Quality parameters in convective dehydrated carrots blanched by ultrasound and conventional treatment

The effect of previous ultrasound and conventional blanching treatments on drying and quality parameters (2-furoylmethyl-amino acids -as indicators of lysine and arginine participation in the Maillard reaction-, carbohydrates, total polyphenols, protein profile, rehydration ratio, microstructure changes) of convective dehydrated carrots has been assessed. The most striking feature was the influence of blanching on the subsequent 2-furoylmethyl-amino acid formation during drying, probably due to changes in the protein structure. The highest values of 2-furoylmethyl-amino acids were found in carrots conventionally blanched with water at 95 °C for 5 min. However, samples previously treated by ultrasound presented intermediate values of 2-furoylmethyl-amino acids and carbohydrates as compared to the conventionally blanched samples. Dried carrots previously subjected to ultrasound blanching preserved their total polyphenol content and showed rehydration properties, which were even better than those of the freeze-dried control sample. The results obtained here underline the usefulness of 2-furoylmethyl-amino acids as indicators of the damage suffered by carrots during their blanching and subsequent drying.

This work has been funded by Ministry of Science and Innovation of Spain (project AGL2007-63462), Fun-c-Food CSD2007-00063 Consolider-INGENIO 2010 and CYTED IBEROFUN (P109AC0302). J.G.S. also thanks CSIC and the EU for a predoctoral JAE grant. A.C.S. thanks the Spanish Ministry of Economy and Competitiveness for a Ramón y Cajal contract.

Peer Reviewed