Alcoholic Extract of (Quercus persica Jaub. & Spach) as a Functional Natural Preservative to Improve Hygienic Quality of Jug Cheese

The alcoholic extract of Iranian oak (Quercus persica) fruit at a final concentration of 0.25% (w/v) was added to cheese-making milk, and some physicochemical, sensory, and microbial properties of Jug cheese were evaluated during 60 days of storage at 4°C. The results showed significantly higher Total Polyphenol Content (TPC), antioxidant activity, and lower acidity for the samples containing the oak extract (T1) compared to the control (T0). At the beginning of the storage time, T1 showed the highest values of TPC (128.83±0.467 mg GAE g-1) and antioxidant activity (97.12±0.095) for DPPH (2,2-DiPhenyl-1-PicrylHydrazyl) radical scavenging activity. The antioxidant activity decreased significantly during the storage period. The flavor, aroma, and overall acceptability scores were higher for T1 than for T0. Short-chain fatty acids content of the cheese varied during the storage period, but no significant change was observed in the content of long chain fatty acids. The amount of butyric, caproic, caprylic, capric, lauric, myristic, palmitic, oleic (trans) and linoleic (cis) fatty acids in T1 were significantly higher than in T0. No significant changes in these fatty acids concentrations were observed during storage period. Total microbial count, Coliforms, mold and yeast were significantly lower in the T1 than in T0. Therefore, the Iranian oak extract as a source of antioxidant and antimicrobial polyphenolic compounds could potentially improve the quality and shelf life of Jug cheese without adversely affecting its sensory and physicochemical properties.