Gonçalves, E.M.Pinheiro, J.Abreu, M.Brandão, Teresa R. S.Silva, C. L. M.2012-01-162012-01-162011Kinetics of quality changes of pumpkin (Curcurbita maxima L.) stored under isothermal and non-isothermal frozen conditions. Journal of Food Engineering. ISSN 0260-8774. Vol. 106, n.º 1 (2011), p. 40–470260-8774http://hdl.handle.net/10400.14/7479The effects of freezing process and frozen storage at isothermal (−7, −15 and −25 °C) and non-isothermal (accelerated life testing with step-stress methodology; temperature range from −30 to −5 °C) conditions on pumpkin quality were investigated. Storage temperature conditions were selected to embrace the limits practiced in the cold chain. Quality changes, such as texture, colour CIE Lab and vitamin C (ascorbic acid) content, were evaluated for both frozen storage regimes. The freezing process (that included a pre-blanching step) and subsequent frozen storage had significant impacts on all quality parameters analysed. A fractional conversion kinetic model was adequate in colour, texture and vitamin C data fits. The storage temperature effect was successfully described by the Arrhenius law. This study shows that non-isothermal frozen storage has a marked effect on pumpkin quality.engPumpkinIsothermal and non-isothermal frozen storage conditionsQualityKineticsjournal article10.1016/j.jfoodeng.2011.04.0041873-5770WOS:000291914000006