Total Tocopherol Content Research Articles

Effect of Moisture and Heat Treatment of Corn Germ on Oil Quality

AbstractThe changes in the quality of crude corn oil caused by moisture and two different thermal pretreatments (oven heating and steam heating) of wet‐milled corn germ were evaluated and compared with those of untreated oil. Increasing the moisture content of the corn germ from 8 to 25% before oil extraction increased the acid value (AV) (3.02–4.01 mg KOH g−1), peroxide value (PV) (0.52–1.05 meq kg−1), and the red value (7.3–8.7) and decreased the content of total tocopherols by 37% and that of γ‐tocopherols by 31%. Oven heating tended to decrease the AV and PV while steam heating significantly increased the total and individual tocopherol contents (P < 0.05). The different moisture contents and thermal pretreatments of corn germ caused no significant differences in the fatty acid composition and the contents of total and individual phytosterols of the crude oils. The γ‐tocopherol contents were found to be highly correlated with the red values (the corresponding R2 reached 0.9977 and 0.9089 for moisture and heat pretreatments, respectively).

Molecular distillation of olive pomace oil ─ Multiobjective optimization for tocopherol and squalene

Olive pomace oil was distilled using a laboratory scale molecular distillation unit aiming a successful separation of squalene. Pressures were 0.02, 0.1 and 0.5 mbar, and temperatures ranged from 160 to 240 °C. Changes in total tocopherol and squalene concentrations of distilled olive pomace oils were monitored. Initial squalene concentration of 10613.1 mg kg−1 was succesfully reduced to 54.58 mg kg−1 at 0.02 mbar and 240 °C which corresponds to a reduction of 99.49% of initial. However, total tocopherol concentration also reduced to 20.2 mg kg−1 from an initial of 204.93 mg kg−1 at the same conditions. Similarly, an unfortunate loss of tocopherols with 90.14% at T = 240 °C and P = 0.02 mbar was observed. As being important antioxidants, tocopherols are desired to remain in oil; therefore, a multiobjective optimization (MOO) was performed to keep tocopherols in the oil at maximum, while minimizing squalene concentration. With an interactive MOO method, namely NIMBUS, 20 different alternative conditions could be generated. 9 of 20 paths could be considered as feasible and applicable for executing both objectives. One of the optimized conditions was 160 °C and 0.072 mbar where the highest tocopherol concentration of 204.721 mg kg−1 was obtained while squalene concentration was reduced to 3741.586 mg kg−1 in oil.

Effect of Wheat Germ Heat Treatment by Fluidised Bed on the Kinetics of Lipase Inactivation

Wheat germ is scrapped during milling due to their unfavourable baking properties and rapid deterioration. Although it is a low-cost by-product with remarkable nutritional features, its widespread utilisation is limited by the action of enzymes. On that basis, the effect of the germ stabilisation process by fluidisation with hot air was studied. Fluidisation, carried out with air between 90 and 150 °C, generated notable lipase inactivation, which reached a minimum residual activity of 15.5% from original. The total tocopherol contents of stabilised samples were not significantly affected. Colour attributes of treated samples showed slight changes compared with raw wheat germ. A mathematical model was fitted to colour data to predict the changes due to heat. A first-order kinetic model was applied to descript the thermal lipase inactivation. The inactivation rate constant, D value, Z value and the activation energy were calculated for this process. The results obtained in this study are expected to contribute to the optimisation of wheat germ stabilisation by fluidisation. This process may enable to obtain a food with good nutritional features for human consumption from a co-product of the wheat milling industry at a short time and high temperature.

Characterization of ‘Castellana’ Virgin Olive Oils with Regard to Olive Ripening

The production of high-quality virgin olive oil from traditional olive (Olea europaea L.) varieties with peculiar and differential characteristics is of great interest for the olive oil market. ‘Castellana’ is an autochthonous variety mainly located in the center of Spain. The aims of this study were 1) the characterization of ‘Castellana’ virgin olive oils and 2) the evaluation of the influence of fruit ripening degree on the oil quality to establish an optimum harvest time for ‘Castellana’ olives. A wide range of physicochemical and sensorial quality parameters were assayed in oils produced at four harvest times during three crop seasons. ‘Castellana’ oils could be classified into the extra virgin category at all ripening degrees studied. This variety provides well-balanced oils from the sensorial point of view with an optimum chemical composition. Nevertheless, fruit maturation had a strong effect in various quality parameters, especially total phenol content, total tocopherol content, sensorial quality, and to a lesser extent in fatty acid composition. Loss of antioxidants and decrease in sensorial quality take place during olive ripening, reducing the nutritional, sensorial, and commercial quality of virgin olives oils as the harvest is delayed. Results suggest that the production of optimal extra virgin olive oil requires that ‘Castellana’ olives should be harvested from the middle of November to the middle of December, coinciding with a ripening index between 3.1 and 4.1. These results are of great importance to the olive oil industry for improving the quality of virgin olive oils produced from ‘Castellana’.

Characterization of Schinziophyton rautanenii (Manketti) nut oil from Namibia rich in conjugated fatty acids and tocopherol

The Schinziophyton rautanenii tree is an important food source for many communities of the African continent. Oil extracted from the Manketti nut is of great economic value, due to its unique composition and properties. In this study, the physical and chemical characteristics of the oil obtained from three extraction methods – cold pressed, traditional and Soxhlet extraction – were investigated and compared. Oil yield of the nut was found to be 42.6 ± 0.84%. Good quality characteristics, including saponification values (184–189 mg KOH/g), iodine values (120–131 g/100 g), acid values (0.959–2.44 mg KOH/g) and peroxide values (1.80–3.98 meqO2/kg) were found for the Manketti nut oil. The total tocopherol content was in the range of 144–206 mg/100 g of oil, with γ-tocopherol as the dominant tocopherol. The oil was rich in conjugated fatty acids, α-eleostearic (9Z,11E,13E-octadecatrienoic acid) (24–36%) and linoleic acid (9Z,12Z-octadeca-9,12-dienoic acid) (31–32%), making it a potential candidate in the nutraceutical and cosmetics industry.

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.

Cytotoxicity of new secondary metabolites, fatty acids and tocols composition of seeds of Ducrosia anethifolia (DC.) Boiss

Two new monoterpene Ducrosin A (1) and sesquiterpene Ducrosin B (2) were isolated along with three known compounds, stigmasterol (3) and two furanocoumarins (4 and 5), from the dichloromethane extract of the seeds of Ducrosia anethifolia (DC.) Boiss. Their structures were determined using extensive 1D and 2D NMR, (ES)-HRMS and IR spectroscopic analyses and by comparison with literature data. Gas chromatography analysis of the fatty acids (FAs) of D. anethifolia seed oils (DAOs) showed high percentages of elaidic acid (C18:1 Δ9t) 65% and oleic acid (C18:1 Δ9c) 15%. The total tocopherol (tocols) content in DAOs was found to be 164 mg/100 g. The cytotoxic effect of the isolates was also evaluated using the MTT assay against the HCT-116 and SKOV-3 cell lines. The results showed that compound 2 was the most cytotoxic agent followed by compounds 1 and 4, which has an epoxide moiety that most likely contributes to its activity.

Characterization of physicochemical and sensory attributes of a novel high-oleic peanut oil cultivar (Arachis hypogaea ssp. Fastigiata L.)

Many efforts by peanut breeders and reseachers have been made to develop high-oleic peanut cultivars because of not limited to their storage stability but also health benefits by oleic acid. Here, we characterized physicochemical properties and sensory attributes of a novel high-oleic peanut oil cultivar (K-Ol; Arachis hypogaea ssp. Fastigiata L.); properties of this cultivar were comprehensively analyzed and compared with two conventional peanut cultivars, Daekwang, and Jopyung. As results, the K-Ol cultivar represented a significantly higher ratio of oleic acid and linoleic acid than conventional cultivars. Further, the K-Ol dramatically increased oxidative stability and oxidation induction time compared to conventional oils. However, we noted no significant difference in physical properties, and the K-Ol showed the lowest total tocopherol content and antioxidant capacity, suggesting that oxidative stability of the K-Ol is likely contributed by the high-oleic acid content. In sensory attributes analyses using electronic nose, overall flavor values were higher in the K-Ol except for the strength. The taste scores of K-Ol measured by electronic tongue were fairly distributed to all tastes compared to conventional cultivars. This study provides important characterization data of the peanut oil, from the high-oleic peanut cultivar; further investigations are warranted with regard to its potential health benefits as well as industrial applications of this stable edible oil.

Determination of Bioactive Compounds and Mineral Contents of Seedless Parts and Seeds of Grapes

In this study, phenolic compounds, minerals, total flavonoids, total phenolic contents and antioxidant activities of the seedless parts (pulp+skin) and seeds of table and wine grapes were determined. Also, the total oil, tocopherol contents and fatty acid composition of seed oils of table and wine grapes were investigated. The highest total phenolic content of the grape pulp was found in Trakya ilkeren (199.063mg/100 g), while total flavonoid and antioxidant activity of the pulp was determined at a high level in Red Globe (6.810 mg/g, 90.948%). Antioxidant activity, and the total phenolic and flavonoid contents of grape seeds varied between 86.688 and 90.974%, 421.563 and 490.625 mg GAE/100 g, and 90.595 and 145.595 mg/g respectively (p < 0.05). Generally, the main phenolic compounds of all grape pulps and seeds were gallic acid, 3,4- dihydroxybenzoic acid, (+)-catechin and 1,2-dihydroxybenzene. In addition, the oil contents of grape seeds ranged from 5.275 (Cavus) to 13.881% (Cinarli karasi) (p < 0.05). The major fatty acids of grape seed oils were linoleic, oleic and palmitic acid. The seed oil of the Trakya ilkeren variety was rich in tocopherols in comparison with the other varieties. The major minerals of both the seedless parts and the seeds were determined as K, Ca, P, S, Mg.

A comparative study of solvent and supercritical CO&lt;sub&gt;2&lt;/sub&gt; extraction of &lt;em&gt;Simarouba gluaca&lt;/em&gt; seed oil

In the present study, the supercritical carbon dioxide (CO2) extraction of oil from Simarouba gluaca seeds was carried out at varying conditions of pressure (300–500 bar), temperature (50–70 °C) and CO2 flow rate (10–30 g·min-1). The extraction condition for maximum oil yield was obtained at 500 bar pressure, 70 °C and at 30 g·min-1 flow rate of CO2. The extracted oil was analyzed thoroughly for physico-chemical properties and compared with those of conventional solvent extracted oil. An interesting observation is a significant reduction in the phosphorus content of the oil (8.4 mg·kg-1) extracted using supercritical CO2 compared to the phosphorous content of the solvent extracted oil (97 mg·kg-1). Moreover, the content of total tocopherols in supercritically extracted oil (135.6 mg·kg-1) was found to be higher than the solvent extracted oil (111 mg·kg-1). The rest of the physico-chemical properties of the two differently extracted oils matched well with each other. The results indicated the possible benefits of supercritical CO2 extraction over solvent extraction of Simarouba gluaca seed oil.

Deterioration of Extra Virgin Olive Oil Caused by Different Processes

Extra virgin olive oil is recognized as a very stable oil because of its composition in fatty acids and its content in natural antioxidants (tocopherols and polyphenols). In the bibliography are works that address different aspects of this stability, from the duration of its useful life to its performance in the frying of foods. Some works also link their stability with the content of natural antioxidants. For example, Franco et al. (2014) studied the content of phenols and their antioxidant capacity in olive oils of seven different varieties. Baccouri et al. (2008) found a good correlation between the oxidative stability (measured in Rancimat) of the oils studied and the concentration of total phenols and tocopherols.

Agronomic, Chemical, and Antioxidant Characterization of Grain Amaranths Grown in a Mediterranean Environment

The use of amaranth (Amaranthus spp.) in the food and dietary supplements industry is increasing. The aim of this work is to promote the Mediterranean area as a production hot spot, by using multivariate statistical analyses on data obtained in two‐year trials and relating to morphological, productive, and qualitative traits and antioxidant activity of 20 accessions of five amaranth species (A. caudatus L., A. cruentus L., A. hybridus L., A. hypochondriacus × hybridus L., A. hypochondriacus L.). Amaranthus cruentus accessions (Mexicane and New Mexico) were stable and highly productive (&gt;2.7 t seeds ha−1), while Kinnaury Dhankar accession showed the highest protein percentage (17%). Amaranthus hypochondriacus (Orange Giant and Burgundy) possessed the highest oil percentage (always above 5.7%). A high amount in linoleic, cis‐oleic, and palmitic acids, and an interesting saturated/unsaturated acids ratio ranging from 0.26 (A. hybridus) to 0.32 (A. hypochondriacus) were detected. The unsaponifiable fraction revealed the abundance of squalene in all species, while total tocopherol concentrations were lower than expected.

Effect of unsaponifiable matter extracted from Pistacia khinjuk fruit oil on the oxidative stability of olive oil.

The present study was carried out to investigate the improvement of oxidative stability of refined olive oil using various concentrations of unsaponifiable matters extracted from Pistacia khinjuk fruit oil (UFO). For further elucidation of UFO antioxidative power, tertbutylhydroquinone (TBHQ) was used in an olive oil sample, too. Oxidative stability of olive oil samples without and with different levels of UFO (50, 100, 250, 500, 750 and 1000 ppm) and TBHQ (100 ppm) were studied via evaluation of conjugated diene value, carbonyl value, oil/oxidative stability index, acid value and total tocopherol (TT) contents through 8h thermal process at 170°C. Results obtained by oxidative stability assays revealed that the highest antioxidative activity of olive oil was obtained by 100ppm of UFO, followed using 100, 250, 500, 750, and 1000ppm of UFO and 100ppm TBHQ, respectively. Evaluation of the relationship between oxidative stability indexes and TT changes indicated a strong correlation (R2=0.9718) between mean relative resistance to oxidation and relative resistance to TT reduction during thermal process. By promotion of relative resistance to TT reduction, olive oil samples' relative resistance to oxidation was enhanced exponentially; implying importance of TT in promotion of oxidative stability of edible oils. The results obtained in this study showed that UFO has higher antioxidative activity compared to TBHQ; thus UFO can be considered as a natural antioxidant with ideal antioxidative activity.

Overexpression of HvHGGT Enhances Tocotrienol Levels and Antioxidant Activity in Barley.

Vitamin E is a potent lipid-soluble antioxidant and essential nutrient for human health. Tocotrienols are the major form of vitamin E in seeds of most monocots. It has been known that homogentisate geranylgeranyl transferase (HGGT) catalyzes the committed step of tocotrienol biosynthesis. In the present study, we generated transgenic barley overexpressing HvHGGT under endogenous D-Hordein promoter (proHor). Overexpression of HvHGGT increased seed size and seed weight in transgenic barley. Notably, total tocotrienol content increased by 10-15% in seeds of transgenic lines, due to the increased levels of δ-, β-, and γ-tocotrienol, but not α-tocotrienol. Total tocopherol content decreased by 14-18% in transgenic lines, compared to wild type. The antioxidant activity of seeds was determined by using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and lipid peroxidation assays. Compared to wild type, radical scavenging activity of seed extracts was enhanced by 17-18% in transgenic lines. Meanwhile, the lipid peroxidation level was decreased by about 20% in transgenic barley seeds. Taken together, overexpression of HvHGGT enhanced the tocotrienol levels and antioxidant capacity in barley seeds.

Effects of deep-fat frying process on the oil quality during French fries preparation.

The performance of the sunflower oil in deep-fat frying was assessed by evaluating the efficacy of linoleic acid level and composition of tocopherol isomeric on its frying stability. The oil was used as a frying media to fry potato strips for 6h daily for 7days. Standard procedures for the measurement of used frying oil degradation such as fatty acid composition, acid value, anisidine value, conjugated diene value, total polar compounds and tocopherol concentration were used. At analogous composition of tocopherol isomers, the high oleic sunflower oil with smaller value of linoleic acid content indicated higher frying stability than the oil with higher linoleic acid level. This, indicating that the high oleic sunflower oil frying efficiency was depended mainly with the oil linoleic acid content and the composition of tocopherol isomers showed no significant effect. Also, the α-tocopherol degradation was lower compared to the corresponding degradation of γ-tocopherol.

Laboratory‐Scale Optimization of Roasting Conditions Followed by Aqueous Extraction of Oil from Wild Almond

AbstractThe effects of roasting and aqueous extraction conditions for oil recovery from wild almond were optimized using response surface methodology (RSM). Optimum conditions for oil extraction were obtained at 142 °C roasting temperature, 16.5 min roasting time, 5.67 extraction pH and 4.6 h extraction time. Under these conditions, the extraction yield of 34.5% (w/w, based on the original weight of the sample) was obtained, which is equivalent to 80.0% of the total oil in the kernel. This was lower than that obtained by hexane Soxhlet (HS) extraction (43.1%, w/w, considered as 100% of total oil) but higher than that of cold pressing (CP) (18.5%, w/w; i.e., 42.9% of total oil). The refractive indices and saponification values of the oils were not affected by the extraction method. However, fatty acid and tocopherol compositions and DPPH radical scavenging capacities as well as unsaponifiable matter, iodine, peroxide and acid values of the obtained oils were impacted by the extraction method. The results showed that the quality attributes (omega‐6 fatty acid content, peroxide and acid values, total tocopherol contents and antioxidant activity) of the oil obtained by AEP were somewhat similar to those of the oil extracted by CP and much superior to those of the oil obtained by HS.

Physico-Chemical Characteristic and Fatty Acids Compositions of Cottonseed Oils

In this study, three cotton genotypes of species Gossypium hirsutum L., Cukurova 1518, PAUM 15 and BA 119 were investigated for their some physicochemical properties of oils such as free fatty acids, peroxide value, iodine value, unsaponifiable matter, total carotenoid and tocopherol contents and fatty acids composition in Cukurova region in Turkey. Seed oil content ranged 17.2-19.6% and PAUM 15 was found to be genotype with the highest oil content. The range of other physicochemical properties and their values are as follows; free fatty acids 1.7-2.8%, peroxide value 5.3- 6.0 meq O2 kg-1, unsaponifiable matters 2.1-2.3%, iodine value 102-110, total carotenoid content 119-140 mg kg-1, total tocopherol content 887-920 mg kg-1, linoleic acid 52.00-55.82%, palmitic acid 24.85-25.63%, oleic acid 14.06-17.00%, stearic acid 3.01-3.13% in the cottonseed oils. PAUM 15 was determined to be more suitable for food consumption as edible oil due to its highest oil content and quality characteristics than the others genotypes.

Heating, microwave and UV irradiation effects on oxidative stability of Sardasht red grape (Vitis vinifera cultiv. Sardasht) seed oil

SummaryIn the current study, for the first time, the oxidation stability of the extracted edible oil from Sardasht red grape at three different accelerated deteriorative conditions (oven, microwave and ultraviolet (UV) irradiation) was investigated. In this context, the peroxide value (PV), conjugated diene value (CDV), carbonyl value (CV), radical scavenging activity (RSA) and oil/oxidative stability indices, as well as fatty acid composition and total tocopherol content, were evaluated. Sardasht grape seed oil as a rich oil in unsaturated fatty acid (about 87%) contains linoleic acid in terms of the principal fatty acid (70.4 ± 1.8%). The excessive oxidative stability of crude oil can be correlated with the extreme content of natural antioxidants (tocopherols and tocotrienols). The findings showed that Sardasht red grape seed oil could be approached as new source of edible oil with acceptable oxidative stability.

Application of response surface methodology for optimizing the deodorization parameters in chemical refining of kenaf seed oil

Kenaf seed oil has been suggested to be used as edible oil but there is limited information available about the optimal parameters to produce refined kenaf seed oil. Response surface methodology was used to study the effects of the temperature (180–260 °C) and time (0.5–2.5 h) in the deodorization stage of the refining process for kenaf seed oil. Free fatty acids, p-Anisidine value, total color difference, and tocopherol and tocotrienol contents were measured. Well-fitting models were successfully generated for the responses of free fatty acids (R2 = 0.9619, p 0.05) between experimental and predicted values, indicating the adequacy of the well-fitting models.

Oxidative stability of olive oil during the thermal process: Effect of Pistacia khinjuk fruit oil

ABSTRACTThe oxidative stability of refined olive oil with incorporated Pistacia khinjuk fruit oil (PKFO; 0.5%, 1%, 2%, 5%, and 10%) during thermal processing at 170ºC for 8 h was evaluated. The conjugated diene values, carbonyl values, acid values, oil/oxidative stability indices, and total tocopherol content were measured during thermal processing. Olive oil containing 0.5% PKFO was identified as the most oxidative stable oil followed by oils containing 100 ppm TBHQ and 1, 5, 10, and 2% PKFO. No significant difference between samples of olive oil containing 100 ppm TBHQ and 1% PKFO was observed. Thus, it was concluded that PKFO at levels lower than 1% could provide stronger antioxidation activity in comparison with TBHQ (the strongest syntactic antioxidant used in the food industry). Moreover, reduction in tocopherol compounds during thermal processing was higher in olive oil containing TBHQ as compared to those in pure olive oil.