Physicochemical characteristics evaluation of Zard olive cultivar prepared with alkaline processing method

The purpose of this research is to investigate the unique properties of Yellow olive harvested from Tarem (Ghazvin province) using alkaline processing method. We looked at different salt concentrations (4%, 8% and 10%) and lactic acid concentrations (0.0% and 0.5%) using alkaline method for 210 days of processing. For different salt and lactic acid concentrations, we measured the physicochemical properties such as pH, total phenol, Reducing sugars and fatty acid profiles for both the olives and the curing liquid. The results shows: Total phenol decreases in the olive and increases in the curing liquid as the processing time increases. Increasing salt concentration, increases total phenol in the olive. Lactic acid decreases total phenol in the olive and increases it in the curing fluid. Longer processing time results in lowering pH in the olive and increasing pH in the curing liquid. Lowering pH in the olive is an important factor in improving quality by reducing product contamination during processing. Reducing sugars are consumed by microorganisms during the processing, thus their concentration decreases as the processing time increases. The highest drop in concentration was noticed in 8% salt group. Also the reducing sugar concentration was more drastically reduced in groups that contained lactic acid compre to the groups without any lactic acid. This is probably due to lactic acid decreasing pH resulting in increased activity of micro-oganisms. Results of fatty acid profile for both saturated and unsaturated fatty acids show an increase in ω6 compare to the raw olive. However the ratio on ω3/ω6 was reduced in all groups compare to the raw olive. Our research shows that increasing salt concentration and using lactic acid can reduce pH and increase the activity levels of desirable micro-organism resulting in cured olives with improved quality and increased shelf life.