Effect of Inert Atmosphere on the Postharvest Browning of Manzanilla Olives and Optimization by Response Surface Methodology of the Aqueous Treatments

Abstract: Subjecting bruised olives to a nitrogen atmosphere during the postharvest period prevented the oxidation of phenols and subsequent browning. However, a rapid phenol oxidation and browning occurred when fruits were re‐exposed to air. Based on models deduced from the effects of aqueous antioxidant solutions on changes in different color parameters in the fermented product, the treatments to prevent browning were optimized. The recommended procedure consists of placing the harvested olives in a cold (4 to 8 °C) solution of 3% sodium metabisulfite with the pH adjusted to 3.0 (by adding food grade HCl) and applying the lye treatment before 8 h from picking. The use of these conditions led to mechanically harvested Spanish style olives with hardly any visible browning. Practical Application: The procedure developed may be applicable to prevent browning on the bruised areas of manually or mechanically harvested olives. The system is simple, requires low investment, and may lead, in fermented olives, to undetectable differences between undamaged and bruised areas and better ratings in the visual observation of healthy fruits.