Oxidative Stability Index Research Articles

Characterization of the Quality and Oxidative Stability of Hemp-Oil-Based Oleogels as an Animal Fat Substitute for Meat Patties.

The effect of the incorporation of rice bran wax (5%; 7%) or candelilla wax (3%; 7%) for production of hemp-oil-based oleogels was analyzed in this study. The experiment was carried out to replace between 0 and 100% of animal fat in meat patties with oleogels. Free fatty acids (FFAs), acid value (AV), oxidative stability index (OSI), conjugated diene value, malondialdehyde value, physicochemical properties, and the sensory properties of oleogels and meat patties were studied. The results indicated that hemp oil had more polyunsaturated fatty acids and lower oxidative stability when compared to oleogels. The OSI for oil was 3.1 h, while for oleogels it was 3.4-3.6 (candelilla case) or 3.7-3.9 (rice bran). Oleogels were able to match pork fat texture properties such as spreadability and adhesiveness in meat patties. However, sensory data for cooked meat patties with animal fat fully replaced by oleogels revealed that samples with 100% pork fat had higher juiciness and taste intensity. Our results showed that a wax-based oleogel had a higher oxidative stability and nutritional profile, but further investigations to mimic pork fat properties in meat patties are necessary.

Evaluation of antioxidant properties of nanoencapsulated sage (Salvia officinalis L.) extract in biopolymer coating basedon whey protein isolate and Qodumeh Shahri (Lepidiumperfoliatum) seed gum to increase the oxidative stability ofsunflower oil.

Sage leaf extract (SLE) is considered an excellent source of bioactive compounds mainly because of its high content of phenolics, widely known as natural antioxidants. This study aimed to compare the performance of free/encapsulated SLE by different coatings in protecting sunflower oil against oxidative deterioration. The coating materials were whey protein isolate and qodumeh seed gum at different ratios (1:0, 1:1, and 0:1). Each nanocapsule was analyzed for particle size, zeta potential, encapsulation efficiency, phenolics release, and SEM images. The total phenolic compounds of SLE were 31.12 mg GA/g. The antioxidant activity of SLE was increased in both DPPH and FRAP assays by increasing extract concentration from 50 to 250 ppm. All nanoparticles exhibited nanometric size, negative zeta potential, encapsulation efficiency higher than 60%, and gradual release during storage. The oxidative stability of sunflower oil with or without the incorporation of 250 ppm of free/encapsulated SLE was evaluated during 24 days of storage at 60°C. Peroxide value (PV), thiobarbituric acid value (TBA), oxidative stability index (OSI), color index (CI), and conjugated dienes (CD) were determined. COPM nanoparticles showed the lowest PV, TBA, CI, and CD but both SGUM and WHEY were more effective in delaying oil oxidation than TBHQ and free extract. Higher OSI was observed in oil-containing nanoparticles with composite coating. Results obtained reinforce the use of whey protein isolate and qodumeh seed gum as a coating for encapsulating SLE to increase the shelf life of sunflower oil as a natural antioxidant.

Effects of different extraction methods on the physicochemical properties and storage stability of tiger nut (Cyperus esculentus L.) oil

Tiger nut (Cyperus esculentus L.) tubers are promising resources in the oil industry due to their high yield and oil content. In this study, five tiger nut oils, namely, cold pressing oil (CPO), roasted-pressing oil (RPO), solvent leaching oil (LPO), aqueous enzymatic extraction oil (AEO), and subcritical fluid extraction oil (SEO) were obtained, with yields of 14.00%, 9.80%, 20.80%, 14.60%, and 23.50%, respectively. After accelerated storage, their unsaturated fatty acid contents and tocopherol contents decreased significantly by 2.20–3.59% and 8.66–23.07 mg/100 g, respectively. Aldehydes formed by oil oxidation were the main volatiles in CPO (58.478%), RPO (34.471%), and AEO (47.780%), while the main volatiles in LPO and SEO were still alkanes (38.488–40.210%). Oxidative deterioration of oils was also characterized by nuclear magnetic resonance, differential scanning calorimetry, and physicochemical properties (e.g., peroxide value, acid values, p-anisidine values, iodine values, 2-thiobarbituric acid levels, conjugated diene/triene values, refractive indices, and color). The above results all demonstrated the superior storage stability of LPO and SEO, which was also consistent with the high oxidative stability indices of LPO (125.0 h) and SEO (61.5 h) than other oils (4.8–11.8 h). This study will benefit to the development of tiger nut oil in the edible oil field.

Dual feedstock pyrolysis of Aegle marmelos pressed seed cake and novel Annona squamosa seed particles: the effect of dual natural antioxidant on the oxidation stability of derived co-pyrolysis liquid-A green approach

Numerous research programs are currently underway to introduce bio-fuel as a substitute for fossil fuels. At present, pyrolysis oil is used as a blend along with diesel but the usage of pyrolysis oil as a fuel in the engine is highly tedious because of its unstable nature. In this study, the stability of pyrolysis oil (ASTM D7467) is examined by adding 10% of Hibiscus rosasinesis (HRS) and 10% of green tea leaves (GTL) extracts as natural anti-oxidants. For the production of pyrolysis oil, co-pyrolysis of Aegle marmelos (AM) pressed seed cake and Annona squamosa (AS) seed particles was used (50:50 wt.%) as a new feedstock. Rancimat apparatus is used to analyze the oxidation stability index (OSI) of the raw co-pyrolysis oil and natural anti-oxidant doped co-pyrolysis oil. The OSI for the co-pyrolysis oil was improved to 3.97 h from 1.5 h by adding the HRS natural anti-oxidant extract, which met ASTM-D 6751 (American) standards. The GTL natural anti-oxidant extract was improved the OSI of co-pyrolytic liquid 6.45 h from 1.5 h, which is satisfied the both American and EN 14214 (European) standard. Hence, HRS and GTL extracts able to use as an eco-friendly anti-oxidant instead of synthetic anti-oxidants for enhancing the bio-fuel stability.

Oxidative stability of microalgae oil and its acylglycerol mixture obtained by enzymatic glycerolysis and the antioxidant effect of supercritical rosemary extract

The oxidative stability of microalgae oil (MO) and its enzymatic glycerolysis product (GP) have been determined by using the accelerated oxidation methods differential scanning calorimetry (DSC) and Rancimat at temperatures in the range 50–90 °C. Kinetic analyses of MO and GP provide Arrhenius activation energy and activation enthalpy and entropy, temperature coefficients, Q10 and oxidative stability index at 20 °C (OSI20), based on secondary and tertiary oxidation products. Susceptibility of microalgae oil to oxidation has been compared to that of fish and vegetable oils, with OSI20 values of 647 h for MO and 381 h for GP. The tcoeff and Q10 values are very similar to those observed for fish and vegetable oils. Protective effect from oxidation of a supercritical rosemary extract (RE) for both MO and GP have been evaluated. In the presence of this antioxidant, up to twofold increase of OSI20 has been obtained for MO. Lower protection for GP was observed. Activity antioxidant Index (AAI), related to the mechanism of action of the antioxidant, should be carefully examined for a reliable determination of OSI20 values.

Combination of Spray-Chilling and Spray-Drying Techniques to Protect Carotenoid-Rich Extracts from Pumpkin (Cucurbita moschata) Byproducts, Aiming at the Production of a Powdered Natural Food Dye.

Reducing waste, using byproducts, and natural food additives are important sustainability trends. In this context, the aim of this study was to produce and evaluate a natural food dye, extracted from pumpkin byproducts, powdered and protected by spray-chilling (SC) and a combination of spray-drying and spray-chilling techniques (SDC). The extract was obtained using ethanol as solvent; vegetable fat and gum Arabic were used as carriers. Formulations were prepared with the following core:carrier ratios: SC 20 (20:80), SC 30 (30:70), SC 40 (40:60), SDC 5 (5:95), SDC 10 (10:90), and SDC 15 (15:85). The physicochemical properties of the formed microparticles were characterised, and their storage stability was evaluated over 90 days. The microparticles exhibited colour variation and size increase over time. SDC particles exhibited the highest encapsulation efficiency (95.2-100.8%) and retention of carotenoids in the storage period (60.8-89.7%). Considering the carotenoid content and its stability, the optimal formulation for each process was selected for further analysis. All of the processes and formulations produced spherical particles that were heterogeneous in size. SDC particles exhibited the highest oxidative stability index and the highest carotenoid release in the intestinal phase (32.6%). The use of combined microencapsulation technologies should be considered promising to protect carotenoid compounds.

Modification of the Nutritional Quality and Oxidative Stability of Lupin (Lupinus mutabilis Sweet) and Sacha Inchi (Plukenetia volubilis L.) Oil Blends.

Andean lupin (Lupinus mutabilis) oil is rich in monounsaturated (54.2%) and polyunsaturated (28.5%) fatty acids but has a ω-3:ω-6 ratio (1:9.2) above the recommended values for human health. Sacha inchi (Plukenetia volubilis) oil presents a high polyunsaturated fatty acid content (linolenic 47.2% and linoleic 34.7%), along a ω-3:ω-6 ratio (1:0.74) good for human consumption. The objective of this research was to study the physico-chemical properties and oxidative stability of tarwi and sacha inchi oil blends (1:4, 1:3, 1:1, 3:1 and 4:1 w:w) with suitable ω-3:ω-6 ratios. All blends showed ω-3:ω-6 ratios between 1:0.8 and 1:1.9, acceptable from a nutritional point of view, and high total tocopherols' content (1834-688 mg/kg), thanks to sacha inchi. The oxidative stability index (OSI) of the mixtures by the Rancimat method at 120 °C ranged from 0.46 to 8.80 h. The shelf-life of 1:1 tarwi/sacha inchi oil blend was 1.26 years; its entropy (-17.43 J/mol), enthalpy (107.04 kJ/mol), activation energy (110.24 kJ/mol) and Gibbs energy (113.76 kJ/mol) suggest low oxidation reaction rates and good stability. Hence, balanced blends of tarwi/sacha inchi oils can achieve optimal nutritional properties and enhanced shelf-life.

Fluorescence Monitoring Oxidation of Extra Virgin Olive Oil Packed in Different Containers.

'Picual' olive oil was stored in different types of containers for 10 months and monitored via quality parameters. In combination with the mentioned analysis, non-destructive fluorescence spectroscopy was performed combined with multivariate analysis to monitor and quantify oil quality levels. Excitation emission matrices (EMMs) were analyzed using parallel factor analysis (PARAFAC). According to the quality parameters, it was observed that Transparent Crystal (TC) and Opaque Crystal (OC) samples were the ones that deteriorated faster due to their higher exposure to light in comparison with Plastic (P) and Canned (C) samples. In a fast and non-destructive manner, the fluorescence spectroscopy-based prototype successfully monitored the oxidation changes in the EVOOs. Unfolded partial least squares (U-PLS) was used to generate a regression model to quantify quality parameters. Good correlation coefficients were found for the peroxide index, K232 and the oxidative stability index (r2 between 0.90 and 0.94 for cross-validation and validation). For all of that, the results obtained confirmed the ability of fluorescence spectroscopy to monitor the quality of olive oil and EEMs combined with U-PLS can be used to analyze these parameters, eluding the classical methods.

Influence of different thermal treatment methods on the processing qualities of sesame seeds and cold-pressed oil

This study investigated the impact of multiple thermal treatments (explosion-puffing, microwave, and roasting) on the processing qualities of sesame seeds and cold-pressed oil. The scanning electron microscopy (SEM) showed fissures and cavities of sesame seed surface upon thermal treatments. The microwave treatment promoted the maximum conversion of sesamolin into sesamol in the sesame oil. Compared with other treatments, explosion-puffing treatment resulted in most significant increases in the multiple beneficial phytochemicals, as well as in vitro antioxidant properties determined by 2,2-dipheny1-1-picrylhydrazyl radical (DPPH) radical scavenging activity, Ferric reducing antioxidant power (FRAP) and oxidative stability index (OSI). Additionally, thermal treatment processing caused varying degrees of damage of crude protein, total amino acids (TAA) and protein structure (tertiary and second structure). In which, explosion-puffing achieved minimal reduction in the first two indicators. Collectively, explosion-puffing might be a preferable thermal treatment method for industrial sesame processing with improved quality specifications.

Oxidative stability and health-related indices of anhydrous milk fat and vegetable oil blends

Anhydrous milk fat (AMF), although relatively resistant to oxidation due to its low content of polyunsaturated fatty acids (FAs), raises certain health concerns due to a high saturated FAs content. Blending AMF with other edible fats is an ideal strategy for modifying its FA profile, health-promoting properties and oxidative stability. Addition of 30% vegetable oils to AMF significantly modified its FA profile. Oils with a high unsaturated FAs content, i.e., walnut, grapeseed and linseed oils, were particularly effective in increasing the content of unsaturated FAs in AMF and reducing its atherogenicity index and thrombogenicity index. AMF and vegetable oil blends were characterised by higher oxidative stability than pure vegetable oils. Blends comprising AMF and oils abundant in monounsaturated FAs, i.e., hazelnut, rapeseed and peanut oils, were most resistant to oxidation. Depending on intended use, the properties of AMF can be easily and cheaply modified through blending with selected vegetable oils.

Oxidative stability of Moringa oleifera seed oil: Effect of degumming and deodorization on tocopherol retention

AbstractMoringa oleifera seed oil (MSO) from Lombok was extracted by n‐hexane and evaluated after refining by several degumming methods to understand the impact of individual tocopherol retention and compared to extra virgin olive oil (EVOO) and high oleic palm oil (HOPO). MSO achieved an Oxidative Stability Index (15.8 h); EVOO (11.7 h) HOPO (8.83 h), based on two factors; the degree of unsaturation and total tocopherols, which did not accurately correlate with oxidation stability. The presence of tocopherol type affected the efficiency of heat stability in MSO, which is caused by a significant level of δ‐tocopherol (13.5 ppm), which was retained, through effective water degumming. Whereas, δ‐tocopherol in EVOO was not detected. This strongly suggests δ‐tocopherol contributes effectively against heat oxidation and thereby improved the overall stability of MSO.Novelty impact statementSeveral novelties are identified in this work, which at the time, could not be found within the literature: first, the type of phosphatide in Moringa Oleifera is in hydratable form. Hence, secondly, we propose the appropriate degumming method for Moringa Oleifera seed oil is by water degumming. And third, the particular tocopherol type most impacting the oxidative stability performance of Moringa Oleifera was identified as δ‐tocopherol.

Impact of infrared and dry‐air roasting on antioxidant potential, oxidative stability, chemical characteristics, and fatty acid profile of black and white sesame (Sesamum indicum L.) oil

AbstractThe present study reports the impact of infrared (IRR) and dry‐air roasting (DAR) at 160, 180, and 200°C for 5, 10, and 15 min on the moisture content of sesame seeds, oil extraction yield (OEY), chemical characteristics, oxidative stability index (OSI), viscosity, color, browning index (BI), pigments, radical scavenging activity (RSA), total flavonoid (TFC), and phenolic (TPC) content and fatty acid composition (FAC) of white sesame oil (WSO) and black sesame oil (BSO). The OEY, OSI, viscosity, BI, pigments, TPC, TFC, and RSA increased, whereas acid, peroxide, L*, and b* values of WSO and BSO declined by increasing DAR and IRR conditions. Fourier transform infra‐red spectra exhibited a minor variation in peak intensities that relate to changes in FAC and p‐AV of WSO and BSO. Both DAR and IRR techniques had improved WSO and BSO quality. However, DAR (180°C for 15 min) is suggested for enhancing WSO and BSO yield and quality characteristics.Novelty impact statementSesame oil is considered a highly nutritious and healthy oil owing to its desirable fatty acid composition. This study reported the impact of dry‐air and infrared roasting on sesame oil quality and stability characteristics. Dry‐air roasting at 180°C for 15 min proved effective for improving sesame oil stability and quality characteristics.

Effects of biodiesel degree of unsaturation, chain length and physical properties on tailpipe oxides of nitrogen (NOx)

Biodiesel degree of unsaturation and chain length have impacts on the NOx emissions in engines. This work presents experimental investigation of the effects of biodiesel degree of unsaturation (numbers of double bonds), chain length and physical properties on NOx emissions. A methodology to decouple the effects of degree of unsaturation and chain length is presented. Results shows that NOx emissions found to increase as the degree of unsaturation increases, peaking at an average degree of unsaturation of 1.5. Shorter chain length esters found to produce lower NOx emissions which were found to decrease until the chain length factor of 0.765 was reached. Finally, NOx emissions with biodiesel para-anisidine (pA), peroxide value (PV), total oxidation (TOTOX), conjugated dienes (CD), the oxidative stability index (OSI), Viscosity, Iodine number, bis-allylic position equivalents (BAPE) is presented.

Calotropis procera (Aiton) seeds fixed oil: Physicochemical analysis, GC–MS profiling and evaluation of its in-vivo anti-inflammatory and in-vitro antiparasitic activities

Calotropis procera (Aiton) is a wildly grown shrubbery that has been used by traditional healers in various remedies for centuries. Its different organs are reported to possess a variety of biological activities. However, a few reports chemically investigated the seed fixed oil, but they didn’t prospect its bioactivity. Accordingly, this study aimed to investigate the phytochemical composition, physicochemical properties, and biological activity of the seed oil. As well, exploration of the best extraction method that give the highest oil yield with the best composition. Physicochemical properties, total phenolic content and oxidative stability index of the oil were estimated. GC–MS analysis identified the oil content. Anti- inflammatory activity was examined using a carrageenan-induced rat paw edema assay. Immunomodulatory activity was determined by measuring the pro-inflammatory cytokines levels. Moreover, In- vitro anti-parasitic and antioxidant activities were studied. Soxhlet extraction method gives the highest yield of 40.5 ± 0.76% with no time interval. The oil shows a physicochemical property within the AOCS standards and low phenol content. GC-MS analysis reveals unsaturated fatty acids account for 75.25% of the oil, with an abundance of oleic acid (33.64%) and linoleic acid (31.95%). The oil exhibited potent anti-inflammatory and immunomodulatory activity. At various dose levels, paw edoema volume, pro-inflammatory cytokines, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO) serum levels were reduced. The seed oil is a promising candidate for the treatment of inflammation and/or inflammatory associated diseases (as parasitic infections) besides its immunomodulatory activity.

Confirmatory assessments of putative quality and nutritional properties of branded and unbranded commercial edible oils

Dietary associated non-communicable diseases have become a major concern and consumption of branded and unbranded vegetables oils may be one out of many probable contributing factors. Thus, the objective of this preliminary study was to access the nutritional qualities and trans-fat contents of 28 randomly selected three commonly consumed vegetable oils (crude palm oil CPO, soybean oil SBO, and peanut oil PNO) from cross-sectional area of the country. CPOs samples exhibited an upper limit of 5.18% for acidity, which is slightly outside minimum standard requirement for crude oil (<5.00%). Similarly, both SBOs and PNOs were above tolerant limit for acidity (>0.30%). Six of the nine CPOs had peroxide value > 8.0 meqO2/kg, while none of the refined oils was <1.63 meqO2/kg – an indication of oxidative instability. Although, moisture content, conjugated trienes and dienes were significantly higher in CPOs, but the oils exhibited lower trans-fat content with a range 0 – 6.27% compared to SBOs (3.73 – 9.72%) and PNOs (0.72 – 7.14%). CPOs were higher in total phenol (TPC), tocopherol (TFR), and carotenoid (CAR) contents, that could make up for the low oxidative stability indices. Among the variables predicting trans-fat contents of the oils using variable important projection (VIP) model, saturated, polyunsaturated (PUFA) fatty acids, acidity, PV and conjugated trienes had positive influence, while TPC, TFR, CAR, monounsaturated fatty acid (MUFA), and MUFA/PUFA ratio showed negative contributions. Thus, only few samples satisfied the ideal quality and nutritional requirements of edible oils.

Synthesis, Characterization, Tribological and Rheological Properties of Di (2-Butyloctyl) Dicarboxylate Esters for Environmentally Friendly Biolubricant Applications

The passion for replacing petroleum-based lubricants with renewable and sustainable alternatives has encouraged the development of plant-based biolubricants. In this work, a synthesis of di (2-butyloctyl) dicarboxylate esters for biolubricant base oil was carried out through esterification between selected dicarboxylic acids (succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, and dodecanedioic) with branched alcohol (2-butyl-1-octanol) catalyzed by sulphuric acid. The synthesized dicarboxylate esters showed high yield percentages in the range of 88 – 98 %. The chemical structures were confirmed using FTIR and NMR (1H and 13C) spectroscopies. The lubrication results show that the synthesized dicarboxylate esters have very good low-temperature properties with pour points less than −70°C. Furthermore, the esters' flash point, oxidative stability, and viscosity indices increased with their molecular weight. Tribological results have indicated that the tested dicarboxylate esters have good lubrication properties with a low friction coefficient (µ) range of 0.18-0.34 at 40 and 100°C. Rheological analysis showed that the di (2-butyloctyl) dicarboxylate esters were non-Newtonian. The synthesized products were categorized as ISO VG 32 and compatible with some selected commercial lubricants. These make them plausible to be used hydraulic fluids for various industrial applications such as gear, hydraulic, and transmission fluids in heavy machinery usage.

Effect of freezing, fast-freezing by liquid nitrogen or refrigeration to preserve premium extra virgin olive oil during storage

During storage, premium extra virgin olive oils (PEVOO), which are oils of exceptional sensory quality, may lose the organoleptic characteristics that define them. This study assessed the effect of applying modified atmospheres and low temperatures (refrigeration and freezing) on the quality of 4 PEVOO for 24 months. Also, the effect of two freezing methods was studied (in the freezer at − 20 °C and in a bath of liquid nitrogen), along with the impact of freezing on the quality of the oils after thawing and storing at room temperature. Official quality parameters, organoleptic assessment, phenolic compounds, volatile compounds and oxidative stability index were measured periodically. While no significant effect of headspace composition was found, the oils stored at − 20 °C maintained their initial quality better than the oils stored at room temperature. Physicochemical quality parameters remained unchanged throughout the 24 months at − 20 °C. Polar phenolic and volatile compounds associated with green and fruity aromas were better preserved at − 20 °C, which translated into a minimum change in the sensory profile of the oils. While no significant difference was observed regarding oxidative parameters, freezing at − 20 °C maintained the initial volatile and sensory profile of the oils better than freezing with liquid nitrogen. Lastly, quality of thawed oils showed no significant differences compared to control oils during storage at room temperature. In conclusion, storage at − 20 °C maintains the quality of PEVOO, especially their sensory profile, and does not compromise their quality after thawing.

Lippia grata essential oil complexed with β-cyclodextrin ameliorates biochemical and behavioral deficits in an animal model of progressive parkinsonism.

Parkinson's disease (PD) is identified by the loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNpc), and is correlated to aggregates of proteins such as α-synuclein, Lewy's bodies. Although the PD etiology remains poorly understood, evidence suggests a main role of oxidative stress on this process. Lippia grata Schauer, known as "alecrim-do-mato", "alecrim-de-vaqueiro", "alecrim-da-chapada", is a native bush from tropical areas mainly distributed throughout the Central and South America. This plant species is commonly used in traditional medicine for relief of pain and inflammation conditions, and that has proven antioxidant effects. We evaluated the effects of essential oil of the L. grata after its complexed with β-cyclodextrin (LIP) on PD animal model induced by reserpine (RES). Behavioral assessments were performed across the treatment. Upon completion the treatment, the animals were euthanized, afterwards their brains were isolated and processed for immunohistochemical and oxidative stress analysis. The LIP treatment delayed the onset of the behavior of catalepsy, decreased the number of oral movements and prevented the memory impairment on the novel object recognition task. In addition, the treatment with LIP protected against dopaminergic depletion in the SNpc and dorsal striatum (STRd), and decreased the α-syn immunoreactivity in the SNpc and hippocampus (HIP). Moreover, there was reduction of the oxidative stability index. These findings demonstrated that the LIP treatment has neuroprotective effect in a progressive parkinsonism model, suggesting that LIP could be an important source for novel treatment approaches in PD.

Comparison of Different Extraction Processes on the Physicochemical Properties, Nutritional Components and Antioxidant Ability of Xanthoceras sorbifolia Bunge Kernel Oil.

In this study, we investigated and compared the oil yield, physicochemical properties, fatty acid composition, nutrient content, and antioxidant ability of Xanthoceras sorbifolia Bunge (X. sorbifolia) kernel oils obtained by cold-pressing (CP), hexane extraction (HE), aqueous enzymatic extraction (AEE), and supercritical fluid extraction (SFE). The results indicated that X. sorbifolia oil contained a high percentage of monounsaturated fatty acids (49.31–50.38%), especially oleic acid (30.73–30.98%) and nervonic acid (2.73–3.09%) and that the extraction methods had little effect on the composition and content of fatty acids. X. sorbifolia oil is an excellent source of nervonic acid. Additionally, the HE method resulted in the highest oil yield (98.04%), oxidation stability index (9.20 h), tocopherol content (530.15 mg/kg) and sterol content (2104.07 mg/kg). The DPPH scavenging activity rates of the oil produced by SFE was the highest. Considering the health and nutritional value of oils, HE is a promising method for X. sorbifolia oil processing. According to multiple linear regression analysis, the antioxidant capacity of the oil was negatively correlated with sterol and stearic acid content and positively correlated with linoleic acid, arachidic acid and polyunsaturated fatty acid content. This information is important for improving the nutritional value and industrial production of X. sorbifolia.

Quality of red tilapia viscera oil (Oreochromis sp.) as a function of extraction methods

This study aimed to propose a simple and efficient heating-freezing method for oil recovery from red tilapia (Oreochromis sp.) viscera, suitable for industrial application and that does not affect its composition. Three methodologies for oil extraction were studied: a) direct heating (69 °C and 29 min) of samples followed by separation of the oil by decantation, b) direct heating with subsequent freezing and c) solvent extraction assisted by ultrasound. For the oil obtained by each methodology, the following factors were determined: peroxide and iodine values, oxidative stability index, yield percentages and fatty acid profile and, to evaluate the changes thereof, a thermal analysis by differential scanning calorimetry was performed. An oil extracted by centrifugation from fresh viscera was used as control. Results showed yields of 92,126%, 60,99% and 55,36% for the oil obtained by heating and freezing, heating and decanting and solvent extraction, respectively, the other evaluated parameters were similar among each other. The content of PUFA was not affected by heating when compared to the control oil, although a decrease was observed in the solvent extracted oil. This behavior was corroborated with the thermal analysis, which showed that the higher PUFA content, the lower the melting temperatures of the oils and the energy required for phase change. A principal component analysis allowed determining that while there are no differences in the abundance of fatty acids C20:1, 14:0, 18:0, 16:1 and C16:0, there are differences for fatty acids C18:1 and C18:2 depending on the method of extraction used in the oil obtention. The results of this study show that the heating-freezing extraction method is a good alternative for acquiring value-added products and facilitates their implementation in rural areas. Furthermore, allows obtaining a product with high content of polyunsaturated fatty acids (at least a third of the total content).