Influence of aerobic fermentation on the quality of natural black Criolla olives

Natural black Criolla olives are a traditional Peruvian product, distinguished by their characteristic violet hue, lack of bitterness, moderate firmness, and lactic fermentation. However, these physicochemical and sensory attributes are not always achieved. A novel fermentation approach incorporating aeration has been proposed to produce olives with traditional quality traits. Microbial dynamics during fermentation were similar between the conventional anaerobic method and the proposed aerobic methods, with lactic acid bacteria and yeasts coexisting throughout the process. A low aeration rate (0.1 L/h/L of brine) did not significantly affect the fermentation process. Final pH (3.60–3.75), titratable acidity (1.15 %–1.74 %), and NaCl concentrations (≥6 %) complied with Codex Alimentarius standards. For the first time, the individual phenolic profile and total pigment concentration of Criolla olives were characterized. The major phenolic compounds included hydroxytyrosol 4-glucoside, hydroxytyrosol, tyrosol, and verbascoside. A significant reduction in total phenolic content was observed, with lower losses in traditional fermenters (50 %–57 %) compared to aerated fermenters (63 %–52 %). Notably, hydroxytyrosol levels were higher in aerated fermenters, which is nutritionally relevant. The persistence of purple coloration was attributed to anthocyanin polymerization during fermentation, which was more pronounced in aerated fruits. Sensory evaluation revealed a positive trend in the overall score and buying predisposition for aerobically fermented olives. These findings support aerobic fermentation as a viable alternative for producing high-quality natural black olives, maintaining traditional sensory traits while enhancing nutritional properties. • A low-flow aerobic system was tested for fermenting natural black Criolla olives. • Aeration did not compromise traditional flavor, texture, or microbial safety. • Hydroxytyrosol levels were maintained or increased under aerobic conditions. • Anthocyanin polymerization influenced final fruit color across treatments. • Sensory analysis showed high buying predisposition for aerated olives.