Chemical and Quality Changes in Natural Green Manzanilla Olives: Impact of Preservation, Brine, and Storage

This study evaluated the effect of different storage conditions on the chemical (pH, acidity, organic acids, polyols, phenolic compounds, and volatilome) and quality characteristics (surface color, brine color, and firmness) of natural green Manzanilla table olives. Three preservation methods were compared: specific chemical characteristics (SCC), refrigeration, and pasteurization, along with two types of covering brine (acidified "white" brine and diluted fermentation brine) and two storage times (2 and 12 months). Olives preserved by SCC showed growth of lactic acid bacteria, mainly those packaged with fermentation brine, and significant chemical changes, including complete degradation of oleuropein after 12 months. Refrigerated samples remained more chemically stable, whereas pasteurized olives showed reduced bitterness and distinctive volatile compounds. The preservation method significantly influenced color and firmness. Refrigeration is recommended to ensure microbial stability, whereas pasteurization may be preferable when a less bitter product is desired. PRACTICAL APPLICATIONS: The present research suggests that companies producing natural green Manzanilla olives should use refrigeration if they want to market a product with superior texture, brine color, and fresh flavor. However, if consumers prefer a less bitter olive, the industry should opt for pasteurization. Overall, these findings help producers choose the best preservation method based on the specific taste and texture profile they want to sell.