of two pumpkin species (Cucurbita argyrosperma Huber [CA] and Cucurbita moschata Duchesne [CM]) were obtained from small-scale pumpkin processors in Yucatán, Mexico. The oils were extracted by two methods: mechanical pressing (MP) and organic solvent (OS). It was found that the oil extraction method, species, and their interaction significantly influenced the physicochemical properties and oxidative stability of the seed oils. The composition and fatty acid content of the oils were comparable to those of other pumpkin species. The oil yield from the MP method was lower than that from the OS method. Also, CA oil extracted by MP had an olive-green colour as compared to the reddish-yellow colour of CM oil, and also had a higher oxidative stability. The viscosity of CA oil extracted by MP was superior to that extracted by OS. Also, CA oil had a higher content of iron, monounsaturated fatty acids (MUFA), stearic acid, and oleic acid as well as viscosity in comparison to CM oil, although CM oil had a higher content of linoleic acid. This information can be used to obtain more stable pumpkin oils with enhanced properties that would benefit both producers and processors.

Lithium‐Metal Anode Instability of the Superionic Halide Solid Electrolytes and the Implications for Solid‐State Batteries

AbstractOwing to high ionic conductivity and good oxidation stability, halide‐based solid electrolytes regain interest for application in solid‐state batteries. While stability at the cathode interface seems to be given, the stability against the lithium metal anode has not been explored yet. Herein, the formation of a reaction layer between Li3InCl6 (Li3YCl6) and lithium is studied by sputter deposition of lithium metal and subsequent in situ X‐ray photoelectron spectroscopy as well as by impedance spectroscopy. The interface is thermodynamically unstable and results in a continuously growing interphase resistance. Additionally, the interface between Li3InCl6 and Li6PS5Cl is characterized by impedance spectroscopy to discern whether a combined use as cathode electrolyte and separator electrolyte, respectively, might enable long‐term stable and low impedance operation. In fact, oxidation stable halide‐based lithium superionic conductors cannot be used against Li, but may be promising candidates as cathode electrolytes.

Lithium-Metal Anode Instability of the Superionic Halide Solid Electrolytes and the Implications for Solid-State Batteries.

Owing to high ionic conductivity and good oxidation stability, halide‐based solid electrolytes regain interest for application in solid‐state batteries. While stability at the cathode interface seems to be given, the stability against the lithium metal anode has not been explored yet. Herein, the formation of a reaction layer between Li3InCl6 (Li3YCl6) and lithium is studied by sputter deposition of lithium metal and subsequent in situ X‐ray photoelectron spectroscopy as well as by impedance spectroscopy. The interface is thermodynamically unstable and results in a continuously growing interphase resistance. Additionally, the interface between Li3InCl6 and Li6PS5Cl is characterized by impedance spectroscopy to discern whether a combined use as cathode electrolyte and separator electrolyte, respectively, might enable long‐term stable and low impedance operation. In fact, oxidation stable halide‐based lithium superionic conductors cannot be used against Li, but may be promising candidates as cathode electrolytes.

Effect of Pd Precursor Salts on the Chemical State, Particle Size, and Performance of Activated Carbon-Supported Pd Catalysts for the Selective Hydrogenation of Palm Biodiesel.

To improve the oxidative stability of biodiesel fuel (BDF), the polyunsaturated fatty acid methyl esters (poly-FAME) presented in commercial palm oil-derived biodiesel fuel (palm-BDF) were selectively hydrogenated to monounsaturated fatty acid methyl esters (mono-FAME) under a mild condition (80 °C, 0.5 MPa) using activated carbon (AC)-supported Pd catalysts with a Pd loading of 1 wt.%. The partially hydrotreated palm-BDF (denoted as H-FAME) which has low poly-FAME components is a new type of BDF with enhanced quality for use in high blends. In this study, we reported that the chemical states and particle sizes of Pd in the prepared Pd/AC catalysts were significantly influenced by the Pd precursors, Pd(NO3)2 and Pd(NH3)4Cl2, and thus varied their hydrogenation activity and product selectivity. The 1%Pd/AC (nit) catalyst, prepared using Pd(NO3)2, presented high performance for selective hydrogenation of poly-FAME into mono-FAME with high oxidation stability, owning to its large Pd particles (8.4 nm). Conversely, the 1%Pd/AC (amc) catalyst, prepared using Pd(NH3)4Cl2, contained small Pd particles (2.7 nm) with a little Cl residues, which could be completely removed by washing with an aqueous solution of 0.1 M NH4OH. The small Pd particles gave increased selectivity toward unwanted-FAME components, particularly the saturated fatty acid methyl esters during the hydrogenation of poly-FAME. This selectivity is unprofitable for improving the biodiesel quality.