Effect of Thymus haussknechtii and Origanum acutidens essential oils on the stability of cow milk butter

The aim of this study was to investigate the effects of different essential oils (from Thymus haussknechtii Velen and Origanum acutidens Hand.‐Mazz. Letswaart; endemic species in Turkey) on butter stability. These essential oils were added to butter at two concentrations (0.1 and 0.2 wt‐%). The antioxidant activities of the essential oils were compared with control samples (without antioxidant) and containing butylated hydroxytoluene (BHT). All samples were stored at 4 ± 1 °C for 90 days and their peroxide values (PV), thiobarbituric acid (TBA) values, % titratable acidity and some microbiological properties were analyzed. As a result, the lowest PV and TBA values were determined in the samples containing BHT and 0.2% essential oils; however, TBA and PV were at the highest levels in the control samples during storage. The amount of 0.2% of essential oils exhibited strong antioxidant activity, which was almost equal to that of BHT. T. haussknechtii essential oil showed a stronger antioxidant effect as compared to O. acutidens. None of the essential oils showed remarkable antifungal activity. However, the antimicrobial activity of O. acutidens on coliform bacteria was found to be higher than that of T. haussknechtii. Sensory analysis of the butter showed that the samples containing 0.2% essential oils had lower flavor scores than those with 0.1% essential oils. The present results indicate that these essential oils can be considered as an alternative source of natural antioxidants in the manufacture of butter.     

Oxidative instability of CLA concentrate and its avoidance with antioxidants

This study evaluated the effectiveness of antioxidants, such as BHA, BHT, TBHQ, propyl gallate (PG), α-tocopherol (α-1), green tea extract (GTE), and rosemary extract (RE) on oxidative stability of CLA concentrate. Stability of CLA concentrate stored in air at 45°C up to 44 d was assessed by PV. During the storage period, the PV of the control CLA concentrate sample increased from 0.20 (fresh oil) to 1654 meq/kg (oxidized oil). On the other hand, the PV for CLA concentrates treated with 200 ppm of the single synthetic antioxidants, BHA, BHT, TBHQ, and PG, increased from 0.20 to 81, 107, 78, and 101 meq/kg, respectively. Also, the PV of CLA concentrate with the addition of 200 ppm single natural antioxidants α-T, GTE, and RE lowered the final PV to 122, 140, and 110 meq/kg, respectively. Under our experimental conditions, the protective effect of 200 ppm antioxidant was in the order of TBHQ>BHA>PG>BHT>RE>α-T> GTE. These results suggest that the appropriate use of antioxidants prolongs the oxidative stability of CLA concentrate.     

Effects of natural and synthetic antioxidants on changes in refined, bleached, and deodorized palm olein during deep-fat frying of potato chips

The effects of antioxidants on the changes in quality characteristics of refined, bleached, and deodorized (RBD) palm olein during deep-fat frying (at 180°C) of potato chips for 3.5 h/d for seven consecutive days in five systems were compared in this study. The systems were RBD palm olein without antioxidant (control), with 200 ppm butylated hydroxytoluene (BHT), 200 ppm butylated hydroxyanisole (BHA), 200 ppm oleoresin rosemary, and 200 ppm sage extract. Fried oil samples were analyzed for peroxide value (PV), thiobarbituric acid (TBA) value, iodine value (IV), free fatty acid (FFA) content, polymer content, viscosity, E^1% _{1 cm} at 232 and 268 nm, color, fatty acid composition, and C_18:2/C_16:0 ratio. Sensory quality of the potato chips fried in these systems prior to storage was also evaluated. The storage stability of fried potato chips for 14 wk at ambient temperature was also determined by means of the TBA values and sensory evaluation for rancid odor. Generally, in the oil, oleoresin rosemary gave the lowest rate of increase of TBA value, polymer content, viscosity, E^1% _{1 cm} at 232 and 268 nm compared to control and three other antioxidants. The order of effectiveness (P<0.05) in inhibiting oil oxidation in RBD palm olein was oleoresin rosemary > BHA > sage extract > BHT > control. Prior to storage, the sensory evaluation of fried potato chips for each system showed that there was no significant (P>0.05) difference in terms of flavor, odor, texture, and overall acceptability. The same order of effectiveness (P<0.05) of antioxidants was observed for storage stability study of fried potato chips by TBA values. However, there was no significant (P > 0.05) difference in sensory evaluation for rancid odor during storage periods.     

Effects of tocopherols and tocotrienols on the inhibition of autoxidation of conjugated linoleic acid

The effect of eight vitamin E homologues, i.e. α‐, β‐, γ‐, and δ‐tocopherol and α‐, β‐, γ, and δ‐tocotrienol, on the inhibition of autoxidation of conjugated linoleic acid (CLA) were investigated. The oxidation was carried out in the dark for 21 days at 50 °C and monitored by peroxide values (PV) and TBA values. The levels of the individual vitamin E homologues in CLA during storage were determined by HPLC. γ‐Tocopherol exhibited the highest antioxidant activity among the homologues tested in this study when the antioxidant activities of the individual homologues in CLA were compared by PV. The order of antioxidant activity of eight homologues was γ‐tocopherol > δ‐tocopherol = δ‐tocotrienol ≥ γ‐tocotrienol > β‐tocopherol = β‐tocotrienol > α‐tocopherol = α‐tocotrienol. The degradation rates of α‐tocopherol and α‐tocotrienol were faster than those of the other homologues, whereas δ‐tocopherol had the highest stability in CLA during storage. All homologues exhibited an antioxidant activity by inhibiting the formation of secondary oxidation products. It appears that α‐tocotrienol and β‐tocotrienol have significantly higher antioxidant activities for secondary oxidation in CLA than α‐tocopherol and β‐tocopherol. Meanwhile, the other homologues, namely γ‐tocopherol, γ‐tocotrienol, δ‐tocopherol, and δ‐tocotrienol, exhibited similar antioxidant activity for secondary oxidation in CLA.     

Canola extract as an alternative natural antioxidant for canola oil

The antioxidative activity of ethanolic extracts of canola meal at 100, 200, 500 and 1000 ppm on refined-bleached (RB) canola oil was examined and compared with commonly used synthetic antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), BHA/BHT/monoglyceride citrate (MGC) andtert-butyl-hydroquinone (TBHQ). Stability of RB oil was monitored under Schaal oven test conditions at 65°C over a 17-d period. Progression of oxidation was monitored by weight gain, peroxide, conjugated diene, 2-thiobarbituric acid and total oxidation values. Canola extracts at 500 and 1000 ppm were more active than BHA, BHT and BHA/BHT/MGC and less effective than TBHQ at a level of 200 ppm.     

A New Antioxidant Active Film Based on HDPE and Peppermint Essential Oil for Packaging Soybean Oil

In this research, the effect of antioxidant active package was studied on oxidative stability of soybean oil at 40 °C during 2‐month storage. A synthetic antioxidant [Butylatedhydroxytoluene (BHT), 200 ppm] and peppermint essential oil (200 and 400 ppm) were added to antioxidant free soybean oil. To prepare active packages, the oil was filled in antioxidant active high‐density polyethylene (HDPE) bottles containing synthetic antioxidant (3700 ppm) and the essential oil (3700 and 8400 ppm). Regarding peroxide and thiobarbituric acid values, the essential oil added to the oil delayed the oil oxidation more than BHT. In active packages, the synthetic and natural antioxidants migrated from the package to the oil (with 68 and 100 % migration rate, respectively) and retarded its oxidation over the storage time. However, no significant difference was observed between essential oil and BHT in antioxidant capacity for active packages. This study demonstrated that active packages containing antioxidants could be introduced as a good replacement for direct addition of synthetic antioxidants to the oil.     

Effectiveness of antioxidants on lipid oxidation and lipid hydrolysis of cod liver oil

The capacity of the natural antioxidant from barley husks to retard oxidation of PUFA in cod liver oil (Gadus morhua) was investigated and compared to synthetic antioxidants. The results confirm the efficacy of a natural antioxidant derived from barley husks to slow down the progress of lipid hydrolysis and increase oxidative stability in cod liver oil. The rates of lipid hydrolysis and lipid oxidation were slowed down with increasing concentration of natural antioxidant used. Using 100 mg of the natural antioxidant was more effective than some synthetic antioxidants (BHA 200 mg and BHT 200 mg) against primary and secondary oxidation. The use of propyl gallate (PG) as an antioxidant (200 mg/kg in cod liver oil) was the most effective antioxidant employed in reducing the production of primary and delaying secondary oxidation products. The formation of free fatty acids (FFA) was significantly lower in samples with natural antioxidant (BE200 and BE100) than in the control samples. BHA and BHT were the most effective antioxidants employed to delay the lipid hydrolysis. Practical applications: The use of barley husks, which are residues of the brewing process, was optimized to obtain a crude antioxidant extract. Natural extracts of phenolic compounds with high antioxidant activity were obtained after prehydrolysis and delignification of barley husks. The raw extracts show more than two‐fold antioxidant capacity compared to BHT in terms of EC50. The results demonstrate the efficacy of a natural antioxidant derived from barley husks. The extract could be used in fatty foods (such as butter, oil, etc.) to prevent rancidity.     

Antioxidant Effect Potential of Garlic In Vitro and Real Food System: Effects of Garlic Supplementation on Oxidation Stability and Sensory Properties of Butter

In this research, the effect of adding garlic and synthetic antioxidant to butter produced on both quality characteristics and oxidation stability during the storage (1st, 15th, 30th, 45th, 60th, 75th, and 90th days) process is investigated. With this aim, two replicates of butter samples as control, containing different proportions of garlic (butter treated with 2.5%, 5%, 7.5%, 10% crushed garlic) and with 50 ppm butylated hydroxytoluene (BHT) added are prepared. 2,2′‐Azinobis‐(3‐ethylbenzthiazoline‐6‐sulfonate) and 2,2‐diphenyl‐1‐picrylhydrazyl free radical‐scavenging ability, ferric reducing antioxidant power value of garlic are found as 26.05%; 87.48%; 70 mm mL^?1, respectively. Total phenolic content, total flavonoids, and total antioxidant capacity of fresh garlic are determined. The main components of essential oil of garlic are determined. The rate of oxidation decreases as the garlic rate increases. The highest sensory analysis scores for the first days of storage are for the control and butter with 50 ppm BHT added, followed by samples with 5%, 2.5%, and 7.5% garlic added. At the end of storage, the highest sensory analysis scores are obtained by the butter with 5% garlic added. The butter with 10% garlic added is not liked in terms of sensory properties. Practical Applications: Oxidation‐causing or accelerating factors are oxygen, light, temperature, metal ions, some pigments, and degree of unsaturation. Oxidation is eliminated when these factors are eliminated. But in practice this is not possible. Therefore, it is very difficult to prevent oxidation without adding any material. Antioxidants are the most effective substances in the food industry for the production, storage, transport, and marketing of vegetable and animal fats and fat‐containing foods, delaying the effect of atmospheric oxygen at normal temperatures, preventing food spoilage, and rancidity for a certain period of time. Due to the carcinogenic effects of synthetic antioxidants, interest in natural antioxidants has increased. It is known that garlic has antioxidant effects. Natural antioxidants are used in the food industry for different purposes due to their extensive bioactivity profile. Peroxide value and thiobarbituric acid tests are generally used to determine the degree of lipid oxidation in butter.     

Effect of antioxidants on the oxidative stability of methyl soyate (biodiesel)

Biodiesel, an alternative diesel fuel derived from transesterification of vegetable oils or animal fats, is composed of saturated and unsaturated long-chain fatty acid alkyl esters. When exposed to air during storage, autoxidation of biodiesel can cause degradation of fuel quality by adversely affecting properties such as kinematic viscosity, acid value and peroxide value. One approach for increasing resistance of fatty derivatives against autoxidation is to treat them with oxidation inhibitors (antioxidants). This study examines the effectiveness of five such antioxidants, tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PrG) and α-Tocopherol in mixtures with soybean oil fatty acid methyl esters (SME). Antioxidant activity in terms of increasing oxidation onset temperature (OT) was determined by non-isothermal pressurized-differential scanning calorimetry (P-DSC). Analyses were conducted in static (zero gas flow) and dynamic (positive gas flow) mode under 2000 kPa (290 psig) pressure and 5 °C/min heating scan rate. Results showed that PrG, BHT and BHA were most effective and α-Tocopherol least effective in increasing OT. Increasing antioxidant loading (concentration) showed sharp increases in activity for loadings up to 1000 ppm followed by smaller increases in activity at higher loadings. Phase equilibrium studies were also conducted to test physical compatibility of antioxidants in SME-No. 2 diesel fuel (D2) blends. Overall, this study recommends BHA or TBHQ (loadings up to 3000 ppm) for safeguarding biodiesel from effects of autoxidation during storage. BHT is also suitable at relatively low loadings (210 ppm after blending). PrG showed some compatibility problems and may not be readily soluble in blends with larger SME ratios. Although α-Tocopherol showed very good compatibility in blends, it was significantly less effective than the synthetic antioxidants screened in this work.     

Influence of Zataria multiflora Boiss. essential oil on oxidative stability of sunflower oil

In this study, the influence of the application of 0.025%, 0.05% and 0.075% of Zataria multiflora Boiss. essential oil (EO) on oxidative stability of sunflower oil was examined and the EO was compared to butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) during storage at 37°C and 47°C. The main components of EO were identified as carvacrol (45.6%), p‐cymene (18.1%) and thymol (16.3%). Peroxide value (PV), anisidine value (AnV) and thiobarbituric acid (TBA) value measurement in sunflower oil showed that all concentrations of EO had a lower antioxidant effect in comparison to BHA and BHT. Samples supplemented with EO concentration of 0.075% were the most stable during storage at both temperatures (p<0.05). Furthermore, Totox value, antioxidant activity (AA), stabilization factor (F) and antioxidant power (AOP) determination confirmed efficacy of this EO as antioxidant in sunflower oil. EO also was able to reduce the stable 2,2‐diphenyl‐1‐picrylhydrazyl free radical (DPPH ^. ) with a 50% inhibition concentration (IC₅₀) of 34.3 ± 0.8 µg/mL. The results indicate that EO could be used as a natural antioxidant in oils for food uses.     

Thermal stability of some commercial synthetic antioxidants

Synthetic antioxidants are widely applied substances in human food and in animal feed industries. These products, which are mainly derived from phenolic structures, were developed to avoid or retard the oxidative rancidity of fats and oils when added either to raw material or to end-products. Synthetic antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tertiary butylhydroxyquinone (TBHQ), and ethoxyquin (EQ) are frequently applied during the cooking of the by-products (viscera, blood, and feathers) in the poultry feed industry. However, results in terms of oxidative prevention are unequal and usually modest. Because information about the thermal stability of synthetic antioxidants is scarce, we developed a laboratory model that simulates the cooking of poultry by-products to study the effectiveness of BHT, BHA, TBHQ, and EQ. The antioxidants were thermally treated at 100–200°C, over 1 or 2 h. The effectiveness of each antioxidant after the thermal treatment was assessed with the Rancimat test by measuring the modification of the induction period for the oxidation of sardine oil and comparing it to the oxidation kinetics of the oil without added antioxidants. Within our experimental conditions, all antioxidants assayed showed different degrees of thermal instability. BHT and TBHQ were effective as antioxidants at temperatures up to 175°C, exhibiting only 25 to 30% inactivation. However, BHA and EQ were inactivated by 70 and 60%, respectively, at 150°C. Heating time (1 and 2 h) at a given temperature did not significantly modify the behavior of the antioxidants assayed. EQ is the most frequently applied antioxidant to prevent oxidative rancidity in the cooking of poultry by-products. However, according to our results, EQ and BHA, which is another antioxidant frequently used by the poultry industry, are less suitable     

Inhibition of butter oxidation by some phenolics

The ability of some phenolic compounds to inhibit butter oxidation was evaluated. Peroxide values and thiobarbituric acid reactive substances were monitored during storage of butter at 50 °C and at 110 °C. Gallic acid, caffeic acid and catechin, each at 80 mg/L, inhibited butter oxidation at 50 °C to a degree equal to that of butylated hydroxyanisole (BHA) at 200 mg/L. Gallic acid, at 80 mg/L, was more effective than BHA, at 200 mg/L, in inhibiting butter oxidation at 110 °C. Present results indicate that some phenolics, and especially gallic acid, may be taken into account as antioxidants in butter.     

Effect of selected antioxidants on the stability of virgin olive oil

Virgin unrefined olive oil was protected from oxidation with the antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tertiary butylhydroquinone (TBHQ) and in one case propyl gallate (PG). All the antioxidants improved the stability of olive oil under accelerated conditions (oven test) and storage conditions at 50 C. In the oven test, where the type of oil used was the same as that used in long-term storage studies (room temperature and 50 C) the relative inhibition effect of the antioxidants was in the following order: TBHQ = BHA > BHT. The combinations of BHA and BHT with TBHQ displayed better stabilizing qualities. Antioxidants did not prevent peroxide formation in olive oil stored at room temperature in daylight; these samples oxidized to a high degree, probably due to the catalytic action of chlorophyll. Citric acid (CA) used alone did not affect the oxidative stability of the oil in the oven test and at room temperature in the dark, but exhibited a negative effect at 50 C. The reduction in peroxide content with teritary butylhydroquinone (TBHQ) in the dark at 50 C was greater than anticipated from the oven studies. Potency of the antioxidants under these conditions (50 C) was in the following order: TBHQ> BHT > BHA. The combinations of BHA 0.01% or BHT 0.01% with TBHQ 0.005% used in the dark at 50 C were less effective than TBHQ 0.01%.     

Food Additives Reducing Volatility of Antioxidants at Frying Temperature

At frying temperature, antioxidants are lost not only by reaction with radicals formed by oil oxidation but also by decomposition and evaporation before they are able to exert antioxidant activity. In this study, it was hypothesized that an additive that can bind or interact with an antioxidant could reduce volatility of the antioxidant at frying temperature. Three synthetic antioxidants, tert‐butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), which have relatively high volatility, were used as antioxidants in this study to examine the hypothesis. Thermogravimetric analysis (TGA) experiments showed that all 22 additives tested in this study effectively reduced volatility of the antioxidants. An NMR study showed that signals of BHT shifted by addition of an additive, evidencing the interaction between the two substances in the chloroform solution. To examine the effect of these interactions on antioxidant activity, heating tests were conducted with soybean oil (SBO) containing 200 ppm antioxidants at 180 °C. Oxidation was monitored with ¹H NMR for loss of olefinic protons and bisallylic protons in SBO and with gel permeation chromatography (GPC) for polymerized triacylglycerols (PTAG). Improved antioxidant activity of the antioxidants were observed when combined with several additives tested in this study, and HPLC analysis showed that the antioxidants were effectively reserved by the additives in SBO during the heating process. The concentrations of the antioxidants retained in SBO were relatively well correlated with the antioxidant activity.     

Kinetics of antioxidant action of α‐ and γ‐toco‐pherols in sunflower and soybean triacylglycerols

A kinetic analysis was performed to evaluate the antioxidant behavior of α‐ and γ‐to‐copherols (5—2000 ppm) in purified triacylglycerols obtained from sunflower oil (TGSO) and soybean oil (TGSBO) at 100 °C. Different kinetic parameters were determined, viz. the stabilization factor as a measure of effectiveness, the oxidation rate ratio as a measure of strength, and the antioxidant activity which combines the other two parameters. In the low concentration range (up to 400 ppm in TGSBO and up to 700 ppm in TGSO) α‐tocopherol was a more active antioxidant than γ‐tocopherol whereas the latter was more active at higher concentrations. It has been found that the different activity of the tocopherols is not due to their participation in chain initiation reactions, but that the loss of antioxidant activity at high tocopherol concentrations is due to their consumption in side reactions. The rates of these reactions are higher in TGSBO than in TGSO. Both α‐tocopherol itself and its radicals participated more readily in side reactions than γ‐tocopherol and its radicals. Both α‐ and γ‐tocopherol reduce lipid hydroperoxides, thus generating alkoxyl radicals which are able to amplify the rate of lipid oxidation by participating in chain propagation reactions.     

Efficacy of myricetin as an antioxidant in methyl esters of soybean oil

The antioxidant activity of myricetin, a natural flavonol found in fruits and vegetables, was determined in soybean oil methyl esters (SME) and compared with α‐tocopherol and tert‐butylhydroquinone (TBHQ) over a 90‐day period employing EN 14112, acid value, and kinematic viscosity methods. Myricetin had greater antioxidant activity than α‐tocopherol, but was inferior to TBHQ. Synergism was observed between myricetin and TBHQ, but antagonism between α‐tocopherol and either myricetin or TBHQ was discovered. A binary mixture of myricetin and TBHQ at 1000 ppm (1:1) was the most effective treatment investigated at inhibiting oxidation of SME. Myricetin was not completely soluble in SME at 1000 ppm, suggesting that 500 ppm is a more appropriate treatment level. Pro‐oxidant activity of α‐tocopherol was observed when added to SME obtained from crude soybean oil, but antioxidant behavior was observed in distilled SME. Addition of α‐tocopherol to methyl esters initially free of antioxidants revealed that 600–700 ppm was the optimum concentration for antioxidant activity. Acid value and kinematic viscosity remained within prescribed specifications after 90 days, despite failure of a number of samples with regard to EN 14112, suggesting that these parameters are insufficient as sole indicators of oxidation stability.     

Antioxidant activity of blackcurrant seeds extract and rosemary extracts in soybean oil

The objective of this research was to investigate the antioxidative properties of extract from blackcurrant seeds (BCSs) and commercially available rosemary extracts (Stabiloton OS, oil‐soluble and WS, water soluble) in soybean oil (SO). The antioxidant activity of plant extracts was compared with those of α‐tocopherol and butylated hydroxytoluene (BHT). The results of present research reveal differentiation of action of investigated extracts toward primary (peroxide value (PV), conjugated dienes (CDs)) and secondary (measured as anisidine value (AV), hexanal) oxidation products in SO. WS and OS rosemary extracts show high efficiency in delaying primary and secondary oxidative changes. BCSs extract markedly retards oxidation, nevertheless its activity falls down with formation and succeeding deterioration of primary products. Although the use of BCSs, residues of fruit processing, as a source of antioxidants would be reasonable because of economic and environmental reasons, it may be limited by low activity toward secondary oxidation products in certain lipid substrates. Taking primary oxidative changes into consideration, all extracts studied perform better than used standard antioxidants – BHT and α‐tocopherol.     

The effect of temperature on the antioxidant activity of tocopherols

The effect of temperature on the antioxidant activity of α‐ and δ‐tocopherol (at 100 mg/kg level) was studied in pork lard, using the Oxipres apparatus, in the temperature range from 80 to 150 °C. The antioxidant activity of δ‐tocopherol decreased with increasing working temperature in the whole temperature range studied. The activity of α‐tocopherol was practically constant in the temperature range from 80 to 110 °C and decreased with increasing temperature at temperatures higher than 110 °C. Both tocopherols were ineffective at 150 °C (p <0.05). Due to different temperature effects on the antioxidant activities of α‐ and δ‐tocopherol, the δ‐tocopherol activity was approximately two times higher than the α‐tocopherol activity at 80 °C, but their activities were the same (p <0.05) at 130 °C.     

Long-term storage stability of biodiesel produced from Karanja oil

Biodiesel is an alternative diesel fuel made from vegetable oil or animal fat. It is more susceptible to oxidation or autoxidation during long-term storage than conventional petrodiesel. Karanja oil methyl ester (KOME) was prepared and stored for a period of 180 days under different storage conditions. The physicochemical parameters, peroxide value (PV) and viscosity (v) of samples were measured at regular interval of time under different storage conditions. The stability of Karanja oil methyl ester (KOME) was studied under different storage conditions. The stability of KOME was improved by adding different antioxidants Tert-Butylated Hydroxy toluene (BHT), Tert-Butylated Hydroxyanisole (BHA), Pyrogallol (PY), Propyl galate (PrG) and Tert-Butyl Hydroxyl Quinone (TBHQ). The effectiveness of three antioxidants BHT, BHA and PrG on Karanja oil methyl ester was examined at varying loading level during the storage period.     

Experimental Design Applied for Cost and Efficiency of Antioxidants in Biodiesel

Oxidation stability is a parameter of great importance for biodiesel quality control to both producers and subsequent consumers. To maintain the quality of biodiesel, currently the most effective and economical method is the addition of antioxidants that prevent or retard the biofuel oxidation reaction. In this study, efficiency and cost of synthetic antioxidants added to B100 biodiesel from soybean oil and pork fat were evaluated, using butylhydroxyanisole (BHA), butylhydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ), in pure form or in mixtures, according to a simplex-centroid mixture experimental design. Results demonstrate an increased induction period (IP) in all trials when compared to the control sample, and TBHQ was the only antioxidant alone that met all the specification standards, while BHT and BHA alone met only the American standard specifications. The antioxidant mixture that presented the highest synergistic effect was that of TBHQ and BHA. Multi-response optimization indicated an optimum formulation containing 75 % TBHQ and 25 % BHA with an IP of 7.27 h at 110 °C and the antioxidant mixture cost of 31.31 USD, to be added for a ton of biodiesel. This simplex-centroid mixture experimental design shows an ability to be applied in the biodiesel, oils and fats industry to evaluate the oxidation stability and the occurrence of synergism between different mixtures of synthetic or natural antioxidants and their costs.