The effect of packaging and storage time on quality of clustered fresh pistachio.

Pistachio is one of the valuable, very nutritious, and high-energy fruits that is mainly dried and used as a snack due to problems with storage. Therefore, to investigate on how to extend clustered fresh pistachios' shelf-life, the effects of various packaging and storage conditions on the pistachios are presented in this study. Thus, clustered in-hull fresh pistachios were packaged in: (a) Polyethylene film, 45 µm in thickness; (b) polypropylene/polyethylene/polyamide/polyethylene/aluminum foil multilayer film, 90 µm in thickness; (c) both films with alcoholic paper; in air, and under two gas mixtures of 88%N2 + 10%CO2 + 2%O2 and 83%N2 + 15%CO2 + 2%O2 . Samples were refrigerated at 5 ± 1°C for 3 months. Quality factors such as moisture content, weight loss, respiration rate, pH, texture, and appearance of the samples were monitored for fresh pistachio kernels and clustered pistachios. Data were analyzed in a completely randomized design using one-way analysis of variance. The results showed that the shelf-life of MAP samples drastically increased compared to the control (packages without gaseous and alcoholic paper). A comparison of means among the groups suggests that the multilayer bags of fresh clustered pistachios with a mixture of 83%N2 + 15%CO2 + 2%O2 for a 3-month storage period is a particularly effective treatment. PRACTICAL APPLICATION: It is the first time that fresh pistachio is packaged in clusters (bundle). It seems that the packaging of fresh pistachio clusters, in addition to the benefits mentioned in this paper has a psychological effect on the consumer in terms of the naturalness of this product and has added value due to being considered an organic, luxurious, and delicacy food product. Therefore, in this study, the active MAP method that includes the technique of injecting carbon dioxide, nitrogen, and oxygen into the packaging was used to investigate its effects on the properties and shelf-life of raw clustered pistachios for fresh consumption.

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 39 days 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 39 days 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.

Development of Pistachio (Pistacia vera L.) spread.

UNLABELLED: Pistachio nut (Pistacia vera L.) is one of the most delicious and nutritious nuts in the world. Pistachio spreads were developed using pistachio paste as the main component, icing sugar, soy protein isolate (SPI), and red palm oil (RPO), at different ratios. The highest mean scores of all the sensory attributes were depicted by spreads that were made without addition of SPI. It was found that the work of shear was 0 to 11.0 kg s for an acceptable spread. Sensory spreadability, overall texture, spreadability, and overall acceptability were negatively correlated (R > 0.83) with the work of shear of spreads. The findings indicated that the presence of RPO had a direct effect on the viscoelastic behavior of the pistachio spreads. The a values, which are related to the green color of the pistachio product ranged from 1.7 to 3.9 for spread without addition of RPO, and 4.0 to 5.3 in the presence of RPO. PRACTICAL APPLICATION: The development of pistachio spread would potentially increase the food uses of pistachio and introduce consumers with a healthier snack food.

Textural, rheological and sensory properties and oxidative stability of nut spreads—a review.

Tree nuts are rich in macro and micronutrients, phytochemicals, tocopherols and phenolic compounds. The development of nut spreads would potentially increase the food uses of nuts and introduce consumers with a healthier, non-animal breakfast snack food. Nut spreads are spreadable products made from nuts that are ground into paste. Roasting and milling (particle size reduction) are two important stages for the production of nut spreads that affected the textural, rheological characteristic and overall quality of the nut spread. Textural, color, and flavor properties of nut spreads play a major role in consumer appeal, buying decisions and eventual consumption. Stability of nut spreads is influenced by its particle size. Proper combination of ingredients (nut paste, sweetener, vegetable oil and protein sources) is also required to ensure a stable nut spread product is produced. Most of the nut spreads behaved like a non-Newtonian pseudo-plastic fluid under yield stress which help the producers how to start pumping and stirring of the nut spreads. Similar to other high oil content products, nut spreads are susceptible to autoxidation. Their oxidation can be controlled by application of antioxidants, using processing techniques that minimize tocopherol and other natural antioxidant losses.

Effect of different types of plastic packaging films on the moisture and aflatoxin contents of pistachio nuts during storage.

Pistachio nut (Pistacia vera L.) is one of the popular tree nuts in the world. Proper selection of packaging materials is necessary to prevent absorption of moisture and aflatoxin formation which will influence the overall product quality and safety. This research is undertaken to study the effect of different type of flexible packaging films on the moisture and aflatoxin contents of whole pistachio nuts during storage at ambient temperature (22-28 °C) and relative humidity of 85-100%. Five types of plastic films tested were low density polyethylene (LDPE) which serves as the control, food-grade polyvinyl chloride (PVC), nylon (LDPE/PA), polyamide/polypropylene (PA/PP) and polyethylene terephthalate (PET). The moisture content and aflatoxin content of pistachio nuts were measured using oven drying method and HPLC, respectively. Sample were analysed at 0, 2, 4, 6, 8 and 10 months during the storage period. Results showed that there was an increase in moisture content with the increase in storage time of pistachio nuts. The increase in moisture content was associated with the aflatoxin level of pistachio nuts during storage time. All the packaging materials except LDPE delayed the moisture absorption and aflatoxin formation of the product. The most suitable packaging materials for maintaining the quality and safety of pistachio nuts is PET films followed by nylon, PA/PP and PVC. The shelf-life of pistachio can be extended from 2 months (Control) to 5 months when PET is used as the packaging material.