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.