table olives

Table olives are olive drupes processed to be eaten as they are. Despite decreasing with fruit ripening, drupes are originally characterized by a strong bitter taste, which reviews summarize as being primarily attributable to oleuropein, a bitter compound. Raw fruit rarely reaches the table unmodified, and only after processing to partially or completely remove bitterness followed by fermentation do drupes become table olives as a pickled product.

The pathway for removing bitterness differs by commercial finishing method. In the Spanish style, prior to lactic fermentation in brine, drupes are immersed in a 1.5–4.5% (w/v) sodium hydroxide solution for chemical hydrolysis of oleuropein. In the Greek style, drupes are fermented directly in brine without using an immersion step. In the Alcaparras style, drupes split in half are immersed over approximately 1 week with water repeatedly changed, and oleuropein is removed by diffusion. Even with the same fruit, the removal pathway differs markedly depending on the finishing method.

Oleuropein that should have been removed sometimes remains measurable in some products. A dry-salted product was reported to have the highest oleuropein content, in contrast to the Spanish style, in which alkali treatment is described as capable of complete removal. In research tracking the processing of naturally green olives, hydrolysis of oleuropein via both enzymatic and chemical reactions has been confirmed during the process; however, these numerical values derive from individual studies compiled by reviews, and must be read with the premise that they vary by processing condition.