Frying of potato crisps - an investigation aiming at reduction oil content and acrylamide formation

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dc.contributor.advisor Professor Xiao Dong Chen en
dc.contributor.advisor Dr Necati Ozkan en Tran, Mai Thu Thi. en 2008-01-24T03:57:16Z en 2008-01-24T03:57:16Z en 2006 en
dc.identifier.citation Thesis (PhD--Chemical and Materials Engineering)--University of Auckland, 2006. en
dc.identifier.uri en
dc.description Note: Part 3 publication restricted due to copyright restrictions. en
dc.description.abstract Reducing oil content, minimizing any carcinogenic acrylamide in the high temperature frying process for potato crisps, and producing good products with considerable crispiness and acceptable color were the objectives of this research. Vacuum frying with pre-treatment of potato crisps was investigated as an effective process for oil content reduction. Pre-drying and subsequent dipping (PSSD) in a sugar solution (‘sugar dipping’) were considered as an advantageous procedure for the treatment of potato crisps before frying in order to reduce oil uptake during frying. Vacuum frying was observed as an excellent process to decrease significantly the acrylamide formation at low temperature frying of potato crisps. In this study, potato crisps were respectively blanched, pre-dried, and dipped in a solution of sugar (23.07 wt %) for two seconds, before vacuum frying at 120oC, 110oC under different vacuum pressures (170mbars, 150mbars, 100mbars and 50mbars in separate experiments). Conventional frying at 180oC was also used as the control to benchmark the reductions in the oil contents and acrylamide formation among various techniques. There was a significant reduction in oil content of the potato crisps observed when the new techniques were applied. The crisps that had been pre-treated and fried with conventional frying have given the result of 30 wt % reduction. The crisps that were fried under vacuum frying achieved greater oil reduction with varying percentages when applying different pretreatments. The lowest oil content was achieved when the potato crisps were fried at 110oC and 150 mbars giving 58 % reduction on the dry basis compared with control samples. There are various advantages of the technique with PSSD as we have discovered: it is simple and can be applied in potato crisp industries in continuous mode in both vacuum and conventional frying systems. The crisps that had been treated with pre-drying and subsequent sugar solution dipping and then fried were crunchier and possibly had better perceived taste to the consumer, due to the small sugar addition. Pre-drying and vacuum frying have all turned out to be excellent techniques to reduce acrylamide formation in potato crisps as we have found in this study. Vacuum frying at 120oC and 150 mbars reduced acrylamide formation by 80 to 85%. The 95% reduction was obtained when the crisps had been pre-dried. Acrylamide was undetectable when crisps were pre-dried and vacuum fried at 110oC, 150 mbars. The crisps with pre-drying subsequent sugar dipping and vacuum fried at low temperature had improved color compared with the control samples, which were produced by conventional frying at high temperatures. en
dc.format Scanned from print thesis en
dc.language.iso en en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA1773345 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. en
dc.rights.uri en
dc.title Frying of potato crisps - an investigation aiming at reduction oil content and acrylamide formation en
dc.type Thesis en Chemical and Materials Engineering en The University of Auckland en Doctoral en PhD en
dc.subject.marsden Fields of Research::290000 Engineering and Technology::290100 Industrial Biotechnology and Food Sciences en
dc.rights.holder Copyright: The author en
pubs.local.anzsrc 0912 - Materials Engineering en Faculty of Engineering en

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