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This paper describes research efforts to improve the operation of industrial scale crisp fryers to ensure that product quality targets are exceeded. The work described was undertaken within a project whose aim is to minimise the acrylamide formation arising during processing operations. The existing fryer temperature control scheme was found to be sub-optimal from an acrylamide perspective and involved considerable operator intervention, particularly at fryer start-up. A new temperature control system was designed and implemented to overcome the shortcomings of the existing strategy. Fryer temperature and crisp moisture were regulated effectively through gas flow and dwell time modifications. Interactions between loops were compensated for and start-up was automated to reduce the impact of operator-to-operator variation. The resulting scheme was found to deliver much-improved temperature control which will lead to a resultant decrease in acrylamide formation. [ABSTRACT FROM AUTHOR]

As part of an overall programme aimed at reducing the acrylamide content of crisps, this paper explores the impact of hot-washing on potato slice sugar concentration during industrial scale manufacture. We investigated cold-washing as an alternative to hot-washing, hot-wash residence time and temperature to optimise sugar removal and therefore reduce the potential for high acrylamide levels after frying. Due to the variable nature of potatoes, an extensive variability study was performed to determine confidence boundaries of results. It was found that the cold-wash unit removed on average 21% of the initial sugar content. In the hot-wash the current operational residence time of 3.5 min at 70 C gave a sugar reduction of 27.5%, which could be increased to 48.5% if residence time is extended to 5 min. Hot-wash temperatures of 40 °C-60 °C were found to increase glucose and fructose content and therefore the potential for acrylamide formation. A "double cold-wash" was trialled and proved to be as successful as hot-washing at 70 °C for all but the highest sugar potatoes, challenging the current operational process and offering the potential for major energy savings. [ABSTRACT FROM AUTHOR]