TURK 2025

Gilaburu (Viburnum opulus L.) is a significant source of vitamin C and phenolic compounds. It contains micronutrients, macronutrients, organic and fatty acids. Gilaburu has anticarcinogenic, antimicrobial and antioxidant properties due to the acids it contains. However, foods are vulnerable to spoilage due to their high water content and organic substances. Drying reduces water content, preventing spoilage and allowing for preservation. Freeze drying involves freezing the product to be dried and then sublimating the water under low pressure. This method preserves heat-sensitive compounds, color and flavor in food products. In this study, it was aimed to investigate the drying kinetics of freeze-dried gilaburu juice and to determine the most appropriate model describing the system. Moisture content, water soluble dry matter, titratable acidity, total phenolic matter, vitamin C, and color were also analyzed in fresh and powdered gilaburu juice. During the process in the lyophilizer, the weight of the samples spread in 2-mm thick petri dishes was measured at 30 min intervals. The time to reach equilibrium moisture content of the dried samples was determined to be as 750±0 min, according to the drying kinetics graphs. It was observed that the decrease in the free moisture content of the dried samples was rapid until 360 minutes and then this decrease slowed down. The compatibility of 7 different models to describe the drying process was tested and the diffusion approximation model was found to be the best model to describe the system. The moisture content of the samples decreased from 84.67±0.47% to 6.66±0.22%. There were no statistical differences between the total phenolic content of fresh gilaburu juice and gilaburu juice powder; nevertheless, a decrease in vitamin C content was observed. Hue angle and chroma values were 19.94±1.78-29.57±3.03 and 14.41±0.34-31.75±0.81 for fresh and powder samples, respectively, while ΔE value was 38.88±1.09 between the samples.