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

TL;DR

This study shows that using edible coatings like alginate and chitosan, along with vacuum packaging, can help keep pistachios fresh for longer by reducing spoilage and harmful substances.

Contribution

The study introduces a multi-objective optimization approach to determine the best edible coatings and storage conditions for extending pistachio freshness.

Findings

Edible coatings reduced free fatty acids and peroxide formation in pistachios during storage.

Zein and chitosan coatings inhibited Aspergillus flavus growth for up to 5 months.

Alginate coating provided the best sensory preservation for in-hull pistachios.

Abstract

The aim of this research was to extend the freshness of pistachio (Pistacia vera 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 Aspergillus flavus 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 (p < 0.05). Zein and chitosan coatings prevented Aspergillus flavus 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.

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