Effect of Various Freezing and Thawing Methods on Physicochemical Characterization of Carrot

This study investigated the combination effects of various freezing and thawing methods on the quality attributes of frozen carrot. Carrot samples were frozen by either individual air blast freezing (ABF, -45C), liquid nitrogen freezing (LNF, -80C) or natural freezing (NF, -24C). Frozen carrots were thawed until the center temperature reached 4C using natural air convection thawing (NT), flowing thawing (FT), sonification thawing (ST), or microwave thawing (MT). Changes in the quality of freezing and thawing combination were determined. In LNF, MT showed the most rapid thawing time (9.4 min) followed by ST (73 min), FT (87 min), and NT (84 min). LNF showed minimal thawing loss compared to those of ABF and NF (p<0.05). Hardness and water-holding capacity were decreased after all the tested combinations of freezing and thawing methods as compared to the control (blanched carrot). The highest thawing loss was observed at all the thawing combinations with NF. In the textural qualities, LNF-FT combination showed the best retention of hardness. In our study, LNF resulted in better quality attributes when it was combined with each thawing method compared to those of ABF and NF.