Pistachio Oil Research Articles

Oil quality of pistachios (Pistacia vera L.) grown in East Azarbaijan, Iran

Pistachio nut as a strategic product has a special place from nutritional and economical points of view. Its quality can be affected by variety, growing origin and climate. In the present study, the chemical composition of pistachio nuts harvested from different parts of East Azarbaijan province in Iran (Jolfa, Marand, Soufian, Azarshahr and Islamic Island) was investigated. The nuts had oil content of 49.9 to 58.5% and moisture content of 35.2 to 47.9. The acidity, peroxide values and the oil stability index (OSI) of the extracted oil were 0.03 to 0.3%, 0.19 to 1.0 meq O2/kg oil and 12.4 to 17 h, respectively. In addition, the chlorophyll content was found to be 15 to 72 mg pheophytin/kg oil and the carotenoid content was 5.4 to 11.5 mg/kg. In the fatty acid composition of the oil samples, oleic acid was the main fatty acid (52.5–63.9%), followed by linoleic acid (27.1–37.2%), palmitic acid (4.6–10.3%), palmitoleic acid (0.6–1.2%), stearic acid (0.1–1.3%) and linolenic acid (0.3–0.4%). Total tocopherol content of the pistachio oil samples was (125–258 mg/kg oil) which γ-tocopherol was the main tocol (112–232 mg/kg oil), followed by δ-tocopherol (5.3–19.3 mg/kg oil) and α- tocopherol (1.2–6.1 mg/kg oil). Total sterol content of the samples found to be (1125–2784 mg/kg oil). The most abundant sterol in the oils was β-sitosterol (966–2419 mg/kg oil) and other detected sterols were Δ5-avenasterol (72.6–170 mg/kg oil), campesterol (47.4–128 mg/kg oil), Stigmasterol (12.3–27.8 mg/kg oil) and cholesterol (8.3–39 mg/kg oil). The obtained results showed that origin had significant effects on oil composition. These data can be used to evaluate the nutritional value and authenticity of the oils and as useful information in establishing standards.

Impact of Microclimate on Fatty Acids and Volatile Terpenes in “Kerman” and “Golden Hills” Pistachio (Pistacia vera) Kernels

Pistachio is an economically important nut crop in California. Since temperature variations among geographical locations can influence biochemical processes during fruit development, it is of great relevance to understand the impact of growing area over the components that define the nutritional and sensory characteristics of pistachio nuts. Changes in moisture, fat content, fatty acid composition and volatile terpenes were studied during kernel development for "Kerman" and "Golden Hills" varieties in two different California Central Valley microclimates, Lost Hills and Parlier. Moisture content decreased from July to September for both cultivars at both locations. Kerman had a higher moisture content at both locations compared with Golden Hills. Harvest time affected fat content only for Kerman, where the values increased drastically from 21-July to 4-Aug, then remained constant. Golden Hills' fat content remained constant during the period of the study. The main fatty acid in pistachio oil is oleic acid (46% to 59%), followed by linoleic acid (26% to 36%) and palmitic acid (11% to 16%). C16:0, C16:1, C18:2, and C18:3 decreased with harvest time, while C18:1 increased. α-Pinene was the most concentrated volatile among the cultivars and locations. It decreased with harvest time for both cultivars at both locations, ranging from 105 to 2464 mg/kg. At harvest, Golden Hills and Kerman at Parlier both had higher concentrations of α-pinene than the two cultivars at Lost Hills. Our results demonstrate that microclimate affects biosynthesis of fatty acids and terpenes in pistachio kernels, the main compounds responsible for pistachio nutritional and sensory characteristics.

Comprehensive Study of the Phenolic Compound Profile and Antioxidant Activity of Eight Pistachio Cultivars and Their Residual Cakes and Virgin Oils.

Phenolic compounds of eight pistachio ( Pistacia vera L.) cultivars and their residual cakes and virgin oils (screw pressing) were studied using high-performance liquid chromatography-diode array detection-electrospray ionization-tandem mass spectrometry. A total of 25 compounds were identified and quantified for pistachio nuts and residual cakes, with the presence of five flavonols, six flavanols, and one gallotannin being reported for the first time. Total phenolics in pistachio nuts showed a concentration from 1359 mg/kg (Kastel) to 4507 mg/kg (Larnaka). Flavanols were the most abundant phenolics, at about 90%, with resulting procyanidin B1 and gallocatechin being the main phenolics, depending upon the cultivar. Other phenolic groups, such as anthocyanins (from 54 to 218 mg/kg), flavonols (from 76 to 130 mg/kg), flavanones (from 12 to 71 mg/kg), and gallotannins (from 4 to 46 mg/kg), were also identified. Residual cakes presented the same phenolic profile but with a concentration almost double because of the concentration effect caused by the oil separation. Virgin pistachio oils showed a very low phenolic content, with eriodyctiol being the only compound identified.

In vitro evaluation of the activity of an essential oil from Pistacia vera L. variety Bronte hull against Candida sp.

BackgroundCandida sp. represent the most common cause of fungal infections worldwide. In the present work, we have evaluated the activity of an essential oil extracted from pistachio hulls against a number of standard and clinical strains of Candida sp.MethodsC. albicans ATCC 64550, C. parapsilosis ATCC 22019, 4 clinical strains of C. albicans, 3 clinical strains of C. parapsilosis and 3 clinical strains of C. glabrata were used. All clinical isolates were identified by species-specific PCR-based methods. Susceptibility studies were performed using pistachio hull essential oil alone or in combination with antifungal compounds. The interactions between pistachio hull essential oil and selected antifungal compounds were also evaluated using the checkerboard method and the mechanisms of interaction investigated by droplet size distribution.ResultsPistachio hull essential oil was fungicidal at the concentrations between 2.50 and 5.0 mg/ml. D-limonene and 3-Carene were the components with major activity. An antagonistic effect was observed with all combinations tested.ConclusionThe antifungal activity of pistachio hull essential oil could be used to help control resistance in Candida species. More studies need to be performed to elucidate the mechanisms responsible for the activity of pistachio hull essential oil.

Preventive Effect of Different Wild Pistachio Oils on Oxidative Stress Markers, Liver Enzymes, and Histopathological Findings in a Metabolic Syndrome Model.

Background: Wild pistachio (Pistacia Atlantica mutica) species with wide distribution in Iran have different nutrition properties and may have therapeutic effects in metabolic syndrome. Metabolic syndrome, as a prevalent health problem, is a main risk factor for different chronic diseases such as diabetes, fatty liver and cardiovascular diseases. The present study aimed to evaluate the preventive effects of mixture, kernel, and hull oil of wild pistachio (WP) on oxidative stress markers, liver function and histopathological findings in metabolic syndrome induced rats. Materials and Methods: After oil extraction by cold press method and chemical analysis, rats were divided into 6 groups. Group 1 received normal saline; group 2 received 2cc fructose solution and 0.5cc normal saline; and groups 3, 4, 5 and 6 received 2 cc fructose solution and 0.5 cc sunflower oil, mixture, hull and kernel oils of WP for 10 weeks, respectively. Then, glycemic indices, oxidative stress, liver enzymes and histopathological examination were determined using standard laboratory tests. Results: WP Kernel and mixture oils notably decreased the fasting blood sugar and insulin resistance compared with the fructose group. Insulin level was significantly increased in the kernel oil group (P<0.05). There was no significant difference in oxidative stress, liver enzymes and histopathology parameters among the groups. Conclusion: Kernel oil of WP improved hyperglycemia, insulin resistance and insulin secretion, but the changes in oxidative stress markers, liver enzymes and histopathologic results were not significant among the groups.

Preventive Effect of Different Wild Pistachio Oils on Oxidative Stress Markers, Liver Enzymes, and Histopathological Findings in a Metabolic Syndrome Model

Background: Wild pistachio (Pistacia Atlantica mutica) species with wide distribution in Iran have different nutrition properties and may have therapeutic effects in metabolic syndrome. Metabolic syndrome, as a prevalent health problem, is a main risk factor for different chronic diseases such as diabetes, fatty liver and cardiovascular diseases. The present study aimed to evaluate the preventive effects of mixture, kernel, and hull oil of wild pistachio (WP) on oxidative stress markers, liver function and histopathological findings in metabolic syndrome induced rats. Materials and Methods: After oil extraction by cold press method and chemical analysis, rats were divided into 6 groups. Group 1 received normal saline;Â group 2 received 2cc fructose solution and 0.5cc normal saline; and groups 3, 4, 5 and 6 received 2 cc fructose solution and 0.5 cc sunflower oil, mixture, hull and kernel oils of WP for 10 weeks, respectively. Then, glycemic indices, oxidative stress, liver enzymes and histopathological examination were determined using standard laboratory tests. Results: WP Kernel and mixture oils notably decreased the fasting blood sugar and insulin resistance compared with the fructose group. Insulin level was significantly increased in the kernel oil group (P&lt;0.05). There was no significant difference in oxidative stress, liver enzymes and histopathology parameters among the groups. Conclusion: Kernel oil of WP improved hyperglycemia, insulin resistance and insulin secretion, but the changes in oxidative stress markers, liver enzymes and histopathologic results were not significant among the groups. [GMJ.2019;8:e1238]

Preventive Effect of Different Wild Pistachio Oils on Oxidative Stress Markers, Liver Enzymes, and Histopathological Findings in a Metabolic Syndrome Model

Background: Wild pistachio (Pistacia Atlantica mutica) species with wide distribution in Iran have different nutrition properties and may have therapeutic effects in metabolic syndrome. Metabolic syndrome, as a prevalent health problem, is a main risk factor for different chronic diseases such as diabetes, fatty liver and cardiovascular diseases. The present study aimed to evaluate the preventive effects of mixture, kernel, and hull oil of wild pistachio (WP) on oxidative stress markers, liver function and histopathological findings in metabolic syndrome induced rats. Materials and Methods: After oil extraction by cold press method and chemical analysis, rats were divided into 6 groups. Group 1 received normal saline; group 2 received 2cc fructose solution and 0.5cc normal saline; and groups 3, 4, 5 and 6 received 2 cc fructose solution and 0.5 cc sunflower oil, mixture, hull and kernel oils of WP for 10 weeks, respectively. Then, glycemic indices, oxidative stress, liver enzymes and histopathological examination were determined using standard laboratory tests. Results: WP Kernel and mixture oils notably decreased the fasting blood sugar and insulin resistance compared with the fructose group. Insulin level was significantly increased in the kernel oil group (P&lt;0.05). There was no significant difference in oxidative stress, liver enzymes and histopathology parameters among the groups. Conclusion: Kernel oil of WP improved hyperglycemia, insulin resistance and insulin secretion, but the changes in oxidative stress markers, liver enzymes and histopathologic results were not significant among the groups. [GMJ.2019;8:e1238]

Preventive Effect of Different Wild Pistachio Oils on Oxidative Stress Markers, Liver Enzymes, and Histopathological Findings in a Metabolic Syndrome Model

Background: Wild pistachio (Pistacia Atlantica mutica) species with wide distribution in Iran have different nutrition properties and may have therapeutic effects in metabolic syndrome. Metabolic syndrome, as a prevalent health problem, is a main risk factor for different chronic diseases such as diabetes, fatty liver and cardiovascular diseases. The present study aimed to evaluate the preventive effects of mixture, kernel, and hull oil of wild pistachio (WP) on oxidative stress markers, liver function and histopathological findings in metabolic syndrome induced rats. Materials and Methods: After oil extraction by cold press method and chemical analysis, rats were divided into 6 groups. Group 1 received normal saline; group 2 received 2cc fructose solution and 0.5cc normal saline; and groups 3, 4, 5 and 6 received 2 cc fructose solution and 0.5 cc sunflower oil, mixture, hull and kernel oils of WP for 10 weeks, respectively. Then, glycemic indices, oxidative stress, liver enzymes and histopathological examination were determined using standard laboratory tests. Results: WP Kernel and mixture oils notably decreased the fasting blood sugar and insulin resistance compared with the fructose group. Insulin level was significantly increased in the kernel oil group (P&lt;0.05). There was no significant difference in oxidative stress, liver enzymes and histopathology parameters among the groups. Conclusion: Kernel oil of WP improved hyperglycemia, insulin resistance and insulin secretion, but the changes in oxidative stress markers, liver enzymes and histopathologic results were not significant among the groups. [GMJ.2019;In press:e1238]

Physical and chemical properties of some pistachio varieties (Pistacia vera L.) and oils grown under irrigated and non-irrigated conditions in Turkey

The purpose of this study was to compare physicochemical characteristics and fatty acid profiles of two varieties (Kirmizi and Siirt) of pistachio nut (Pistacia vera L.) and to determine the effect...

Wild pistachio (Pistacia atlantica mutica) oil improve metabolic syndrome features in rats with high fructose ingestion.

Objective(s):Metabolic syndrome is a multiplex risk factor for diabetes and cardiovascular disease. Since some dietary fats such as mono-unsaturated fatty acids (MUFA) modify metabolic syndrome components the aim of the present study was to evaluate the preventive effects of mixture, kernel and hull oils of wild pistachio (WP) (Pistacia atlantica mutica) as good sources of MUFA on different features of this abnormality in rats under induction. Materials and Methods: In this study rats were randomly assigned to six groups with 12 animals per group. Metabolic syndrome was induced by fructose solution in groups 2, 3, 4, 5, and 6. Group 3 received sunflower oil and groups 4, 5, and 6 received mixture, hull and kernel oils of WP (2 ml/kg/day), respectively, for 10 weeks. Then, lipid profiles, glycemic indices, oxidative stress and inflammatory parameters were measured using standard laboratory tests.Results:Different forms of WP oil induced hypotriglyceridemia, but the hypocholesterolemia effect was seen only in the mixed and kernel oil groups. Kernel oil also significantly reduced LDL and HDL cholesterol (P<0.05). In addition, mixed and kernel oils notably decreased glycemic indices (fasting blood glucose and insulin resistance) compared with the fructose group. Serum insulin levels were significantly increased in the kernel oil group (P<0.05). All WP oils also significantly decreased inflammation (IL-6).Conclusion:The results showed that the consumption of WP kernel oil may have beneficial effects on preventing hyperglycemia, hypertriglyceridemia, hypercholesterolemia, inflammation and pancreatic secretory disorders.

Phenolics, Tocopherols, and Volatiles Changes During Virgin Pistachio Oil Processing Under Different Technological Conditions

The present work aims to study the influence of different processing conditions, including temperature, roasting, the use of whole nuts, pressure (nozzle size) and speed of the screw‐press extraction process, on the minor components, mainly tocopherols, phenolics, and volatile components, contained in virgin pistachio oils (VPO) and their corresponding partially defatted residual cakes. An important increase in total polar phenolic (TPP) is observed in VPO processed at a temperature above 60 °C (e.g., 16.7–65.3 and 76.4 mg kg−1 at 130 °C and roasting conditions). TPP and the corresponding antioxidant activity also increase when a smaller nozzle diameter (3 mm) is used (16.7–35.4 mg kg−1; DPPH increases 36%), but no differences are observed when changing the screw speed. It is remarkable that the use of the whole pistachio (with its shell) helps to greatly enrich the oil in aromatic volatile compounds by up to 135%, with terpenes being the main family (e.g., 38.6–90.9 mg kg−1). Phenolic compounds and their antioxidant activity are higher in the residual cake when a higher processing temperature is used, for example, from 7260 to 12 250 mg kg−1 (at 40 and 130 °C, respectively). This result indicates their potential use as functional ingredients in food formulations.Practical Applications: The edible oil market is expanding and creating new products, where nut oils are gaining space in the preferences of consumers. In this sense, the study of the effect of different oil extraction conditions on the minor composition may help to produce VPOs with a higher bioactive compound content and/or with desired organoleptic characteristics.Virgin nut oils are minimally processed foods characterized by their typical aroma, taste, and minor bioactive compounds depending on the extraction and processing methods employed. Different technological conditions are studied using a screw‐press expeller to produce added value pistachio virgin oils and their residual cakes.

Comparison of cold-pressing and soxhlet extraction systems for bioactive compounds, antioxidant properties, polyphenols, fatty acids and tocopherols in eight nut oils.

Antioxidant activities of different nut oils ranged from 11.43 (peanut) to 65.58% (pistachio) in cold pressed oils whereas in case of soxhlet extracted oils they were in the range of 11.32 (hazelnut) to 51.28% (pistachio). β-Carotene contents of oils obtained by cold pressing and soxhlet extraction changed between 7.53 (almond) and 13.58µg/100g (pistachio). The highest total phenol contents (2.36mg gallic acid equivalent/100g) were observed in pistachio oils obtained by cold press. The oleic acid contents of cold pressed and soxhlet extracted oils were between 19.88 (walnut) and 69.43% (pecan) to 19.07 (walnut) and 68.53% (pecan), respectively. The linoleic acid contents of nut oils from cold press system vary between 12.78 (hazelnut) and 63.56% (walnut), whereas in case of soxhlet extraction, it changed between 11.78 (hazelnut) and 62.41% (walnut). The α-tocopherol contents of cold pressed nut oils changed between 0.07 (walnut) and 257.42mg/kg (hazelnut) α-tocopherol contents of nut oils extracted by soxhlet extraction changed between 0.03 (pistachio) and 209.73mg/kg (hazelnut). The catechin contents of cold pressed nut oils were between 0.56 (cashew) and 3.76µg/100g (pistachio), whereas that of soxhlet extracted oil varied between 0.64 (cashew) and 3.82µg/100g (cashew).

Characterization of pistachio oils and defatted flours regarding cultivar and geographic origin

The present study analyses pistachio oil and defatted flour obtained from twenty cultivars originating in eight different countries. To identify the cultivar effect, all pistachio varieties were grown in the same plot to control environmental and agricultural management effects on kernel chemical traits. Regarding oil, three different groups were defined according to the physicochemical parameters of interest. Cultivars in group 1 showed a higher content of linoleic fatty acid (higher than 26.4%), while cultivars in group 3 type showed a stronger presence of oleic acid (higher than 67.8%), resulting in oils that were more stable to oxidation. Cultivars with intermediate characteristics were included in group 2. Defatted flours showed significant differences in nutritional quality parameters, such as protein content (34.6–46.1%) or concentration of essential minerals, such as Fe (17.3–45.1 mg/kg) or Mg (0.13–0.18 g/100 g). Beyond the cultivar effect, the geographical origin of the cultivar was identified for the first time as a source of variability in pistachio product traits. The content of Fe in pistachio flours and the content of stigmasterol in pistachio oils are proposed as useful parameters for discrimination of cultivars attending to the place where the cultivar was originated.

Effect of roasting conditions on pigment composition and some quality parameters of pistachio oil

Pistachio roasting before oil extraction increases consumer preference but may cause changes in the oil composition. In this work, the effect of different roasting conditions on the physical parameters, oxidative stability, and pigment composition of pistachio oil extracted by pressure was studied. Density value of pistachio oil was reduced with severe roasting conditions (125 °C), while viscosity increased slightly. This adverse effect was compensated by a significant increase in both oxidative stability and, especially, in the content of chlorophyll and carotenoid pigments. Pistachio roasting temperature had a clear impact on the color of the pistachio oils, changing from yellow in oils from raw or minimally roasted pistachios (50–75 °C) to brilliant green in oils from pistachios subjected to higher temperature treatments (100–125 °C). An increase in temperature favored the pigment transfer to the oil. The green oils had a total pigment content between 2.3 and 4 times higher than the yellow oils.

Influence of temperature in the extraction of nut oils by means of screw pressing

The extraction of vegetable oils by means of screw pressing is considered a cold extraction method. However, this type of machinery needs the nozzle to be pre-heated, during which separation of the oil occurs so that it is produced in a satisfactory manner. In this study, the screw press extraction of almond, pistachio and walnut oil has been evaluated, analysing the effect of the temperature applied in the barrel and the selected rotational speed on the oils obtained. When applying low temperatures in the heating ring, the friction of the raw material led almond and pistachio oils to reach temperatures of approximately 60 °C, with somewhat lower temperatures reached in walnut oil. However, at higher temperatures (up to 200 °C), the oil temperature was not increased above 84 °C due to the cooling produced by the continuous supply of raw material. Increasing the rotational speed decreased the contact time of the material with the heater ring, decreasing the output temperature. Generally, the rotational speed had a larger effect on oil temperature than did the temperature applied in the heating ring. The results show that the contents of fatty acids and sterols are not affected by the nut oil extraction temperature; however, the physicochemical parameters of regulated quality are affected.

Storage stability and composition changes of three cold-pressed nut oils under refrigeration and room temperature conditions

Chemical composition and stability parameters of three cold-pressed nut oils (almond, walnut and pistachio) were monitored for up to 16 months of storage at 5 °C, 10 °C, 20 °C and room temperature. Freshly pressed pistachio oil had lower peroxide value than almond oil and higher induction period than almond and walnut oils, indicating a higher stability. The peroxide values increased faster at room temperature than at lower temperatures during the storage time, and the highest increase was for pistachio oil stored at room temperature exposed to daylight. The induction period decreased for all three nut oils during the storage time, regardless of the storage conditions. Pistachio oil remained the most stable oil at the end of the storage time, followed by almond oil. The percentage of polyunsaturated fatty acids decreased slightly throughout the storage.

Improving Storage Stability of Pistachio Oil Packaged in Different Containers by Using Rosemary (Rosmarinus officinalis L.) and Peppermint (Mentha piperita) Essential Oils

In this study, the antioxidant capacity of rosemary (REO) and peppermint (PEO) essential oils along with butylated hydroxytoluene (BHT) is investigated on oxidative stability of pistachio oil packaged in glass and polyethylene terephthalate (PET). The essential oils (EOs) and their mixture are added at 1500 and 3000 ppm concentrations into the oil stored for 80 days at 60 °C under darkness. In order to evaluate the efficacy of antioxidants, peroxide value (PV), thiobarbituric acid, total phenolic compounds, oxidative stability index (OSI), conjugated dienes and trienes, free fatty acids (FFAs), and iodine value is measured at intervals of 20 days. The results show that natural antioxidants can reduce PV and FFA levels about five‐ and threefolds compared to control, respectively. The OSI in raw pistachio oil (16 h) reduces to 5 h, while in treated sample by REO the reduction is only to 13 h after storage. Generally, the results reveal that in all measured parameters, following order can be observed for antioxidant activity: 3000 ppm REO&gt;3000 ppm PEO&gt;100 ppm BHT &gt;1500 ppm REO &gt;1500 ppm mixed &gt;1500 ppm PEO &gt; control. Moreover, the findings show that glass container is better than PET to retard oxidation process.Practical Application: Pistachio oil is known as a functional and commercial oil that is susceptible to oxidation due to its high level of unsaturated fatty acids. In this work, rosemary and mint essential oils as natural antioxidant are applied for improving oxidation stability of pistachio oil.Antioxidant capacity of rosemary (REO) and peppermint (PEO) essential oils is investigated on oxidative stability of pistachio oil packaged in glass and polyethylene terephthalate (PET). The essential oils are added at 1500 and 3000 ppm concentrations into the oil stored for 80 days at 60 ºC under darkness. The results reveal that in all measured parameters, following order can be observed for antioxidant activity: 3000 ppm REO &gt;3000 ppm PEO &gt;100 ppm BHT &gt;1500 ppm REO &gt;1500 ppm mixed &gt;1500 ppm PEO &gt; control. The findings show that glass container is better than PET to retard oxidation process.

Composition and properties of virgin pistachio oils and their by-products from different cultivars

Pistachios (Pistacia vera) exhibit an interesting nutritional value, due to the high content of oleic acid and minor components with antioxidant and bioactive properties. This work aimed to characterize pistachio virgin oils and their partially defatted residual cakes, obtained from eight cultivars (Aegina, Avdat, Kastel, Kerman, Larnaka, Mateur, Napoletana, and Sirora). Interesting results on phenolics, tocopherols and antioxidant activity were observed, which were greatly affected by variety. Pistachio virgin oils are rich in healthy oleic acid (55–74%), phytosterols (3200–7600mg/kg) and γ-tocopherol (550–720mg/kg). A high content of phenolic compounds (8600–15000mg/kg gallic acid equivalents) and the corresponding antioxidant activities (12–46 and 155–496mmol/kg for DPPH and ORAC) of the residual cakes demonstrate their potential applications as functional ingredients and as rich sources of bioactive compounds. Moreover, virgin pistachio oils possess peculiar and pleasant sensory characteristics, contributing greater added value to the consumers compared to refined vegetable oils.

Pistachio oil (Pistacia vera L. cv. Uzun): Characterization of key odorants in a representative aromatic extract by GC-MS-olfactometry and phenolic profile by LC-ESI-MS/MS

Volatile, aroma-active, and phenolic compounds of pistachio oil obtained from cv. Uzun were investigated in the current study. To obtain a representative aromatic extract, three of the most widely used extraction methods were compared using a representative test; the solvent-assisted flavour extraction (SAFE) aromatic extract from pistachio oil was found to be the most representative. A total of 50 aroma compounds were determined in pistachio oil and it was found that terpenes, aldehydes, and alcohols were the most abundant volatile compounds. Applying GC-MS-olfactometry and aroma extract dilution analysis (AEDA) resulted in a total of 14 aroma-active areas being detected in the extract of pistachio oil. In the phenolic fraction obtained by the LC-ESI-MS/MS method, a total of 12 phenolic compounds was found in the pistachio oil, of which seven compounds were reported for the first time. Eriodictyol-7-O-glucoside and protocatechuic acid were the most dominant phenolic compounds.

Usefulness of physical parameters for pistachio cultivar differentiation

Pistachio kernel characteristics are influenced by cultivar on a greater way than other tree nuts. Previous studies have focused on the analysis of chemical traits of pistachio cultivars, with little attention been paid to differences in their physical parameters. To solve this disregard, differences in the physical traits of twenty different cultivars from nine different countries are evaluated in this study. To identify the cultivar effect, all pistachio varieties were grown in the same plot to remove environmental and land management effects on kernel traits. Regarding kernel size, significant differences were found in the kernel length and width, but not in the relation length/width. Significant differences in the colour of pistachio by-products, pistachio oil and flour, were found. Colour parameter b* in oils and L* in flours allowed the differentiation of 25% and 40% of considered cultivars, respectively. The differences in the fatty acid profile of cultivars seems to affect oil viscosity, allowing the calculation of the content in oleic and linoleic acids with the viscosity data. Viscosity values ranged from 59.71mPas in Kerman to 63.93mPas in Avdat. By grouping the considered cultivars depending on their origin countries, significant differences were found in the kernel length and oil viscosity but not in the colour parameters (L*, a*, b*). This study certifies the usefulness of some physical parameters to confirm authenticity of kernels and pistachio by products depending on the cultivar and its origin.