• Feasibility Study on the Use of Visible–Near-Infrared Spectroscopy for the Screening of Individual and Total Glucosinolate Contents in Broccoli

      Hernandez-Hierro, Jose Miguel; Valverde, Juan; Villacreces, Salvador; Reilly, Kim; Gaffney, Michael; Gonzalez-Miret, Maria Lourdes; Heredia, Francisco J.; Downey, Gerard; Spanish MICINN; Junta de Andalucia; et al. (American Chemical Society, 11/07/2012)
      The potential of visible–near-infrared spectroscopy to determine selected individual and total glucosinolates in broccoli has been evaluated. Modified partial least-squares regression was used to develop quantitative models to predict glucosinolate contents. Both the whole spectrum and different spectral regions were separately evaluated to develop the quantitative models; in all cases the best results were obtained using the near-infrared zone between 2000 and 2498 nm. These models have been externally validated for the screening of glucoraphanin, glucobrassicin, 4-methoxyglucobrassicin, neoglucobrassicin, and total glucosinolates contents. In addition, discriminant partial least-squares was used to distinguish between two possible broccoli cultivars and showed a high degree of accuracy. In the case of the qualitative analysis, best results were obtained using the whole spectrum (i.e., 400–2498 nm) with a correct classification rate of 100% in external validation being obtained.
    • Preliminary study on the use of near infrared hyperspectral imaging for quantitation and localisation of total glucosinolates in freeze-dried broccoli

      Hernandez-Hierro, Jose Miguel; Esquerre, Carlos; Valverde, Juan; Villacreces, Salvador; Reilly, Kim; Gaffney, Michael; Gonzalez-Miret, Maria Lourdes; Heredia, Francisco J.; O'Donnell, Colm P.; Downey, Gerard; et al. (Elsevier, 15/11/2013)
      The use of hyperspectral imaging to (a) quantify and (b) localise total glucosinolates in florets of a single broccoli species has been examined. Two different spectral regions (vis–NIR and NIR), a number of spectral pre-treatments and different mask development strategies were studied to develop the quantitative models. These models were then applied to freeze-dried slices of broccoli to identify regions within individual florets which were rich in glucosinolates. The procedure demonstrates potential for the quantitative screening and localisation of total glucosinolates in broccoli using the 950–1650 nm wavelength range. These compounds were mainly located in the external part of florets.
    • Variation in bioactive content in broccoli (Brassica oleracea var. italica) grown under conventional and organic production systems

      Valverde, Juan; Reilly, Kim; Villacreces, Salvador; Gaffney, Michael; Grant, Jim; Brunton, Nigel; Department of Agriculture, Food and the Marine, Ireland; 06/NITAFRC6 (Wiley on behalf of Society of Chemical Industry, 30/07/2014)
      BACKGROUND Broccoli and other cruciferous vegetables contain a number of bioactive compounds, in particular glucosinolates and polyphenols, which are proposed to confer health benefits to the consumer. Demand for organic crops is at least partly based on a perception that organic crops may contain higher levels of bioactive compounds; however, insufficient research has been carried out to either support or refute such claims. RESULTS In this study we examined the effect of conventional, organic, and mixed cultivation practices on the content of total phenolics, total flavonoids, and total and individual glucosinolates in two varieties of broccoli grown over 2 years in a split-plot factorial systems comparison trial. Levels of total phenolics and total flavonoids showed a significant year-on-year variation but were not significantly different between organic and conventional production systems. In contrast, levels of the indolyl glucosinolates glucobrassicin and neoglucobrassicin were significantly higher (P < 0.05) under fully organic compared to fully conventional management. CONCLUSION Organic cultivation practices resulted in significantly higher levels of glucobrassicin and neoglucobrassicin in broccoli florets; however, other investigated compounds were unaffected by production practices.