Significance of osmotic temperature treatment and storage time on physical and chemical properties of a strawberry-gel product.

Background: The development of fruit-based foods that maintain the nutritional and sensory properties of fresh fruit may help to stimulate fruit consumption by consumers. The possibility of formulating a fruit-gel product with osmodehydrated fruit and the reused osmotic solution (OS) obtained from the dehydration step has been demonstrated. However, the conditions of the osmotic process can significantly affect the properties of the obtained product. In this work an osmotic process at 22 °C for 6 h and at 30 °C for 3 h was employed to formulate a strawberry-gel product.

Results: Significant losses of ascorbic and citric acids and anthocyanins were observed and some relevant volatile compounds of the strawberry aroma profile were developed during the osmotic process. Changes in all analysed parameters occurred mainly during the first 2 days of storage. The flux of anthocyanins from the fruit to the gel gave an attractive appearance to the formulated product. These changes were more marked for samples obtained at 30 °C.

Conclusion: Osmotic treatment at 30 °C was more suitable for formulation of the product, because the presence of nutritional/functional compounds in the OS, and consequently in the gel matrix, was higher and the aroma and colour were more stable and homogeneous during storage.