The Antimicrobial and Antioxidation Activities of Olive Pomace Extract in Pasteurized White Cheese

Olive pomace from an olive mill was collected in December 2021. Proximate analysis revealed that the major constituents of the pomace were fiber (60.85 %) and fat (11.91%). Extraction of the olive pomace by methanol provided a higher yield, phenolic content, and free radical scavenging ability than the ethanol extract, but the latter was used due to its lower toxicity level as the extract is used in foods.  The extract contained high concentrations of phenolic compounds, particularly syringic, p-coumaric, vanillin, and caffeic acid which accounted for ~80% of the total phenolic content. When the olive pomace extract (OPE) was used (0.08%) in pasteurized white cheese (PWC), the counts of mesophilic aerobes were significantly reduced to 3.62 log10 CFU/g after 30d of storage at 5°C compared to the control (4.04 log10CFU/g) after the same storage period. The corresponding values for LAB were 3.38 log10 CFU/g and 3.79 log10 CFU/g, respectively. The yeasts and molds were eliminated from the cheese for 14d at all of the tested OPE concentrations (0.01% to 0.08%). Fortification of cheese with OPE alleviated the increase in titrable acidity in cheese during storage, but the fortified cheese exhibited sensory attributes similar to those of the control cheese. It can thus be concluded that fortification of PWC with OPE improves the chemical and microbial attributes of the cheese