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Walnut oil (WNO) is considered as natural functional food of high economic interest due to its nutritional and medicinal benefits. Adulteration in WNO seriously damages the interests of consumers and the health of market. In this paper, a new strategy has been developed to identify the adulteration of WNO with other cheaper vegetable oils. The study was based on the chemometric analysis of excitation-emission matrix (EEM) fluorescence spectroscopy data of WNO samples containing different adulterants. First, alternating normalization-weighted error (ANWE) method was used for the data decomposition of oil samples to obtain spectral characteristics and chemical meaning information. Then, three pattern recognition methods were employed to build the classification models, including partial least squares discriminant analysis employing ANWE scores (ANWE-PLS-DA), k-nearest neighbor (kNN), and N-way partial least squares discriminant analysis (N-PLS-DA). Results showed that all models obtained good classification performances for the WNO and other vegetable oils (case 1). Moreover, N-PLS-DA outperformed ANWE-PLS-DA and kNN in the identification of pure and adulterated WNO samples (case 2). The accuracy rates of N-PLS-DA were 87.1–90.6% when predicting WNO samples with adulteration level above 5%. The proposed methods were simple, rapid, and available for the identification of cheaper vegetable oil adulterated in WNO. [ABSTRACT FROM AUTHOR]

Walnut is a precious marketed nut characterised by kernels containing more than 60% of oil. Gas chromatography (GC) is the most used method to analyse oils; nonetheless, polyunsaturated (PUFA)s and monounsaturated fatty acids (MUFA)s were not separated sufficiently. Therefore, our study is based on the employment of two GC systems with different columns. However, for determination of PUFAs and MUFAs composition, 13C nuclear magnetic resonance (NMR) seems to be a promising technique by showing the resonance for each unsaturated fatty acids (UFA)s in olefinic region, and also for saturated fatty acids (SFA) in the aliphatic region. 13C NMR was able to distinguish between fatty acid isomers such as oleic (C18:1 Δ9) and vaccenic (C18:1 Δ11) acid. In addition, different fatty acid length with same position of unsaturated carbon were distinguished and determined by 13C NMR, for instance between vaccenic (C18:1 Δ11) and eicosenoic (C20:1 Δ11) acid. NMR quantification takes the advantages of chemical shifts to accurately calculate fatty acid contents for both saturated and unsaturated one. Besides providing the full profile of fatty acids, this study adds information regarding quantitative and qualitative composition of walnut oil. This can expand the analytical methods used to improve the knowledge of nutritional values of oil and food products. [ABSTRACT FROM AUTHOR]

A new method for the determination of the induction period (IP) of walnut oil through polyethylene-film-based Fourier transform infrared (PE-FTIR) spectroscopy was developed. The IP value was used to represent the oxidation stability of walnut oil. The characteristic infrared spectrum peaks at 3008, 1654, 914, and 723 cm−1 changed significantly as the IP value decreased. The prediction model was established on the basis of these changes. The optimal partial least squares model was established under the following conditions: constant, original spectra, no smoothing, and wavelength range of 1640–440 cm−1. The calibration set of the model provided a coefficient of determination (R2) of 0.9847 and a root mean error of calibration of 3.38. The R2 and the root mean square error of prediction for the validation set were 0.9878 and 2.32, respectively, and were 0.9948 and 3.61 for the blind sample validation set, respectively. In precision evaluation, the standard deviation and coefficient of variation of the predicted values were 4.13 and 4.19%, respectively. The present results indicated that the polyethylene-FTIR method for analyzing the IP value of walnut oil was simple and rapid and could be used as a highly effective alternative to the traditional determination method. [ABSTRACT FROM AUTHOR]

Walnut oil is endowed with a variety of physiological functions due to abundant natural compounds, and the effect of unsaturated fatty acids is crucial. In order to accurately and conveniently detect the fatty acids components and content in walnut oil, a quantitative method was developed to detect fatty acids content based on the 1H-NMR and 13C-NMR techniques. In addition, HPLC combined with MS was used to conduct qualitative analysis. HPLC method with an evaporative light-scattering detector was for the quantitative analysis and the fatty acids content was compared with the content from NMR. The result showed that there was no significant difference between 1H-NMR, 13C-NMR and HPLC (P > 0.05) and indicated that the NMR has the potential to be applied as a routine method for the analysis of fatty acids content in walnut oil. [ABSTRACT FROM AUTHOR]

In this study, the effect of phenolic extract obtained from walnut press-cake on oxidative stability of walnut oil was evaluated. Besides this, the oxidative stability of ultrasound applied walnut oil with added press-cake, as a valuable source of phenolic compounds, was determined. Oxidative stability of walnut oils upon addition of phenolic extracts (50, 100 and 200 mg/kg oil) and α-tocopherol (100 mg/kg oil) was monitored under accelerated oxidation conditions at 65 °C for 20 day. Total phenolic content (TPC) of walnut press-cake and phenolic extract from walnut press-cake were 58207.3 and 332679.8 mg GAE/kg, respectively. All concentrations of phenolic extracts significantly reduced the formation of oxidation products compared to control. Especially, the walnut oils enriched with 200 mg/kg phenolic extract showed the highest oxidative stability. While direct enrichment using ultrasonic maceration (1:100) (walnut press-cake:walnut oil) caused a significant increase in TPC of walnut oil (from 9.76 to 78.80 mg GAE/kg), ultrasonic macerated walnut oil had low oxidative stability. Results showed that 200 mg/kg oil phenolic extracts from walnut press-cake can be successfully used as a natural antioxidant preparate to improve the oxidative stability of walnut oil. [ABSTRACT FROM AUTHOR]

The purpose of investigation was to assess the effect of lycopene on the peroxide value, acid value, fatty acids, total phenolic content and ferric-reducing antioxidant power of walnut oil. Walnut oil was extracted from Xinjiang walnut variety using cold pressing method. Our study reported that after 45 days of accelerated oxidation at 60 °C (Schaal oven test), 0.005% lycopene exhibited the greatest antioxidant effect than other addition levels of lycopene. Therefore, under ambient storage conditions, the shelf-life of walnut oil could be extended up to 16 months by 0.005% lycopene. Moreover, 0.005% lycopene added to walnut oil had a significantly higher content of saturated fatty acid, unsaturated fatty acid, total phenol, reducing ability of the polar and non-polar components than the blank sample (walnut oil without any addition of lycopene). In conclusion, lycopene improved the quality of walnut oil because of its antioxidant effect against lipid oxidation. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells have been extensively used for cell-based therapies especially in neuronal diseases. Studies still continue to delineate mechanisms involved in differentiating mesenchymal stem cells into neuronal cells under experimental conditions as they have low mortality rate and hence, the number of cells available for experiments is much more limited. Culturing and differentiating of neuronal cell is more challenging as they do not undergo cell division thus, bringing them to differentiate proves to be a difficult task. Here, the aim of this study is to investigate whether Juglans regia L. (walnut oil) differentiates multipotent, C3H10T1/2 cells, a murine mesenchymal stem cell line, into neuronal cells. A simple treatment protocol induced C3H10T1/2 cells to exhibit a neuronal phenotype. With this optimal differentiation protocol, almost all cells exhibited neuronal morphology. The cell bodies extended long processes. C3H10T1/2 cells were plated and treated with walnut oil post 24 h of plating. The treatment was given (with walnut oil treated cultures with or without control cultures) at different concentrations. The cultured cells were then stained with cresyl violet acetate solution which was used to stain the Nissl substance in the cytoplasm of the induced neuronal culture. The results indicated that the C3H10T1/2 cells differentiated into neuronal-like cells with long outgrowths of axon-like structures able to take up the cresyl violet acetate stain indicating their preliminary differentiation into neuronal-like morphology with walnut oil treatment. Treating the mesenchymal stem cells can in future establish a cultured mesenchymal stem cell line as neuronal differentiating cell line model. [ABSTRACT FROM AUTHOR]

Antioxidant activity of phenolic extract isolated from Tunisian walnut ( Juglans regia L.) fruits has been investigated. Preliminarily, composition of walnut kernels was determined. Fat content varied from 53.5 to 66.9% (w/w), while total phenol ranged from 1.2 to 5.2 g/100 g of kernel as gallic acid equivalent (GAE). High amounts of ellagic acid (EA) and its derivatives were evidenced by HPLC analysis of the phenolic extract. Walnut fat showed induction time ranging from 2.5 to 3.7 h at 110 °C (rancimat test) and these values unchanged by adding 300 mg/kg of kernel phenolic extract which so showed to have no antioxidant effect. In addition, activities of the ellagic and gallic acids and trolox were compared in vitro by using the Folin-Ciocalteu's, rancimat and DPPH radical scavenging methods. EA exhibited an antioxidant and radical scavenging activity significantly lower than other tested substances. In conclusion, EA showed to have a negligible role in preventing walnut fat oxidation. [ABSTRACT FROM AUTHOR]

Adulteration of walnut oil with sunflower oil is a major issue for the walnut oil industry. In this paper, the potential use of total synchronous fluorescence (TSyF) spectra to differentiate walnut oil from sunflower oil and synchronous fluorescence spectra combined with multivariate analysis to assess the adulteration of walnut oil is demonstrated. TSyF spectra were acquired by varying the excitation wavelength in the region 250-700 nm and the wavelength interval (Δ λ) in the region from 10 to 100 nm. TSyF contour plots for walnut oil, in contrast to sunflower oil, show an extra fluorescence region in the excitation wavelength lower than 280 nm. Fifty-one oil mixtures were prepared by adulterating walnut oil with sunflower oil at varying levels (0-100 %). The partial least-squares regression model was used for the quantification of adulteration using wavelength intervals of 20, 40, 60 and 80 nm. This technique is useful for the detection of sunflower oil in walnut oil at levels down to 0.3 % ( v/ v) in just 2.5 min using an 80-nm wavelength interval. [ABSTRACT FROM AUTHOR]

Several studies have demonstrated the benefits of vegetable oil on cardiovascular risk factors in diabetes. The goal of the present study was to compare the effects of olive, almond and walnut oil on serum glucose, lipids and blood pressure in type 2 diabetic patients. In this cross over clinical study 24 hypercholesterolemic type 2 diabetic patients were recruited. Subjects consecutively assigned to consume 40 cc olive, almond and walnut oil daily over a 4-week period with a two-week washout period, accompanied by the Step I diet. Anthropometric measurements, HbA1c, lipid profile and serum glucose and blood pressure were measured initially and at the end of the study. Serum levels of total cholesterol (TC) and LDL-cholesterol at baseline and at the end of trial differed significantly after olive oil ( P = 0.007, P = 0.02) and triglyceride (TG) after almond oil ( P = 0.02). When the differences of these laboratory levels between olive, almond and walnut were tested, no significant differences were found. Our findings showed olive oil could reduce significantly serum levels of TC and LDL. Almond consumption could decrease TG significantly. Our research could not show significant reduction in blood pressure. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of the addition of tiger nut fibre (TNF) as a carrier of unsaturated fatty acids (UFA) rich oil on some quality parameters in a dry-cured sausage. Nine formulations of 'Longaniza de Pascua', a traditional Spanish dry-cured fermented sausage, were manufactured under normal industrial conditions but incorporating different combinations of TNF (1-2%) as a source of fibre and walnut oil (WO; 2.5-5%) as a source of UFA. The addition of TNF improved WO incorporation into the meat batter: the higher the amount of TNF added, the more WO incorporated. Sausages with TNF + WO had a higher moisture content than the control (hence lower weight loss), lower pH values, higher water activity, similar L* values and higher a* and b* values than the control. The only microorganisms that were affected by the formula were mould and yeasts, but in all cases the counts at the end of ripening were comparable to the results of the most studies on fermented sausages. The increase in lipid oxidation in sausages due to the addition of WO was controlled by the TNF, probably due to the antioxidant compounds (phenolics) it contains. The samples with 1% TNF + 2.5% WO and 2% TNF + 5% WO scored the same in terms of overall liking as the control. [ABSTRACT FROM AUTHOR]

The application of walnut oil (WO) as a functional component in the production of beverage emulsion was investigated using response surface methodology (RSM). The effects of three critical structuring components (considered as independent variables), namely gum arabic (GA; 6-10% ( w/ w)), xanthan gum (XG; 0.10-0.30% ( w/ w)), and WO (3.5-6.5% ( w/ w)) on the turbidity loss rate, stability, size index, opacity, and pH (considered as dependent variables) of these emulsions, were studied. For each response parameter, a second-order polynomial model versus independent variables was determined and statistically obtained with high coefficient of determination values ( R > 0.96). Most significant ( p < 0.0001) effect was attributed to the linear function of WO in all reduced models. Numerical optimization defined the optimum formulation where the highest stability and opacity and the lowest turbidity loss rate, size index, and pH (GA content 10.0% ( w/ w), XG content 0.13% ( w/ w), and WO concentration 5.09% ( w/ w)) were expected. Under the optimum condition, the corresponding predicted response values for turbidity loss rate, stability, size index, opacity, and pH were predicted to be 0.366 Å/day, 99.40%, 0.599, 1.034, and 3.69, respectively. RSM analysis indicated good correlation between experimental and predicted values. [ABSTRACT FROM AUTHOR]

The effects of temperature on the oxidation of walnut oil (WO) and grape seed oil (GSO) were investigated. Both oils were stored at 25, 40, 60, and 80°C for 60, 30, 12, and 6 day, respectively. Degree of oxidation was measured in terms of peroxide value (POV), conjugated dienoic acid (CDA) value, and p-anisidine value ( p-AV). The rates of increase in POV, CDA, and p-AV in both oils were strongly dependent on storage temperature. The induction period (IP) decreased gradually with increasing storage temperature in both oils. WO showed shorter IPs (23.0, 9.2, and 1.0 day at 25, 40, and 60°C, respectively) than those of GSO (41.5, 12.0, and 1.8 day at 25, 40, and 60°C, respectively), indicating the higher susceptibility of WO to oxidation. The activation energy (Ea) for the IP of WO and GSO autoxidation was similar (75.87 and 75.66 kJ/mol, respectively), revealing similar temperature dependence for autoxidation in WO and GSO. [ABSTRACT FROM AUTHOR]

Tree cultivars (Jupiter, Sejnov, and Elit) of walnut ( Juglans regia L.) were collected during the 2004 harvest from Cacak, Central Serbia. The chemical composition, including moisture, total oil content, crude protein, ash, and carbohydrates, was determined. Afterwards, two techniques of oil extraction were implemented: cold pressing extraction and organic solvent extraction. Iodine value, saponification value, acid value, and peroxide value of obtained walnut oils were analyzed. The fatty acid composition of the walnut oils was determined using gas chromatography with flame ionization detector. The oleic acid content of the oils ranged from 15.9–23.7% of the total acids, while linoleic acid content ranged from 57.2–65.1% and the linolenic acid from 9.1–13.6%. The process of oil extraction had no significant effect on content and composition of fatty acids. [ABSTRACT FROM AUTHOR]