Optical methods for quality evaluation of fruits (part 3)-relationships between optical density, slopes of the optical density distribution of fruits and fruit firmness

摘要

A light transmittance measurement system consisting of a 783nm low power laser was examined to determine the optical density and slope of the distribution of optical density in cylindrical flesh samples of apple and Japanese pears. Furthermore,the relationships between these optical properties and the firmness of samples were examined. There were relationships (r >0.80) between the optical density and the firmness of fruits. The relationships between the slope and fruit firmness were very poor(r<0.53), except for Raritan apple (r=0.80). Changes in optical density and firmness were probably due to the ultra structural changes in the cell wall and in the middle lamella of fruit tissue.