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Exploring the use of a modified high-temperature, short-time continuous heat exchanger with extended holding time (HTST-EHT) for thermal inactivation of trypsin following selective enzymatic hydrolysis of the ß- lactoglobulin fraction in whey protein isolate

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dc.contributor.author Sáez, Laura
dc.contributor.author Murphy, Eoin
dc.contributor.author Fitzgerald, Richard J.
dc.contributor.author Kelly, Phillip M.
dc.date.accessioned 2019-10-07T13:46:36Z
dc.date.available 2019-10-07T13:46:36Z
dc.date.issued 2019
dc.identifier.uri http://hdl.handle.net/10344/8113
dc.description peer-reviewed en_US
dc.description.abstract Tryptic hydrolysis of whey protein isolate under specific incubation conditions including a relatively high enzyme:substrate (E:S) ratio of 1:10 is known to preferentially hydrolyse ß-lactoglobulin (ß-LG), while retaining the other major whey protein fraction, i.e., x-lactalbumin(x-LA) mainly intact. An objective of the present work was to explore the e ects of reducing E:S (1:10 1:30, 1:50, 1:100) on the selective hydrolysis of ß-LG by trypsin at pH 8.5 and 25 °C in a 5% (w/v) WPI solution during incubation periods ranging from 1 to 7 h. In addition, the use of a pilot-scale continuous high-temperature, short-time (HTST) heat exchanger with an extended holding time (EHT) of 5 min as a means of inactivating trypsin to terminate hydrolysis was compared with laboratory-based acidification to <pH 3 by the addition of HCl, and batch sample heating in a water bath at 85 °C. An E:S of 1:10 resulted in 100% and 30% of ßLG and x-LA hydrolysis, respectively, after 3 h, while an E:S reduction to 1:30 and 1:50 led >90% ß-LG hydrolysis after respective incubation periods of 4 and 6 h, with <5% hydrolysis of x-LA in the case of 1:50. Continuous HTST-EHT treatment was shown to be an e ective inactivation process allowing for the maintenance of substrate selectivity. However, HTST-EHT heating resulted in protein aggregation, which negatively impacts the downstream recovery of intact -LA. An optimum E:S was determined to be 1:50, with an incubation time ranging from 3 h to 7 h leading to 90% ß-LG hydrolysis and minimal degradation of x-LA. Alternative batch heating by means of a water bath to inactivate trypsin caused considerable digestion of x-LA, while acidification to <pH 3.0 restricted subsequent functional applications of the protein. en_US
dc.language.iso eng en_US
dc.publisher MDPI en_US
dc.relation.ispartofseries Foods;8, 367
dc.subject hydrolysis en_US
dc.subject WPI en_US
dc.subject trypsin en_US
dc.subject x-lactalbumin en_US
dc.subject ß-lactoglobulin en_US
dc.subject thermal inactivation en_US
dc.title Exploring the use of a modified high-temperature, short-time continuous heat exchanger with extended holding time (HTST-EHT) for thermal inactivation of trypsin following selective enzymatic hydrolysis of the ß- lactoglobulin fraction in whey protein isolate en_US
dc.type info:eu-repo/semantics/article en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.identifier.doi 10.3390/foods8090367
dc.contributor.sponsor Enterprise Ireland-funded ‘Food for Health Ireland’ (FHI) en_US
dc.relation.projectid TC20130001 en_US
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US


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