Physical and sensory changes in pistachio nuts as affected by roasting temperature and storage

Abstract: The effect of roasting temperature and storage period on the moisture, texture and sensory attributes of pistachio nuts were investigated. Pistachio nuts were salted and roasted with conventional method at 90, 120 and 150°C for 30 min. The changes of moisture, textural properties including hardness, fracture force and firmness as a sensory attribute of salted roasted pistachio nuts were determined during 3 months of storage. In order to analyze results, Pearson correlation method, response surface methodology (RSM) and least mean square regression were used. The textural properties were correlated with sensory attributes, RSM was used to predict the effects of roasting temperature and storage on textural properties and the first-order model was used to describe textural changes at different roasting temperatures during storage period. Firmness as well as hardness and fracture force increased with the storage time. Furthermore, during the storage period, the moisture content of roasted pistachio nuts increased. Using high roasting temperature led to less firmness, moisture content, hardness and fracture force were significantly decreased. The results indicated that the correlation between instrumental and sensory properties was highly significant. Key words: Pistachio nuts Roasting Storage Moisture content Textural and sensory attributes INTRODUCTION Drying is one of the processes occurring during Pistachio nuts are the most important agricultural during roasting [3, 6, 7]. In spite of low initial moistur