Maintaining Quality of Bulk-handled, Unhulled Pistachio Nuts
Laboratory studies revealed that staining of pistachio nut shells increases with increasing temperature and increasing holding times. Unhulled pistachio nuts varied in their susceptibly to staining. Some nuts can be held for more than 32 h at 40°C without increases in shell staining, others are damaged after only 16 h. In solid-sided bulk trailers unhulled pistachio nuts were shipped to the processor with no average increase in shell staining. Nuts can cool in highway transport, particularly if they are shipped in pallet bins, mesh-sided trailers, or solid sided trailers with vent pipes. Highway transport can be a method of cooling nuts if processing equipment breakdowns cause hulling delays.