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The purpose of this study was to analyze some chemical elements and to determine the content of total phenols and pigments in the brown seaweed Cystoseira barbata from Rusalka Cape near the Black Sea. In addition, the antioxidant potential of this algae was also evaluated by four methods based on different mechanisms. The obtained results were compared with other scientific studies related to inorganic and organized compositions of Cystoseira barbata from different marine regions.It was found that the seaweed from Rusalka Cape contained high values of manganese, chromium and boron and a high concentration of carotenoids. Therefore, this seaweed was evaluated as a source of microelements, carotenoids and antioxidants.

Experiments were conducted to study the rheological behavior of iota-carrageenan Gels to which potato starch and low-esterified amidated pectin were added. The rheological measurements of carrageenan jellies were performed by a texture analyzer at different concentrations of gelling agent (iota-carrageenan) and fixed concentrations of starch (1.3 %) and pectin (0.3%). Following the experiments, rheological patterns related to rupture force, rupture deformation and firmness of the gels were evaluated. Potato starch and low esterified amidated pectin at certain concentrations do not show synergistic effects with iota-carrageenan. The addition of low esterified amidated pectin or potato starch in iota-carrageenan gel results in a significant reduction in deformation and a minimal reduction in the rupture force.

Alginate beads attract attention as a encapsulation matrix of bioactive substances in food. However, the stability of beads depends on calcium ion and sodium alginate concentration, gelling time and others factors. The aim of this study is to investigate the influence of different types of calcium salts on the structural and mechanical parameters - the rupture force and rupture deformation at different gelling times of the pear jam prepared with soluble dietary fibers and inulin. The relationships between the rupture force and rupture deformation of the fruit jams were established. By increasing the gelling time from 24 hours to 48 hours, the rupture deformation of jams with 7% calcium lactate were reduced and in those with 7% CaCl2 the rupture forces increases. Any change in rupture force was observed for the jam with 3.5% CaCl2. This study demonstrated the practical application of different calcium salts for preparation of stable pear jam.

This study aimed to investigate the effect of ultraviolet light and ultrasound on the antioxidant activity and rheological properties of pear fruit jam. The antioxidant potential of fruit jam was determined by three methods based on different mechanisms (DPPH ABTS and CUPRAC assays) in six samples treated with ultrasonic waves and ultraviolet light. The antioxidant activity and the content of total phenols were preserved to the greatest extent during the irradiation of the fruit jam with ultraviolet light at a wavelength of 254 nm for a certain time. Ultrasound irradiation reduces the antioxidant activity and lowers the content of total phenols to a greater extent than the ultraviolet light. In addition, seven types of rheological parameters were determined on the pear fruit jam by a texture analyzer and their changes during processing with ultraviolet light and ultrasound was studied. Ultraviolet light demonstrated a smaller reducing effect on the rheological parameters of the fruit jam compared to ultrasonic irradiation. From the obtained results, the irradiation with ultraviolet light should be considered as a better technique for treatment of pear jam with minor changes in the antioxidant potential, phenolic content, and structural mechanical properties of the final product.