Effect of packing conditions on the acrylamide content in black ripe olives.

Background: Black ripe olives are considered a 'low-acid canned food' and must be sterilized in order to be safe. Acrylamide, a potential carcinogen, is formed in black olives during the thermal treatment. It is known that the formation of acrylamide is dependent on the pH of the olive flesh. The purpose of this study was designed to assess the influence of packing conditions on the acrylamide production in black olives.

Results: A reduction in acrylamide content of up to 20-30% was achieved by raising the pH of the fruit before packing above 7. Lactic acid improved color and addition of calcium chloride to the cover brine enhanced firmness. Sodium bicarbonate decreased acrylamide by up to 35%, although severe softening occurred. Packaging under CO₂ atmosphere increased acrylamide relative to air or nitrogen, indicating its unsuitability for packing this product. Likewise, no effect on acrylamide levels was observed among pitted and sliced olives, unlike in whole fruits, in which a higher concentration of acrylamide was detected, attributable to precursor localization in the seed, which produced significantly more acrylamide than the flesh or woody endocarp during isolated sterilization.

Conclusion: The study identifies pH modulation as an effective mitigation strategy for acrylamide in black olives, but highlights trade-offs between reduction efficacy, texture quality and packaging conditions. The proposal does not solve the problem completely, but it may be viable on an industrial scale and will therefore provide the table olive industry with new tools to mitigate the presence of acrylamide in black olives. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.