Oxidative Stability Index Research Articles

Protective effect of hydroxytyrosol and rosemary extract in a comparative study of the oxidative stability of Echium oil

The oxidative stability of Echium oil has been studied by two accelerated oxidation methodologies namely Rancimat and differential scanning calorimetry at selected temperatures in the range 50–110 °C. Kinetic analyses have provided Arrhenius parameters, oxidative stability indexes (OSI), temperature coefficients (tcoef), Q10 and OSI at 20 °C (OSI20) for both methodologies focussing on secondary and tertiary oxidation products. Peroxide, p-anisidine and polar compounds values have been measured to characterize from primary to tertiary oxidation products. In general, susceptibility of this oil to oxidation has been found to be larger than for other vegetable oils, according to the OSI20 values estimated by Rancimat and differential scanning calorimetry. However, the values of tcoeff and Q10 are found to be similar to those described for vegetable oils. In addition, a study of the influence of two antioxidants, namely hydroxytyrosol and rosemary extract on the oxidative stability of Echium oil has been carried out using both methodologies. Protective effects over oxidation by up to a threefold increase of OSI20 values have been found for both antioxidants at the highest dose utilized.

Physicochemical, chromatographic, oxidative, and thermogravimetric parameters of high-oleic peanut oil (Arachis hypogaea L. IAC-505)

The objective of this study is to evaluate the physicochemical, chromatographic, and thermogravimetric parameters and the oxidative stability of the high-oleic peanut oil (IAC-505) obtained by hydraulic pressing extraction. The analyses were performed according to the International and Official Methods of Analysis (AOAC, AOCS). The high-oleic peanut oil (IAC-505) was obtained by hydraulic pressing and stored at 4 °C. The acidity value (1.20 mg KOH g−1) and peroxide value (3.75 mEq kg−1) obtained were within the maximum values established by the National Health Surveillance Agency (ANVISA) for cold-pressed oil. The fatty acid profile showed high levels of oleic fatty acid (81.88%). The thermogravimetric behavior and differential analysis indicated good stability upon gradual temperature increase around 200 °C. The oxidative stability index or oxidation induction period of the oil was 15.74 h. The differential scanning calorimetry showed crystallization temperature of − 5 °C and − 33 °C and melting temperature of − 16 °C and − 6 °C. Based on the results obtained, the nutritional and functional quality, mass loss pattern, and oxidative stability of the high-oleic peanut oil (IAC-505) were determined, demonstrating its potential applications in various industrial segments and in food technology research.

Frying stability time of olive oils estimated from the oxidative stability index

Six refined olive oil samples were characterized to have wide ranges of compositional indicators (the ratio between monounsaturated and polyunsaturated fatty acids = 3.9–9.6; peroxide value = 1.3–7.0 meq/kg; acid value = 0.4–0.6 mg/g; total tocopherols = 150–459 mg/kg; total phenolics = 11–39 mg/kg). Oxidative stability index (OSI) and frying stability time (the time required to reach a total polar compounds, TPC, of 25%, a conjugated diene value, CDV, of 25 mmol/l, and a carbonyl value, CV, of 47 µmol/g) of the olive oils were monitored under two thermal (Rancimat at 110–140 °C) and frying (at 180 °C) processes, respectively. The values of OSI ranged from 7.1 to 16.9 h at 110 °C, which significantly decreased to 0.9–1.9 h at 140 °C. Frying stability times were calculated to be 38.3–56.6 h, 25.6–64.1 h, and 32.4–55.3 h in terms of TPC, CDV, and CV, respectively. The greatest correlations (R2 ≥ 0.97) were obtained between the OSI at 110 °C and the frying stability times. The CV-based frying stability times provided the highest correlations at all temperatures used in the thermal process.

Effect of Added Black Cumin Seed (Nigella sativa L) Oil on Oxidative Stability of Flaxseed Oil

Background: Lipid oxidation has adverse effect on food deterioration and human health. Oxidative reactions limit the shelf-life of fresh and processed foodstuffs which are of great concern in the vegetable oil and fat industry.
 Aim: The antioxidant activity of Black Cumin (Nigella sativa L) Oil (BCO) as a source of natural antioxidants was compared against a synthetic antioxidant (BHA). Its oxidative stability was evaluated in Flaxseed oil (as the most sensitive oil against oxidation) in concentrations of BHA (200ppm).
 Study Design: Oils were analyzed for the composition of fatty acids, tocopherols and for some physicochemical properties [Peroxide (PV), P-Anisidine (AV),TOTOX values, Thiobarbituric acid, Iodine value, Oxidative stability (OS)and Refractive index]to assess the extent of oil deterioration during 30th days of storage.
 Place and Duration of Study: Islamic Azad University of Varamin and Tehran University, Tehran, Iran, From March 2018 to April 2018.
 Methodology: Optimal condition was investigated to protect edible oil like flaxseed oil from oxidative reaction. Black cumin seeds and flaxseeds were pressed separately by cold press. Then BCO was prepared at five concentration levels of 5, 10, 15, 20 and 25% (w/w) and added to Flaxseed oil. In terms of antioxidant activity, they were analyzed by Gas Chromatography and compared with sample containing 200 ppm of synthetic antioxidant (BHA) during 30thdays at ambient temperature (22-25° C).
 Results and Conclusion: The results showed that different levels of BCO were able to slow down the lipid oxidation well, but the effect of sample contained 5% BCO was higher than other levels and has potential source of natural antioxidant for the application in food industry to prevent lipid oxidation.

Bioactive compounds, antioxidant and antimicrobial activities of Arum maculatum leaves extracts as affected by various solvents and extraction methods.

The different species of Arum maculatum plant can be found in all over the world, and a wide range of medicinal applications has been mentioned for them. Thus, it can also be valued as a source of natural compounds with antioxidant and antimicrobial activities. In this study, the effect of solvents (water, ethanol, ethanol:water (50:50)) and extraction methods (maceration and ultrasound) on the extraction yields and bioactive properties of extracts were analyzed. The antioxidant capacity of Arum maculatum leaves extracts was investigated, and the concentrations of total phenolics, tocopherols, tannins and flavonoids were determined. 1,1‐diphenyl 2‐picrylhydrazyl free radical (DPPH), β‐Carotene bleaching, and oxidative stability index (OSI) were used to determine antioxidant activity. The ability to scavenge radicals was measured in these experiments by the discoloration of the solution. Also, the antimicrobial activity of different extracts against Gram‐positive (Staphylococcus aureus and Listeria monocytogenes) and Gram‐negative bacteria (Escherichia coli, Salmonella enteritidis, and Pseudomonas aeruginosa) was evaluated by using of microdilution and agar diffusion assays. The results demonstrated that ultrasonic extracts (especially ethanol:water (50:50) solvent) had the higher extraction yield and antioxidant potential than maceration extracts. All extracts were effective against all tested bacteria, and Listeria monocytogenes was the most sensitive bacterium with lowest MIC value (12.5 mg/ml) and biggest diameter of growth inhibition zone (13.77 mm). Generally, this Arum maculatum leaves extracts can be suggested as an economical source of antioxidant and antimicrobial agents and can be a suitable substitute for artificial and chemical food preservatives.

Stability and volatile oxidation compounds of grape seed, flax seed and black cumin seed cold-pressed oils as affected by thermal oxidation

The old-pressed oils (CPO) from grape seeds (GSO), flax seeds (FSO) and black cumin seeds (BSO) were analyzed for their fatty acid profiles, tocopherols, total phenolics, bioactives and phenolic compositions. The stability of CPO under thermal oxidation conditions was evaluated. The main fatty acid in FSO was linolenic acid (56.5% of total fatty acids); while GSO and BSO were rich in linoleic acid, which accounted for 66.8 and 56.8%, respectively. GSO was rich in ?-tocopherol (123.0 mg/kg), while ?-tocopherol was a prevalent isomer in FSO and BSO (137.9 and 128.9 mg/kg, respectively). The total phenolic contents in the oils ranged from 554 mg GAE/kg oil (FSO) to 1140 mg GAE/kg oil (BSO). Luteolin, dihydroquercetin and benzoic acids were the dominant bioactives and phenolics in FSO, GSO and BSO, respectively. Based on the oxidative stability index (OSI) value, BSO showed the highest value (6.14 h) among the other oils. The oxidative stability of FSO and BSO were higher than GSO according to peroxide value (PV) and conjugated diene (CD) values of the oils during storage at 60 °C. Hexanal, 2,4-heptadienal and (E,E)-2,4-heptadienal were the major volatile oxidation compounds (VOC) in FSO. Hexanal and (E)-2-heptanal were the main identified VOC in the GSO and BSO under the same oxidation conditions.

Nutritional composition of raw and fried big-scale sand smelt (Atherina boyeri) from trasimeno lake

The aim of this research was to investigate the nutritional composition of raw and fried big-scale sand smelt (Atherina boyeri) from Trasimeno Lake. Four hundred big-scale sand smelts were caught with nets and analysed immediately. We created a total of 20 batches with 20 whole fish in each batch. Ten batches were analysed as raw samples, while the other 10 batches were analysed after being fried in sunflower oil at a temperature of 190 °C for 3 min (deep fat frying). The pH, proximate composition, fatty acid profile, oxidative stability and nutritional indexes of both groups were assessed. As expected, cooking strongly influenced the characteristics of the meat, mainly in terms of lipids, which were seven times greater in the fried product due to the oil. Frying also affected the fatty acid profile of the meat because oil absorption caused a significant increase in oleic and linoleic acids. Furthermore, we found a slight reduction in long chain n-3 fatty acids (eicosapentaenoic and docosahexaenoic acids). Frying increased oxidative processes and decreased the nutritional value of sand smelt. The obtained results can be considered preliminary because the effects of the fishing season and different physiological phases of sand smelt require further analytical confirmation.HighlightsThe aim of the research was to investigate the nutritional composition of raw and fried big-scale sand smelt (Atherina boyeri) from Trasimeno Lake.The fried big-scale sand smelt had a meat lipids content 7-times greater than the control, due to the oil adsorbition.Frying increased oxidative processes and decreased the nutritional value of big-scale sand smelt.

Characterization of Seed Oils of Pterodon emarginatus Vogel (Sucupira) Obtained by Different Extraction Methods

Abstract The present study aims to evaluate the influence of extraction methods on the quality of bioactive compounds and antioxidant capacity in Pterodon emarginatusVogel (sucupira) oils. The oils were extracted from the sucupira seeds by Soxhlet and by the extraction system of Bligh & Dyer. The oils were analyzed as to fatty acid profile, tocopherols, phytosterols, carotenoids, total phenolics, and total antioxidant capacity. The extraction by Soxhlet showed better yield of total lipids and was more efficient to extract tocopherols, phytosterols, and carotenoids, besides presenting better antioxidant activity by DPPH•. However, this method showed insufficient capacity to extract the polar lipid components of the sample, as evidenced by the low results of total phenolic compounds. On the other hand, the Bligh & Dyer method preserved the fatty acid profile and was also effective to extract higher phenolic compounds content and presented superior antioxidant activity when assessed by FRAP, ABTS•+, and oxidative stability index.

CHARACTERISTICS OF LIPIDS FROM IMMUNOCASTRATED MEDIUM-HEAVY PIGS FED EITHER A RESTRICTED DIET OR AD LIBITUM

We studied the feeding level-related variations in lipid characteristics in the adipose tissues of pigs. The lipid content, fatty acid profile, oxidative stability, iodine value, thrombogenic and atherogenic indices were determined in individual samples from 24 immunocastrated males (Duroc x Large White), fed either restricted or ad libitum. In backfat, feed restriction increased the polyunsaturated fatty acid proportion and iodine value and lowered the thrombogenic and atherogenic indices. Intramuscular lipid content was reduced by restriction, which did not affect either the fatty acid composition or the oxidative stability in both raw and cooked muscle. Feed restriction improved the nutritional quality of lipids without impairing their technological attributes.

Comparative study of chemical compositions and antioxidant capacities of oils obtained from two species of walnut: Juglans regia and Juglans sigillata

This study compared the lipid compositions, minor components contents, oxidative stability index, and free radical scavenging capacities of walnut oils from two species in China: Juglans regia (common walnut) and Juglans sigillata (iron walnut). The results showed that iron walnut oil contained lower C16:0 (4.97–5.25%) and special fatty acid (erucic acid C22:1). Common walnut oil provided higher tocopherols (441.03–490.32 mg/kg), phytosterols (1014.49–1211.40 mg/kg), squalene (4.41–5.21 mg/kg), and polyphenols (44.78–64.61 mg GAE/kg) and better antioxidant capacities. The walnut oil of the different walnut species could be distinguished by principal component analysis and hierarchical cluster analysis. In addition, multiple linear regression was employed to evaluate the contributions of minor components to the free radical scavenging capacity of the walnut oils and develop a predictive model for the antioxidant capacity of the oil. This information has important implications for the nutritional value and industrial production of walnut oil in China.

Stabilizing corn oil using the lemon balm (Melissa officinalis) antioxidants extracted by subcritical water.

This research was set up to identify the impact of the antioxidant compounds present in lemon balm extract (LBE) as obtained by the subcritical water (SBCW) method on the oxidative stability of corn oil. An extraction yield of 28.52% was obtained for the SBCW and rosmarinic acid was identified to be the predominant phenolic compound present in the LBE. The total phenolic content of the LBE was found to be 212.74mg gallic acid/g extract. Subsequently, 200, 400, 800, 1600 and 3200ppm of the LBE were added to corn oil and its peroxide value (PV), acid value (AV), conjugated diene (CD), carbonyl value (CV), oxidative stability index (OSI), total polar compound and total phenolic compounds were compared to control and the sample containing 200ppm of the BHA throughout the 16-day Schaal oven test at 70°C. Our findings indicated that the corn oil containing greater LBE concentration had lower PV, AV, CD, and CV but greater OSI than the control sample. Evaluation of total polar compounds confirmed lower extent of the compounds with high polarity in the greater levels of the LBE. Finally, the LBE was able to slow down the rancidity of corn oil and the samples with higher LBE exhibited gentle oxidation rate.

EFFECTS OF DIFFERENT ANTIOXIDANTS ON OXIDATIVE STABILITY OF SOYBEAN OIL IN PET BOTTLES EFEITOS DE DIFERENTES ANTIOXIDANTES NA ESTABILIDADE OXIDATIVA DO ÓLEO DE SOJA EM GARRAFAS PET

Lipid oxidation is responsible for physicochemical and organoleptic changes which reduce not only the food shelf life but also its acceptability. However, this deterioration process can be delayed or prevented by the addition of antioxidants. The aim of this study was to evaluate the effect of different antioxidants, pure and in combination (ascorbyl palmitate, rosemary extract and mix of tocopherols) compared to TBHQ (tert-butylhydroquinone) on oxidative stability index (OSI) of soybean oil stored in PET bottles by Rancimat at 120°C. The rancimat method is included in the AOCS Cd 12b-92 standard, due to the ease of use and reproducibility that allows the OSI evaluation in a relatively short period. Therefore, an accelerated shelf life study was performed at 60°C for 30 days. The results showed that all evaluated antioxidants and their combinations delayed the lipid oxidation of soybean oil. However, a mix containing ascorbyl palmitate and rosemary extract presented OSI (Oxidative Stability Index) similar to TBHQ. At the end of the 30th day, this referred blend of antioxidants had OSI of 4.83 hours at 120 °C, while treatment with TBHQ showed 5.90 hours at the same temperature. Thus, it was concluded that the evaluated concentration of the ascorbyl palmitate and rosemary extract blend may be an excellent alternative to TBHQ during the maintenance of the soybean oil shelf life in PET bottles.

Determination of the oxidative stability of olive oil using an integrated system based on dielectric spectroscopy and computer vision

During storage, olive oil may suffer degradation leading to an inferior quality level when purchased and consumed. Oxidative stability is one of the most important parameters for maintaining the quality of olive oil, which affects its acceptability and market value. The current methods of predicting the oxidative stability of edible oils are costly and time-consuming. The aim of the present research is to demonstrate the use of dielectric spectroscopy integrated with computer vision for determining the oxidative stability index (OSI) of olive oil. The most effective features were selected from the extracted dielectric and visual features for each olive oil sample. Three machine learning techniques were employed to process the raw data to develop an oxidative stability prediction algorithm, including artificial neural network (ANN), support vector machine (SVM) and multiple linear regression (MLR). The predictive models showed a great agreement with the results obtained by the Rancimat instrument that was used as a reference method. The best result for modelling the oxidative stability of olive oil was obtained using SVM technique with the R-value of 0.979. It can be concluded that this new approach may be utilized as a perfect replacement for quicker and cheaper assessment of olive oil oxidation.

Phytochemical Content, Minor‐Constituent Compositions, and Antioxidant Capacity of Screw‐Pressed Walnut Oil Obtained from Roasted Kernels

The screw‐pressed walnut oil produced from unroasted kernels and roasted kernels subjected to roasting at 140, 160, and 180 °C for 5, 10, and 15 min is analyzed and compared. The effects of roasting on the chemical compositions (acid value, peroxide value, fatty acid composition, tocopherols, phytosterols, squalene, and polyphenols), oxidative stability index (OSI), and free radical scavenging capacity (via DPPH, ABTS, FRAP, and ORAC assays) of walnut oil is investigated. It is observed that roasting yields slight changes in the acid values and fatty acid contents of walnut oils. Upon roasting walnut kernels at 180 °C for 10 and 15 min, the peroxide values (5.10 and 5.87 mmol kg−1) of oil are significantly increased. Roasting is observed to cause an increase in the amount of tocopherols (470.16–508.68 mg kg−1), phytosterols (1740.91–2048.05 mg kg−1), and polyphenols (30.08–44.82 mg GAE/kg) in the oil whereas the level of squalene (3.17–5.90 mg kg−1) decreases. In addition, the oxidative stability and antioxidant capacity of walnut oil increases with roasting, which could increase the amount of natural antioxidants in walnut oil, and produce Maillard reaction products with antioxidant effects.Practical Applications: Cold‐pressed oil is a good source of bioactive components and is favored by consumers. Screw‐pressed walnut oil obtained from roasted kernels has higher amounts of micronutrients, such as tocopherols, polyphenols, and phytosterols. These compounds exhibit strong antioxidant properties and thus are considered as health‐promoting substances. In effect, roasting is a suitable cold‐press pre‐processing method to produce walnut oil for application in healthcare.An analytic comparison is made of cold‐pressed walnut oil produced from unroasted kernels and roasted kernels that had previously undergone roasting. The qualitative and quantitative effects of roasting temperature and duration on the content of natural antioxidants in walnut oil are determined. Roasting walnut oil has significantly higher oxidative stability and free radical scavenging capacity than unroasted walnut oil.

Comparing Oil Color and Oxidative Stability among Mustard Genotypes under Nitrogen Fertilization

Core Ideas The oxidative stability index (OSI) which is the ratio of monounsaturated fatty acid/polyunsaturated fatty acid was slightly improved under N‐fertilization (N80). It is worthy to mention this is the first report on Brassica juncea studying the effect of fertilizer application on oil quality and a comparison among genotypes. Under the control (N0), the oxidative stability of oil was contributed by β‐carotene and at N80 application it was contributed by pheophytins. The change in the contents level of pigments and the rate of transformation of chlorophyll a to pheophytin a is was high compared to chlorophyll b to pheophytin b under N80. The oil with a shift in L*coordinate from 78 to 72 at N80 application showed a reduction in β‐carotene and an increase in pheophytin a. Effect of N fertilization (N80) on oil color was investigated in 24 genotypes of Indian mustard (Brassica juncea). Most of the genotypes were found to have oil color coordinates of L* 72 to 78, while a* and b* color coordinates did not vary. Genotypes with a shift in L* coordinates from 78 to 72 under N80 had lower β‐carotene content, which decreased from 11.3% (IC212031) to 68% (Maya). Among the two classes of pheophytins, pheophytin a was dominant under N80. Chlorophyll a was absent in almost all oil samples. In N80, the rate of degradation of chlorophyll a into its product pheophytin a was greater over that of the control (N0) as evident from the negative correlation of chlorophyll a and pheophytin a (r = –0.54). Peroxide value (PV) was negatively correlated to all pigments under N0. In the case of acid value (AV), under N0, the stability of oil seems to be more contributed by β‐carotene, whereas under N80, the oxidative stability of oil indicated by AV and PV appears to be contributed more by pheophytins. There was also improvement in oil stability index (OSI) under N80 as compared to N0 application. It is inferred that N fertilization does influence the oil pigmentation and its stability which is important for good quality oil.

Evaluation of oxidative stability, fatty acid profile, and antioxidant properties of black cumin seed oil and extract

Black cumin is a strong aromatic seed which can be used as a nutraceutical or medicinal food. Our aim was to evaluate the fatty acid profile and oxidative stability of black cumin seed (BCS) oil as well as the antioxidant activity of water–methanol extract of BCS compared with BHT. In fact, it was going to understand what kind of fatty acids exist in BCS oil and whether is it possible to apply BCS extract as a natural antioxidant or not. The physicochemical properties of BCS oil included an iodine value of 105.17 g/100 g oil, a PV of 11.88 meq/kg, an oxidative stability index of 16.48 h, viscosity of 21.3 mPas, and a refractive index of 1.45. BCS oil contained more than 79% unsaturated fatty acids. Its saturated fatty acids were composed mainly of palmitic acid (8.38%) and stearic acid (2.26%). The BCS extract contained 955.77 mg/kg total phenolics. In a DPPH assay, the IC50 of the BCS extract was measured as 104.76 mg/mL, while for BHT it was 8.06 mg/mL. In the incubation assay, the BCS extract inhibited the formation of oxidation primary products in raw soybean oil at a concentration of 100 mg/mL. To conclude, BCS oil had a high content of polyunsaturated fatty acids and in spite of its high degree of unsaturation, the presence of phenolic compounds in BCS oil led to an increase in its relative oxidative stability. Also, at higher concentrations, BCS extract can compete with BHT in terms of antioxidant effects, and thus can be added into edible oils.

Recovery and Characterization of Enzymatic Protein Hydrolyzates and Fat from Chicken Skin

AbstractChicken skin is a valuable source of proteins and fat. In this work, the efficacy of five commercial proteases (Alcalase, Protamex, Pancreatic trypsin, Neutrase, and Flavourzyme) was evaluated in enzymatic recovery of fat and protein hydrolyzates from chicken skin. The highest (49.19%) and lowest (8.92%) degrees of hydrolysis (DH) of protein were obtained using Alcalase and Flavourzyme, respectively. Protein hydrolyzates obtained using Flavourzyme showed the highest water‐holding capacity (WHC), oil‐holding capacity (OHC), and emulsifying activity index (EAI). The highest foaming capacity was observed in the hydrolyzate produced using Alcalase, Protamex, or Trypsin treatments. Hydrolysis using Protamex or Trypsin resulted in the highest fat yield (34.48–35.85%). Fatty‐acid composition, iodine value, unsaponifiable matter, and the amount of iron in chicken‐skin fats were not affected by the enzyme's type. The phosphorus content of chicken‐skin fat was in the range of 5.6–10.8 ppm, the lowest obtained by Flavourzyme. The oxidative stability index of the enzymatically extracted fat was in the range of 0.98–1.51 h at 110 °C. In conclusion, the enzyme type had a significant effect on some physicochemical properties of fat and protein hydrolyzates.

The impact of saturated monoacylglycerols on the oxidative stability of Canola oil under various time/temperature conditions

Due to the inconsistency of monoacylglycerols’ (MAGs) impacts and the lack of research concerning the weight of saturated monoacylglycerols on the oxidative stability of oils, the current study was designed. For this purpose, saturated MAGs at 0.5, 3.0 and 5.0% were added to canola oil and subsequently exposed to a Schaall oven test at 60 °C for 31 days (to assimilate moderate thermal conditions and a prolonged treatment time) and a Rancimat test at 110 °C (to assimilate extreme thermal conditions and shorter treatment time). To evaluate the quality and oxidative stability parameters of MAG-containing canola oil, free fatty acids (FFA), peroxide value (PV), and the oxidative stability index (OSI) were determined. The findings indicated that with the increase in MAG levels, the FFA increased from 0.05 up to 0.2%. The PV increased from 2 to 100 meq/L with the increase in MAG concentration. Also, it was shown that OSI increased from 12.20 to 13.10 h, which was proportional to MAG concentration.

Influence of Ultrasound-Assisted Extraction on Bioavailibity of Bene Hull (Pistacia Atlantica Subsp. Mutica) Extract: Testing Optimal Conditions and Antioxidant Activity

The central composite rotatable design by response surface methodology was applied for optimization of ultrasonic extraction conditions of Bene hull (Pistacia atlantica subsp. Mutica) polyphenols. The sonication time, temperature and ethanol-water ratio were independent parameters studied for the extraction optimization. Total polyphenols and antioxidant potentials of extracts in terms of ferric reducing antioxidant potential (FRAP), DPPH scavenging activity and oxidative stability index (OSI) were determined. The obtained data were well consistent with the polynomial equations by significant variation in linear, quadratic and interaction impacts of the process factors. The optimized extraction conditions were sonication time, 26.91 min, temperature, 50.42 °C and ethanol concentration, 55.84%. The total polyphenols, DPPH, FRAP an OSI of optimal extract were 304.47 mg GAE/g, 72.47%, 54.04 mmol/100g and 8.55 h, respectively. High performance liquid chromatography (HPLC) analysis of optimal extract detected presence of epicatechin, chlorogenic, sinapic, caffeic and gallic acids.

Jussara berry (Euterpe edulis M.) oil-in-water emulsions are highly stable: the role of natural antioxidants in the fruit oil.

Antioxidants help prevent lipid oxidation, and therefore are critical to maintain sensory quality and chemical characteristics of edible oils. Jussara berry (Euterpe edulis M.) oil is a source of minor compounds with potential antioxidant activity. The aim of this work was to investigate the role of such compounds on the effectiveness to prevent or delay oxidation of oil present in oil-in-water emulsions, and how the emulsions' physical stability would be affected. Jussara berry oil extracted by ethanol extraction, its stripped variations (partially stripped, highly stripped and highly stripped with added butylhydroxytoluene), and expeller-pressed oil were used to prepare oil-in-water emulsions. Jussara berry oils were analyzed before emulsions preparation to ensure their initial quality and composition, and oil-in-water emulsions were analyzed regarding their oxidative and physical stability. Ethanol extracted oil emulsion presented higher oxidative stability than highly stripped oil emulsion with added synthetic antioxidant butylahydroxytoluene (oxidative stability index 45% lower, after 60 days, and reached undetectable levels after 90 days). All emulsions remained physically stable for up to 120 days of storage. Our results indicate that natural antioxidants in jussara berry oil protect emulsions from oxidation while keeping physical stability unchanged. © 2018 Society of Chemical Industry.