Kinetic study of the effect of the osmotic dehydration pre-treatment with alternative osmotic solutes to the shelf life of frozen strawberry

Quality of frozen strawberry can significantly be improved by means of osmotic dehydration as a pre-freezing treatment. The objective of this work was to study the effect of osmotic pre-treatment with alternative osmotic solutes, oligofructose and a high DE maltodextrin, on the quality and sensory properties of frozen strawberry tissue. Vitamin C, colour, texture, drip loss after thawing and sensory characteristics of pre-treated and conventionally frozen samples were kinetically studied at isothermal conditions, and their temperature dependence was modelled by the Arrhenius equation. Dehydrofrozen samples exhibited a significantly improved vitamin C stability especially at temperatures, below −12 °C. The cryostabilization result of the oligofructose could be related to the glass transition behaviour of the modified osmo-dehydrofrozen food matrix. Colour deterioration was more intense in the case of untreated frozen strawberry samples. Osmo-dehydrofrozen compared to conventionally frozen strawberry halves showed an improved firmness for prolonged storage period and less water loss during thawing maintaining the strawberry tissue integrity. Sensory evaluation confirmed a good organoleptic quality in osmo-dehydrofrozen strawberries. The shelf life of all samples was calculated based on vitamin C (30% loss) and colour (50% chroma index retention) kinetic study results.