Elastic Fibers in the Intervertebral Disc: From Form to Function and toward Regeneration.

Despite extensive efforts over the past 40 years, there is still a significant gap in knowledge of the characteristics of elastic fibers in the intervertebral disc (IVD). More studies are required to clarify the potential contribution of elastic fibers to the IVD (healthy and diseased) function and recommend critical areas for future investigations. On the other hand, current IVD in-vitro models are not true reflections of the complex biological IVD tissue and the role of elastic fibers has often been ignored in developing relevant tissue-engineered scaffolds and realistic computational models. This has affected the progress of IVD studies (tissue engineering solutions, biomechanics, fundamental biology) and translation into clinical practice. Motivated by the current gap, the current review paper presents a comprehensive study (from the early 1980s to 2022) that explores the current understanding of structural (multi-scale hierarchy), biological (development and aging, elastin content, and cell-fiber interaction), and biomechanical properties of the IVD elastic fibers, and provides new insights into future investigations in this domain.

Developing Novel Fabrication and Optimisation Strategies on Aggregation-Induced Emission Nanoprobe/Polyvinyl Alcohol Hydrogels for Bio-Applications.

The current study describes a new technology, effective for readily preparing a fluorescent (FL) nanoprobe-based on hyperbranched polymer (HB) and aggregation-induced emission (AIE) fluorogen with high brightness to ultimately develop FL hydrogels. We prepared the AIE nanoprobe using a microfluidic platform to mix hyperbranched polymers (HB, generations 2, 3, and 4) with AIE (TPE-2BA) under shear stress and different rotation speeds (0-5 K RPM) and explored the FL properties of the AIE nanoprobe. Our results reveal that the use of HB generation 4 exhibits 30-times higher FL intensity compared to the AIE alone and is significantly brighter and more stable compared to those that are prepared using HB generations 3 and 2. In contrast to traditional methods, which are expensive and time-consuming and involve polymerization and post-functionalization to develop FL hyperbranched molecules, our proposed method offers a one-step method to prepare an AIE-HB nanoprobe with excellent FL characteristics. We employed the nanoprobe to fabricate fluorescent injectable bioadhesive gel and a hydrogel microchip based on polyvinyl alcohol (PVA). The addition of borax (50 mM) to the PVA + AIE nanoprobe results in the development of an injectable bioadhesive fluorescent gel with the ability to control AIEgen release for 300 min. When borax concentration increases two times (100 mM), the adhesion stress is more than two times bigger (7.1 mN/mm2) compared to that of gel alone (3.4 mN/mm2). Excellent dimensional stability and cell viability of the fluorescent microchip, along with its enhanced mechanical properties, proposes its potential applications in mechanobiology and understanding the impact of microstructure in cell studies.

Advanced Strategies for the Regeneration of Lumbar Disc Annulus Fibrosus.

Damage to the annulus fibrosus (AF), the outer region of the intervertebral disc (IVD), results in an undesirable condition that may accelerate IVD degeneration causing low back pain. Despite intense research interest, attempts to regenerate the IVD have failed so far and no effective strategy has translated into a successful clinical outcome. Of particular significance, the failure of strategies to repair the AF has been a major drawback in the regeneration of IVD and nucleus replacement. It is unlikely to secure regenerative mediators (cells, genes, and biomolecules) and artificial nucleus materials after injection with an unsealed AF, as IVD is exposed to significant load and large deformation during daily activities. The AF defects strongly change the mechanical properties of the IVD and activate catabolic routes that are responsible for accelerating IVD degeneration. Therefore, there is a strong need to develop effective therapeutic strategies to prevent or reconstruct AF damage to support operational IVD regenerative strategies and nucleus replacement. By the way of this review, repair and regenerative strategies for AF reconstruction, their current status, challenges ahead, and future outlooks were discussed.

Tuning Surface Morphology of Fluorescent Hydrogels Using a Vortex Fluidic Device.

In recent decades, microfluidic techniques have been extensively used to advance hydrogel design and control the architectural features on the micro- and nanoscale. The major challenges with the microfluidic approach are clogging and limited architectural features: notably, the creation of the sphere, core-shell, and fibers. Implementation of batch production is almost impossible with the relatively lengthy time of production, which is another disadvantage. This minireview aims to introduce a new microfluidic platform, a vortex fluidic device (VFD), for one-step fabrication of hydrogels with different architectural features and properties. The application of a VFD in the fabrication of physically crosslinked hydrogels with different surface morphologies, the creation of fluorescent hydrogels with excellent photostability and fluorescence properties, and tuning of the structure-property relationship in hydrogels are discussed. We conceive, on the basis of this minireview, that future studies will provide new opportunities to develop hydrogel nanocomposites with superior properties for different biomedical and engineering applications.

Weyl Prior and Bayesian Statistics.

When using Bayesian inference, one needs to choose a prior distribution for parameters. The well-known Jeffreys prior is based on the Riemann metric tensor on a statistical manifold. Takeuchi and Amari defined the α -parallel prior, which generalized the Jeffreys prior by exploiting a higher-order geometric object, known as a Chentsov-Amari tensor. In this paper, we propose a new prior based on the Weyl structure on a statistical manifold. It turns out that our prior is a special case of the α -parallel prior with the parameter α equaling - n , where n is the dimension of the underlying statistical manifold and the minus sign is a result of conventions used in the definition of α -connections. This makes the choice for the parameter α more canonical. We calculated the Weyl prior for univariate Gaussian and multivariate Gaussian distribution. The Weyl prior of the univariate Gaussian turns out to be the uniform prior.

Antioxidant activity of Pistacia atlantica var mutica kernel oil and it's unsaponifiable matters.

In this research, antioxidant activity of Pistacia atlantica var mutica (a wild type of pistachio in Iran) kernel oil (PAKO) and unsaponifiable matters of kernel oil (UKO) were compared with those of sesame seed oil (SSO) and rice bran oil (RBO) as well as with their unsaponifiable matters (USO and UBO) and α-tocopherol (natural antioxidant) was selected as control. Also, some chemical properties such as (FRAP, DPPH radical-scavenging, rancimat and oven assays (peroxide value and carbonyl value) were assessed. The amount of unsaponifiable matters of studied oils was between 1.4 and 3.5%. The highest total phenolics was observed in SSO (1024 mg/kg), followed by RBO, and PAKO was 174, and 75 mg/kg, respectively. In DPPH radical-scavenging assay, the EC50 values of PAKO, SSO, RBO, UKO, USO, UBO, and α-tocopherol were determined as 38.9, 50, 48.4, 14, 12.7, 15.9 and 61.4 mg/mL, respectively. In FRAP assay, the highest value was nominated for UKO (434 mmol/L); followed by USO, UBO, PAKO, SSO, RBO and α-tocopherol (404, 357, 364, 298, 210 and 58 mmol/L; respectively). Also, considering the results of oven test, the incorporation of UKO into pure sunflower oil resulted in the highest oxidative stability; followed by UBO, USO, PAKO, SSO, RBO and α-tocopherol. According to results of the rancimat test, the incorporation of unsaponifiable matters (UKO, USO, and UBO) resulted in the highest oil/oxidative stability index (OSI) in pure sunflower oil, followed by oils studied (PAKO, SSO, and RBO). According to results, UKO had the highest antioxidant activity, followed by USO, UBO, PAKO, SSO, RBO, and α-tocopherol.

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 8 h thermal process at 170 °C. Results obtained by oxidative stability assays revealed that the highest antioxidative activity of olive oil was obtained by 100 ppm of UFO, followed using 100, 250, 500, 750, and 1000 ppm of UFO and 100 ppm 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.

Lumbar Total Disc Replacements for Degenerative Disc Disease: A Systematic Review of Outcomes With a Minimum of 5 years Follow-Up.

STUDY DESIGN: Systematic Review. OBJECTIVES: To systematically review the clinical outcomes, re-operation, and complication rates of lumbar TDR devices at mid-to long-term follow-up studies for the treatment of lumbar degenerative disc disease (DDD). METHODS: A systematic search was conducted on PubMed, SCOPUS, and Google Scholar to identify follow-up studies that evaluated clinical outcomes of lumbar TDR in patients with DDD. The included studies met the following criteria: prospective or retrospective studies published from 2012 to 2022; a minimum of 5 years post-operative follow-up; a study sample size >10 patients; patients >18 years of age; containing clinical outcomes with Oswestry Disability Index (ODI), Visual Analog Scale (VAS), complication or reoperation rates. RESULTS: Twenty-two studies were included with data on 2284 patients. The mean follow-up time was 8.30 years, with a mean follow-up rate of 86.91%. The study population was 54.97% female, with a mean age of 42.34 years. The mean VAS and ODI pain score improvements were 50.71 ± 6.91 and 30.39 ± 5.32 respectively. The mean clinical success and patient satisfaction rates were 74.79% ± 7.55% and 86.34% ± 5.64%, respectively. The mean complication and reoperation rates were 18.53% ± 6.33% and 13.6% ± 3.83%, respectively. There was no significant difference when comparing mid-term and long-term follow-up studies for all clinical outcomes. CONCLUSIONS: There were significant improvements in pain reduction at last follow-up in patients with TDRs. Mid-term follow-up data on clinical outcomes, complication and reoperation rates of lumbar TDRs were maintained longer term.

Thermal processing of pomegranate seed oils underscores their antioxidant stability and nutritional value: Comparison of pomegranate seed oil with sesame seed oil.

In the present study, the oxidative stability and antioxidant activity of seed oils were investigated in three Iranian pomegranate cultivars, Shirin Khafr, Torsh Sabz, and Rabab, along with the sesame (Sesamum indicume L. cv Dezful) seed oil. Punicic acid was the primary fatty acid in the pomegranate seed oils, with contents ranging from 75.5 to 80.9% (w/w). The tocopherol levels in pomegranate seed oils ranged from 1439 to 2053 mg/kg, whereas the phenolics ranged from 130 to 199.3 mg/kg, respectively. Comparatively, in the seed oil of sesame "Dezful," these substances' contents were 1053 and 79 mg/kg, respectively. Contrary to common perception, the seed oil of the three pomegranate cultivars cultivated in Iran had high oxidative stability and antioxidative activity during the 32 h of thermal processing at 170°C. The oxidation stability assayed by peroxide value, p-anisidine value, and TOTOX index revealed that the pomegranate seed oils had a much higher resistance to the oxidation process than the sesame oil. The content of tocopherols increased during thermal processing due to the regeneration phenomenon. Tocopherols are not always free and may form a matrix with themselves or other compounds. Changes in the antioxidant activity during the thermal processing assessed by DPPH free radical scavenging power and by the FRAP test were consistent with those for the antioxidants. Therefore, these oils can be added to other edible oils as a natural antioxidant to improve their oxidative stability.

Surgeon Preference Regarding Wound Dressing Management in Lumbar Fusion Surgery: An AO Spine Global Cross-Sectional Study.

OBJECTIVE: To evaluate the global practice pattern of wound dressing use after lumbar fusion for degenerative conditions. METHODS: A survey issued by AO Spine Knowledge Forums Deformity and Degenerative was sent out to AO Spine members. The type of postoperative dressing employed, timing of initial dressing removal, and type of subsequent dressing applied were investigated. Differences in the type of surgery and regional distribution of surgeons' preferences were analyzed. RESULTS: Right following surgery, 60.6% utilized a dry dressing, 23.2% a plastic occlusive dressing, 5.7% glue, 6% a combination of glue and polyester mesh, 2.6% a wound vacuum, and 1.2% other dressings. The initial dressing was removed on postoperative day 1 (11.6%), 2 (39.2%), 3 (20.3%), 4 (1.7%), 5 (4.3%), 6 (0.4%), 7 or later (12.5%), or depending on drain removal (9.9%). Following initial dressing removal, 75.9% applied a dry dressing, 17.7% a plastic occlusive dressing, and 1.3% glue, while 12.1% used no dressing. The use of no additional coverage after initial dressing removal was significantly associated with a later dressing change (p < 0.001). Significant differences emerged after comparing dressing management among different AO Spine regions (p < 0.001). CONCLUSION: Most spine surgeons utilized a dry or plastic occlusive dressing initially applied after surgery. The first dressing was more frequently changed during the first 3 postoperative days and replaced with the same type of dressing. While dressing policies tended not to vary according to the type of surgery, regional differences suggest that actual practice may be based on personal experience rather than available evidence.

Intervertebral disc-on-a-chip: a precision engineered toolbox for low back pain studies.

Current in vitro intervertebral disc (IVD) models do not fully recapitulate the complex mechanobiology of native tissue, and so far there is no strategy to effectively evaluate IVD regeneration. The development of a modular microfluidic on-chip model is expected to enhance the physiological relevance of experimental data leading to successful clinical outcomes.

Ostrich oil as a fat substitute in milk-based infant formula.

In this study, the possibility of replacing vegetable fats with ostrich oil in infant formula (IF) production was investigated. The fatty acid profile, the positional distribution of fatty acids in the triacylglycerols, the cholesterol content, and the physicochemical properties of ostrich oil were determined and compared with breast milk fat and vegetable oils. In the next step, two infant formulas were produced using ostrich oil and vegetable oils and the physicochemical properties, rheological properties, color parameters, and sensory analysis of the resultant powders were compared. The results showed that the predominant fatty acids in ostrich oil are palmitic acid, oleic acid, and linoleic acid which is similar to breast milk fat and vegetable oils. The presence of appropriate cholesterol content in ostrich oil makes it more similar to breast milk fat compared to vegetable fats. Palmitic acid was located at sn-2 position in 15% triacylglycerol from ostrich fat, which was equal to the amount reported for vegetable fats. The incorporation of ostrich oil in infant formula production showed that there is no statistically significant difference between quality attributes of powder formulated with ostrich oil or vegetable oils. Therefore, ostrich oil can be introduced as a new source of edible oil, and addition of ostrich oil is an effective way to reduce the gap between the composition of breast milk and infant formula.

Extraction of phenol compound from Mentha piperita by ultrasonic waves based on a response surface methodology.

In this study, optimization of the extraction of phenol compounds from Mentha piperita using ultrasonic waves with response surface methodology (RSM) was assessed. In this regard, a central composite design with three independent variables of time (5, 27.5, and 50 min), temperature (25, 45, and 65°C), and concentrations of ethanol in the water-ethanol solution (0%, 50%, and 100%) was used. Besides, the antioxidant activity tests (DPPH radical scavenging assay, ferric reducing antioxidant power [FRAP], and oxidative stability indexes [OSI]) were examined. Significant effects of independent variables on the extraction of phenol compound, DPPH radical scavenging power, and OSI of M. piperita extract, with the regression coefficients of 0.89, 0.92, and 0.94, respectively, were noted. However, no significant difference in terms of the FRAP among different treatments was noted. Also, the best antioxidant activity of M. piperita was obtained by using the ultrasonic wave for 50 min at 65°C and 59.6% v/v ethanol/water solution. While the findings of RSM confirmed the experimental results, due to the favored properties of M. piperita extract by the proposed method, further research to investigate possible applications in the food industry is recommended.

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.

Structure-function characterization of the transition zone in the intervertebral disc.

Understanding the structure-function relationship in the intervertebral disk (IVD) is crucial for the development of novel tissue engineering strategies to regenerate IVD and the establishment of accurate computational models for low back pain research. A large number of studies have improved our knowledge of the mechanical and structural properties of the nucleus pulposus (NP) and annulus fibrosus (AF), two of the main regions in the IVD. However, few studies have focused on the AF-NP interface (transition zone; TZ). Therefore, the current study aims to, for the first time, characterize the cyclic and failure mechanical properties of the TZ region under physiological loading (1, 3, and 5%s-1 strain rates) and investigate the structural integration mechanisms between the NP, TZ, and AF regions. The results of the current study reveal significant effects of region (NP, TZ, and AF) and strain rates (1, 3, and 5%s-1) on stiffness (p < 0.001). In addition, energy absorption is significantly higher for the AF compared to the TZ and NP (p <0.001) as well as between the TZ and NP (p <0.001). The current research finds adaptation, direct penetration, and entanglement between TZ and AF fibers as three common mechanisms for structural integration between the TZ and AF regions. STATEMENT OF SIGNIFICANCE: Despite a large number of studies that have mechanically, structurally, and biologically characterized the nucleus pulposus (NP) and annulus fibrosus (AF) regions, few studies have focused on the NP-AF interface region (known as Transition Zone; TZ) in the IVD; hence, our understanding of the TZ structure-function relationship is still incomplete. Of particular importance, the cyclic mechanical properties of the TZ, compared to the adjacent regions (NP and AF), are yet to be explored and the precise nature of the structural integration between the NP and AF via the TZ region is not yet known. The current study explores both the mechanical and structural properties of the TZ region to ultimately identify the mechanism of integration between the NP and AF.

Detailed mechanical characterization of the transition zone: New insight into the integration between the annulus and nucleus of the intervertebral disc.

The Nucleus Pulposus (NP) and Annulus Fibrous (AF) are two primary regions of the intervertebral disc (IVD). The interface between the AF and NP, where the gradual transition in structure and type of fibers are observed, is known as the Transition Zone (TZ). Recent structural studies have shown that the TZ contains organized fibers that appear to connect the NP to the AF. However, the mechanical characteristics of the TZ are yet to be explored. The current study aimed to investigate the mechanical properties of the TZ at the anterolateral (AL) and posterolateral (PL) regions in both radial and circumferential directions of loading using ovine IVDs (N = 28). Young's and toe moduli, maximum stress, failure strain, strain at maximum stress, and toughness were calculated mechanical parameters. The findings from this study revealed that the mechanical properties of the TZ, including young's modulus (p = 0.001), failure strain (p < 0.001), strain at maximum stress (p = 0.002), toughness (p = 0.027), and toe modulus (p = 0.005), were significantly lower for the PL compared to the AL region. Maximum stress was not significantly different between the PL and AL regions (p = 0.164). We found that maximum stress (p = 0.002), failure strain (p < 0.001), and toughness (p = 0.001) were significantly different in different loading directions. No significant differences for modulus (young's; p = 0.169 and toe; p = 0.352) and strain at maximum stress (p = 0.727) were found between the radial and circumferential loading directions. STATEMENT OF SIGNIFICANCE: To date there has not been a study that has investigated the mechanical characterization of the annulus (AF)-nucleus (NP) interface (transition zone; TZ) in the intervertebral disc (IVD), nor is it known whether the posterolateral (PL) and anterolateral (AL) regions of the TZ exhibit different mechanical properties. Accordingly, the TZ mechanical properties have been rarely used in the development of computational IVD models and relevant tissue-engineered scaffolds. The current research reported the mechanical properties of the TZ region and revealed that its mechanical properties were significantly lower for the PL compared to the AL region. These new findings enhance our knowledge about the nature of AF-NP integration and may help to develop more realistic tissue-engineered or computational IVD models.

ALTEN: A High-Fidelity Primary Tissue-Engineering Platform to Assess Cellular Responses Ex Vivo.

To fully investigate cellular responses to stimuli and perturbations within tissues, it is essential to replicate the complex molecular interactions within the local microenvironment of cellular niches. Here, the authors introduce Alginate-based tissue engineering (ALTEN), a biomimetic tissue platform that allows ex vivo analysis of explanted tissue biopsies. This method preserves the original characteristics of the source tissue's cellular milieu, allowing multiple and diverse cell types to be maintained over an extended period of time. As a result, ALTEN enables rapid and faithful characterization of perturbations across specific cell types within a tissue. Importantly, using single-cell genomics, this approach provides integrated cellular responses at the resolution of individual cells. ALTEN is a powerful tool for the analysis of cellular responses upon exposure to cytotoxic agents and immunomodulators. Additionally, ALTEN's scalability using automated microfluidic devices for tissue encapsulation and subsequent transport, to enable centralized high-throughput analysis of samples gathered by large-scale multicenter studies, is shown.

Aggregation-Induced Emission Fluorescent Gels: Current Trends and Future Perspectives.

The development of fluorescent gels, if not the current focus, is at the center of recent efforts devoted to the invention of a new generation of gels. Fluorescent gels have numerous properties that are intrinsic to the gel structure, with additional light-emitting properties making them attractive for different applications. This review focuses on current studies associated with the development of fluorescent gels using aggregation-induced emission fluorophores (AIEgens) to ultimately suggest new directions for future research. Here, we discuss major drawbacks of the methodologies used frequently for the fabrication of fluorescent gels using traditional fluorophores compared to those using AIEgens. The fabrication strategies to develop AIE-based fluorescent gels, including physical mixing, soaking, self-assembly, noncovalent interactions, and permanent chemical reactions, are discussed thoroughly. New and recent findings on developing AIE-active gels are explained. Specifically, physically prepared AIE-based gels including supramolecular, ionic, and chemically prepared AIE-based gels are discussed. In addition, the intrinsic fluorescent properties of natural gels, known as clustering-triggered fluorescent gel, and new and recent relevant findings published in peer-reviewed journals are explained. This review also revealed the biomedical applications of AIE-based fluorescent hydrogels including drug delivery, biosensors, bioimaging, and tissue engineering. In conclusion, the current research situation and future directions are identified.

The aplication of Pistacia khinjuk extract nanoemulsion in a biopolymeric coating to improve the shelf life extension of sunflower oil.

In the present study, a hydroalcoholic extract of P. khinjuk was obtained by sonication method at 60°C for 50 min. The measurement revealed that the total phenolic content of the extract was 46.0 mg/g. The results showed that the extract has an antioxidant activity of 73.5% and 8.3 (µmol TE/g DW) in DPPH radical scavenging method and FRAP assay, respectively. Also, Balango (Lallemantia royleana) and Fenugreek (Trigonella foenum-graecum) seed gum and their composition (1:1) were used to prepare the nanoemulsion with P. khinjuk extract. The droplet mean size of nanoemulsions was ranged from 310.34 to 354.19 nm. The highest encapsulation efficiency was observed in Balango nanoemulsion. P. khinjuk extract nanoemulsion coating with Balango and TBHQ was added to sunflower oil at 200 and 100 ppm, respectively. During 24-day storage at 60°C, samples were investigated for peroxide, acid, and p-anisidine values at 4-day intervals. The results showed that oils containing nanoemulsion had the highest stability during storage. However, in all samples peroxide, acid and p-anisidine values increased but the rate of oxidation in samples containing both synthetic and natural antioxidants was slower than the control sample.

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.