evaluation and comparison of three types of pistachio hullers used in kerman province

the objective of this study was to evaluate different pistachio hullers and determine the proper harvest time of pistachio nuts for hulling. three pistachio hulling machines (helical drum, helical- blade drum, rubber drum) at three harvest times and 15 days interval were evaluated. the hulling efficiency, percentage of damaged nuts, faulty hulled nuts and unhulled nuts were measured at each time interval. a factorial experiment was carried out using a randomized complete block design with three replicates. data were compared using analyses of variance and employing duncan's multiple range test. the results showed that the interaction effect of hulling machine type and harvesting time on the hulling efficiency and nut damage in the outlet of hull and nut was significant at the five percent level (p<0.05) and on the faulty hulled and non-hulled nuts was also significant at the one percent level (p<0.01). the rubber drum machine had the most hulling efficiency (90.81%) at the end of harvest season. this machine also produced the least percentage of damaged nuts in the outlet of hull and nut at all three harvest times. the least percentage of damage in the outlet of hull (0.47%) and nut (0.23%) was observed for the rubber drum machine at the middle of harvest time. the helical drum machine produced the most damage for hull (3.86%) and nut (2.75%) at the beginning of harvest season. the least percentage of non-hulled nuts (2.5%) was obtained from the helical-blade drum machine at the end of harvest season.