Walnut Oil Research Articles

Combination of Analytical and Chemometric Methods as a Useful Tool for the Characterization of Extra Virgin Argan Oil and Other Edible Virgin Oils. Role of Polyphenols and Tocopherols.

Analysis of phenolic profile and tocopherol fractions in conjunction with chemometrics techniques were used for the accurate characterization of extra virgin argan oil and eight other edible vegetable virgin oils (olive, soybean, wheat germ, walnut, almond, sesame, avocado, and linseed) and to establish similarities among them. Phenolic profile and tocopherols were determined by HPLC coupled with diode-array and fluorescence detectors, respectively. Multivariate factor analysis (MFA) and linear correlations were applied. Significant negative correlations were found between tocopherols and some of the polyphenols identified, but more intensely (P < 0.001) between the γ-tocopherol and oleuropein, pinoresinol, and luteolin. MFA revealed that tocopherols, especially γ-fraction, most strongly influenced the oil characterization. Among the phenolic compounds, syringic acid, dihydroxybenzoic acid, oleuropein, pinoresinol, and luteolin also contributed to the discrimination of the oils. According to the variables analyzed in the present study, argan oil presented the greatest similarity with walnut oil, followed by sesame and linseed oils. Olive, avocado, and almond oils showed close similarities.

Genotype and year variability of the chemical composition of walnut oil of Moroccan seedlings from the high Atlas Mountains

Protein and oil content, fatty acid composition and tocopherol concentration were determined for two years in the kernel of ten candidate walnut selections from the high Atlas Mountains in Morocco. Considerable variation between genotypes was found for all parameters. The ranges of protein content (11.58–14.5% of kernel dry weight, DW), oil content (54.4–67.48% of kernel DW), oleic (12.47–22.01% of total oil), linoleic (55.03–60.01%), linolenic (9.3–15.87%), palmitic (6.84–9.12%), and stearic (1.7–2.92%) acid percentages, γ-tocopherol (188.1–230.7 mg·kg -1 of oil), δ-tocopherol (23.3–43.4 mg·kg -1 ), and α-tocopherol (8.9–16.57 mg·kg -1 ) contents agreed with previous results obtained from other commercial walnut cultivars. The effect of year was significant for all the chemical components, except for oil content and palmitic acid percentage. Some genotypes showed high oil contents and consistently high values of γ-tocopherol in both years of study. The introduction of these genotypes as new cultivars by vegetative propagation may result in a an increase in quality of the walnuts from the high Atlas Mountains of Morocco, and as a seed source for forest walnut propagation in the same region.

Fatty acid profile of new promising unconventional plant oils for cosmetic use

Oils have been used on the cosmetic application since antiquity. With the growing interest in cosmetic formulation of strictly natural origin there has been also an increased interest in the use of alternative oils obtained from nuts, herbs, fruit and vegetable seeds. Due to lack of good scientific reports on the cosmetic plant oils available in Poland, the aim of our research was to characterize fatty acids (FA) profile and oxidative quality of selected unconventional plant oils, which are used as cosmetics or potential cosmetic ingredients. Oils were purchased from cosmetic health shops in Warsaw (Poland); FA profile was analysed by gas chromatography with flame-ionization detection. Peroxide index (PI), content of hydroperoxides (PV) and free fatty acids (AV) were also determined. Oxidative quality and FA composition of examined oils varied widely among analyzed oils. Cluster analysis revealed three clusters. Clusters S1 and S3 include only one oil (Perilla and sea buckthorn, respectively). Perilla oil is characterized by relatively small content of both saturated FA (8.5%) and monounsaturated FA (14.2%) and much higher amount of polyunsaturated FA (73.5%) whereas in sea buckthorn these proportions are opposite (saturated FA and monounsaturated FA - 33.5% and 51.0% respectively, and the lowest amount of polyunsaturated FA - 5.2%). In cluster S2 two sub-clusters were distinguished and the content of linoleic (p = 0.0015), α-linolenic (p = 0.0092) and oleic (p = 0.0015) acid caused this distinction. PI ranged from 8.9 in sea buckthorn oil to 135 in Perilla oil. Perilla oil and raspberry seed oil were also characterized by the highest PV (225 ± 14.9 mEq O/kg oil and 232 ± 13.8 mEq O/kg oil, respectively), whereas the lowest PV was determined for walnut oil (0.82 ± 0.18 mEq O/kg oil) and carrot seed oil (0.87 ± 0.21 mEq O/kg oil) oils. FA composition of cosmetic oils in combination with data concerning their oxidative quality, is very important for determining their safe and effective use. It is very important to standardize and test the FA content in commercially available oils of cosmetic use.

Formulation and Environmental Impact Evaluation of Walnut and Soya Bean Oil Based Drilling Fluid

One of the oil and gas hazard that associated with drilling operation is oil based drilling fluid and its associated cutting disposition. It is highly imperative for policy maker to propagate the use of environmental friendly oil based mud for drilling operation. This paper formulated environmentally friendly oil based mud (using walnut and soya bean plant oil) that can carry out the same function as convectional oil based drilling fluid and equally meeting up with the HSE (Health, safety and environment) standard. Mud laboratory tests were carried out at standard condition on plant oil samples so as to ascertain the rheological properties of the drilling fluid formulations. The synthetic oil based was obtained from drilling company in Nigeria and was used as control experiment. At the end of the experiment, the properties of the walnut and soya beans based mud wascompared with industry oil based mud (synthetic oil based mud). All the results were shown to be similar to that of commercial synthetic oil based drilling mud which was gotten from the industry.From the results it can be seen that walnut and soya beans based mud actually gives a less toxic,better rheological properties, requires less waste disposal costs, hence making them more economically and technically viable for oil and gas drilling operation.

Green Fabrication of Copper Nanoparticles Dispersed in Walnut Oil Using Laser Ablation Technique

Synthesis of copper nanoparticles was achieved by laser irradiation of copper plate in walnut oil. The copper plate was irradiated using Nd:YAG pulse laser at different ablation time from 5 to 50 minutes, and the prepared samples were characterized using analytical methods to find the optical absorption, morphology, particle size, and capping of copper nanoparticles with walnut oil. Consequently, the absorption peak appeared at about 615, 606, 588, 576, and 561 nm; and the nanoparticles formed in spherical shape in walnut oil. The particle size varied from 25 to 4.01 nm, and the tail of the carbonyl band capped the copper nanoparticles through the electron transfer from the carboxylic group to copper nanoparticles. The refractive indices of the nanofluid were measured using a surface plasmon resonance technique and changed from 1.4691 + 0.008i to 1.4682 + 0.043i as the volume fraction increased from 0.0257 × 10−5to 1.26 × 10−5. Consequently, the laser ablation method is environmentally sensitive (i.e., green) and thus is suitable for the fabrication of copper nanoparticles in walnut oil without any agent.

Levels of bioactive lipids in cooking oils: olive oil is the richest source of oleoyl serine.

Rates of osteoporosis are significantly lower in regions of the world where olive oil consumption is a dietary cornerstone. Olive oil may represent a source of oleoyl serine (OS), which showed efficacy in animal models of osteoporosis. Here, we tested the hypothesis that OS as well as structurally analogous N-acyl amide and 2-acyl glycerol lipids are present in the following cooking oils: olive, walnut, canola, high heat canola, peanut, safflower, sesame, toasted sesame, grape seed, and smart balance omega. Methanolic lipid extracts from each of the cooking oils were partially purified on C-18 solid-phase extraction columns. Extracts were analyzed with high-performance liquid chromatography-tandem mass spectrometry, and 33 lipids were measured in each sample, including OS and bioactive analogs. Of the oils screened here, walnut oil had the highest number of lipids detected (22/33). Olive oil had the second highest number of lipids detected (20/33), whereas grape-seed and high-heat canola oil were tied for lowest number of detected lipids (6/33). OS was detected in 8 of the 10 oils tested and the levels were highest in olive oil, suggesting that there is something about the olive plant that enriches this lipid. Cooking oils contain varying levels of bioactive lipids from the N-acyl amide and 2-acyl glycerol families. Olive oil is a dietary source of OS, which may contribute to lowered prevalence of osteoporosis in countries with high consumption of this oil.

Identification of antioxidative peptides from defatted walnut meal hydrolysate with potential for improving learning and memory

Defatted walnut meal (DWM), a main byproduct of walnut oil production, is rich in proteins with a high essential amino acid content. Our research was focused on the functional activities of defatted walnut meal hydrolysate (DWMH). DWMH exhibited relatively strong hydroxyl scavenging and oxygen radical absorbance capacities, protective effect on H2O2-injured PC12 cells compared with GSH and cerebrolysin. Besides, DWMH could combat d-galactose induced learning and memory impairments in the Morris water maze test and in the Dark/light avoidance test of mice. Seventy-seven peptides were identified by UPLC-ESI-MS/MS in the most potent antioxidative fraction of DWMH. WSREEQEREE and ADIYTEEAGR were the peptides that most likely accounted for the suppression of H2O2-induced apoptosis in PC12 cells. The mixture of the commercially available amino acids did not offer any protection on H2O2-injured PC12 cells, suggesting that amino acid sequence rather than amino acid composition was the dominant influencing factor. DWMH could be recommended as natural antioxidants for the development of functional foods targeting memory impairments.

Bioactive Compounds, Physical and Sensory Properties of Cake Made with Walnut Press‐Cake

AbstractWalnut press‐cake, a rich source of phenolics, is a by‐product of walnut oil processing. In this study, the effects of walnut press‐cake on cake quality, health‐enhancing substances and antioxidant activity were determined. Wheat flour was replaced with walnut press‐cake at 0, 5, 10, 15 and 20% levels. Results show that specific volume, firmness, resilience, cohesiveness, chewiness, crust a, b and crumb L, b values reduced with increasing walnut press‐cake levels. However, polyunsaturated fatty acids, tocopherols, total phenolic content and antioxidant capacity of cakes increased. Antioxidant capacity measured by 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) assays of cakes prepared with 20% walnut press‐cake were 10.04‐ and 5.56‐fold, respectively, greater than that of the cake without walnut press‐cake. Cakes added with 15% walnut press‐cake to wheat flour had the highest scores in all sensory parameters. Walnut press‐cake can be successfully incorporated into cake formulation to improve sensory properties and antioxidant activity of the cake.Practical ApplicationsInterest in walnut oil has increased during the past years due to its high polyunsaturated fatty acid content. Although walnut oil has been used in the food, pharmaceutical and cosmetic industries, there is no information about the use of walnut press‐cake. Walnut press‐cake is a rich source of bioactive compounds, and it is a new by‐product with potential use in the baking industry as a supplement. The results of this study provide guidance for the use of walnut press‐cake in the manufacture of cakes with higher sensory and nutritional quality.

Impact of pH, freeze–thaw and thermal sterilization on physicochemical stability of walnut beverage emulsion

The effects of environment stresses on the stability of walnut emulsion were investigated. The physical stability of walnut emulsion was characterized by droplet size, zeta potential and chemical stability of walnut oil in the emulsion was evaluated by determining the peroxide concentration during the storage. The results showed that emulsion in the presence of xanthan gum and mixed emulsifiers exhibited better stability after 4 freeze–thaw cycles. At pH 3–10, the mixed emulsifiers could improve the stability through their absorption on the oil–water interface. However, xanthan gum couldn’t protect the droplets against the aggregation in high acid environment, but greatly enhanced the physical stability at pH 6–10. During the thermal sterilization process, the physical stability of walnut emulsion was decreased with a rise of sterilization temperature and the extension of sterilization time. The sterilization temperature above 121°C and time over 25min led to the poor physical and oxidative stability.

Walnut Oil - Unexplored Raw Material for Lipase-Catalyzed Synthesis of Low-Calorie Structured Lipids for Clinical Nutrition

Low-calorie structured lipids that contain medium-chain fatty acids in the sn-1 and sn-3 positions of the glycerol backbone, and long-chain fatty acid in the sn-2 (MLM type) were synthesized in one-step acidolysis of walnut oil with caprylic acid. Caprylic acid residues were incorporated selectively into sn-1,3 positions of triacylglycerols using 1,3-specific immobilized lipases from Rhizomucor miehei (Lipozyme) and Rhizopus delemar (PP-RhDL) as catalysts. Under the optimal reaction conditions, we achieved an excellent yield of the desired MLM-type structured lipids (97 mole % with Lipozyme and 96.4 mole % with PP-RhDL). The synthetic activity of PP-RhDL was not influenced by the reaction medium whereas the Lipozyme was more effective in hexane than in solvent-free medium. The same degree of conversion of initial triacylglycerols was observed for the two enzymes in four consecutive reaction cycles. The amount of MLM-type structured lipids, however, decreased with each following cycle at the expense of mono-substituted with caprylic acid triacylglycerols (MLL type). Practical Applications Structured lipids (SLs) that contain medium-chain fatty acids in the sn-1 and sn-3 positions of the glycerol backbone, and long-chain fatty acids in the sn-2 (MLM type) are known to improve liver function, minimize risk of infections, and reduce the number of gastrointestinal complications in patients undergoing major abdominal surgery and are used in clinical nutrition as well as specialized food for athletes because they provide fast energy supply. After an enzymatic modification of walnut oil, high yield of SLs with caprylic acid residue in the sn-1 and sn-3 positions of the glycerol backbone and long-chain fatty acid residue in the sn-2 position of triglycerides was obtained.

Multivariate Analysis of Combined Fourier Transform Near-Infrared Spectrometry (FT-NIR) and Raman Datasets for Improved Discrimination of Drying Oils.

This work explores the application of chemometric techniques to the analysis of lipidic paint binders (i.e., drying oils) by means of Raman and near-infrared spectroscopy. These binders have been widely used by artists throughout history, both individually and in mixtures. We prepared various model samples of the pure binders (linseed, poppy seed, and walnut oils) obtained from different manufacturers. These model samples were left to dry and then characterized by Raman and reflectance near-infrared spectroscopy. Multivariate analysis was performed by applying principal component analysis (PCA) on the first derivative of the corresponding Raman spectra (1800-750 cm(-1)), near-infrared spectra (6000-3900 cm(-1)), and their combination to test whether spectral differences could enable samples to be distinguished on the basis of their composition. The vibrational bands we found most useful to discriminate between the different products we studied are the fundamental ν(C=C) stretching and methylenic stretching and bending combination bands. The results of the multivariate analysis demonstrated the potential of chemometric approaches for characterizing and identifying drying oils, and also for gaining a deeper insight into the aging process. Comparison with high-performance liquid chromatography data was conducted to check the PCA results.

Whey protein edible films modified with almond and walnut oils

Whey protein isolate films with almond or walnut oils at low concentrations (0.5 and 1.0%) were prepared through emulsification in order to modify the functional properties of the films. Optical (colour and opacity), mechanical (tensile strength, Young's modulus, and elongation at break), barrier (water vapour, oxygen, and carbon dioxide permeability), surface (contact angle on both air and support film sides through time) properties and microstructure of whey protein emulsified films were determined. Bimodal distribution of oil droplets in film-forming solutions was observed by light scattering granulometry. The reduction of lipid droplet size upon increasing oil content caused weakened mechanical resistance of the films. Addition of oils leads to opaque films with heterogeneous microstructure, resulting in an increase in film opacity. The swelling, water vapour permeability, and surface hydrophilicity of the whey protein films were reduced due to the addition of the oils. An increase in oxygen and carbon dioxide permeability with increasing oil content was observed. Contact angle measurements through time showed the absorption of water droplets by the emulsified films, whereas the control film showed a swelling effect. Almond oil had a stronger plasticizing effect and was more effective in modifying the properties of whey protein films. The obtained results revealed that almond and walnut oils used at low concentrations enhanced the hydrophobic character of the whey protein films and have a good potential for incorporation into whey protein isolate to make edible films or coatings for some food applications.

Surfactant Concentration, Antioxidants, and Chelators Influencing Oxidative Stability of Water‐in‐Walnut Oil Emulsions

AbstractEffects of surfactant concentration, antioxidants with different polarities, and chelator type on the oxidative stability of water‐in‐stripped walnut oil (W/O) emulsions stabilized by polyglycerol polyricinoleate (PGPR) were evaluated. The formation of primary oxidation products (lipid hydroperoxides) and secondary oxidation products (hexanal) decreased with increasing PGPR concentrations (0.3–1.0 wt% of emulsions). Excess surfactant might solubilize lipid hydroperoxides out of the oil–water interface, resulting in the decreased lipid oxidation rates in W/O emulsions. At concentrations of 10–1000 μM, the polar Trolox demonstrated concentration‐dependent antioxidant activity according to both hydroperoxide and hexanal formation. The antioxidant efficiency of the non‐polar α‐tocopherol was slightly reduced at the higher range of 500–1000 μM based on hydroperoxide formation. Both ethylenediaminetetraacetic acid (EDTA) and deferoxamine (DFO) at concentrations of 5–100 μM reduced the rates of lipid oxidation at varying degrees, indicating that endogenous transition metals may promote lipid oxidation in W/O emulsions. EDTA was a stronger inhibitor of lipid oxidation than DFO. These results suggest that the oxidative stability of W/O emulsions could be improved by the appropriate choice of surfactant concentration, antioxidants, and chelators.

Stability of Emulsions Containing Interesterified Fats Based on Mutton Tallow and Walnut Oil

AbstractIn this work, modified fats were produced by enzymatic interesterification of mutton tallow with walnut oil. As a result of forcing the fat hydrolysis process by addition of water to the enzymatic preparation (11.5, 13.0, 14.5, 16.0 wt %), additional levels of polar fractions (MAGs, DAGs, and FFAs) were observed. The aim of this work was to evaluate the stability of emulsions of modified fats containing natural emulsifiers resulting from enzymatic interesterification of mutton tallow with walnut oil. The physical‐chemical parameters of obtained fats were determined in this study. Using several methods, the stability of the formed emulsions was also evaluated. The results showed that the fats resulting from interesterification in the presence of Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, Novozymes Bagsvaerd, Denmark) with 13.0, 14.5, and 16.0 wt % of water in the enzymatic preparation could form stable emulsion systems. On the other hand, the emulsion of the interesterification system where the amount of water in the enzymatic preparation was 11.5 % showed very low stability. The number of natural emulsifiers (MAGs and DAGs) that arose after interesterification was insufficient to stabilize the emulsion system. The work has shown the possibility of using interesterified fats as the fat phase. Emulsions formed on the basis of interesterified fats without any additional emulsifiers such as sunflower lecithin had properties comparable to emulsions containing mixed non‐interesterified fat containing additional emulsifier. The natural emulsifiers formed as part of enzymatic interesterification allow formation of stable emulsion systems.

Effect of two series ionic liquids based on non-nutritive sweeteners on catalytic activity and stability of the industrially important lipases from Candida rugosa and Rhizopus delemar

This is the first study on the effect of ionic liquids (ILs) based on non-nutritive sweeteners on the catalytic efficiency and the structural and the thermal stability of lipases from Candida rugosa (CRL) and Rhizopus delemar (RhDL). Initially, we synthesized two series of ILs, namely 1-akyl-3-methylimidazolium saccharinates {[CnC1im][Sac]} and 1-akyl-3-methylimidazolium acesulfamates {[CnC1im][Ace]}, where the alkyl substituent was butyl, hexyl, octyl or decyl. The activities of the two enzymes were tested in two hydrolytic reactions using walnut oil and 4-nitrophenyl acetate as substrates. The activity of CRL toward walnut oil was strongly influenced by the chain-length of the N-alkyl substituents at the imidazolium cation of the compounds. The ILs with short alkyl substituents (butyl or hexyl) activated moderately (up to 30%) or had no effect on CRL activity, while those with medium chain-length substituents strongly inhibited CRL. In the case of CRL, we observed the same behavior pattern for the two tested series of ILs, while for RhDL the same tendency was displayed only for the series of saccharinates. The coating of RhDL with 0.1M [C8C1im][Sac] or [C8C1im][Ace] resulted in up to 1.5-fold increase in the enzyme initial activity. In contrast, CRL was strongly inhibited by these two ILs. We found that the effect of [C8C1im][Ace] on enzyme activity adopted concentration- and time-dependent manner for the two lipases.We observed a moderate increase in hydrolytic activity (by 1.2-fold factor) and good storage stability of RhDL (more than 30 days at 25°C) when small quantities of all ionic liquids (<0.04M), were added to the enzyme solutions. At the same time, by adding of 0.02M [C4C1im][Sac] or [C4C1im][Ace], CRL was also stabilized and its activity was preserved for more than 25 days at room temperature. For comparison, the activities of the stored at 25°C non-treated with ILs soluble CRL and RhDL were reduced by half for 7 days and 5 days, respectively. In contrast, we observed rapid inactivation at higher temperatures for all ionic liquid-coated enzymes. For example, half-lives of 25min and 57.3min at 50°C were estimated for the pre-treated with [C4C1im][Ace]-CRL and for the non-treated-CRL, respectively. In addition, applying Fourier transform infrared spectroscopy, we monitored the changes in the secondary structure of the two enzymes in presence of the tested ILs which explained the altered stability and the activities of the two enzymes. Interestingly, coating with small amounts of ILs prevents aggregation of the two lipases even at high protein concentration.

Evaluation of the phenolic compounds and fatty acid profiles of English walnut (J. regia) extract

The purpose of the present study was to determine various ingredients of English walnut (J. regia), including phenolic acids, flavonoids, essential fatty acids, and tocopherols which are expected to provide health benefits. A high‐performance liquid chromatographic (HPLC) method was used to evaluate the contents of phenolic acids and tocopherols in walnut extracts. HPLC separation was performed on a symmetry C18 column for phenolic components and u‐Porasil column for tocopherols analysis. Saturated and unsaturated fatty acids were also quantified through gas chromatography (GC) using a SP‐2560 column and a flame ionization detector. We found that catechin (137.54 mg/ 100g) was a dominating phenolic acid in walnut extracts followed by chlorogenic acid (13.60 mg/100 g), ellagic acid (12.57 mg/100 g), and gallic acid (10.70 mg/100 g). In lipid extraction, a high content of polyunsaturated fatty acids and a low concentration of saturated fatty acids were observed. The most predominant component of walnut oil was linoleic acid, comprising 64.6 %, followed by 14.6 % of linolenic acid and 12.6 % of oleic acid, which agreed with previous published data. We also found that γ‐tocopherol was the most abundant tocopherol, followed by minor quantities of α‐tocopherol. In conclusion, our data provide each ingredient of walnut extract and indicate walnut contains high concentration of various polyphenolic and antioxidative compounds which are suggested to be the major bioactive compounds for the health benefits.

Investigating effects of walnut oil on some sperm parameters in rats undergoing treated with busulfan

Investigating effects of walnut oil on some sperm parameters in rats undergoing treated with busulfan

Rapid detection of authenticity and adulteration of walnut oil by FTIR and fluorescence spectroscopy: A comparative study

Fourier transform infrared (FTIR) and fluorescence spectroscopy combined with soft independent modeling of class analogies (SIMCA) and partial least square (PLS) were used to detect the authenticity of walnut oil and adulteration amount of soybean oil in walnut oil. A SIMCA model of FTIR spectra could differentiate walnut oil and other oils into separate categories; the classification limit of soybean oil in walnut oil was 10%. Fluorescence spectroscopy could differentiate oil composition by the peak position and intensity of emission spectrum without multivariate analysis. The classification limit of soybean oil adulterated in walnut oil by fluorescence spectroscopy was below 5%. The deviation of the prediction model for fluorescence spectra was lower than that for FTIR spectra. Fluorescence spectroscopy was more applicable than FTIR in the adulteration detection of walnut oil, both from the determination limit and prediction deviation.

Weight loss with a modified Mediterranean-type diet using fat modification: a randomized controlled trial.

There is evidence that Mediterranean diets with a high proportion of olive oil and nuts can be effective for weight management and prevention of cardiovascular disease. It might be difficult for populations with other eating habits to follow such diets. Therefore, a modified Mediterranean-type diet using fat modification through neutral and butter-flavored canola oil, walnuts and walnut oil with two portion-controlled sweet daily snacks was tested in Germany. Randomized waiting-list control study with overweight/grade 1 obese subjects: 12-week self-help modified Mediterranean-type diet, 6 weeks of diet plans and 6 weeks of weight loss maintenance training. Trial duration was 12 months. Intervention group (IG) included 100 participants (average age of 52.4 years, weight 85.1 kg and body mass index (BMI) 30.1 kg/m(2)), waiting-list control group (CG) included 112 participants (52.6 years, 84.1 kg and 30.1 kg/m(2)). Per-protocol weight loss after 12 weeks was 5.2 kg in IG vs 0.4 kg in CG (P ⩽ 0.0001), BMI -1.8 vs -0.1 kg/m(2) (P ⩽ 0.0001), waist circumference -4.7 vs -0.9 cm (P ⩽ 0.0001). Triglycerides, total cholesterol and LDL cholesterol improved significantly in IG but not in CG. One-year dropouts: 44% in IG and 53% in CG. Weight loss after 12 months: 4.2 kg (pooled data). A five-meal modified Mediterranean-type diet with two daily portion-controlled sweet snacks was effective for weight management in a self-help setting for overweight and grade 1 obese subjects. Fat modification through canola oil, walnuts and walnut oil improved blood lipids even at 12 months.

Use of Fourier Transform Infrared Spectroscopy in Combination with Partial Least Square for Authentication of Black Seed Oil

Fourier transform infrared spectroscopy in combination with multivariate calibration of partial least square is intended for quantitative analysis of black seed oil in binary mixture with sunflower oil and walnut oil, as well as in ternary mixture with sunflower oil and walnut oil. The spectra of black seed oil, sunflower oil, walnut oil, and their mixture with certain concentration were scanned using attenuated total reflectance at mid infrared region of 4000–650 cm−1. For quantitatve analysis, Fourier transform infrared spectral treatment (normal or derivatives) with the highest values of coefficient of determination (R2) and the lowest values of root mean square error of calibration was selected as optimal calibration model. Partial least square at whole mid infrared region of 4000–650 cm−1 is well suited for quantitative analysis of black seed oil either in binary mixture or ternary mixture with walnut oil and sunflower oil. Furthermore, using absorbancies at frequency region of 3009–721 cm−1, principal component analysis is succesfully used for classification of black seed oil and that mixed with sunflower oil and walnut oil. The developed method is rapid, no sample preparation needed, and is not involving the use of chemical reagents and solvents.Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ljfp.