Optimization of Ripe Olive Processing with a Single Lye Treatment.

Area of Science:

• Food Science
• Horticultural Science
• Agricultural Chemistry

Background:

• Traditional methods for processing black ripe olives often involve multiple steps.
• Achieving optimal color and texture in processed olives can be challenging.
• Enhancing the nutritional profile of processed olives is of commercial interest.

Purpose of the Study:

• To develop an improved method for darkening black ripe olives.
• To evaluate the impact of using a preservation liquid and water mixture on olive quality.
• To investigate the effect of reusing preservation solution on antioxidant content.

Main Methods:

• Hojiblanca cultivar olives were processed at a pilot plant scale.
• Olives underwent a single sodium hydroxide (NaOH) treatment and washing step.
• A mixture of preservation liquid and water (1:1 ratio) was used for the initial wash.
• Packed olives were sterilized and stored for 2 months at ambient temperature for analysis.

Main Results:

• Using a 1:1 preservation liquid:water mixture resulted in darker olives with improved firmness.
• Olive sensory quality remained unaffected by the modified washing process.
• Preservation solutions with acetic acid concentration >25 g/L negatively impacted olive color due to low pH.
• Reusing the preservation solution increased the total phenolic content (629 mg/kg vs. 376 mg/kg) and specific antioxidants like hydroxytyrosol.

Conclusions:

• A single NaOH treatment combined with a 1:1 preservation liquid:water wash effectively darkens black ripe olives.
• Reusing preservation solution during the washing step enriches olives with beneficial antioxidant compounds.
• Careful control of acetic acid concentration in the preservation liquid is crucial to avoid adverse color effects.