• 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.
    • Potential of cultivar and crop management to affect phytochemical content in winter-grown sprouting broccoli (Brassica oleracea L. var. italica)

      Reilly, Kim; Valverde, Juan; Finn, Leo; Rai, Dilip K.; Brunton, Nigel; Sorenson, Jens C; Sorenson, Hilmer; Gaffney, Michael; Department of Agriculture, Food and the Marine, Ireland; 06/NITAFRC6 (Wiley, 08/07/2013)
      BACKGROUND: Variety and crop management strategies affect the content of bioactive compounds (phenolics, flavonoids and glucosinolates) in green broccoli (calabrese) types, which are cultivated during summer and autumn in temperate European climates. Sprouting broccoli types are morphologically distinct and are grown over the winter season and harvested until early spring. Thus they show considerable potential for development as an import substitution crop for growers and consumers during the ‘hungry gap’ of early spring. The present study investigated the effect of variety and management practices on phytochemical content in a range of sprouting broccoli varieties. RESULTS: Yields were significantly higher in white sprouting broccoli varieties. Levels of phenolics and flavonoids were in the range 81.6-270.4 and 16.9–104.8 mg 100g -1 FW respectively depending on year and cultivar, and were highest in varieties TZ 5052, TZ 5055, Red Admiral and Improved White Sprouting. In-row spacing did not affect flavonoid content. Phenolic and flavonoid content generally increased with increasing floret maturity and levels were high in edible portions of the crop. Crop wastes (leaf and flower) contained 145.9-239.3 and 21.5–116.6 mg 100g -1 FW total phenolics and flavonoids respectively depending on cultivar, tissue and year. Climatic factors had a significant effect on phenolic and flavonoid content. Levels of total and some individual glucosinolates were higher in sprouting broccoli than in the green broccoli variety Ironman. CONCLUSION: Levels of total phenolics, flavonoids and glucosinolates are higher in sprouting than green broccoli types. Sprouting broccoli represents an excellent source of dietary bioactive compounds.
    • 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.