Determinação de parâmetros (sólidos solúveis, pH e acidez titulável) em ameixas intactas usando espectroscopia no infravermelho próximo e seleção de comprimento deonda

摘要

The aim of this study was to evaluate the potential of near-infrared reflectancespectroscopy (NIRS) as a rapid and non-destructive method to determine the solublesolid content (SSC), pH and titratable acidity of intact plums. Samples of plum with atotal solids content ranging from 5.7 to 15%, pH from 2.72 to 3.84 and titratable acidityfrom 0.88 a 3.6% were collected from supermarkets in Natal-Brazil, and NIR spectrawere acquired in the 714 2500 nm range. A comparison of several multivariatecalibration techniques with respect to several pre-processing data and variable selectionalgorithms, such as interval Partial Least Squares (iPLS), genetic algorithm (GA),successive projections algorithm (SPA) and ordered predictors selection (OPS), wasperformed. Validation models for SSC, pH and titratable acidity had a coefficient ofcorrelation (R) of 0.95 0.90 and 0.80, as well as a root mean square error of prediction(RMSEP) of 0.45ºBrix, 0.07 and 0.40%, respectively. From these results, it can beconcluded that NIR spectroscopy can be used as a non-destructive alternative formeasuring the SSC, pH and titratable acidity in plums