ANALYSIS OF TOTAL GLUCOSINOLATE CONTENT AND INDIVIDUAL GLUCOSINOLATESIN BRASSICA SPP. BY NEAR-INFRARED REFLECTANCE SPECTROSCOPY

This study was conducted to lest the applicability of near-infrared re flectance spectroscopy (NIRS) for estimating the total glucosinolate ( GSL) content in samples of intact seed from a wide range of Brassica s pecies, and to develop calibration equations to estimate simultaneousl y the percentage of individual GSLs. A total of 290 samples from 15 di fferent Brassica species were scanned by NIRS and analysed for glucosi nolate content by high-pressure liquid chromatography (HPLC). A calibr ation equation for total GSL content was developed using 270 samples o f 14 species in a range between 6 and 193 mu mol/g seed, resulting in an r(2) of 0.99 in calibration and cross-validation, and 0.95 in indep endent validation with 20 samples of Brassica rapa, a species not repr esented in the calibration. Furthermore, calibration equations to esti mate the relative amount (mol/mol) of progoitrin, sinigrin, and glucon apin were successfully developed (r(2) > 0.85 in cross-validation) and validated with samples from species not included in the calibration. It was also possible to discriminate between entries with high and low values of glucoiberin, 4-hydroxyglucobrassicin and glucoerucin.