Firmness of Mandarin at Different Picking Dates

Abstract

The objective of this work was to characterise the firmness of ‘Satsuma’ mandarin fruit ( Citrus reticulate) at different picking dates. The firmness of mandarin was monitored using non-destructive impulse response (I-R) and traditional compression test. The dominant frequency (f), stiffness coefficient (SC) and elasticity coefficient (EC) as a function of picking date were expressed. The mandarin at different picking dates is characterised for a decrease in the f, SC and EC. The higher f, SC and EC corresponded to the firmer mandarin. A good correlation was established between the impulse response parameters (SC and EC) and compression force (CF) and determination coefficients were 0.89 and 0.90, respectively. The low correlation was found between SC (or EC) and sugar content (or pH). SC and EC were better firmness prediction, and the results implied that these two parameters could be used to distinguish different picking dates and firmness.