Production of butter with added carotenoid extract from gracilaria dura macroalgae collected from the sea of Türkiye: Investigation of effects on physicochemical properties, antioxidant activity and oxidation stability

In the present thesis, changes in physicochemical properties, antioxidant activity and oxidation stability of butter added carotenoid extract from Gracilaria dura, which is a red macroalgae, were investigated during storage. For this purpose, butter samples (control) without G. dura carotenoid extract and with G. dura carotenoid extract in different ratios (1%, 3% and 5%) were prepared. The samples were stored at +4 ºC and pH, titratable acidity, peroxide value (PV), thiobarbituric acid reagents (TBARS) and antioxidant activity (AOA) analysis were performed on the 1st, 7th, 14th, 21st days of storage. According to the results of the study, an increase in carotenoid content of butter samples caused an increase in pH and AOA values and a decrease in PV and TBARS values (p<0.05). The highest titratable acidity value of all butter samples was reached on the 1st day of storage. Oxidation stability increased with the decrease of lipid oxidation in butter. On the other hand, on the 7th, 14th and 21st days of storage, TBARS values of control samples without carotenoids were higher compared to samples with 1%, 3% and 5% G. dura extract added (p<0.05). Moreover, AOA of butter sample with 5% G. dura extract was found to be highest (p<0.05). The results showed that G. dura carotenoid extract could be used as a natural antioxidant. Keywords: Butter, oxidation, Gracilaria dura, carotenoid, antioxidation.