Effect of Drying Methods on Quality of Pistachio Nuts

Abstract

The effect of various methods of drying (sun drying, bin drying, vertical continuous drying, vertical cylindrical drying, and funnel cylindrical drying) on moisture content, lipid quality (peroxide value, thiobarbituric acid value, and free fatty acids), sensory attributes (firmness, sweetness, rancidity, roasted flavor, split shell, shell appearance, and overall palatability), and percent split shell of pistachio nuts (Pistacia vera L.) were studied. Sun drying and bin drying resulted in higher split shell percent on pistachio nuts than other drying methods. The different drying methods used in this study did not have any significant influence on the free fatty acids, peroxide value, and thiobarbituric acid of lipids in pistachio nuts. Drying significantly affected shell appearance and split shell. Overall, the bin drying method produced pistachio nuts with the best quality.

Keywords:

• Bin dryer
• Commercial pistachio drying
• Composition
• Cylindrical dryer
• Firmness
• Free fatty acids
• Funnel dryer
• Hedonic scale
• Lipid quality
• Peroxide value
• Sensory attributes
• Split shell
• Sun drying

Acknowledgments

The authors gratefully acknowledge the Rafsanjan Pistachio Research Institute and Rafsanjan Pistachio Producers' Cooperative (RPPC) of Rafsanjan, Iran for providing the pistachio samples and facilities. Many thanks to Mr. M. Nikkho who assisted the research.