ACCURATE DETECTION OF FIRMNESS AND COLOR CHANGES IN THE PACKING OF TABLE GRAPES WITH PAPER DIVIDERS

Accurate measurement of colour and firmness of grape berries was done during storage under simulated shelf life conditions (18-degrees-C, 60 % r.h.). Darkening of their yellow colour was expressed by the rapid i ncrease in total colour difference (DELTA E) following the rise of wei ght loss. Hue and chroma (brightness) slightly decreased during the th ree days of shelf life. Changes in colour were closely related to the weight loss and within 40 h the limit of marketability (1.2%) was surp assed. Weight loss affected berry firmness more than colour and the us e of cushioning paper dividers in the box controlled the percentage of damaged berries but diminished their firmness. Water stress was the m ain cause of this quality decline, therefore use of cushioning or othe r packing materials with high absorbing surface has to be considered c arefully.