Effect of rosemary extract on physicochemical properties and stability of butter from sour cream

This research was investigated effect of rosemary extract, as rich source of antioxidant compounds, on physicochemical properties and stability of butter from sour cream. Rosemary extract was added to butter from samples at concentrations, 0 (control), 0.05, 0.1, 0.3 and 0.5% and after vacuum packaging, samples were stored in refrigerator for 60 days. Acid and peroxide values, polyphenol content, hardness, oxidative stability, sensory characteristics of samples including flavor, textural and apparent characteristics of samples and DPPH radical scavenging assay of rosemary extract were evaluated. Results showed that samples which contained rosemary extract had higher acid value, higher oxidative stability and plyphenol content and peroxide value than control sample. During storage, acid value of all samples increased but extract enriched samples showed lower increase. Peroxide value and polyphenol content of samples were decreased during storage. DPPH radical scavenging assay proved that antioxidant activity of rosemary extract is lower than quercetin. Moreover, sensory characteristics evaluation showed that samples containing more than 0.5% rosemary extract in comparison with control sample had significant difference in extract flavor (P<0.05). The results showed that adding rosemary extract to the butter could devolve a new butter formula enriched with phenolic substances and higher stability and introduce a new product with high shelf-life to the market.