Effect of osmotic dehydration and vacuum impregnation on respiration rate of cut strawberries

Respiration rate in terms of O-2 consumption and CO2 production was determined in strawberry halves, both fresh-cut and vacuum impregnated with an isotonic solution. The experimental measurements were also carried out in osmodehydrated samples for different concentration levels (to 30 degrees Brix) at atmospheric pressure and by applying a vacuum pulse. Changes throughout time of O-2 and CO2 concentration in the headspace of chambers containing the samples were analysed to determine respiration rates. The effect of temperature on respiration rate in fresh-cut and impregnated samples showed sigmoid behaviour where a sharp increase in respiration levels occurred between 5 and 10 degrees C. Osmodehydration treatments resulted in a great decrease in O-2 consumption but no notable changes in CO2 generation, which suggests that anaerobic biochemical pathway became dominant respiration mode due to the treatments. Production of ethanol and acetaldehyde was detected in these cases in agreement with the anaerobic process. (c) 2005 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.