COLOR CHANGES IN BRUISED APPLE FRUIT TISSUE

A study of changes with time in aspects of bruise colour in 'Granny Sm ith' apples (Malus domestica) was undertaken in an attempt to identify the optimum time for assessment of bruise severity in experiments on apples. Bruised cortical tissue became darker (decreased lightness), b rowner (decreased hue angle), and increased in colour intensity (incre ased chroma) in the first few hours following impact. Discoloration su bsequently faded gradually with time. Bruises became further discolour ed with delays between sectioning and measurement, even when bruising had occurred 48 h before hand. Colour data on bruises should therefore be collected at a standard time interval after cutting them open. Moi sture and dry matter began to migrate out of bruises within 1 h of imp act, providing a mechanism for ''bruise recovery'' in which bruises ar e observed to fade and develop a dry appearance with time. To assess b ruises at their most intense degree of discoloration, they should be a llowed to develop for a period of 4-14 h before sectioning.