Reducing water leakage by fructooligosaccharides enhancing treatment in strawberries

Abstract

Strawberries, highly appreciated for their excellent flavor, have relevant economic and nutritional benefits. However, their quality deteriorates rapidly due mainly to water loss. Water is very important component in fruit, mainly in strawberries that exhibit a large quantity of water. More than moisture contenti it is of great interest to quantify the amount of freezable and unfreezable water fraction in strawberries. Some varieties are classified as a high CO2 tolerant fruit and atmospheres with high CO2 concentrations have been used successfully to control fungal decay and to incresase flesh firmness. interestingly, the metabolic adjustment caused by high CO2 treatment involved the enhancement of hydrophilic compounds, facilitating water retention, thereby improving the quality of chilled and frozen strawberries. The aims of this work were first, to determine how protective short treatment such as 20 kPa CO2 for 3 days at low temperature, modifies fruit water status. For that, the freezable and unfreezable water content in strawberries from two different harvesting time were studied using differential scanning calorimetry. second, to analyze how changes in unfreezable water fraction was correlated with endogenous fructo-oligosaccharides levels and cell structure in strawberries fruit stored under high CO2 atmosphere. Finally, in the present work we also tried to determine whether the changes in the levels of unfreezable water content in CO2-treated strawberries might affect the thawing behaviour of fruit tissues. The water-holding capacity of strawberries after thawing was determined by analysing the drip loss of CO2- treated and untreated samples. Our results suggest that by increasing the concentrations of fructo-oligosaccharides, protective high CO2 concentrations reduce the amount of water available to be frozen, thus reducing water leakage associated with the freezing-thawing process.