Evaluation of thermal processing variables for reducing acrylamide in canned black ripe olives

Abstract

Acrylamide, formed in certain plant foods at elevated cooking temperatures, has been identified as a probable carcinogen. A wide variation in acrylamide concentration has been reported for commercial canned black ripe olives, with some levels being quite high. Standards for olive sterilization were developed before acrylamide was discovered to be present in food. The objective of this study was to determine if alternative sterilization conditions during thermal processing could substantially reduce acrylamide levels in black ripe olives, while still maintaining safety and quality. Heat penetration tests for six thermal processes were used to evaluate process F0 – a sterilization value –which was correlated to acrylamide formation and changes in quality attributes of black ripe olives. Acrylamide concentration followed a positively correlated second order polynomial regression with process F0. This correlation was further demonstrated by two of the experimental processes with different initial temperatures and different processing times, but with ultimately similar F0, that produced very similar levels of acrylamide. The amounts of solids leaching from olives in brine increased at higher temperatures of thermal processing, whereas pH variation in olives and brine was most likely related to the differences in lye-wash cycles. Skin color was unaffected, whereas increasing (time/temperature) thermal processing reduced the firmness of whole olives. Optimization of safe thermal processing conditions while lowering process F0 is a practical and efficient strategy to reduce acrylamide formation and improve the safety of black ripe olives.