Determination of glucosinolates in broccoli (Brassica oleracea var. italica) by combining mid-infrared (MIR) spectroscopy with chemometrics

Glucosinolates (GSLs), compounds with potential chemo-preventative properties, can be affected by pre and post-harvest processes. Therefore, monitoring their content is important for the food and agricultural industries. This study evaluates the application of mid-infrared (MIR) spectroscopy for the determination of GSLs in commercial broccoli (Brassica oleracea var. italica). Broccoli (n = 53) from different varieties were analysed using MIR spectroscopy and high-performance liquid chromatography to develop partial least squares models for six individual GLSs, total indolic glucosinolates and total GSLs. The coefficient of determination in cross-validation (R-cv(2)) of 0.50-0.78 whereas residual predictive deviation (RPD) values of 1.35-2.19 for different GSLs. Cross-validation models developed using Tenderstem (R) broccoli yielded an R-cv(2) of 0.41-0.91 and an RPD of 0.81-2.97. This study showed that MIR spectroscopy can be considered for the determination of some broccoli GSLs. Differences in the loadings between the models demonstrated that variations in broccoli composition can influence the cross-validation models for GSLs.