Oxidative Stability Of Oils Research Articles

The effect of refining process on the volatile compounds, oxidation stability and fatty acids profile of soybean oil using an electrostatic field

The effect of refining process on the volatile compounds, oxidation stability and fatty acids profile of soybean oil using an electrostatic field

Effects of succinylation and chitosan assembly at the interface layer on the stability and digestion characteristics of soy protein isolate-stabilized quercetin emulsions

This study investigated the effect of succinylation and chitosan (CS) assembly at the interfacial layer on the stability and digestion behavior of quercetin (QUE) loaded soy protein isolate (SPI) emulsions. Four emulsions were compared: two monolayer emulsions with SPI or succinylated SPI (SSPI) and two bilayer emulsions with SPI and CS or with SSPI and CS, formed via layer-by-layer electrostatic self-assembly. Compared with the emulsion stabilized by SPI, the emulsion stabilized by SSPI not only exhibited higher storage stability, but also exhibited superior oxidation stability. CS assembly at the interfacial layer increased the interfacial adsorbed protein content and resulted in a lower creaming index during storage. The presence of CS decreased the hydroperoxide, thiobarbituric acid-reactive substances, and carbonyl contents, and increased the sulfhydryl content, indicating better oil and protein oxidation stability. Moreover, succinylation and CS assembly increased the bioavailability of QUE by 18.38% and 41.64% with respect to that of the emulsion stabilized by SPI, respectively, and simultaneous succinylation and CS assembly treatments increased the bioavailability of QUE by 43.50%. The SSPI/CS-stabilized emulsion has the best potential for encapsulation and delivery of QUE. Our research can guide the development of an effective QUE delivery system with increased stability and bioavailability.

Improving Oxidation Stability of Base Oil Based on Azophenols Additives: Experimental and Theoretical Studies

Improving Oxidation Stability of Base Oil Based on Azophenols Additives: Experimental and Theoretical Studies

The effect of the hydrophilic and lipophilic herbal extracts on the oxidative stability of cooking plant oils during low- and high-temperature heating

BackgroundRecently, the most commonly used cooking oils in the world are obtained from corn germ, soybean, sunflower and rape seeds. Also, refined flaxseed oil is preferred for low-heat cooking in some countries. Use these oils instead of solid fats (including butter, shortening, lard and margarine) and tropical oils (including palm and coconut oil) can be healthy choice, because of lower saturated fat content. Unfortunately, repeated or high-temperature heating may result in oil decompose to form unwanted hazardous substances which can pose harmful effects to the health. The well-known natural method to limit oil oxidation is the used of herbs and spices, which also can improve the taste and aroma properties of food. The aim of the study was to evaluate the effect of added herbal extracts on the oxidative stability of two cooking plant oils (refined rapeseed oil, refined flaxseed oil) during low- and high-temperature heating. MethodsHydro- and lipophilic extracts were prepared from popular commercial dried herbs (thyme, parsley, caraway, oregano, basil, dill) using 70% methanol and n-hexane, respectively. Cooking plant oils were characterized by quality indices, fatty acid composition and content of bioactive compounds, while in the herbal extracts' composition and content of pigments, total phenolic compounds, flavonoids, tocols and antioxidant capacity were examined. The oxidative stability of cooking plant oils, without and with the addition of herbal extracts, was determined in the Rancimat test at 110 and 150 °C for refined rapeseed oil and 80 and 110 °C for refined flaxseed oil. ResultsIt was found that the addition of herbal extracts had varied effect on oxidative stability of flaxseed and rapeseed oils at low- and high-temperature heating. Flaxseed oil was generally well-protected by thyme hydro- and lipophilic extracts regardless of temperature heating (induction period increase by 18–24%). Also, hydrophilic parsley and lipophilic oregano extracts improved this oil oxidative stability at low temperature (induction period increase by 10–17%), while lipophilic extracts from caraway and dill were more effective at high temperature (induction period increase by 20–26%). In turn, all extracts improved the rapeseed oil oxidative stability under low-temperature heating (induction period increase by 11–24%), but they were ineffective during high-temperature heating. The better additives for this oil were both type extracts obtained from thyme and oregano, which were characterized by the highest content of antioxidants, total phenolic compounds and tocopherols, mainly α-tocopherol. The results suggest a greater difference in content of phenolic compounds for extracts obtained by using of different solvents then from different herbs. In turn, the herb type had a strong impact on the content of pigments and tocopherols. ConclusionsResults confirmed the possibility of using herbal extracts to increase the oxidative stability of cooking plant oils during thermal heating. However, the type of solvent and herb should be adjusted individually to cooking oil type and heating temperature.

Oxidative stability, fatty-acid and phenolic composition of Cypriot monovarietal virgin olive oils with progressive fruit maturity

Oil content, extractability, chemical composition and oxidative stability of three monovarietal (‘Ladoelia’, ‘Kato Drys’ and ‘Korakou’) virgin olive oils (VOOs) were examined at progressive stages of fruit maturity. Oxidative stability was assessed on a Rancimat System, phenols and tocopherols by HPLC-DAD and fatty acid (FA) profiles by GC-FID. Oil extractability was highly cultivar-specific and unaffected by maturity stage. ‘Ladoelia’ exhibited excellent extractability and satisfactory VOO composition and oxidative stability, with moderate phenolic and diverse tocopherol content. ‘Kato Drys’ was rich in monounsaturated FA that imparted superior oxidative stability and poor in polyunsaturated and saturated FA. Monovarietal VOOs exhibited higher correlation of oxidative stability with the C18:1/C18:2 ratio (r = 0.80, p < 0.0001) than with the total phenolic content (TPC; r = 0.436, p < 0.05), suggesting that phenolic association with oxidative stability might be specific to individual phenolic compounds than to TPC. Late harvest of ‘Ladoelia’ and ‘Kato Drys’ was liable to drastic rise in free acidity. Poor extractability, low oil and oleic acid contents undermined the suitability of ‘Korakou’ for VOO production. The current findings contribute towards the establishment of typicity for monovarietal VOOs.

Valorization of Winery Waste: Prokupac Grape Seed as a Source of Nutritionally Valuable Oil

Valorization of winery waste is a promising solution for waste management with additional benefit of bioactive compounds isolation. The aim of this study was to analyze the nutritional and bioactive potential of oil derived from Serbian autochthonous grape seed variety Prokupac and to compare it with known international grape varieties. Additionally, two extraction methods (ultrasound assisted extraction and cold pressing) were used in order to determine their influence on physico-chemical and nutritive characteristics of grape seed oil. Different methods, including determination of physicochemical properties, content of bioactive compounds, oxidative stability and antioxidative capacity were used for the characterization of grape seed oils. Results indicated that the higher yield was obtained by ultrasound assisted extraction compared to cold pressing. The application of ultrasound assisted extraction resulted in increased α-tocopherol content and better antioxidant capacity and oxidative stability of oil. Significant differences in bioactive composition were observed for Prokupac seed oil compared to the other grape varieties. Oil extracted from Prokupac grape seed had the lowest content of polyunsaturated and the highest content of saturated fatty acids, the highest content of α-tocopherol and consequently, the best antioxidative capacity. Prokupac grape seed has a great potential for isolation of nutritive and bioactive valuable oil.

Cold-pressed cactus pear seed oil: Quality and stability

Cold-pressed seed oil from twelve commercially produced cactus pear cultivars was assessed for oil yield, fatty acid composition, physicochemical properties, quality and stability. Large differences in oil content, fatty acid composition and physicochemical properties (IV, PV, RI, tocopherols, ORAC, % FFA, OSI and induction time) were observed. Oil content ranged between 2.51% and 5.96% (Meyers and American Giant). The important fatty acids detected were C16:0, C18:0, C18:1c9 and C18:2c9,12, with C18:2c9,12, the dominating fatty acid, ranging from 58.56-65.73%, followed by C18:1c9, ranging between 13.18-16.07%, C16:0, which ranged between 10.97 - 15.07% and C18:0, which ranged between 2.62-3.18%. Other fatty acids such as C14:0, C16:1c9, C17:0, C17:1c10, C20:0, C18:3c9,12,15 and C20:3c8,11,14 were detected in small amounts. The quality parameters of the oils were strongly influenced by oil content, fatty acid composition and physicochemical properties. Oil content, PV, % FFA, RI, IV, tocopherols, ORAC and ρ-anisidine value were negatively correlated with OSI. C18:0; C18:1c9; C18:2c9,12; MUFA; PUFA; n-6 and PUFA/SFA were also negatively correlated with OSI. Among all the cultivars, American Giant was identified as the paramount cultivar with good quality traits (oil content and oxidative stability).

NMR study on the oxidation of vegetable oils for assessing the antioxidant function of trehalose

The objective of this study was to investigate the antioxidant activity of trehalose in vegetable oils after 16 h deep-frying at 180 °C by using nuclear magnetic resonance (NMR) spectroscopy. 1 H NMR spectroscopy is a useful technique for determining structure which requires small sample volumes and short processing time. The results of this study indicate the oxidation stability of vegetable oils can be improved with the addition of trehalose at 0.05% (w/w) concentration. The antioxidant activity of trehalose positively affected all vegetable oils studied with notable differences when used in conjunction with soybean oil. For example, the measured percent loss of olefinic protons in soybean oil (oil-0 control) changed from 6.17 to 2.52 (integral value) in sample soybean oil-1 with the addition of trehalose. Similarly, the percent loss of bisallylic protons changed from 8.19 to 3.32. Further, with respect to the percent loss of allylic protons changing from 3.02 to 0, the oxidation of an allylic proton was greatly depressed. Trehalose improved the oxidation stability of soybean oil much better than that of corn oil, canola oil, cottonseed oil and peanut oil. In summary, trehalose can be used as a safe and effective antioxidant for these edible oils. • Efficiently antioxidant activity of trehalose in deep-frying vegetable oils. • 1 H NMR spectroscopy is a useful technique for determining structure change of oil. • Trehalose improved greatly the oxidation stability of vegetable oils.

Study on antioxidants extraction from oak bark and their use for oxidation stability of sunflower oil

Study on antioxidants extraction from oak bark and their use for oxidation stability of sunflower oil

Composition analysis and microencapsulation of Eucommia ulmoides seed oil

BackgroundEucommia ulmoides seed oil is a functional health oil with a high content of unsaturated fatty acids. However, excessively high content of unsaturated fatty acids can cause E. ulmoides seed oil to easily spoil. Microencapsulation technology can effectively encapsulate substances, thereby prolonging the spoilage time of oil products.MethodsIn the present study, E. ulmoides seed oil from different manufacturers were analyzed by Agilent 7890B-5977A gas chromatography–mass spectrometry. Encapsulation efficiency, yield rate, and scanning electron microscopy results between microcapsules prepared use different wall materials and different methods (spray drying and complex coagulation) were compared to determine the best preparation process for microcapsules. The Wantong 892 professional oil oxidation stability tester was used to measure the induced oxidation time of the E. ulmoides seed oil and microcapsules.ConclusionE. ulmoides seed oil comprises > 80% unsaturated fatty acids with a high α-linolenic acid content, followed by linoleic acid. The most promising combination was chitosan:gum arabic at 1:8 as the wall material and complex coagulation. The best preparation had a wall material concentration, stirring speed, aggregation pH, and core-to-wall ratio of 2.5%, 500 rpm, 4.2, and 1:4, respectively. Microcapsules prepared under these conditions exhibited higher yield and encapsulation efficiency (94.0% and 73.3%, respectively). The induced oxidation time of the E. ulmoides seed oil and microcapsules were 3.8 h and 13.9 h, respectively, indicating that microencapsulation can increase the oxidation induction time of this oil.

Investigation of antioxidant effect of Rosmarinus officinalis L. on oxidation stability of sunflower oil

The present study was conducted to investigate the chemical properties and antioxidant effects of rosemary (Rosmarinus officinalis L.) on sunflower oil by the Rancimat method. The plant material was provided from Afyonkarahisar Medicinal and Aromatic Plants Center had grown under controlled conditions. The identification of essential oil compositions of plant was performed by GC-MS. 1,8-Cineole (15.18%), Camphor (11.39%), Borneol (11.39%), Germacrene D (11.12%), Carvacrol (11.05%), α-Pinene (6.01%) and ρ-Cimene (3.07%) were as the major constituents of the plant essential oil. Total antioxidant determination was carried out by using DPPH and EC50 value calculated 3.35 mg/ml. The shelf life of sunflower oil increased to 7% and 14% by adding 1 and 5g/100g rosemary leaves powder, respectively. According to the results, rosemary as a commercial medicinal and aromatic plant that is grown in Turkey, raised the oxidation stability of sunflower oil significantly. It can be suggested as a natural antioxidant to extend shelf life of eddible fixed oils. However, tasting tests seem necessary.

Comparison of Chemical and Antioxidant Properties of Mentha Piperita L., Salvia Officinalis L., Rosmarinus Officinalis L. and Lavandula Angustifolia L.

4 different plant species belonging to the same family mint (Mentha piperita), sage (Salvia officinalis), rosemary (Rosmarinus officinalis), lavender (Lavandula angustifolia) were harvested from the Afyon region. Total antioxidant and phenolic contents were analyzed by DPPH and Folin-Ciocalteu method. The effect of extra virgin olive oils oxidation stability was tested by means of rancimat method. According to DPPH analysis results, M. piperita is the highest antioxidant capacity and the radical scavenging activity is 95.31%. The radical scavenging activities of S. officinalis, R. officinalis and L. angustifolia are respectively 91.83%, 54.28%, and 18.85%. The total phenolic content of M. piperita, S. officinalis, R. officinalis and L. angustifolia plants as gallic acid were respectively; 0.32, 0.28; 0.26 and 0.18 mg/100ml. According to the results of the study, the order of the plants did not change in terms of phenolic and antioxidant content, M. piperita has the highest values and L. angustifolia has the lowest. It was also found that the plants are effective on the oxidation stability of extra virgin olive oil and prevent oxidation in the order of large to small R. officinalis, M. piperita, S. officinalis and L. angustifolia.

Enhancement of antioxidant activity, antifungal activity, and oxidation stability of Citrus reticulata essential oil nanocapsules by clove and cinnamon essential oils

This study aimed to enhance the antioxidant activity, antifungal activity, and oxidation stability of Citrus reticulata essential oil (EO) nanocapsules by using cinnamon EO and clove EO. The encapsulation efficiency, moisture content, water activity, particle properties, glass transition temperatures, relative crystallinity, and chemical structure were analyzed. Results showed that all formulas have stable moisture levels (less than 6%), water activity (less than 0.6), and an encapsulation efficiency higher than 91%, which were confirmed by the Fourier transform infrared spectroscopy results. Compared with C. reticulata EO (CEO), the addition of cinnamon EO and clove EO increased the total phenolic content by 1.75 and 1.54 times, respectively. The results indicated that the addition of cinnamon EO and clove EO increased the antioxidant activity by 3.57 and 2.08 times, as well as increased the antioxidant capacity by 4.43 and 3.52 times, respectively. The antifungal efficacy of CEO nanocapsules was enhanced by 3.13, 1.24, 2.76, and 2.97 times, and by 2.43, 1.24, 1.32, and 2.09 times against Candida albicans, Zygosaccharomyces rouxii, Aspergillus niger, and Penicillium roqueforti by the addition of cinnamon EO and clove EO, respectively. Furthermore, the peroxide values were reduced by 16.88% and 15.58% with the addition of cinnamon EO and clove EO. These results indicated that C. reticulata oil nanocapsules' properties could be improved by adding cinnamon EO and clove EO to enhance the use of CEO.

Incorporation of essential oils in Iranian traditional animal oil: an assessment of physicochemical and sensory assessment

This study aimed to incorporate the herbal essential oils (Ziziphora tenuior L. (Z. tenuior), Ferulago angulata (F. angulata), and Bunium persicum (B. persicum)) all in three levels (5, 7, and 10% w/w) and tertiary butyl hydroquinone (100, 200, and 300 ppm) to evaluate the oxidation stability of Iranian animal oil (IAO). Z. tenuior, F. angulata, and B. persicum (5, 7, and 10% w/w) and tertiary butyl hydroquinone (100, 200, and 300 ppm) were added to IAO. The physicochemical properties and color analysis, and sensory characteristics (odor, taste, rancidity, and overall acceptability) of the treatments were investigated on days 0, 7, 14, 21, and 28. The results showed that increasing the amounts of Z. tenuior, F. angulata, and B. persicum was associated with reducing acid, peroxide, and thiobarbituric acid values. It also lowered brightness and yellowness while the oxidative stability of the IAO significantly was increasing. It was concluded that the incorporation of B. persicum had the highest effectiveness regarding the proposed criteria with the least effect on sensory properties.

Eco-Friendly Production of AuNPs and Their Impact on the Oil Oxidative Stability.

Vegetable oils have been used for different applications and, more recently, as an active host medium to obtain nanoparticles for employment in bionanotechnological applications. Nevertheless, oils are very susceptible to oxidation during production, storage, and transportation because of their chemical composition. Consequently, any modification in their production must be accompanied by an analysis of the oxidative stability. In this study, naked and biocompatible gold nanoparticles (AuNPs) were grown on sunflower oil during sputtering deposition using different deposition times. Size and morphology were determined by transmission electron microscopy (TEM) and their concentrations were found by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Rancimat® method was employed to evaluate the AuNPs influence on the oxidative stability of the vegetable oil. Well-dispersed quasi-spherical NPs were produced with a mean diameter in the 2.9–3.7 nm range and they were concentration-dependent on the deposition time. A concentration of about 11 mg/L, 38 mg/L, and 225 mg/L of AuNPs was obtained for a deposition time of 5 min, 15 min, and 30 min, respectively. The results also revealed that AuNPs negatively affected the oxidative stability of the sunflower oil and exponentially reduced the induction period (IP) with the increase in AuNPs content. IP reductions of 63%, 77%, and 81% were determined for the AuNPs containing samples at 11 mg/L, 38 mg/L, and 225 mg/L. For the first time, it is reported that naked AuNPs promote the rapid degradation of vegetable oil and this points out the need for attention relative to the quality of vegetable oils used to host metal nanoparticles.

Proton Low Field NMR Relaxation Time Domain Sensor for Monitoring of Oxidation Stability of PUFA-Rich Oils and Emulsion Products.

The nutritional characteristics of fatty acid (FA) containing foods are strongly dependent on the FA’s chemical/morphological arrangements. Paradoxically the nutritional, health enhancing FA polyunsaturated fatty acids (PUFAs) are highly susceptible to oxidation into harmful toxic side products during food preparation and storage. Current analytical technologies are not effective in the facile characterization of both the morphological and chemical structures of PUFA domains within materials for monitoring the parameters affecting their oxidation and antioxidant efficacy. The present paper is a review of our work on the development and application of a proton low field NMR relaxation sensor (1H LF NMR) and signal to time domain (TD) spectra reconstruction for chemical and morphological characterization of PUFA-rich oils and their oil in water emulsions, for assessing their degree and susceptibility to oxidation and the efficacy of antioxidants. The NMR signals are energy relaxation signals generated by spin–lattice interactions (T1) and spin–spin interactions (T2). These signals are reconstructed into 1D (T1 or T2) and 2D graphics (T1 vs. T2) by an optimal primal-dual interior method using a convex objectives (PDCO) solver. This is a direct measurement on non-modified samples where the individual graph peaks correlate to structural domains within the bulk oil or its emulsions. The emulsions of this review include relatively complex PUFA-rich oleosome-oil bodies based on the aqueous extraction from linseed seeds with and without encapsulation of externally added oils such as fish oil. Potential applications are shown in identifying optimal health enhancing PUFA-rich food formulations with maximal stability against oxidation and the potential for on-line quality control during preparation and storage.

Drying methodology effect on the phenolic content, antioxidant activity of Myrtus communis L. leaves ethanol extracts and soybean oil oxidative stability

In this study, different drying methodologies (convective air, oven and microwave) of Myrtus communis L. (M. communis L.) leaves were conducted to investigate their effects on the levels of phenolic compounds, antioxidant capacity of ethanolic extracts (EEs) as well as the soybean oil oxidative stability. Drying methodology significantly influenced the extractability of phenolic compounds. Microwave drying led to an increase in the amounts of total phenols, flavonoids and proanthocyanidins followed by oven drying at 70 °C. Higher temperature of drying (100 and 120 °C) led to a significant reduction of their amounts (p < 0.05). An ultra-performance liquid chromatography method combined with high resolution mass spectroscopic detection was used to analyze the phenolic fraction of extracts. Higher amounts of the identified compounds were observed when leaves were heat treated. Furthermore, the evaluation of the antioxidant activity showed that the studied extracts possess in general high antioxidant capacities, significantly dependent on the employed drying methodology. The incorporation of the different extracts at 200 ppm in soybean oil showed that its oxidative stability was significantly improved. Extracts from leaves treated with microwave (EE_MW) and at 70 °C (EE_70) have better effect than BHT. The results of the present study suggest that microwave drying could be useful to enhance the extractability of phenolic compounds and the antioxidant capacity of M. communis L. leaf extract.

Optimization and Validation of Rancimat Operational Parameters to Determine Walnut Oil Oxidative Stability

This study was performed to optimize and validate Rancimat (Metrohm Ltd., Herisau, Switzerland) operational parameters including temperature, air-flow, and sample weight to minimize Induction-Time (IT) and IT-Coefficient-of-Variation (CV), using Response Surface Methodology (RSM). According to a Box–Behnken experimental design, walnut oil equivalent to 3-, 6-, or 9-g was added to each reaction vessel and heated to 100, 110, or 120 °C, while an air-flow equal to 10-, 15-, or 20-L·h−1 was forced through the reaction vessels. A stationary point was found per response variable (IT and CV), and optimal parameters were defined considering the determined stationary points for both response variables at 100 °C, 25 L·h−1, and 3.9 g. Optimal parameters provided an IT of 5.42 ± 0.02 h with a CV of 1.25 ± 0.83%. RSM proved to be a useful methodology to find Rancimat operational parameters that translate to accurate and efficient values of walnut oil IT.

Storage Stability of Oleogels Made from Monoglycerides and High Oleic Sunflower Oil

The aim of this study was to investigate the effects of storage time on physicochemical properties of oleogels from high oleic sunflower oil and monoglycerides (6.6 wt%). Oleogels were stored for eight weeks at 5 °C and tested weekly. The analyzed properties were: oil binding capacity, elastic modulus described by parameters of a power law equation, textural properties (hardness, adhesiveness, and cohesiveness), melting behavior, mean crystals length (Lc), polymorphism, peroxide value, and color. The main physicochemical parameters were not significantly altered over the first three weeks of storage, evidencing some changes thereafter. Hardness, cohesiveness, elasticity and Lc were the most affected properties. In addition, oleogelation allowed to improve the oil oxidative stability. No changes in melting behavior nor in polymorphism were found during storage time. The results of this work contribute to a better knowledge of the storage stability of monoglycerides oleogels, improving prospects for using them as trans-free substitutes for foods production.

Efficient encapsulation of fish oil: Capitalizing on the unique inherent characteristics of whey cream and hydrolyzed whey protein

The effects of protein concentration and of blending a phospholipid-rich whey coproduct, Procream (Salibra 700 Procream, Glanbia Nutritionals), with intact or hydrolyzed whey protein concentrate, on fish oil microencapsulation efficiency and oxidative stability were assessed. Trypsin and protease M, from Aspergillus oryzae, were used to produce 2 unique hydrolysates. All microcapsules had excellent encapsulation efficiencies (>92%) and good physical properties, regardless of protein content and Procream inclusion. Intact α-lactalbumin and β-lactoglobulin and their peptides were involved in stabilizing oil droplets. Disulfide interchange resulted in formation of protein aggregates, which were more pronounced in samples containing Procream. Although all microcapsules had relatively good oxidative stability, most had better stability at 2 versus 0.5% protein. Protease M hydrolysate + Procream microcapsules had the highest stability, regardless of protein content. Results demonstrated that Procream, at a reduced protein inclusion level, can partially replace more expensive whey protein ingredients in microencapsulation, when blended with a select hydrolysate.