# Cyamopsis tetragonoloba Gum‐Based Active Coatings Incorporated With Pycnocycla bashagardiana Essential Oil for Reducing Postharvest Losses of Fresh Pistachio Fruits

## TL;DR

This study explores using guar gum coatings with essential oil to extend the shelf life of fresh pistachios by reducing fungal contamination and preserving quality.

## Contribution

The novel contribution is the development of a guar gum-based active coating with Pycnocycla bashagardiana essential oil to extend pistachio storage life.

## Key findings

- PBEO-loaded guar coatings significantly enhanced phenolic content and antioxidant capacity of pistachios.
- Coatings reduced weight loss, peroxide value, and fungal growth, extending shelf life to 60 days.
- GC/MS analysis identified key components of PBEO, including E-beta-ocimene and oleic acid.

## Abstract

Fresh pistachios, prized for their distinct flavor and aroma, suffer from limited postharvest shelf life due to fungal contamination, particularly aflatoxin‐producing species. This study investigates the efficacy of guar coatings (0.25%, 0.5%, and 1%), incorporating Pycnocycla bashagardiana essential oil (PBEO) with varying concentrations (50, 100, and 200 μL), in extending the storage life of fresh pistachios over 60 days. The physicochemical properties of the coating solutions (zeta potential (ζ), particle size (PD) and contact angle (CA)) were characterized, alongside pistachio quality attributes including weight loss, peroxide value (PV), phenolic content (PC), titratable acidity (TA), texture firmness, antioxidant capacity, and total soluble solids (TSS). Antifungal activity against Aspergillus and Penicillium was also assessed. GC/MS and GC‐FID analysis identified E‐beta‐(ocimene), Myristicin, Z‐beta (‐ocimene), and oleic acid as major components and fatty acids profile of PBEO and guar gum, respectively. The FTIR spectrum of guar gum reveals the presence of key functional groups within the polysaccharide structure. Increasing the concentration of PBEO in the solution preparation led to a significant increase in PSD, ζ, and CA magnitude. Results indicate that PBEO‐loaded guar coatings significantly enhanced PC and antioxidant capacity, reduced weight loss and PV, maintained TSS and firmness, and retarded loss of TA. 200 μL PBEO‐loaded guar at 0.25% effectively inhibited Penicillium growth, while 50 μL demonstrated optimal control of both Aspergillus and Penicillium. The PBEO‐loaded guar coating extended pistachio shelf life from 30 to 60 days based on microbial counts.

Treated pistachio retained phenolics and total antioxidant capacity. The guar gum‐PBEO coating had the best antifungal effects on Penicillium and Aspergillus growth. The guar gum, along with PBEO, elevates the storage period of fresh pistachio up to 60 days.