Scientists at the Department of Food Science and Technology of Ljubljana University (Slovenia) evaluated the influence of mechanical damage intensity (mild processing vs. severe processing) and of storage temperature (8 and 20 °C before minimally processing) on changes in glucosinolates (GLS) content in fresh-cut white cabbage. Scientists shredded white cabbage and analyzed the changes in GLS content at specific times (at 5 min, 30 min, 2 h, 12 h, and 27 h after shredding). The influence of storage temperature and the processing severity were assessed immediately after shredding and after up to one day of storage in air. The intensity of mechanical stress and the temperature significantly affected the GLS in shredded white cabbage (cv. Galaxy). Mild processing (shredding to 2mm thickness) at 8°C resulted in 40% increase in GLS compared to unshredded cabbage, which was already seen 5 min after the mechanical stress. Severe processing (shredding to 0.5mm thickness) at 20°C, however, resulted in an initial 50% decrease in GLS.
The glucosinolates accumulated in all samples 30 min after processing, resulting in higher levels than in unshredded cabbage, except for the severe processing at 20°C where the increase was not sufficient to compensate for the initial loss. Glucobrassicin and neoglucobrassicin resulted the major glucosinolates identified in the cabbage samples.
Scientists concluded that the increase in GLS content was observed within a timescale that is too short to be explained by enzyme biosynthesis at the DNA level. The relative proportions of the two major glucosinolates, neoglucobrassicin and glucobrassicin, were also changed after shredding, in favour of higher glucobrassicin levels.
The full study is available at: www.hindawi.com/journals/jchem/2015/963034/
Source: T. PoDrl, B. CigiT, L. Demšar, J. Hribar, and T. Polak, 'Mechanical stress results in immediate accumulation of glucosinolates in fresh-cut cabbage', Journal of Chemistry, Volume 2015, Article ID 963034, 7 pages.
Contacts:
T. Polak
Department of Food Science and Technology, Biotechnical Faculty, University of Ljubljana,
Jamnikarjeva 101, SI-1111 Ljubljana
Slovenia
Email: tomaz.polak@bf.uni-lj.si