Effect of antibrowning treatment on color and firmness of fresh-cut pears

A 30-second dip in a solution of 4-hexylresorcinol, isoascorbic acid, N-acetylcysteine, and potassium sorbate prevented browning of fresh-cut 'Anjou' and 'Bartleu' pears (Pyrus communis L.) for 9 days at 5C in air, regardless of initial ripeness. Firmness of pears did,not change in response to chemical treatments or time in storage, except that pears slices initially < 25 N, quite ripe, generally became translucent and excessively soft during storage. Firmness of the 5-mm thick slices was measured by puncturing to 2.5 mm using a 4 mm diameter cylindrical probe and by a three point bending test. A puncture test was more suitable (and more convenient) than bending for measuring firmness of the slices. Color (L*, a*, and b*) and transmittance through the slices in the visible and near infrared range (400 to 1900 nm) were measured. The a* value was more sensitive to browning and less affected by ripeness and storage than transmittance at specific wavelengths or the overall absorbance in the visible range.