Changes in the quality of oil extracted by hot pressing from black cumin (Nigella sativa) seeds and by solvent from the obtained cake during refining

In this study, oil was extracted from black cumin (Nigella sativa) seed (BCS) by press, and oil was extracted from the obtained cake with a solvent. The changes in the quality of both crude oils obtained by pressing and by solvent were investigated during refining. Findings revealed that the p-anisidin value (p-AV) and fatty acid profile did not change significantly, but there were significant differences (p < .05) in the peroxide value (PV), reflective index, pigment contents, free fatty acid content (FFA%), and antioxidant activity (total phenol content (TPC), thymoquinone, and DPPH inhibition) of BCS oils obtained by the two different methods. PV and FFA decreased to less than 15 meqO2/kg and 0.3%, respectively, in the refined oil. The TPC (65%), thymoquinone (45-97%), carotenoids (86-89%), and chlorophyll (75-85%) were removed from BCS oil, but the DPPH value was raised by about 33%. The current study gives a clear picture of the changes during refining in BCS oil, which can be a useful guide in food applications.

Shade of Innovative Food Processing Techniques: Potential Inducing Factors of Lipid Oxidation

With increasing environmental awareness and consumer demand for high-quality food products, industries are strongly required for technical innovations. The use of various emerging techniques in food processing indeed brings many economic and environmental benefits compared to conventional processes. However, lipid oxidation induced by some "innovative" processes is often "an inconvenient truth", which is scarcely mentioned in most studies but should not be ignored for the further improvement and optimization of existing processes. Lipid oxidation poses a risk to consumer health, as a result of the possible ingestion of secondary oxidation products. From this point of view, this review summarizes the advance of lipid oxidation mechanism studies and mainly discloses the shade of innovative food processing concerning lipid degradation. Sections involving a revisit of classic three-stage chain reaction, the advances of polar paradox and cut-off theories, and potential lipid oxidation factors from emerging techniques are described, which might help in developing more robust guidelines to ensure a good practice of these innovative food processing techniques in future.

Microalgal polyunsaturated fatty acids: Hotspots and production techniques

Algae play a crucial role in the earth’s primary productivity by producing not only oxygen but also a variety of high-value nutrients. One such nutrient is polyunsaturated fatty acids (PUFAs), which are accumulated in many algae and can be consumed by animals through the food chain and eventually by humans. Omega-3 and omega-6 PUFAs are essential nutrients for human and animal health. However, compared with plants and aquatic sourced PUFA, the production of PUFA-rich oil from microalgae is still in the early stages of exploration. This study has collected recent reports on algae-based PUFA production and analyzed related research hotspots and directions, including algae cultivation, lipids extraction, lipids purification, and PUFA enrichment processes. The entire technological process for the extraction, purification and enrichment of PUFA oils from algae is systemically summarized in this review, providing important guidance and technical reference for scientific research and industrialization of algae-based PUFA production.

Kinetics and Thermodynamics of β-Carotene Adsorption onto Acid-Activated Clays Modified by Zero Valent Iron

The adsorption of β-carotene from crude palm oil onto acid-activated clay and clay modified by zero valent iron (ZVI) was investigated in this work. Spectroscopic studies including FTIR, XRD, and SEM were used for its characterization. The adsorption characteristics such as kinetics, mechanism, isotherms, and thermodynamics of β-carotene were studied. The kinetic data were analyzed using the pseudo-first-order kinetic equation, pseudo-second-order kinetic equation, and intraparticle diffusion model. The pseudo-second-order kinetic model is the only one that describes the experimental data well (R2 ≥ 0.969). The chemical analysis of bulk clay showed that the predominant oxides are Al2O3 (57.91 wt%), Fe2O3 (32.54 wt%), SiO2 (3.09 wt%), K2O (2.37 wt%), and CaO2 (1.73 wt%). The adsorption capacity increases with an increase in temperature. The equilibrium data were described better by the Freundlich model for all clays. To determine the best fit kinetic model for each system, three error analysis methods, namely, chi-square (χ2), residual mean squared error (RMSE), and mean percent error (%APE) were used to evaluate the data. A thermodynamic study demonstrated that β-carotene adsorption is spontaneous, endothermic, and an entropy driven process for both forms of clay.

Proximate Composition, Physicochemical, and Lipids Profiling and Elemental Profiling of Rapeseed (Brassica napus L.) and Sunflower (Helianthus annuus L.) Grown in Morocco

We investigate and compare the nutritional and physicochemical properties of rapeseed and sunflower grown in Morocco. In order to examine a complete physicochemical characterization, various parameters such as mineral profile, fatty acid composition, sterols contents, total flavonoids content (TFC), total polyphenols content (TPC), and quality oil parameters were evaluated. The results showed a relatively small difference in the physicochemical composition of the seeds, as sunflower seeds recorded higher amounts of protein and oil content (22.98 ± 0.01 g/100 g and 41.30 ± 0.50 g/100 g) than rapeseed (22.98 ± 0.01 and 38.80 ± 0.50), while mineral elements profile was observed to be statistically different. Nevertheless, both seeds were rich in K, Ca, P, Mg, and Na and they were relatively poor in Na, Fe, Mn, Cu, and Zn. The most represented macroelement was K with the amount of 7936.53 ± 63.87 mg/Kg in rapeseed and 7739.22 ± 59.50 mg/Kg in sunflower. On the other hand, Cu was present in the analyzed samples the least, mostly below 20 mg/kg. For TPC and TFC, the sunflower recorded higher values (49.73 ± 0.50 and 25.37 ± 0.39 mg GAE/g) than rapeseed (38.49 ± 0.24 and 22.55 ± 1.76 mg QE/g). The fatty acid composition showed that both extracted oils have beneficial proprieties, as they are rich in unsaturated fatty acids; namely, rapeseed oil contains a high level of oleic acid (C18 : 1) (62.19%), while sunflower oil was richer in linoleic acid (C18 : 2) (55.7%). As a result, we conclude that the studied varieties have major importance in terms of both nutritional and seed improvement potentials.

Vitamin E in foodstuff: Nutritional, analytical, and food technology aspects

Vitamin E is a group of isoprenoid chromanols with different biological activities. It comprises eight oil-soluble compounds: four tocopherols, namely, α-, β-, γ-, and δ-tocopherols; and four tocotrienols, namely, α-, β-, γ, and δ-tocotrienols. Vitamin E isomers are well-known for their antioxidant activity, gene-regulation effects, and anti-inflammatory and nephroprotective properties. Considering that vitamin E is exclusively synthesized by photosynthetic organisms, animals can only acquire it through their diet. Plant-based food is the primary source of vitamin E; hence, oils, nuts, fruits, and vegetables with high contents of vitamin E are mostly consumed after processing, including industrial processes and home-cooking, which involve vitamin E profile and content alteration during their preparation. Accordingly, it is essential to identify the vitamin E content and profile in foodstuff to match daily intake requirements. This review summarizes recent advances in vitamin E chemistry, metabolism and metabolites, current knowledge on their contents and profiles in raw and processed plant foods, and finally, their modern developments in analytical methods.

Application of Aqueous Saline Process to Extract Silkworm Pupae Oil (Bombyx mori): Process Optimization and Composition Analysis

Silkworm pupae, a waste product from the silk production industry, can be an alternative source of edible oil, thus reducing the industry’s waste. In the present work, frozen silkworm pupae were used as raw material to extract oil via an aqueous saline process. The Box–Behnken design (BBD) and response surface methodology (RSM) were used to optimize the extraction process. The extraction conditions with the highest oil yield and a low peroxide value were obtained when using a saline solution concentration of 1.7% w/v, a ratio of aqueous liquid to silkworm pupae of 3.3 mL/g, and a 119 min stirring time at the stirring speed of 100 rpm. Under these conditions, silkworm oil with a yield of 3.32%, peroxide values of approximately 1.55 mM, and an acid value of 0.67 mg KOH/g oil was obtained. The extracted oil contained omega-3 acids (α-linolenic acid), which constituted around 25% of the total fatty acids, with approximate cholesterol levels of 109 mg/100 g oil. The amounts of β-carotene and α-tocopherol were approximately 785 and 9434 μg/100 g oil, respectively. Overall, the results demonstrated that oil extracted from silkworm pupae has good quality parameters and thus can be used as a new valuable source of edible lipids.

Different effect of chemical refining process on Baneh (Pistacia atlantica var mutica) kernel oil: Regeneration of tocopherols

The present study was conducted to investigate the impact of refining process on the chemical properties (fatty acid composition and tocopherols, sterols, and polyphenolic contents), qualitative parameters (peroxide value, acid value, and p-anisidine value), and antioxidant activity (DPPH radical scavenging assay and FRAP test) of Baneh (Pistacia atlantica var mutica) kernel oil. The results revealed that the refining process had no significant effect on the fatty acid composition. A major finding of this research was the increase in the tocopherol and sterol content up to the bleaching stage followed by their decrease in the deodorizing phase. Some tocopherol and sterol compounds in crude oil were dimerized or attached to other compounds by ester bonding, which are released during some stages of the refining process and this factor is responsible for their increase. In fact, during this process, these compounds are regenerated. The occurrence of this phenomenon in the refining process improved the DPPH radical scavenging power of Baneh kernel oil up to the bleaching stage. Moreover, the content of phenolic compounds decreased after refining of Baneh kernel oil, and only in the deodorizing stage, an increase of these compounds was observed. In general, the results of this study showed that the refining process had a completely different effect on the antioxidant compounds (especially tocopherols) compared to other oils.

Attempts of Physical Refining of Sterol-Rich Sunflower Press Oil to Obtain Minimally Processed Edible Oil

New phytosterol (PS)-enriched sunflower seeds, which are higher in campesterol and ∆7-stigmastenol, have recently been developed. Crude oils obtained from these new sunflower seeds in 2015 and 2017 were used in this study. Oils extracted only by press (PO) and with subsequent solvent extraction (SO) were characterized. Physical refining (PhR) was used to obtain edible PO by minimal processing and to keep the PS levels as high as possible. Oils obtained by chemical processing were also studied for comparative purposes. Different bleaching treatments were examined to reduce the contents of phospholipids in the PO to levels required for PhR (<10 mg kg^-1). Phosphorous levels in PO from 2015 (9-12 mg kg^-1) were reduced to optimal levels by bleaching with 0.1% Trisyl and 1% Tonsil 278 FF. Contrarily, treatments with Trisyl and Tonsil (278 FF or 114 FF) were not sufficient to reduce the higher levels in PO from 2017 (15-36 mg/kg^-1), thereby they were subjected to chemical refining (ChR). The PhR applied to PO from 2015 did not lead to substantial changes in the composition and total content of PS. In contrast, losses of up to approximately 30% of total PS were found owing to ChR, although the oils preserved their unique PS profiles.

A comparative study on performance of industrial and microwave techniques for sunflower oil bleaching process

The main objective of this study is to compare the quality characteristics of the sunflower oils bleached with microwave and industrial techniques. The bleaching efficiencies of microwave and industrial bleaching methods were found as 83.76% and 85.68%, respectively. The totox values of bleached oil were found as 22.39 and 18.86 in microwave and industrial bleaching, respectively. The free fatty acid content was almost not changed with microwave bleaching, it was decreased by the industrial bleaching. No significant difference was reported in tocopherol content and sterol composition of oil after both industrial and microwave methods. The amount of clay and the bleaching time were reduced by 50% and 73%, respectively in microwave bleaching. The possibility of the repetitive use of bleaching clay was also evaluated and it was found that the clay used in microwave bleaching was efficient at least twice for bleaching of sunflower oil.

Recommendations for Oil Extraction and Refining Process to Prevent the Formation of Monochloropropane-diol Esters in Sunflower Oil

The aim of this study was to identify the chlorine source during sunflower oil production and propose mitigation strategies in order to prevent monochloropropane-diol ester (MCPDE) formation. Whole sunflower seeds, the separated kernel, hulls, and pressed cake were studied to pinpoint the location of chlorine donors originating from the crop. Acid-water-based degumming, bleaching, cooling, and heat treatment were performed to mimic the current refining process practices. Various oil extraction and refining scenarios were tested. MCPDE and total monochloropropane-diol (MCPD) content of the heat-treated samples were determined by liquid chromatography-HRMS and by an AOCS Official method. The results show that the oil produced from crop hulls and the bleaching clay used are the strongest chlorine sources boosting the MCPDE formation. Using a mixture of pressed and solvent extracted cake oil as model, total 3-MCPD decreased by a factor of 2 when applying static cooling in combination with a washed bleaching clay.

The influence of industrial refining stages on the physico-chemical properties, fatty acid composition and sterol contents in hazelnut oil

In this study determined influence of industrial refining stages on the physico-chemical properties, fatty acid composition and sterol contents in hazelnut oil. According to this, while acidity values of hazelnut oil obtained from refining stages change between 0.11 (deodorized) and 1.44 (crude), peroxide values of oil samples were determined between 10.4 meqO₂/kg (winterized) and 12.5 meqO₂/kg (crude oil). In addition, iodine values of oils taken from each refining stages varied between 85.06 (nötralized) and 87.45 (deodorized). While oleic acid contents of hazelnut oils taken from refining stages change between 84.08% (winterized) and 84.68% (neutralized), linoleic acid contents of oil samples ranged from 6.79% (neutralized) to 8.56% (winterized). Total saturated and unsaturated fatty acids of oil samples changed between 6.84% (deodorized) and 8.00% (neutralized) to 92.00% (neutralized) and 93.16% (deodorized), respectively. While campesterol contents of oil sample change between 3.56% (deodorized) and 4.87% (crude), δ-5,23-stigmastadienol contents of oil varied between 0.48% (deodorized) and 2.87% (neutralized). The highest sterol had β-sitosterol, its amount changed between 54.98% (deodorized) and 73.96% (crude oil). In addition, δ-7-avenasterol contents of hazelnut oil obtained from refining stages varied between 4.85% (crude oil) and 28.33% (deodorized).

Influence of refining processes on the bioactive composition, in vitro antioxidant capacity, and their correlation of perilla seed oil

The effect of chemical refining process on the bioactive composition, in vitro antioxidant capacity, and their correlation of perilla seed oil (PSO) were investigated. In this paper, seven samples corresponding to each step of the refining process (degumming, neutralization, bleaching, deodorization, winterization, crude, and refined oils) were studied. The results showed that phenolic compounds and tocopherols were removed from PSO to a degree of 19.4% and 5.4%, respectively. In addition, the carotenoid content of PSO decreased during the refining process. The main carotenoid of PSO was found to be lutein, and the compound was lost completely during the bleaching step of the refining process. In this paper, we analyzed the variation of carotenoid content in PSO during the refining process for the first time. Neutralization affected the contents of phytosterols the most, followed by the effects of degumming and bleaching. The demonstrated results of Pearson product-moment correlation indicated that total tocopherols were significantly correlated with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorption capacity (ORAC) values, whereas carotenoids were significantly correlated with the DPPH value. However, phenolic compounds and phytosterols have no significant difference with DPPH, 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, ORAC, and ferric reducing antioxidant power values. The collected information can be applied to seeking out optimum factors needed to suffice the fundamental requirements for PSO production and minimize micronutrient losses to enhance its market value. PRACTICAL APPLICATION: The present study aimed to determine influence of chemical refining in the bioactive composition of perilla seed oil (PSO) as well as its antioxidant capacity in vitro. Moreover, we also intend to find the correlation between them. Results indicated that this study supplies a good reference for the industrial parameters of the refining process to minimize micronutrient losses and further obtain high-quality PSO products for consumers.

Dietary fats and cardiometabolic disease: mechanisms and effects on risk factors and outcomes

The effect of dietary fats on cardiometabolic diseases, including cardiovascular diseases and type 2 diabetes mellitus, has generated tremendous interest. Many earlier investigations focused on total fat and conventional fat classes (such as saturated and unsaturated fats) and their influence on a limited number of risk factors. However, dietary fats comprise heterogeneous molecules with diverse structures, and growing research in the past two decades supports correspondingly complex health effects of individual dietary fats. Moreover, health effects of dietary fats might be modified by additional factors, such as accompanying nutrients and food-processing methods, emphasizing the importance of the food sources. Accordingly, the rapidly increasing scientific findings on dietary fats and cardiometabolic diseases have generated debate among scientists, caused confusion for the general public and present challenges for translation into dietary advice and policies. This Review summarizes the evidence on the effects of different dietary fats and their food sources on cell function and on risk factors and clinical events of cardiometabolic diseases. The aim is not to provide an exhaustive review but rather to focus on the most important evidence from randomized controlled trials and prospective cohort studies and to highlight current areas of controversy and the most relevant future research directions for understanding how to improve the prevention and management of cardiometabolic diseases through optimization of dietary fat intake.

Different Processing Practices and the Frying Life of Refined Canola Oil

Refined expeller-pressed (RCanO-I and RCanO-II) and expeller-pressed and solvent-extracted blended (RCanO-III and RCanO-IV) canola oils were compared to determine the effect of processing (extraction) practice on the frying life of canola oil. Samples were from the 2016/2017 and 2017/2018 production seasons and were used to fry potato chips for 36 to 48 cycles. Frying life was assessed by the total polar compounds, retention of tocopherols, antioxidant activity, and other quality indices. RCanO-II exhibited significantly, the longest frying life as compared with the other three oils and this correlated with tocopherol retention and antioxidant activity (p < 0.05). The extraction practice influenced the frying life of canola oil, but this was dependent on other processing practices employed by the individual processors. Variations in initial oil quality dictated the rates of chemical reactions occurring in the oils during frying and influenced oil stability.

The effect of refining process on the physicochemical properties and micronutrients of rapeseed oils

Information on the physicochemical variability in rapeseed oil from different varieties during each refining process is lacking. Our purpose was to investigate the physicochemical properties, micronutrients and oxidative stability of the oil extracted from the five varieties of rapeseeds during their different stages of refining process. Increase in the acid value, peroxide value and p-anisidine value were detected in the refining, while content of tocopherols, sterols, β-carotene and phenols, which are regarded as important nutritional compounds diminished. Moreover, the loss rate of total phytosterols of all oils during neutralization (9.23–7.3%) and deodorization (9.97–8.27%) were higher than that of degumming (3.01–0.87%) and bleaching (2.75–1.18%). Deodorization affected total tocopherols contents the most, followed by bleaching, neutralization and degumming. There was a remarkable reduction in total content of phenol, β-carotene and oxygen radical absorbance of all oils during refining. The accumulated information can be used in looking for the optimum condition to meet the basic requirements for oil and minimize micronutrients losses so as to increase their market value.

The effect of temperature on rice oil bleaching to reduce oxidation and loss in bioactive compounds

Refining conditions are very important to obtain high-quality rice oil. This work aimed at evaluating the effect of bleaching temperature in chemical and physical refining processes to avoid losses in γ-oryzanol and carotenoids. In addition, the aspects related to rancidity were investigated. Samples of degummed oil (obtained by a physical procedure) and of neutralized oil (obtained by a chemical procedure) were provided by a local industry. The oils were bleached at 80, 95 and 110 °C using 1% (w w-1) activated earth. The temperature of 95 °C was the best in relation to oxidative stability. The γ-oryzanol and carotenoids were better preserved through physical refining than by the chemical procedure by about 64 and 84%, respectively. However, the oxidation indicators were high for the oil bleached by the physical procedure, indicating that bleaching without prior neutralization is viable, but it is necessary to obtain an industrial crude oil with less oxidation.

Evaluation and comparison of in vitro antioxidant activities of unsaponifiable fraction of 11 kinds of edible vegetable oils

The radical scavenging capabilities of the extracts from eleven edible vegetable oils were investigated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3- ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing ability of plasma (FRAP) assays. The results indicated that rapeseed oil and sesame oil showed higher radical scavenging abilities than other vegetable oils. When the radical scavenging capabilities of the extracts from virgin camellia oils and commercially available refined camellia oils were evaluated by FRAP assay, the results showed that the antioxidant capabilities of the former were higher than the latter. Therefore, it is recommended that moderate refining processes should be taken to minimize the loss of antioxidant components and people consume virgin oils or less processed edible vegetable oils for higher antioxidant activities.

Evaluation of antioxidant properties of lemon verbena (Lippia citriodora) essential oil and its capacity in sunflower oil stabilization during storage time

In this study, lemon verbena essential oil as a natural antioxidant was used to increase the stability of sunflower oil, and stabilization effects in terms of storage conditions were compared with synthetic antioxidant (BHT). For this purpose, the antioxidant activity of the essential oil was determined by DPPH assay and β-carotene bleaching method. Then, lemon verbena essential oil (0, 400, 800, and 1,600 ppm) was added to sunflower oil without synthetic antioxidant and stored at 60°C for 60 days. Results from different parameters (peroxide value, free fatty acid, iodine value, total polar compound, carbonyl value, conjugated dienes, and oxidative stability index) were in agreement with each other, suggesting that lemon verbena essential oil (1,600 ppm) could act better than BHT in inhibition of lipid oxidation in sunflower oil and can be used as predominant alternative of synthetic antioxidants.

Sacha inchi (Plukenetia volubilis L.): Nutritional composition, biological activity, and uses

Sacha inchi (Plukenetia volubilis L.) is native to the Peruvian Amazon and is recognised in other parts of the world as a sustainable crop with viable commercial applications. In recent years, there has been growing interest in developing the sacha inchi plant as a novel source of oil rich in unsaturated fatty acids. This review presents information on the major and minor chemical components, health effects and utilization of different parts (seeds, seed shells and leaves) of this plant. In particular, the physicochemical properties and oxidative stability of sacha inchi seed oil are described. The whole sacha inchi plant has been utilized to generate nutritional, cosmetic and pharmaceutical products with the goal to maximize its economic value. The sacha inchi plant may become a valuable resource for high value-added compounds used in many diverse food and non-food products.

Effect of black cumin oil on the oxidative stability and sensory characteristics of mayonnaise

Mayonnaise is one of the most commonly used sauces all over the world but it is vulnerable to oxidation because of its high oil content. Using natural antioxidants instead of synthetic ones is a popular and promising topic in the food industry. The aim of this study was to increase the oxidative stability of mayonnaise using cold-pressed black cumin oil (BCO), which has high antioxidant activity due to its phenolic content. Four different mayonnaise formulations were used: Mayo-Control, Mayo-5% BCO, Mayo-10% BCO, and Mayo-20% BCO, which refer to a 0 (control), 5, 10, and 20% BCO replacement of total sunflower oil content, respectively. Thymoquinone content of the mayonnaises including BCO increased with the increasing BCO ratios. At the end of the storage for 4 weeks at 20 °C, peroxide values of Mayo-Control, Mayo-5% BCO, Mayo-10% BCO, and Mayo-20% BCO samples were recorded as 36.07 ± 1.51, 26.76 ± 0.67, 25.60 ± 0.57, and 17.66 ± 1.93 meq O₂/kg oil, respectively. The conjugated diene and triene values of the mayonnaises prepared by adding BCO were lower than those of the control group during storage. Overall acceptability of Mayo-5% BCO in sensory analysis was higher than that of Mayo-Control. Using BCO in mayonnaise improved its oxidative stability and flavor.

Comparative study of crude and refined kenaf (Hibiscus cannabinus L.) seed oil during accelerated storage

This study assessed the changes of antioxidant activity and bioactive compounds of crude and refined kenaf seed oil during accelerated storage at 65°C for 24 days. 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assays were used to determine their antioxidant activity. The changes of phenolic, tocopherol, and phytosterol contents during the storage were also studied. The phenolic content and antioxidant activity of refined oil were significantly lower than those of crude oil after the accelerated storage. There was a decrease of 72.5% tocopherol content and 31.1% phytosterol content in the crude oil and a decrease of 67% tocopherol content and 12.1% phytosterol content in the refined oil during the accelerated storage. There was no significant difference in tocopherol and phytosterol contents for crude and refined oils after the storage. The rate of degradation of tocopherol and phytosterol contents in refined oil was slower than that in crude oil during the storage.