title: Raman spectroscopy application in frozen carrot cooked in different ways and the relationship with carotenoids.
abstract: BACKGROUND
  Raman spectroscopy, in its confocal micro-Raman variation, has been recently proposed as a spatially resolved method to identify carotenoids in various food matrices, being faster, non-destructive, and avoiding sample extraction, but no data are present in the literature concerning its application to the evaluation of carotenoid pattern changes after thermal treatment of carrots.
  
  
  RESULTS
  The effect of three cooking methods (i.e. boiling, steaming and microwaving) was evaluated on frozen carrot, comparing changes on carotenoid profiles measured by means of Raman spectroscopy with their high-performance liquid chromatographic determination and colour. A more pronounced detrimental effect on carotenoids was detected in steamed carrots, in accordance with colour data. Conversely, boiling and, to a lesser extent, microwaving caused an increase in carotenoid concentration. Cooking procedures affected the Raman spectral features of carotenoids, causing a shift of vibration frequencies towards a higher energy, increase in the spectral baseline and peak intensities as well as a broadening of their width, probably in relation to the thermal degradation of longer carotenoids (i.e. the all-trans form) and the isomerization process. In particular, steamed samples showed a significantly higher increase of centre frequency, in accordance with a more pronounced isomerization and changes in colour parameters.
  
  
  CONCLUSIONS
  This work showed that the evolution of Raman spectral parameters could provide information on carotenoid bioaccessibility for carrots cooked using various methods. This paves the way for a future use of this technique to monitor and optimize cooking processes aimed at maximizing carotenoid bioaccessibility and bioavailability.
authors.affiliation: Department of Physics and Earth Sciences, University of Parma, I-43124, Parma, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Camorani
authors.affiliation: Department of Food Science, University of Parma, I-43124, Parma, Italy.
authors.forename: Emma
authors.initials: E
authors.lastname: Chiavaro
authors.affiliation: Department of Physics and Earth Sciences, University of Parma, I-43124, Parma, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Cristofolini
authors.affiliation: Department of Food Science, University of Parma, I-43124, Parma, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Paciulli
authors.affiliation: Department of Food Science, University of Parma, I-43124, Parma, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Zaupa
authors.affiliation: Department of Agriculture and Food Science, University of Naples Federico II, I-80055, Portici, (Naples), Italy.
authors.forename: Attilio
authors.initials: A
authors.lastname: Visconti
authors.affiliation: Food Quality Design group, Wageningen University, 6700, EV, Wageningen, The Netherlands.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Fogliano
authors.affiliation: Department of Food Science, University of Parma, I-43124, Parma, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Pellegrini
mesh_terms: D001682:Biological Availability; D002338:Carotenoids / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003296:Cooking / Q000379:methods*; D018552:Daucus carota / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D008872:Microwaves; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013227:Steam; D014675:Vegetables / Q000737:chemistry*
chemical_list: D013227:Steam; D002338:Carotenoids
keywords: Raman spectroscopy; carotenoids; carrot; cooking; freezing