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Industrially Relevant Canning Trials with a Sterilisation Time–Temperature Integrator

Brown, I., Tucker, G. S., Fryer, P. J., Cox, P. W.
Food and bioprocess technology 2013 v.6 no.12 pp. 3433-3440
Clostridium botulinum, Pyrococcus, canning, enzyme activity, foods, mangoes, pasteurization, spores, temperature
Food sterilisation, i.e. heating to above 120 °C for several min, still remains a primary method of food preservation. Current time-temperature integrators (TTIs), used to assess the thermal impact, only work at pasteurisation temperatures (below 100 °C). The aim of this work was to develop and validate a sterilisation TTI using an α-amylase from the hyperthermophile Pyrococcus furiosus. Previous experiments have found that this α-amylase has a z value similar to that of Clostridium botulinum spores and the enzyme is sufficiently heat resistant to show a measurable residual activity after 30 min at 121 °C. Analysis found a D value of 24 min and a slightly variable z value of around 11 °C. The decrease in enzymatic activity from thermal processing was found after a F121°C process of 5 min to be 67 %, and for a F121°C of 30 min it was 12 %, thus making P. furiosus α-amylase a strong and relevant candidate for a sterilisation TTI. Trials with canned water and mango chutney as test materials have confirmed the potential application of the enzyme within an industrially relevant setting of a model reel and spiral retort. The thermal data showed that at low or marginal F121°C values, of less than 15 min, the correlation between the TTI and thermocouple data was closely comparable (R 2 = 0.96). The applicability of these TTIs over the range of industrial processes is also shown. ©Springer Science+Business Media New York 2012.