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

Authors: TANG, ALICE - University Of California; Avena-Bustillos, Roberto; LEAR, MOLLY - University Of California; SEDEJ, IVANA - University Of California; HOLSTEGE, DIRK - University Of California; WANG, SELINA - University Of California; Friedman, Mendel; McHugh, Tara

Submitted to: Journal of Food Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2016
Publication Date: 7/27/2016
Citation: Tang, A., Avena-Bustillos, R.D., Lear, M., Sedej, I., Holstege, D.M., Wang, S., Friedman, M., McHugh, T.H. 2016. Evaluation of thermal processing variables for reducing acrylamide in canned black ripe olives. Journal of Food Engineering. 191:124-130. https://doi.org/10.1016/j.jfoodeng.2016.07.011.
DOI: https://doi.org/10.1016/j.jfoodeng.2016.07.011

Interpretive Summary: Acrylamide formed in plant foods at elevated cooking temperatures has been identified as a probable carcinogen. A wide variation and high acrylamide concentration in commercial canned black ripe olives has been reported. California-style black ripe olives as a low-acid canned food (LACF) usually require sterilization temperatures above 110°C. In contrast Spanish- and Greek-style table olives are considered acidified foods (AF) and only require pasteurization temperatures below 65°C and/or additives for preservation and as a consequence acrylamide is negligible in these two olive styles. It is hypothesized that the wide variation of acrylamide in commercial canned black ripe olives is a consequence of different thermal processes used by industry due to different container sizes and ways to deliver the thermal processing in different retort types, as well as required heat sterilization requirements established by thermal process authorities and regulatory agencies. Even if has been reported that acrylamide in canned black ripe olives is caused by high temperature processing, there is a lack of systematic studies to reduce acrylamide concentrations by reducing thermal processing during commercial sterilization. For LACF it is imperative to assure commercial sterility and then look if it is still possible to reduce acrylamide concentrations, compared to common commercial canning practices. We demonstrated that optimization of safe thermal processing conditions is a practical and efficient alternative to reduce acrylamide formation and improve quality of black ripe olives.

Technical Abstract: Acrylamide formed in plant foods at elevated cooking temperatures has been identified as a probable carcinogen. A wide variation and high acrylamide concentration in commercial canned black ripe olives has been reported. The objective of this study was to determine if different safe sterilization conditions during thermal processing can reduce substantially acrylamide levels in black ripe olives. Sterilization time and temperature for six thermal processes were adjusted and by heat penetration tests, process sterilizing value (Fo) was measured and 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 Fo. Similar process Fo, obtained by different processing conditions, gave similar acrylamide concentrations. Solids leaching from olives increased while pH decreased in brine at higher thermal processes. Skin color did not change, while firmness of whole olives was reduced by increasing thermal processing. Optimization of safe thermal processing conditions is a practical and efficient alternative to reduce acrylamide formation and improve quality of black ripe olives.