Oxidative Stability Of Canola Oil Research Articles

Improving the efficacy of phenolic extract from Pimpinella affinis in edible oils through nanoencapsulation: Utilizing chitosan and Salvia macrosiphon gum as coating agents

AbstractIn the present study, a phenolic extract derived from the Pimpinella affinis plant underwent nanoencapsulation. The nanoencapsulation process employed chitosan, Salvia macrosiphon gum (SMG), and a chitosan–SMG complex (1:1) (CCS) as coating agents. The evaluation of nanoemulsions encompassed measurements of particle size, polydispersity index (PDI), ζ‐potential, encapsulation efficiency, and intensity distribution parameters. The overall results of these assessments indicated that the nanoemulsion coated with CCS exhibited the most favorable characteristics when compared to other treatments. Subsequently, this specific nanoencapsulated sample was utilized to enhance the oxidative stability of canola oil at concentrations of 100, 200, and 300 ppm (parts per million). Oxidative stability tests, assessed through the total oxidation value (TOTOX) index, highlighted the superior performance of the nanoencapsulated extract, particularly at a concentration of 300 ppm. This enhancement can be attributed to the increased release of phenolic compounds from the CCS coating into the canola oil. The findings illustrate that the nanoencapsulation process can significantly enhance the efficacy of P. affinis extract in improving the oxidative stability of canola oil.

Enhancing canola oil's shelf life with nano-encapsulated Mentha aquatica extract for optimal antioxidant performance.

Incorporation of antioxidants, such as phenolic compounds into edible oils has limitations such as rapid release of phenolic compounds, low solubility, low penetration, low accessibility, and rapid degradation by environmental compounds. To solve this problem, the nano-encapsulation process is offering promising opportunities. In this research, for the first time, the phenolic extract of Mentha aquatica was nano-encapsulated in nano-emulsions coated with chitosan, Lepidium perfoliatum gum (LPG), and complex of chitosan and LPG (CCL) (1:1 ratio). Based on various tests (particle size measurement, ζ-potential, polydispersity index, encapsulation efficiency index, and intensity curve), the LPG coating was the most optimum option for nano-encapsulation compared to the other coatings. Thus, the LPG-assisted nano-encapsulated phenolic extract of M. aquatica was used to improve the oxidative stability of canola oil at three concentrations (100, 200, and 300 ppm). The results of peroxide value and anisidine index tests (as initial and secondary oxidation indicators, respectively) showed that the nano-encapsulation improved the antioxidant effect of M. aquatica when compared with free extract in canola oil. In a comparative approach, the best sample was obtained from the LPG-assisted nano-encapsulated extract (200 ppm) due to the release of more phenolic compounds. The findings from this study showcase how nano-encapsulation enhances the efficacy of antioxidants in edible oils.

Genetic improvement of tocotrienol content enhances the oxidative stability of canola oil.

Tocotrienols and tocopherols, which are synthesized in plastids of plant cells with similar functionalities, comprise vitamin E to serve as a potent lipid-soluble antioxidant in plants. The synthesis of tocopherols involves the condensation of homogentisic acid (HGA) and phytyl diphosphate (PDP) under the catalysis of homogentisate phytyltransferase (HPT). Tocotrienol synthesis is initiated by the condensation of HGA and geranylgeranyl diphosphate (GGDP) mediated by homogentisate geranylgeranyl transferase (HGGT). As one of the most important oil crops, canola seed is regarded as an ideal plant to efficiently improve the production of vitamin E tocochromanols through genetic engineering approaches. However, only a modest increase in tocopherol content has been achieved in canola seed to date. In this study, we transformed barley HGGT (HvHGGT) into canola to improve total tocochromanol content in canola seeds. The results showed that the total tocochromanol content in the transgenic canola seeds could be maximally increased by fourfold relative to that in wild-type canola seeds. Notably, no negative impact on important agronomic traits was observed in transgenic canola plants, indicating great application potential of the HvHGGT gene in enhancing tocochromanol content in canola in the future. Moreover, the oil extracted from the transgenic canola seeds exhibited significantly enhanced oxidative stability under high temperature in addition to the increase in total tocochromanol content, demonstrating multiple desirable properties of HvHGGT.

Fabrication of double nano-emulsions loaded with hyssop (Hyssopus officinalis L.) extract stabilized with soy protein isolate alone and combined with chia seed gum in controlling the oxidative stability of canola oil

The aim of this study was to encapsulate hyssop (Hyssopus officinalis L.) extract obtained through ultrasound-assisted cold plasma pretreatment extraction within a double emulsion stabilized by soy protein isolate alone (SPI) and combined with chia seed gum (CSG) in the external aqueous phase on the stabilization of canola oil. FTIR analysis verified that there were electrostatic interactions between CSG and SPI. The SPI/CSG-stabilized emulsion demonstrated lower viscosity, smaller droplets, higher ζ-potential, and encapsulation efficiency compared to the SPI-stabilized emulsion. Non-Newtonian, pseudoplastic behaviors were shown by emulsions. Also, according to the dynamic rheological parameters (G' and G''), the SPI/CSG-stabilized emulsion had elastic behavior with weak gel properties. The antioxidant activity of the encapsulated extract at 1500 ppm during the storage in canola oil was investigated and compared to unencapsulated extract and TBHQ. The results showed that oil containing encapsulated extract had lower oxidative alterations than the unencapsulated form.

The monoglyceride oleogel characteristics modified by carnauba wax

This study investigated the properties of distilled monoglyceride (DMG) and carnauba wax (CBW) oleogels at different weight ratios (100:0, 85:15, 70:30, 55:45, 40:60, and 0:100) (DMG:CBW) and two total gelator concentrations (GsC) (50 and 100 g/kg). In two-component oleogels, the presence of CBW slowed the polymorphic transition rate, reduced the releasable oil, and prevented the formation of large clusters. Both co-assembly and self-sorting gels developed in two-component oleogels. At the 85:15 ratio, the development of just mixed crystals over a long time and the formation of the eutectic system increased the oleogel properties. At high temperatures, the reduction rate of solid fat content (SFC) decreased with the increase in the CBW ratio. Bene kernel oil (BKO) considerably increased the oxidative stability of canola oil in the oleogel structure. Overall, the specific ratio of 85:15 demonstrated higher microstructure, oil binding capacity (OBC), texture, thermal, and oxidative stability properties. Moreover, the minimum extent of CBW and the formation of the eutectic system in this ratio restricted the waxy mouthfeel development.

The effect of antioxidant properties of free and encapsulated rosemary extract in liposome on the oxidation process of canola oil

SummaryThe antioxidant property of rosemary extract as a natural antioxidant on the oxidation process of canola oil has been reported and compared with the synthetic antioxidant butylated hydroxytoluene (BHT) (at 200 mg Lˉ1). The effect of free and liposomal encapsulated rosemary extract at concentrations of 200, 600 and 1000 mg Lˉ1 was evaluated on improving the oxidative stability of canola oil at 120°C using the Rancimat method. The changes in peroxide value, anisidine, TOTOX and thiobarbituric acid (TBA) have been determined by the Schaal oven test at 60°C. Liposomal rosemary extracts were prepared by the Mozafari method. Then physicochemical properties (Z‐potential, particle size and encapsulation efficiency (EE)) were determined. EE and the Z‐potential of liposomes were obtained at 54.59% and −65.1 mV, respectively. The particle size of empty and extract containing liposomes was determined 583.5 nm and 265.4 nm, respectively. The total polyphenol content of the rosemary extract by reagent of the Folin–Ciocalteu's phenol was determined as 164.2 mg gallic acid gˉ1 extract. Also, the activity of free radical scavenging of both liposomal encapsulated and free extracts, by the 2‐2‐diphenyl‐1‐picrylhydrazyl (DPPH) method, were 84.57% and 92.5%, respectively. The induction periods of oil containing liposomal rosemary extract at 600, 1000 mg Lˉ1 and free extract in level 1000 mg Lˉ1 was higher in comparison with samples containing BHT and blank (P ≤ 0.05). The incorporation of rosemary extract especially in liposome form into oil delayed the oxidation process. Based on the results of this study, to inhibit oil oxidation, rosemary extract, especially in the liposomal form, can be applied instead of synthetic antioxidants such as BHT.

Canola meal phenolic compounds electrosprayed into capsules to increase the oxidative stability of canola oil

Nano-encapsulation is a developing area of study across several fields, including the food, pharmaceutical, and cosmetic sectors. In this study, nanocapsules containing polyphenols were made from canola meal by electrospraying, and it was determined how the capsules' walls affected their shape, encapsulation efficiency, ζ-potential, and particle size. Furthermore, the impact of nanocapsules on canola oil was examined using the TBA index, oxidative stability, and iodine value. Our findings demonstrated that spherical nanoparticles were produced using electrospraying, and that the amount of wall materials used to create them had an impact on their size. Maltodextrin/β-cyclodextrin at a ratio of 1:1 resulted in the smallest capsule sizes, with an encapsulation efficiency of 68% and an 80% release over 40 days at ambient temperature. The ζ-potential of each particle was negative. With a PDI of 0.074–0.650 and a mean size of 232.3–659.8 nm, the population of electrosprayed nanoparticles was found to be heterogeneous. By increasing nanocapsules of polyphenols to the canola oil, the oil stability and oil quality were increased. Our results showed that 800 ppm of polyphenols can improve the oil stability similarly to TBHQ, and therefore it is possible to use canola meal polyphenols as natural antioxidants in the oil industry.Graphical

Characterization and incorporation of extracts from olive leaves obtained through maceration and supercritical extraction in Canola oil: Oxidative stability evaluation

Olive leaves (OL) are considered a potential source of bioactive compounds mainly due to its high content of phenolic compounds, widely known as natural antioxidants. The main objective of this study was to compare the performance of three OL extracts obtained by different extraction techniques in protecting canola oil against oxidative damage. The technologies evaluated were maceration with ethanol/water 75:25 (v/v), supercritical fluid extraction with CO2 (SC–CO2) and SC-CO2 with 10% ethanol as modifier (SC–CO2/EtOH). Each extract was analyzed as for total phenolic compounds (TPC), antioxidant activity (ABTS assay) and phenolic composition by reversed phase liquid chromatography-quadrupole-time of flight mass spectrometry. The oxidative stability of canola oil with or without the incorporation of 250 mg/kg of each extract was assessed during five weeks of storage at 60 °C. Peroxide, K232, K270, and Rancimat values, besides tocopherols content were determined. Macerated extract showed the highest TPC and antioxidant activity, but both SC-CO2 extracts were more effective in preserving tocopherols. In addition, SC-CO2 extracts delayed the oxidation progress as they lead to higher induction periods than control and macerated extracts, and a slower increase in peroxide values. Results obtained reinforce the use of supercritical fluid technology to obtain antioxidants compounds from natural sources.

Extraction of pumpkin peel extract using supercritical CO2 and subcritical water technology: Enhancing oxidative stability of canola oil

In this study, subcritical water extraction (SWE) and the supercritical fluid extraction (SFE) methods were used for the extraction of pumpkin peel extract. Total phenolic content and carotenoid compounds of extracts were measured. The extracts were added to canola oil at a concentration of 400 ppm and were stored at 30 °C for 60 days. The peroxide, carbonyl and acid values of the oil samples were measured, then compared with 100 ppm of tert-butylhydroquinone (TBHQ) synthetic antioxidants. The results showed that the total phenol content of obtained extract by SFE (353.5 mg GA/100 g extract) was higher than by SWE (213.6 mg GA/100 g extract), while the carotenoid content was higher for obtained extract by SWE (15.22 mg/100 g extract) compared to SFE (11.48 mg/100 g extract). The result of oil oxidation showed that the oxidative stability of the oil containing the mixed extract (SFE–SWE) is higher than the separate extract, consequently showing higher performance in preventing oil oxidation compared to TBHQ.

Effect of Punicalagin as natural antioxidant on the oxidative stability of Canola oil during storage

The present study intends to determine the effect of punicalagin as natural antioxidant on stabilising canola oil during 90 days storage and also to compare its strength with the synthetic antioxidant Butylated hydroxytoluene (BHT). Canola oil samples were categorized into three groups; pure oil (control), oil with Punicalagin and oil with BHT. Peroxide value (PV) and free fatty acid (FFA) were used to estimate the primary products of oil oxidation while Thiobarbituric Acid Reactive Substances (TBARS) and P-Anisidine values (PAV) were used to estimate the secondary products. Finally, total oxidation index was calculated to evaluate the overall oxidation of oil samples. The results showed that PV, FFA, PAV and TOTOX were significantly increased in all canola oil samples with increased in storage time. In contrast, The TBARS values continued to increase from the starting storage period until 60 days and then decreased significantly until the end of the storage period. Punicalagin effectively reduces the production of the first and second oxidation products of canola oil during storage as indicated by the reduction in the PV, FFA, PAV and TOTOX of canola oil. When compared to BHT, punicalagin showed similar effect in inhibiting primary oxidation products whereas BHT showed stronger effect in reducing the secondary oxidation products. In conclusion, punicalagin can be used as a suitable replacement for chemically synthetic antioxidants on stabilising canola oil.

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.

Oxidative stability of canola oil by Biarum bovei bioactive components during storage at ambient temperature.

In this study, antioxidative activities of aqueous extract of Biarum bovei (BBE) in stabilizing of canola oil during storage at 20°C was evaluated. For this purpose, the total phenolic (TP), flavonoids (TFC), and tocopherol content (TTC) of the extract were determined and β‐carotene bleaching system was used to assess the antioxidant efficacy of BBE. The amount of TP, TFC, and TTC in BBE indicated high antioxidant activity. So, different concentrations (0, 200, 800, and 1400 ppm) of BBE and butylatedhydroxyanisole (BHA; 100 ppm), were added to canola oil for 60 days at 20°C. Peroxide value (PV), carbonyl value (CV), Total polar compounds (TPC), acid value (AV), iodine values (IV), and conjugated dienes (CD) were employed to evaluate the BBE effect on canola oil stabilizing. Results indicated that 1,400 ppm of BBE exhibited stronger antioxidant activity in canola oil than BHA.

Influence of Teucrium polium L. essential oil on the oxidative stability of canola oil during storage.

The susceptibility of Teucrium polium essential oil (EO) as an antioxidant for canola oil was studied. Major compounds of the EO were 11-acetoxyeudesman-4-α-ol (26.3%) and α-bisabolol (24.6%). Different concentrations (200, 600 and 1200ppm) of EO and synthetic antioxidant BHA (200ppm) were added to canola oil and incubated for 60days at room temperature. Acid value (AV), peroxide value (PV), carbonyl value (CV), iodine value (IV), total phenolics (TP), total polar compounds (TPC) and oxidative stability index (OSI) of canola oil were determined. Antioxidant capacity of the EO was measured by DPPH and β-carotene-linoleic acid assays. Results exhibited that DPPH and β-carotene-linoleic acid experiment detections on the EO were analogous in high concentrations to those detected on BHA. Moreover, incorporated EO samples had better AV, PV, CV, IV, TP and TPC than control. EO at concentration of 600 ppm indicated higher antioxidant activity in canola oil compared with BHA.

Proximate composition, phenolic content and in vitro antioxidant activity of aqueous extracts of the seaweeds Ascophyllum nodosum, Bifurcaria bifurcata and Fucus vesiculosus. Effect of addition of the extracts on the oxidative stability of canola oil under accelerated storage conditions

Extracts from three macroalgae species (Ascophyllum nodosum (ANE), Bifurcaria bifurcata (BBE) and Fucus vesiculosus (FVE)) were tested for proximate composition (total solid, protein and total carbohydrate contents), total phenols content (TPC), and for their antioxidant activities in vitro in comparison to that of BHT compound by using four different assays (ABTS radical cation decolouration, DPPH free radical scavenging activity, ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC)). The inclusion of the extracts as oil stabilizers in canola oil in substitution of the synthetic antioxidant (BHT) was also evaluated by assessing lipid oxidation parameters (peroxide value (PV), p-anisidine value (AV), TBARS value, conjugated dienes (CD) and TOTOX index) under accelerated storage conditions (16days, 60°C). There was an inverse relationship between total solid content and total polyphenols content in the seaweed extracts. FVE showed an intermediate TPC (1.15g PGE/100g extract), but it presented the highest in vitro antioxidant activity when measured using the ABTS, DPPH and FRAP tests. BBE, that displayed the highest TPC (1.99g PGE/100g extract), only showed the highest in vitro antioxidant activity when measured using the ORAC test. ANE showed the lowest TPC and the lowest antioxidant activity in all the tests performed. The seaweed extracts added in a 500ppm concentration significantly reduced the oxidation during canola oil storage at 60°C, being this antioxidant effect significantly higher than that of BHT added at 50ppm. Results indicate that seaweed extracts can effectively inhibit the oxidation of canola oil and they can be a healthier alternative to the synthetic antioxidants in the oil industry.

Assessment of the antioxidant activity of Bifurcaria bifurcata aqueous extract on canola oil. Effect of extract concentration on the oxidation stability and volatile compound generation during oil storage

In this research the antioxidant activity of water extracts of Bifurcaria bifurcata (BBE) at different dose against butylated hydroxytoluene (BHT) was evaluated in canola oil. Water extracts were firstly characterized in terms of total solid and polyphenolic compound contents, and their antioxidant activity together with that of BHT was evaluated using several in vitro tests (DPPH, ABTS, ORAC and FRAP). Next, the progress of lipid oxidation was assessed in canola oil added with five BBE concentrations (200, 400, 600, 800 and 1000ppm) and two BHT concentrations (50 and 200ppm) using an accelerated oxidation test. The progress in lipid oxidation was monitored by assessing some chemical indices (peroxide value, p-anisidine value, and conjugated dienes) during oil storage and some volatile compounds at the end of the storage period. BBE showed a significant antioxidant effect, being this ability concentration-dependent. The extent of lipid oxidation was inversely related to BBE dose, specially with regard to primary oxidation products. At the highest level of BBE, significant decreases of primary and secondary oxidation products, with respect to the control, were obtained with reduction percentages of 71.53%, 72.78%, 68.17% and 71.3% for peroxides, conjugated dienes, p-anisidine and TOTOX values, respectively. A level of 600ppm or higher concentration of the extract inhibits the lipid oxidation in a similar way than BHT at 200ppm. Regarding the inhibition of the formation of volatile compounds, both BBE and BHT strongly inhibited the formation of volatiles during oil storage, being this inhibition similar for all the concentrations of BBE and BHT essayed. Overall, results indicated that BBE can be used as a potential natural additive for improving oxidative stability of canola oil.

Evaluation of Antioxidant Activity of Fig (Ficus carica) Pulp and Skin Extract and Its Application in Enhancing Oxidative Stability of Canola Oil

This study was carried out to determine the antioxidant activity of pulp (P) and skin (S) extract of two fig varieties of figs (Sabz(G) and Siyah(B)) by subcritical water extraction. The antioxidant activity of the extracts was evaluated by using 2,2′-diphenyl-1-picryl hydrazyl radical, reducing power and rancimat tests. The Siyah variety contained higher levels of polyphenols and flavonoids in comparison with Sabz variety. Generally, Siyah variety revealed higher levels of phenolic compounds and flavonoids. Moreover, the lowest IC50 in DPPH tests and reducing power was related to Siyah fig skin extract, and rancimat test showed no significant difference between antioxidant activity of fig extracts. The efficiency of Siyah fig skin extract for oxidative stability was assessed using peroxide, thiobarbituric acid, conjugate dien, acid value and color indicator in canola oil, compared with synthetic antioxidants of tert-Butylhydroquinone (TBHQ). The results showed that Siyah skin extract had the highest antioxidant activity and were comparable with TBHQ. Furthermore, skin of Siyah fig variety can be considered as a good source of phenolic compounds. Practical Applications Several novel techniques, notably subcritical water extraction, have been developed for the extraction of natural antioxidants from plants in order to shorten the extraction time, decrease the organic solvent consumption and increase the quality of extracts. One of the most important applications of natural antioxidants is retardation or inhibition of oil oxidation. This paper reveals that the natural extracts have antioxidant activity comparable to that of synthetic antioxidants used in oil industry. Therefore, skin of Siyah fig extract can be used to replace synthetic antioxidants.

Effects of Celery Extracts on the Oxidative Stability of Canola Oil Under Thermal Condition

The effect of extraction methods (ultrasound and supercritical fluid) and solvents (ethanol, ethanol/water (50:50) and water) on the phenolic compounds and antioxidant activities of celery (Apium graveolens) extracts was evaluated to determine the most suitable extraction method for protective effects on stabilizing canola oil (CAO) during thermal condition (24 h at 180C). Ultrasound ethanol/water extract was found to have the highest phenols compounds (438.75 mg gallic acid equivalents/g sample) and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [DPPH] and oxidative stability index 98.71 % and 7.1 h, respectively). Then, this extract was added to CAO. Peroxide value, carbonyl value, polar compound, acid value conjugated dienes value and color index were taken as parameters for evaluation of stabilization efficacy of the celery extract. Results from different parameters were in agreement with each other, suggesting higher efficiency of celery extracts followed by tertiary butylhydroquinone and control treated (without additives), respectively. Practical Applications Lipid peroxidation is responsible for the quality deterioration of vegetable oil, fats and other food systems. Thus, the use of antioxidants to minimize the oxidation of lipids in food materials is extensively practiced. Recently natural antioxidants have gained increased interest because natural food ingredients are safer than synthetic ones. The result of this study showed that celery extracts have antioxidant activity and it can replace synthetic antioxidant tertiary butylhydroquinone in canola oil.

Phenolic extract from wild rose hip with seed: Composition, antioxidant activity, and performance in canola oil

AbstractIn this study, the effectiveness of phenolic extracts from Rosa woodsii hip with seed (Rosae pseudofructus cum fructibus) in protecting vegetable oils against oxidative and thermal deterioration was assessed during accelerated storage of canola oil at 65°C, Rancimat at 120°C, and frying at 180°C. At the end of the 7‐day storage, formation of lipid hydroperoxides was 2.5 times higher in control canola oil compared to the fortified sample. Accumulation of polar components, polymerized TAGs and other secondary degradation products during frying was reduced by up to 30% in the presence of the applied phenolic extracts. Similarly, the oxidative stability of canola oil significantly increased in the presence of extract as measured by Rancimat induction period (IP). HPLC‐MS analysis indicated that quercetin, catechin, and gallic acid were the major phenolic constituents of Rosa woodsii fruit extract, and are possibly the active antioxidant compounds of the extract.Practical applications: Oxidation of fats and oils or fatty fractions of foods is one of the major reasons for the deterioration of food. Therefore the search for highly effective antioxidants from natural sources to stabilize frying oils or food preparations is an ongoing story. The present paper demonstrates that phenolic extracts from Rosa woodsii Lindl (Rosaceae) can improve the frying and storage stability of edible oils. The findings can help food processors to improve quality and safety of food.Phenolic extract from Rosa woodsii improved the thermo‐oxidative stability of canola oil.

Effects of Some Plant Extracts on the Oxidative Stability of Canola Oil and Its Purified Triacylglycerols

AbstractIn this study, the effects of rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.), sage (Salvia officinalis L.) and bay (Laurus nobilis) extracts on the oxidative stability of canola oil and its purified triacylglycerols (TAGs) were studied. The effects of extraction solvents (methanol, ethanol and acetone) on the extraction yields, phenolic contents and antioxidant activities of these plant extracts were also determined. Methanol extracts had the highest total phenolics (78.4–177.4 mg gallic acid equivalent/g extracts), with the exception of thyme extract. In linoleic acid emulsion, antioxidant activities of all plant extracts were above 89.7% at the studied concentrations. The highest 2,2′‐diphenyl‐1‐picrylhydrazyl radical scavenging activities were found for methanol extracts. There was no significant difference between induction periods of canola oils supplemented with ethanol, methanol or acetone extracts of rosemary, thyme and bay (P > 0.05) in differential scanning calorimeter. Protection factors of rosemary and thyme extracts were higher than those of the sage and bay extracts in canola oil and its purified TAGs in Rancimat test.Practical ApplicationsRosemary, sage, thyme and bay extracts had high antioxidant and antiradical activities. They contain many bioactive components such as, carnosic acid, carnosol, methyl carnosate, rosmarinic acid, rosmanol, thymol, carvacrol and hydroxycinnamic acid. In addition to this, when the rosemary and thyme extracts were added into canola oil, they increased induction period of oil. These herbal extracts can be incorporated into oils or lipid‐containing foods to prevent oxidation.

Effect of Seed Heat-Treatment on the Oxidative Stability of Canola Oil Body Emulsions

Enhancement of oxidative stability of canola oil extracted from seed subjected to prior heat-treatment has been attributed to heat-induced generation of antioxidants from phenolic precursors occurring in canola seed. Dispersion of aqueous extracts of intact seed oil bodies (OBs) in water is a novel and interesting way of producing natural and oxidatively stable food emulsions with minimal use of synthetic antioxidants and emulsifiers. As there is growing interest in natural food emulsions containing unsaturated oils, we investigated whether the oxidative stability of canola OB emulsions could be further improved by subjecting canola seed to heat-treatment prior to oil body extraction. Oil-in-water (5%, w/w) emulsions of OBs extracted from canola seed before and after heat-treatment were considerably more resistant to oxidation than emulsions prepared from refined canola oil and Tween? 40 emulsifier. However, only small amounts (0.9% - 4.5% by weight) of the phenolic compounds present in canola seed were transferred to the OBs after aqueous extraction, and consequently there was no discernible effect on oxidative stability as a result of prior heat-treatment of the seed. Thus, in contrast to oil, there is no oxidative stability benefit to be gained by subjecting canola seed to heat-treatment prior to extraction of OBs.