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 ۰.۲۵% (w/v) was added to cheese-making milk, and some physicochemical, sensory, and microbial properties of Jug cheese were evaluated during ۶۰ days of storage at ۴°C. The results showed significantly higher Total Polyphenol Content (TPC), antioxidant activity, and lower acidity for the samples containing the oak extract (T۱) compared to the control (T۰). At the beginning of the storage time, T۱ showed the highest values of TPC (۱۲۸.۸۳±۰.۴۶۷ mg GAE g-۱) and antioxidant activity (۹۷.۱۲±۰.۰۹۵) for DPPH (۲,۲-DiPhenyl-۱-PicrylHydrazyl) radical scavenging activity. The antioxidant activity decreased significantly during the storage period. The flavor, aroma, and overall acceptability scores were higher for T۱ than for T۰. 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 T۱ were significantly higher than in T۰. 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 T۱ than in T۰. 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.

Keywords:

Antimicrobial activity , Antioxidant activity , Oak extract , Total polyphenol content.