The influence of raw material on the quality of dried mango slices (Mangifera indica L.) with special reference to postharvest ripening

The general objectives of this study were to utilize the NIR to determine postharvest ripening stages of mangoes without destroying the fruit and to optimise fruit ripeness with special reference to the ripening requirement for producing non-sulfitized dried mango slices. To accomplish these objectives, the research work was divided into the following sections: i) Evaluation of cultivar specific ripening behaviour ii) Deduction of ripening index (RPI) iii) Non-destructive determination of mango fruit ripeness by NIR using the developed calibration and prediction model between spectra and physiological parameters including RPI iv) Investigation of the impact of established postharvest ripening procedures on fruit quality v) Definition of the full fruit maturity stage vi) Investigation of the optimum ripeness for the production of dried mango slices. The postharvest ripening process of the most important cultivars was monitored by analysing weight loss, fruit firmness, pulp acidity, TSS and sugar-acid ratio according to standard procedures. A mathematical model was applied to generate a function of firmness, TSS, TA and TSS/TA with ripening time. RPI combining each kinetic was thus derived. Simultaneously, the NIR spectrum was measured using FT-NIR spectrometry. A calibration and validation model between NIR spectra and quality parameters including newly developed RPI was established. The experiments were carried out using various mango fruit lots from two harvesting years. They were aimed at evaluating the possibility to create a general calibration model which is not available so far. The results should contribute to the improvement of the fruits homogeneity in terms of maturity. This would ultimately increase the quality standard of exported fruits. In addition, a more rapid and better selection of raw materials for processing can be expected.