Effects of Passive- and Active-Modified Atmosphere Packaging on Physio-Chemical and Quality Attributes of Fresh In-Hull Pistachios (Pistacia vera L. cv. Badami).

The effects of passive- and active-modified atmosphere packaging (passive- and active-MAP) were investigated on the physio-chemical and quality attributes of fresh in-hull pistachios stored at 4 ± 1 °C and 90 ± 5% R.H. Fresh pistachios were packaged under each of the following gas combinations: active-MAP1 (AMA1) (5% O₂ + 5% CO₂), AMA2 (5% O₂ + 25% CO₂), AMA3 (5% O₂ + 45% CO₂), AMA4 (2.5% O₂ + 5% CO₂), AMA5 (2.5% O₂ + 25% CO₂), and AMA6 (2.5% O₂ + 45% CO₂), all balanced with N₂, as well as passive-MAP (PMA) with ambient air (21% O₂ + 0.03% CO₂ + 78% N₂). Changes in quality parameters were evaluated after 0, 15, 30 and 45 days of storage. Results demonstrated that AMA6 and PMA had significantly lower (7.96 Log CFU g^-1) and higher (9.81 Log CFU g^-1) aerobic mesophilic bacteria counts than the other treatments. However, the AMA6 treatment decreased, kernel chlorophyll and carotenoid content, hull antioxidant capacity, and anthocyanin content. The PMA treatment produced a significant weight loss, 0.18%, relative to the other treatments. The active-MAP treatments were more effective than the passive-MAP in decreasing weight loss, microbial counts, kernel total chlorophyll (Kernel TCL), and kernel carotenoid content (Kernel CAC). The postharvest quality of fresh in-hull pistachios was maintained best by the AMA3 (5% O₂ + 45% CO₂ + 50% N₂) treatment.