Analysis of total glucosinolate content and individual glucosinolates in Brassica spp. by near‐infrared reflectance spectroscopy

Abstract

This study was conducted to test the applicability of near-infrared reflectance spectroscopy (NIRS) for estimating the total glucosinolate (GSL) content in samples of intact seed from a wide range of Brassica species, and to develop calibration equations to estimate simultaneously the percentage of individual GSLs. A total of 290 samples from 15 different Brassica species were scanned by NIRS and analysed for glucosinolate content by high-pressure liquid chromatography (HPLC). A calibration equation for total GSL content was developed using 270 samples of 14 species in a range between 6 and 193 /imol/g seed, resulting in an r^ of 0.99 in calibration and cross-validation, and 0.95 in independent validation with 20 samples of Brassica rapa, a species not represented in the calibration. Furthermore, calibration equations to estimate the relative amount (mol/mol) of progoitrin, sinigrin, and gluconapin were successfully developed (r^ > 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.Key words: Brassica spp. -individual glucosinolates -nearinfrared reflectance spectroscopy -NIRS -total glucosinolate content Breeding for low glucosinolate (GSL) content in Brassica oilseeds has been the subject of intensive research during recent decades because of the toxic and antinutritive effects of these compounds (Downey and Robbelen 1989). Success in this field was facihtated considerably by the development of rapid and accurate methods which permit large screenings to be made in a short time and at a low cost (Thies 1982). These methods were designed to estimate the total GSL content, and do not provide simultaneous information on the GSL profile (Sorensen 1985). The development of near-infrared reflectance spectroscopy (NIRS) calibrations to estimate the total GSL content in intact seeds represented a further advance, since it could be estimated in parallel with the analysis of other traits such as oil and protein content (Renard et al. 1987).NIRS calibrations for the analysis of total GSL content have been developed for Brassica napus and Brassica rapa (Renard et al. 1987, Daun et al. 1994, Brassica carinata (Velasco et al. 1995), and Brassica juncea (A. De Haro, personal communication) because breeding for low GSL content has focused mainly on these species. The use of this technique for the analysis of other Brassica species is now of great interest because of new research lines developed in recent years which involve alternative uses for glucosinolates, such as application in pest and disease control (Mithen 1992) or characterization as substances with anticancer activity (Giamoustaris and Mithen 1996). This will demand rapid analysis of GSLs in a wide range of Brassica species and it would be a very helpful analytical tool in interspecific breeding. The analysis of total GSL content in several Brassica species could be made possible by devel...

Non-destructive analysis of rapeseed quality by NIRS of small seed samples and single seeds

“…Hence, the correct estimation of the glucosinolate content of single seeds requires the development of specific calibration equations. The coefficient of determination in cross validation of the single seed glucosinolate calibration developed in the present study was excellent (R 2 = 0.96) and compares well to the single seed results (R 2 = 0.98) of Velasco et al (1999b), but also to calibrations for 300 mg seed samples with R 2 = 0.99 reported by Velasco and Becker (1998a). The relatively large SECV of 10.04 and a SD/SECV ratio of 2.7 indicates that this calibration equation can, however, only be applied successfully when there is a large variation among single seeds.…”

“…For the aromatic glucosinolate gluconasturtiin the calibration statistic was not convincing. This can be explained by the limited range found in the present sample collection and the generally very Velasco and Becker (1998a) and by Font et al (1999). In summary, the results of the present work show that NIRS calibrations equations developed for standard seed sample sizes of 3-4 g can be used to reliably predict the oil, protein, and glucosinolate content of smaller seed sample ranging from 450 to 100 mg. With some limitations the oil and protein content of single seeds can also be estimated.…”

Fruits and Vegetables

“…Applying NIR refl ectance spectroscopy, a number of species belonging to the Brassicaceae family have been analyzed for their total glucosinolates content ( Salgo et al , 1992 ;Velasco and Becker, 1998 ). Recently, even the individual glucosinolates occurring in Brassica juncea (sinigrin), Raphanus sativus (glucoerysolin, glucobrassicin, glucoraphenin), and Brassica oleracea (glucobrassicin, sinigrin) have been successfully predicted using reliable NIR correlation equations ( Quilitzsch et al , 2005b ).…”

Development and characterisation of a Brassica carinata inbred line incorporating genes for low glucosinolate content from B. juncea

“…The different evaluations for seed glucosinolate content of selected BC 1 F 4 derived lines were conducted using the Pd-GSL complex method. Additionally, seeds of the parents and the best selected BC 1 F 4 derived line from the field evaluation of 2004/ 05 were analysed for glucosinolate content and profile by high performance liquid chromatography (HPLC) as described by Velasco and Becker (1998).…”