MICROSCOPIC OBSERVATION OF MEALINESS IN APPLES - A QUANTITATIVE APPROACH

Mealiness is a quality characteristic that is used to describe fruit w hich is soft and which causes a dry feeling in the mouth during mastic ation. The purpose of this work was to visualise the difference betwee n fresh and mealy apples and to quantify those differences. Three comm ercially important Belgian apple cultivars, 'Jonagold', 'Cox's Orange Pippin' and 'Boskoop' apples (Malus domestica Borkh.) were used in the experiments. Mealy apples were produced by holding apples at 20 degre es C and 95% RH for periods of time depending on the cultivar and the required mealiness level. Images were made with a light microscope. Ce ll parameters such as area and perimeter, and two roundness parameters were measured. 'Cox's Orange Pippin' and 'Boskoop' apples could be se parated into the two groups: fresh and mealy, using the four calculate d cell parameters. The number of broken and intact cells at the ruptur e surface of a fractured tissue sample after tensile loading was also calculated. After one week's storage of fruit in mealiness-inducing co nditions, the amount of broken cells at the surface of a fractured sam ple was significantly lower than in fresh apples. (C) 1998 Elsevier Sc ience B.V. All rights reserved.