Accelerated aging in chia nutlets (Salvia hispanica l.) for the evaluation of deterioration by ATR-FTIR and DSC

Abstract

Seed deterioration is assessed by germination and vigor tests, which require a certainsample amount and operating times. Differential scanning calorimetry (DSC) andinfrared spectroscopy (FTIR) are interesting tools for this study type because they donot require too much sample, are non-destructive, and consume little experimentaltime. It’s necessary to find correlations between conventional and biophysical methodsto apply these biophysical tools for germplasm monitoring. This study deals withthe physiological and biophysical characteristics of two chia varieties (WN and MN).The nutlets were aged for 56 d at 99% of relative humidity, and 41 °C, monitoringevery 7 d. The germination test was conducted at 25 °C, 12 h light and 4 repetitionsof 25 nutlets. The number of germinated nutlets (GN) and the mean germinationtime (MGT) were determined. Spectral images were analyzed by ATR-FTIR and thethermal behavior was studied by DSC at t=0 and t=56 d. After 47 d, GN decreasedsignificantly from 100 to 57 and from 98 to 3, and TMG increased significantly from1.01 to 2.44 d and from 1.03 to 3 d for WN and MN, respectively. PCA separatedtreatments into two clusters. The 92% and 88% of the variance were explained bytwo components for WN and MN, respectively. The fusion enthalpy increased from15.86 to 18.87 and from 17.54 to 19.06 J/g for WN and MN, respectively, negativelycorrelating with GN and positively with TMG. Unconventional techniques for the rapidstudy of physiological quality are promising.