Influence of alternating air injection on the color and “alambrado” of natural black olives cv. Arauco, as compared with the traditional Argentine method

Abstract

Ripe black olives cv. Arauco were processed under different conditions to evaluate the effects of alternating air injection (AI) on the color of olives and on spoilage known as “alambrado”, using a system based on the one patented by the “Instituto de la Grasa” (Sevilla, Spain), as compared with the traditional Argentine processing method, which consists of drying the olives in natural air (“extendido”) for 24 hours at 7, 14 and 21 days of fermentation. Four types of fermentation were used: brine at 2% NaCl plus AI; brine at 2% NaCl plus three “extendidos”; brine at 9% NaCl plus three “extendidos”; and brine at 9% NaCl plus AI and one “extendido”. As previously observed in other varieties by other authors, we noticed that lower pH values were achieved in 2% NaCl fermentations vs. 9% NaCl fermentations. AI prevented the “alambrado” whereas brine at 2% NaCl reduced this spoilage as compared with brine at 9% NaCl. The darkest color of olives was obtained with three “extendidos”, but 83% of brightness reduction was achieved with only one “extendido”. The “extendido” process decreased the texture. We conclude that the combination of AI and “extendido” can add benefits to natural black olives of the Arauco variety.