The effects of moisture content and type of cultivars on physical properties of pistachio nuts

Background: Characterization of the gravimetric and geometric properties of whole pistachios plays an essential role in the processes of transportation and handling, drying, processing, and storage of this valuable product. Material and methods: This study measured some physical properties (i.e. axial dimensions, geometric and arithmetic mean diameter, aspect ratio, surface, and sphericity) and gravimetrical properties (i.e. bulk density, true density, and porosity) of two common Iranian pistachio cultivars (Ahmad Aghaei and Badami Sefid) with moisture content ranging from 37.11 to 4.28 and 4.33 to 41.35, respectively. Results: The ANOVA results showed that moisture content had a significant effect (p<0.05) on the geometrical properties of whole pistachios. Moreover, mean comparisons by Duncan's multiple range test showed that the gravimetrical and geometrical properties of Ahmad Aghaei pistachio cultivar have higher scores than those of the Badami Sefid cultivar. In addition, a comparison of the various models (Mohsenin, Jain & Bal and Maccabe) used to evaluate the sphericity coefficients showed that the models proposed by McCabe and Jain & Bal had the highest efficiency in predicting the sphericity coefficients of Ahmad Aghaei (R2=0.9838) and Badami Sefid cultivars (R2=0.878). Conclusion: The findings of the present study can have some implications for design processing machines for pistachios as a valuable product.