Optimization of Fresh Storage of Pistachio (Pistacia vera L.) by Use of Different Coatings Under Vacuum

The aim of this research was to extend the freshness of pistachio (<i>Pistacia vera</i> L.) by using edible coatings during cold storage. Different coatings-chitosan with potassium sorbate, alginate with propionic acid, and zein with EDTA-were used for both in-hull and dehulled pistachios. Effects of coatings on <i>Aspergillus flavus</i> count, peroxide, free fatty acids (FFA), water activity, and aflatoxin levels were investigated. Principal component analysis (PCA), correlation analysis, and multi-objective optimization were applied to interpret the data. The used coatings and pistachio hulls were effective in slowing down the formation of FFA and peroxides (<i>p</i> < 0.05). Zein and chitosan coatings prevented <i>Aspergillus flavus</i> growth up to 5 months while the alginate coating provided superior sensory preservation. PCA revealed that pistachio hulls decreased the aflatoxin, FFA, and peroxide formation, and the hulls of the pistachios showed a protective effect. Also, sensory parameters had negative correlations with FFA and peroxide value. From the optimization study, the best way to increase the freshness of pistachio is through the use of an alginate coating for in-hull. This study showed that alginate and chitosan coatings combined with ozone treatment and vacuum packaging can be used to prolong the freshness of pistachio.