Measurement of mango firmness by non-destructive limited compression technique

Thai mango 'Nam Dok Mai Si-Thong' has an attractive golden yellow skin colour even in immature fruit, not ready for consumption. Firmness becomes an important quality attribute to assess the ripening stage of the fruit during storage. In this study, the possibility of a non-destructive method using a texture analyser for assessing the firmness behaviour during storage was investigated in three different experiments for (1) probe selection, (2) distance selection using the selected probe and (3) evaluation of the selected probe and distance on mango quality. The results revealed that an aluminium flat probe with 35 mm diameter is a suitable probe for measurement. Limited distance compression at 1 mm was selected since that combination did not leave any compression marks on the fully ripened mangoes. Evaluation of mango quality attributes obtained by this technique could be used to assess non-destructively the firmness behaviour of the mango fruit during storage. The technique can be used to monitor the firmness of mango fruit on an individual basis, using the same fruit in successive assessments. Non-linear indexed regression can be applied to extract information on the behaviour and variation of firmness of individual mangoes. Obtained explained parts (R² adj) frequently are well over 90%.