The effects of blanching treatment on peroxidase inactivation, colour and texture of pumpkin (Cucurbita maxima L.) were studied in the temperature range of 75-95°C.Peroxidase inactivation followed a first-order Arrhenius model, where the activation energy and rate of the reaction at a reference temperature of 85°C were 86.20 ± 5.57 kJ mol À1 and 0.27 ± 0.01 min À1 , respectively.During blanching, pumpkin became darker and softer with processing time. The degradation of colour (evaluated throughout CIE L * a * b * colour system, with chroma index and total colour difference) and texture parameters (firmness and energy) showed a fractional conversion model kinetics, being the temperature effect on kinetic parameters well described by the Arrhenius law.The results of this work are a good tool to further optimise pumpkin blanching conditions.

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a b s t r a c tAbiotic stresses such as heat shock and UV-C irradiation can be used to induce synthesis of bioactive compounds and to prevent decay in fresh-cut fruits and vegetables. This study aimed to evaluate the effects of heat shock and UV-C radiation stress treatments, applied in whole carrots, on the overall quality of fresh-cut carrot cv. Nantes during storage (5 C). Heat shock (HS, 100 C/45 s) and UV-C (0.78 AE 0.36 kJ/m 2 ) treated samples had higher phenolic content and exhibited reduced POD activities during storage when compared to control (Ctr) samples (200 mg/L free chlorine/1 min). All samples showed reduced carotenoid content considering raw material. Nonetheless, UV samples registered a three-fold increase in carotenoid content in subsequent storage. Fresh-cut carrot colour showed a continuous increase in whiteness index (WI) values during storage regardless of treatment without impairing visual quality. Respiratory metabolism was affected by both abiotic stress treatments since reduced O 2 /CO 2 rates were found, more significant in HS samples. The decontamination effect was more expressive in HS samples, where a 2.5 Log 10 cfu/g reduction in initial microbial load and reduced microbial growth were achieved.

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