The effects of osmotic dehydration process paramterets on antioxidant capacity of celery leaves

Celery (Apium graveolens) is widely perceived as a medicinal plant and spice, due to its numerous health benefits, such as lowering cholesterol level, prevention of cardiovascular disease, mitigating, antimicrobial and anticancer activity, and also a good source of minerals, vitamins and pigments, phenols. Various dehydration treatments were applied to preserve celery, and while traditional drying procedures may be inappropriate, osmotic treatment preserves initial nutritional value, functional properties and sensory characteristic. In this research osmotic treatment of celery leaves was studied in two osmotic solutions (ternary aqueous solution and sugar beet molasses), at three temperatures (20, 35 and 50°C), and diverse immersion periods (1, 3 and 5 h). The aim was to examine the influence of the used hypertonic agent, temperature and immersion time on antioxidant capacity of the celery leaves' samples. Antioxidant capacity of celery leaves was assessed by the spectrophotometric assay: DPPH. The obtained results indicated statistically insignificant decrease of celery leaves antioxidant capacity with the increase of time and temperature during the treatment in ternary solution. Maximal decrease of celery leaves antioxidant capacity after the treatment in ternary solution, in comparison to the untreated celery leaves, was 5.80%. Increase of time and temperature of the treatment of celery leaves in molasses had led to the statistically significant increase of antioxidant capacity. In comparison to the fresh celery leaves, antioxidant capacity after the treatment in molasses increased for maximal 6.28%. From the results it can be concluded that solid gain originating from molasses had increased osmotically dehydrated celery leaves' antioxidant capacity, enhancing the functionality of the final product. Celery leaves osmotically treated in molasses, with extended shelf-life and enhanced antioxidant properties are suitable as food additive or functional food ingredient.