COMPARISON OF THE QUALITY OF HAZELNUTS UNSHELLED WITH DIFFERENT SIZING AND CRACKING SYSTEMS

The quality of hazelnuts, sized and cracked by different systems was c ompared in a commercial processing plant by determining the percentage s of nuts that were damaged, broken, left-in the-shell, cracked, unbro ken, recyclable, or undamaged. Hazelnuts larger than 16 mm diameter ha d different cracking behaviour, as compared with smaller ones. In expe riments with a traditional Turkish cylindrical sizer and stone cracker combination, 3.3% (standard error 2.7%) damaged nuts were produced wh en the diameter of the nuts were larger than 16 mm, and 15.9% (7.5%) d amaged nuts were produced when the diameter of the nuts was less than 16 mm. The average of the damaged nuts was around 16% with all the con ical cracker combinations. Hidden-damage (apparently good appearance f rom the outside, but darker colour and oily appearance inside) was 38% (4.0%) for the cylindrical sizer/stone cracker combinations, and 41.7 % (5.8%) for the cylinder sizer and conical cracker equipped with a bi g head template combination. Quality control charts (p-charts) for dam aged and recyclable nuts were constructed for the hazelnuts from the s tone cracker for two diameter ranges. (C) 1997 Silsoe Research Institu te.