Evaluation of quality attributes in Rocha pear and Gala apple with infrared spectroscopy (NIRS)

Mestrado em Engenharia Agronómica - Hortofruticultura e Viticultura - Instituto Superior de AgronomiaFirmness, soluble solids content (SSC) and dry matter (DM) were assessed in pear ‘Rocha’ and ‘Gala’ apple through the performance of calibration equations by the comparison between the values of quality attributes obtained with destructive methods and the values predicted by the spectrophotometer NIR CASE (NIRS). Measurements were done in 750 ‘Rocha’ pears and 450 ‘Gala’ apples. These fruits were from different growers, orchards, picking date, stages of maturation and storage conditions. The model for ‘Rocha’ pear gave good prediction for SSC (r2 = 0,87; SEP = 0,56 ºBrix; ME = 0,86) and excellent prediction for DM (r2 = 0,96; SEP = 0,29 %; ME = 0,94). For firmness the model wasn’t suitable (r2 = 0,16; SEP = 8,83 N; ME = -1,09). For ‘Gala’ apple the model gave good results for SSC (r2 = 0,77; SEP = 0,47 ºBrix; ME = 0,69) but for firmness the model wasn’t appropriated (r2 = 0,10; SEP = 9,97 N; ME = -3,25). The results show that NIR CASE can be used to predict SSC and DM in pear and SSC in apple. NIR CASE values for firmness do not correlate with those measured with the penetrometer