Fresh Pistachio Research Articles

Effect of Sodium Alginate in Combination with Zataria multiflora Boiss. on Phenolic Compounds, Antioxidant Activity, and Browning Enzymes of Fresh In-Hull Pistachio (Pistacia vera L.)

The color of fresh pistachio is used as a postharvest quality indicator. The present study was performed to investigate the chemical properties of fresh pistachios coated with different sodium alginate concentrations (1 and 1.5%), various amounts of Shirazi thyme essential oil (0.3 and 0.5%), and their combination during storage (2 ± 1°C and 85 ± 5% RH). Over the storage duration, chemical parameters were measured on days 13, 26, and 39. The results showed that although the application of sodium alginate in combination with thyme essential oil decreased polyphenol oxidase activity in comparison with other treatments, the highest total phenolics and phenylalanine ammonia lyase activity were found in pistachios coated with alginate (1%) + thyme essential oil (0.3% and 0.5%). In general, it was proven that treatments containing 1% alginate + 0.3% essential oil had the ability to maintain the quality of fresh pistachio fruit approximately over 39 days of storage.

Shelf life of fresh in-hull pistachio in perforated polyethylene packaging

Shelf life of fresh in-hull pistachio in perforated polyethylene packaging

Incorporation of Zataria multiflora Boiss essential oil into gum Arabic edible coating to maintain the quality properties of fresh in-hull pistachio (Pistacia vera L.)

Edible coatings of gum Arabic (GA) (6.0 and 8.0 %) with Shirazi thyme (Zataria multiflora) (0.3 and 0.5 %) were assessed as potential postharvest treatments to protect the quality of fresh in-hull pistachio when stored at 85 ± 5 % RH and 2 ± 1 °C for up to 36 days. The results showed that 6 % GA combined with thyme at the concentrations of 0.3 and 0.5 % decreased color change and PPO activity of fresh pistachio in comparison with untreated control fruits. Treated fruit (6 % GA alone with the addition of 0.3 % thyme) also had higher PAL activity and total phenolics. Higher free fatty acid and peroxide value were also found in fruits coated with GA (8 %) containing thyme (0.5 %). Both 0.3 % thyme and 6 % GA solutions were found to be the most effective on saturated and unsaturated fatty acids of kernel.

Risk Assessment of Contamination of Soil, Water and Plants to Arsenic in Pistachio Orchards of Kerman Province, Iran

Arsenic (As) is a natural occurring element which poses a potential risk to groundwater quality, as well as food safety through As transportation in soil-water-plant systems. The present study investigated the level of As contamination in water, soil, and pistachio plants (leaves and seeds) in 7 regions of Kerman province, as one of the most important pistachio cultivation regions in Iran. The results revealed that the concentration in the soil of the sampled areas varied from 15 to 1200 mg/kg The highest As concentrations was observed in the Shahr-e Babak, Bayaz, and Sirjan regions. The As concentration in the water of the sampled areas was between 0.62 and 483 µg/L, and the regions of Sirjan and Shahr-e Babak had the highest levels of arsenic contamination. The highest accumulation of As in pistachio leaves and seeds was observed in the Shahr-e Babak, Bayaz, and Sirjan areas, which had a positive correlation with the As concentration in the soil and water of the area. Thus, the level of As in fresh pistachios in Shahr-e Babak, Sirjan, and Bayaz regions can be considered a threat to the safety of the Iranian population.

Shelf life modeling of Badami's fresh pistachios coated with chitosan under modified atmosphere packaging conditions

Shelf life modeling of Badami's fresh pistachios coated with chitosan under modified atmosphere packaging conditions

Effect of high CO2 atmospheric packaging on postharvest quality of fresh pistachio fruits (‘Badami’)

Effect of high CO₂ atmospheric packaging on postharvest quality of fresh pistachio fruits (‘Badami’)

Effect of exogenous melatonin treatment onAspergillusdecay, aflatoxin B1 accumulation and nutritional quality of fresh “Akbari” pistachio fruit

This study aimed to investigate the mechanisms activated by melatonin treatment for attenuating Aspergillus decay, suppressing aflatoxin B1 (AB1) accumulation, and preserving nutritional quality in fresh pistachio fruits during storage at 25°C for 18 days. At 6-day intervals, samples from each of three replications were selected, and subjected to biochemical analysis. Our results showed that fresh pistachio fruits treated with 1,000 µM melatonin and inoculated with Aspergillus flavus, exhibited lower Aspergillus decay accompanied by lower endogenous AB1 accumulation. Melatonin treated fruit also showed lower H2O2 and malondialdehyde accumulation during storage. Furthermore, higher linolenic acid accumulation accompanied by higher phenols and flavonoids accumulation as well as superior DPPH scavenging capacity in fresh pistachio fruits treated with 1,000 µM melatonin, could be ascribed to lower lipoxygenase and higher phenylalanine ammonia-lyase enzymes activity, respectively, during storage. Besides, melatonin applying at 1,000 µM suppressed spore germination and germ tube elongation in A. flavus. Practical applications Aflatoxin B1 (AB1) accumulation as carcinogenic mycotoxin in pistachio fruits during Aspergillus flavus infection have been considered as a risk for human health. Since ROS generating from kernels could be responsible for triggering A. flavus growth and AB1 biosynthesis. Therefore, alleviating oxidative stress by melatonin treatment not only could be operative for attenuating fungal decay and decreasing AB1 accumulation but also could be favorable for maintaining the quality of fresh pistachio fruits.

Investigation of the effect of combined treatment of clove plant essential oil (Syzygium aromaticum) with carboxymethylcellulose on storage of fresh pistachio

Investigation of the effect of combined treatment of clove plant essential oil (Syzygium aromaticum) with carboxymethylcellulose on storage of fresh pistachio

Application of modified packaging and nano ZnO for extending the shelf life of fresh pistachio

AbstractThe aim of this study was to investigate how a modified packaging system designing to increase the shelf lives of fresh pistachio samples. Packaging systems include modified packaging containing cinnamon essential oil, spraying of zinc oxide (ZnO) nanoparticles, modified atmosphere with nitrogen packaging (MAP), and the combinations of the three. As sensory quality is usually considered in selecting the best packaging system, a comprehensive sensory study was performed for the assessment of each option, and some parameters, such as peroxide index, microbial assessment, and aflatoxin concentration, were examined. Results revealed that, when these parameters were considered in total, modified packaging with sprayed nano ZnO was noted as an effective approach for shelf life extension as iodine and peroxide values are 70 ± 1.2 and 0.52 ± 0.09, respectively, after 12 weeks. Specifically, modified packaging with sprayed ZnO simultaneously preserves the high quality of sensorial properties for packaged fresh pistachio and inhibits microbial growth.Practical ApplicationsBy applying modified packaging to fresh pistachio can extend the nut's shelf life; important parameters, such as odor, taste, and texture, are not altered. From a health perspective, modified packaging prevents microbial growth and aflatoxin accumulation in pistachio. Improving the efficiency of packaging systems is an effective strategy that will enable the export of fresh pistachio.

The effect of pistachio by-product extracts treatment in protecting soybean meal and canola meal protein from rumen microbial degradation.

The industrial de-hulling of fresh pistachio generates a large quantity of pistachio by-products (PBP). The present study aimed to investigate the effects of treating soybean meal (SBM) and canola meal (CM) with tannin extracts derived from PBP on the protein fractions according to the Cornell Net Carbohydrates and Protein System (CNCPS), rumen degradability, and ruminal and post-ruminal crude protein (CP) disappearance in an in situ trials using three fistulated steers. The extracts of PBP were obtained via different solvents and then added to SBM and CM, so that the final concentrations of added tannins were 0, 5 and 10 g kg-1 dry matter. The CNCPS soluble proteins (fractions A + B1 ) of CP and B1 fraction of CP were lower (P < 0.01) in SBM and CM treated with PBP extracts than untreated meals. Treating SBM with different PBP extracts (except 5 g kg-1 tannin water extract) and CM with 5 g kg-1 tannin water extract and 10 g kg-1 tannin ethanol extract decreased (P < 0.01) ruminal disappearance of CP. From the in situ results, the rapidly degradable fraction (a) of CP decreased (P < 0.01) by treating SBM with different PBP extracts and CM with 5 and 10 g kg-1 tannin water extracts, whereas the slowly degradable fraction (b) of CP remained unchanged in SBM. Treatment of SBM and CM with PBP extracts decreased (P < 0.01) the effective degradability of crude protein estimated with different outflow rates. Some of the tannin extracts derived from PBP by water, ethanol and methanol could be effective with respect to protein protection of SBM and CM from degradation in the rumen; however, the use of tannin from water extracts can be more economical and practical. © 2020 Society of Chemical Industry.

Effect of alginate coating enriched with Shirazi thyme essential oil on quality of the fresh pistachio (Pistacia vera L.).

In this study, different concentrations of alginate (0%, 1% and 1.5% w/v) enriched with various concentrations of Shirazi thyme (Zataria multiflora Boiss) essential oil (0%, 0.3% and 0.5% w/v), were examined on postharvest characteristics of the fresh pistachio. The measurements (including total phenolic compounds, antioxidant capacity, free fatty acid, peroxide value, aerobic mesophilic bacteria, mold and yeast, saturated and unsaturated fatty acids) were performed after 0, 13, 26 and 39days during storage (3 ± 1°C, 80 ± 5% RH). The results showed that alginate edible coating enriched with thyme's essential oil (EO), contributed to the maintenance of higher values of phenolic content and antioxidant activity in comparison with the control. Edible coating treatment of enriched alginate with thyme oil reduced mold and yeast growth compared to the control and the alginate without thyme oil. Peroxide value and free fatty acid content were significantly lower in fruits treated with alginate-thyme in comparison with the control. All fruits which had been treated with alginate-thyme EO showed lower changes in saturated and unsaturated fatty acids after 39days of storage, and fruits coated with combination of 1% alginate and 0.3% EO showed the highest content of palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, compared with other treatments.

Effect of Salicylic Acid Incorporated Chitosan Coating on Shelf Life Extension of Fresh In-Hull Pistachio Fruit

The effect of edible coating on the postharvest quality of fresh pistachio covered by a yellow-red colored soft shell (hull) was evaluated. Fresh pistachio fruit were immersed in different surface treatment solutions of 2% (w/v) chitosan (CT) in 0.5% acetic acid solution, 2 mmol L−1 salicylic acid (SA), and the combination of CT and SA (CT-SA), then packed in perforated polyethylene terephthalate (PET), and stored in a refrigerator for 28 days at 4 °C. Distilled water and 0.5% acetic acid solution containing 0.1% Tween were considered as control treatments. The weight loss and also the peroxide and free fatty acid values of treated fresh pistachio fruit were lower than the controls at the end of the storage period. The activity of superoxide dismutase, catalase, and peroxidase enzymes in the treated pistachio fruit was significantly higher compared to controls (p < 0.05). The SA-treated pistachio fruit shows the lowest activity of polyphenol oxidase. Also, the pistachio fruit treated with CT and SA were lighter (L*), redder (a*), and more yellow (b*) in color as compared with controls, so that the highest sensory scores of color, texture, and overall acceptance were attributed to these treatments. Interestingly, SA treatment resulted in a remarkable superiority of the fruit color score among the samples. Furthermore, the CT and SA treatments alone or in combination significantly reduced the growth of bacteria and fungi. Overall, it can be concluded that SA and CT-SA treatments can assure the safety and quality of fresh pistachio fruit in refrigerated storage.

The synergistic effects of cinnamon essential oil and nano TiO2 on antimicrobial and functional properties of sago starch films

This study describes a sago starch-based film by incorporation of cinnamon essential oil (CEO) and nano titanium dioxide (TiO2-N). Different concentrations (i.e., 0%, 1%, 3%, and 5%, w/w) of TiO2-N and CEO (i.e., 0%, 1%, 2%, and 3%, v/w) were incorporated into sago starch film, and the physicochemical, barrier, mechanical, and antimicrobial properties of the bionanocomposite films were estimated. Incorporation of CEO into the sago starch matrix increased oxygen and water vapor permeability of starch films while increasing TiO2-N concentration decreased barrier properties. Moisture content also decreased from 12.96% to 8.04%, solubility in water decreased from 25% to 13.7%, and the mechanical properties of sago starch films improved. Sago starch bionanocomposite films showed excellent antimicrobial activity against Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus. Results also showed that incorporation of TiO2-N and CEO had synergistic effects on functional properties of sago starch films. In summary, sago starch films incorporated with both TiO2-N and CEO shows potential application for active packaging in food industries such as fresh pistachio packaging.

Novel organic-based postharvest sanitizer formulation using Box Behnken design and mathematical modeling approach: A case study of fresh pistachio storage under modified atmosphere packaging

In the present study Box Behnken Design (BBD) and Artificial Neural Network-Genetic Algorithm (ANN-GA) hybrid system were used for predicting and optimizing a new organic-based postharvest sanitizer for fresh pistachio nuts under modified atmosphere packaging, combining different concentrations of five generally recognized as safe (GRAS) ingredients including H2O2 (1, 3 and 5%), Na2CO3 (1, 3 and 5%), K2CO3 (1, 3 and 5%), citric acid (CA) and acetic acid (AA, 1000, 5500 and 10,000 mg L−1). The nuts were submerged in sanitizer solutions for two minutes then dried for five minutes in ambient condition and packaged in polyethylene bags injected with ambient atmospheric gas (21% O2, 0.03% CO2, and 87% N2). BBD as a computer-based design of experiment (DOE) tool reduced the cost, labor and time needed to perform the experiment by reducing the number of treatments from 243 to 40 while ensuring the well-sampled experiment design. NaOCl (100 mg L−1) and distilled water (DW) were used as controls for the validation experiment. The ANN-GA described relations between five input (H2O2, Na2CO3, K2CO3, CA, and AA) and four output (total viable count, enzymatic browning, overall acceptability, and taste) variables. Sensitivity analysis was used to find the most important ingredient as input variable affecting output variables. ANN-based models could effectively fit the supplied data on the total viable count and quality parameters of pistachios to various concentrations of the ingredients in the sanitizers. Based on the ANN-GA results, the input variables concentrations of 3.6% H2O2, 3.9% Na2CO3, 3.2% K2CO3, 8118.5 (mg L−1) CA, and 8202.8 mg L−1 AA could result in the lowest total viable count (0.07 log colony forming units (CFU g-1)). The lowest amount of enzymatic browning (1.48%) can be obtained by applying a mixture of 4.26% H2O2, 3.7% Na2CO3, 3.7% K2CO3, 7785.4 mg L−1 CA, and 7363.5 mg L−1 AA. The highest overall acceptability (1.38) can be achieved using a mixture of 3.0% H2O2, 3.0% Na2CO3, 3.4% K2CO3, 8190.1 mg L−1 CA, and 8316.7 mg L−1 AA. The best taste (1.21) was predicted to be attained using a combination of 3.3% H2O2, 4.1% Na2CO3, 3.9% K2CO3, 8114.5 mg L−1 CA, and 7574.0 mg L−1 AA. According to the sensitivity analysis, AA was the most important factor in reducing total viable count and enzymatic browning and enhancing overall acceptability. The validation test showed that the optimized sanitizer for total viable count was superior to the 100 mg L−1 NaOCl which is the most used commercial sanitizer for fresh crops.

Effects of harvesting time and irrigation on aroma active compounds and quality parameters of pistachio

The effects of harvesting time and irrigation on volatile and aroma active compounds with some quality parameters (fat content, total protein, total sugar, moisture content, pH and texture) of Uzun and Siirt type pistachios harvested at two different harvest times (Early harvest: Boz, mature harvest: Ben) were investigated. It was found that, moisture content of fresh pistachio increased (P < 0.05) by irrigation whereas oil content, protein content, sugar content, pH and hardness of pistachio were not affected (P > 0.05) by irrigation. The moisture content of fresh pistachio changed between 46.42 % and 54.95 % depending on type of pistachio, harvest time and irrigation. Protein content changed between 20.77 % and 23.15 %. Boz pistachios had significantly higher (P < 0.05) protein content than those of Ben pistachios. pH values of the pistachio depended on the harvesting time, which ranged between 6.08 and 6.44. Totally 39 volatile compounds were determined in the dried pistachio nut. Volatile compounds of pistachio nut were mostly composed of terpenes. In the olfactometric analyses, 35 odor active compounds were determined in pistachio nut. As a result, cultivation of pistachio in irrigated conditions had lowered the concentration of volatile compounds and intensities of odor active compounds than those of non-irrigated condition.

The inhibitory effect of nitric oxide on enzymatic browning reactions of in-package fresh pistachios (Pistacia vera L.)

Hull browning decreases the postharvest-life and marketability window of fresh pistachio fruit in which to the current study aims to evaluate the inhibitory effect of nitric oxide (NO), as an anti-browning chemical substance, on controlling enzymatic browning of harvested fresh pistachio cv. ‘Ahmad Aghaei’. Fruit were sprayed with sodium nitroprusside (nitric oxide donor) with 0 (control), 15, 30, 45 and 60 μM for 30 s and thereafter packed in plastic tray wrapped with low density polyethylene (LDPE) then stored at 2 ± 1 °C with 93 ± 2% relative humidity for 60 d. The nitric oxide treated fruit showed lower browning index and ΔE and higher normalized L* value than control. Nitric oxide also could prevent the activity of polyphenol oxidase enzyme (PPO), phenylalanine ammonialyase (PAL) and peroxidase (POD), and keep the highest activity of superoxide dismutase (SOD). Total phenolic, flavonoids content and antioxidant activity of fresh pistachio hull were maintained by nitric oxide treatments. Our results demonstrated that the concentration of 15 and 30 μM sodium nitroprusside (SNP) were most effective on reducing of hull browning and extending postharvest life as compared to the control treatment. From these results, it can be concluded that the percentage of acceptable fruit treated with 15 μM of SNP was higher than 30 μM, respectively. Overall, the application of SNP can be considered as an alternative approach for decreasing the hull browning and maintaining the quality of harvested fresh pistachio fruit.

Aflatoxin-Contaminated Nut Separation by Applied Machinery and Processing Stages in Fresh Pistachio Processing Plant.

In pistachio nuts, aflatoxin is mainly concentrated in the green hull-cracked nuts in the orchard even prior to harvest. However, during the hull-removal process, the hulls of all nuts including the cracked, identifiable nuts are removed causing an important characterization criterion of the contaminated nuts, to be lost. This, in turn, makes it harder to detect the contaminated nuts. However, during the processing stage, there is a good possibility of sorting the contaminated nuts based on their other inherent features, such as specific gravity and stain on the hard shell. In this study, we aimed to explore the effect of applied processing machinery and related sequences in the aflatoxin flow during post-harvest processing and the possible ways of reducing aflatoxin contamination in the Iranian pistachio industry. We planned a systematic sampling from the main and reject streams in two major prevailing processing methods, namely, wet and dry. In the dry processing method, the reject streams such as the adhering-hull rejects, air floaters, and manual hand pick-outs from the final inspection were found to be significantly more contaminated than the main stream. However, in the wet processing method, the input stream was considered highly contaminated. Among the sorting stages, only the adhering-hull rejects of the sinkers were considered more contaminated than the main stream. A contamination removal index was developed and applied to compare the effectiveness of the processing procedures. The water flotation tank was deemed responsible for 52.5% of aflatoxin contamination removal compared to 2.1% in the air flotation system. More effective sorting was achieved by the adhering-hull remover, which was preceded by a rubber-drum huller instead of the metal-drum type. Thus, by combining the most effective techniques of aflatoxin removal, an improved and more efficient method may be designed for pistachio processing plants.

Effects of solar drying along with air recycling system on physicochemical and sensory properties of dehydrated pistachio nuts

Fresh pistachio was dehydrated with shade drying, sun drying, solar drying (without and with air recycling) systems (Methods I, II, III and IV). Then their impacts were studied on drying time, physical properties and also organoleptic criterions (shell appearance, color, roasted flavor, finger releasing kernel, sweetness, shell splitting and overall palatability) of dehydrated pistachio. The ambient-air temperature rise and drying time of pistachio in Methods I, II, III and IV reached to 1, 1, 14, & 17 °C; and 48, 19, 16, & 13 h, respectively. While the trends of drying rates in all methods were completely quadratic (R2 = 0.99), Method IV had the lowest shrinkage and the highest drying rate, shell splitting (70% more than Method I), bulk density and kernel density in comparison with other Methods. Whereas the pistachio's color properties (a, b and L), changed significantly when dried with Methods of I, II and III, the “L”, and “a” values of pistachio dried with Method IV had no significant difference with those dried with Method I (having the best color properties). The pistachio dried with Method IV (had the best sweetness and roasting flavor) in comparison with those dried with other methods because of higher drying rate.

Investigation Into Shelf Life of Fresh Dates and Pistachios in a Package Modified With Nano-Silver.

Aims:The aim of this study was to apply polymer films containing silver nanoparticles as a new method for increasing the shelf life and preserving the quality of export/commercial products of Kerman Province and determine the ideal temperature for preserving these products.Methods:After preparing nano-composite films containing silver nanoparticles (3% and 5% by weight), Mazafati dates were packed in them and stored with their control samples under four temperatures. In the second series, the films were filled with fresh pistachios and stored at four temperatures. In date samples, after 2, 7, 21 and 53 days of storing the samples were examined under the certified test of Iran Institute of Industrial Standard for Dates, which includes pH, TSS, acidity and reducing sugars tests. In pistachio samples the color values and market-friendly quality were evaluated after 1, 2, 3, 6, 7 and 8 days of storage.Results:In date samples, the pH value decreased with increasing acidity in 3 and 5 wt% of nano-silver and their control samples. In addition, in 5 wt% samples the acidity was higher than that in 3% samples, with pH being lower in the controls at almost all the intervals. Furthermore, pH values in 5% samples were higher in comparison with 3 wt% samples and controls. The amount of reducing sugars in the control samples was lower than those in 3 and 5 wt% samples. In relation to pistachio samples, the damage over time was greater in sample stored under higher temperatures.Conclusion:The maximum shelf life of the dates packaged in 5 wt% of silver nano-powder was 53 days and the best temperature to store samples was determined at 4°C. Packages containing nano-silver increased shelf life of fresh pistachios, with the best temperatures being 25°C and 0°C.

Polyphenols of Pistachio (Pistacia vera L.) Oil Samples and Geographical Differentiation by Principal Component Analysis

AbstractThe phenolic compounds of Italian and Turkish pistachio oil samples were investigated by gas chromatography–mass spectrometry (GC–MS) with the aim of identifying substances also present in very low concentration; 21 compounds were identified by means of the mass spectra of the trimethylsilyl (TMS) derivatives. Benzoic acid derivatives (protocatechuic acid, gallic acid, 4‐hydroxybenzoic acid) were the main components; 14 polyphenols were detected in pistachios for the first time. The concentrations of the compounds found were in the range 0.02–5.64 μg/g of fresh pistachio. No appreciable qualitative differences were found between samples of different origin; a multivariate approach was successfully tried to differentiate the samples according to their geographical origin, using Principal Component Analysis (PCA). Finally, Canonical Discriminant Analysis (CDA) was further conducted to classify different pistachio samples.