{"id":{"repo_id":"helsinki","oai_identifier":"oai:helda.helsinki.fi:10138/163547"},"canonical_url":"https://search.dev.ndltd.org/etd/helsinki/oai:helda.helsinki.fi:10138/163547","repository":{"repo_id":"helsinki","name":"University of Helsinki","base_url":"https://helda.helsinki.fi/server/oai/request"},"display":{"title":"Denaturation of myofibrillar and sarcoplasmic proteins in pale, soft and exudative-like meat : effects on water-holding","abstract":"The aim of the thesis was to investigate the interaction between sarcoplasmic proteins and myofibrillar proteins, considering the effects on the loss of water-holding in mild heat induced denaturation such as occurring in pale, soft and exudative (PSE) condition. Porcine longissimus thoracis et lumborum muscles were incubated at temperature 0, 10, 20, 30 or 40 ˚C to 6 h post mortem. Incubation at 40 ˚C reduced the water-holding of meat compared to the lower temperatures (P < 0.001). SDS-PAGE and Western blot analyses indicated that glycogen phosphorylase and creatine kinase precipitated with the myofilaments, which was already accomplished at 6 h post mortem. Substantial meat tenderization was measured after incubation at 40 ˚C, but with less activity of extracted μ- and m- calpains compared to lower temperatures (P < 0.001), which suggests that an early activation of calpains at the highest incubation temperature could have been the reason for the tenderization. Surface hydrophobicity of myofilanments was higher after the pre-rigor incubation at 40 ˚C compared to lower temperatures (P < 0.001). Less myosin subfragment-1 (S1) units were released by chymotryptic cleavage simultaneously with the loss of Ca2+ ATPase activity after incubation at 40 ˚C than at lower incubation temperatures (P < 0.001). The results suggest that the high temperature incubation induce microstructural alterations on the myosin head (S1) region, which may in turn have been related to the loss of water-holding. The roles of the denaturation of sarcoplasmic proteins and myofibrillar proteins were compared. Sarcoplasm not-incubated or incubated at 44 ˚C were mixed with protein-depleted sarcoplasm in different rations and the mixtures were combined with myofibrils and subjected to PSE-like condition pH 5.6/44 ˚C for 1 h . Water-holding was the poorest without the incubated sarcoplasmic proteins. Precipitated sarcoplasmic proteins shrank the myofilamental lattice spacing by 6.3%, compared to protein-free sarcoplasm, during post-rigor incubation at 44 ˚C, shown by X-ray diffraction. These results challenge the current understanding of the role of the denaturation of different proteins in water-holding, and therefore, a new hypothesis is proposed in this thesis: 1) in the intramyofibrillar space, the presence of precipitating sarcoplasmic proteins is associated with the filamental lattice compression that expels water; 2) in the space outside the myofibrils (intermyofibrillar space) within fiber and up to the extracellular space, the coagulated sarcoplasmic proteins form a network that traps water expelled from the intramyofibrillar space.","abstract_html":"The aim of the thesis was to investigate the interaction between sarcoplasmic proteins and myofibrillar proteins, considering the effects on the loss of water-holding in mild heat induced denaturation such as occurring in pale, soft and exudative (PSE) condition. Porcine longissimus thoracis et lumborum muscles were incubated at temperature 0, 10, 20, 30 or 40 ˚C to 6 h post mortem. Incubation at 40 ˚C reduced the water-holding of meat compared to the lower temperatures (P &lt; 0.001). SDS-PAGE and Western blot analyses indicated that glycogen phosphorylase and creatine kinase precipitated with the myofilaments, which was already accomplished at 6 h post mortem. Substantial meat tenderization was measured after incubation at 40 ˚C, but with less activity of extracted μ- and m- calpains compared to lower temperatures (P &lt; 0.001), which suggests that an early activation of calpains at the highest incubation temperature could have been the reason for the tenderization. Surface hydrophobicity of myofilanments was higher after the pre-rigor incubation at 40 ˚C compared to lower temperatures (P &lt; 0.001). Less myosin subfragment-1 (S1) units were released by chymotryptic cleavage simultaneously with the loss of Ca2+ ATPase activity after incubation at 40 ˚C than at lower incubation temperatures (P &lt; 0.001). The results suggest that the high temperature incubation induce microstructural alterations on the myosin head (S1) region, which may in turn have been related to the loss of water-holding. The roles of the denaturation of sarcoplasmic proteins and myofibrillar proteins were compared. Sarcoplasm not-incubated or incubated at 44 ˚C were mixed with protein-depleted sarcoplasm in different rations and the mixtures were combined with myofibrils and subjected to PSE-like condition pH 5.6/44 ˚C for 1 h . Water-holding was the poorest without the incubated sarcoplasmic proteins. Precipitated sarcoplasmic proteins shrank the myofilamental lattice spacing by 6.3%, compared to protein-free sarcoplasm, during post-rigor incubation at 44 ˚C, shown by X-ray diffraction. These results challenge the current understanding of the role of the denaturation of different proteins in water-holding, and therefore, a new hypothesis is proposed in this thesis: 1) in the intramyofibrillar space, the presence of precipitating sarcoplasmic proteins is associated with the filamental lattice compression that expels water; 2) in the space outside the myofibrils (intermyofibrillar space) within fiber and up to the extracellular space, the coagulated sarcoplasmic proteins form a network that traps water expelled from the intramyofibrillar space.","abstract_has_math":false,"creators":["Liu, Jiao"],"institution":"Helsingin yliopisto","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-06-29","date_published":"2016-06-29","updated_at":"2026-08-21T22:21:56Z","subjects":["Meat Science"],"languages":["eng"],"rights":["Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.","This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.","Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10138/163547","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"source_record":{"url":"https://helda.helsinki.fi/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Ahelda.helsinki.fi%3A10138%2F163547","prefix":"dim"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Liu, Jiao"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-06-09T13:26:32Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-06-19","2016-06-09T13:26:32Z"]},{"key":"dc:date.issued","label":"Date","values":["2016-06-29"]},{"key":"dc:publisher","label":"Institution","values":["Helsingin yliopisto","Helsingfors universitet","University of Helsinki"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Meat Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.","This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.","Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10138/163547"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The aim of the thesis was to investigate the interaction between sarcoplasmic proteins and myofibrillar proteins, considering the effects on the loss of water-holding in mild heat induced denaturation such as occurring in pale, soft and exudative (PSE) condition. Porcine longissimus thoracis et lumborum muscles were incubated at temperature 0, 10, 20, 30 or 40 ˚C to 6 h post mortem. Incubation at 40 ˚C reduced the water-holding of meat compared to the lower temperatures (P < 0.001). SDS-PAGE and Western blot analyses indicated that glycogen phosphorylase and creatine kinase precipitated with the myofilaments, which was already accomplished at 6 h post mortem. Substantial meat tenderization was measured after incubation at 40 ˚C, but with less activity of extracted μ- and m- calpains compared to lower temperatures (P < 0.001), which suggests that an early activation of calpains at the highest incubation temperature could have been the reason for the tenderization. Surface hydrophobicity of myofilanments was higher after the pre-rigor incubation at 40 ˚C compared to lower temperatures (P < 0.001). Less myosin subfragment-1 (S1) units were released by chymotryptic cleavage simultaneously with the loss of Ca2+ ATPase activity after incubation at 40 ˚C than at lower incubation temperatures (P < 0.001). The results suggest that the high temperature incubation induce microstructural alterations on the myosin head (S1) region, which may in turn have been related to the loss of water-holding. The roles of the denaturation of sarcoplasmic proteins and myofibrillar proteins were compared. Sarcoplasm not-incubated or incubated at 44 ˚C were mixed with protein-depleted sarcoplasm in different rations and the mixtures were combined with myofibrils and subjected to PSE-like condition pH 5.6/44 ˚C for 1 h . Water-holding was the poorest without the incubated sarcoplasmic proteins. Precipitated sarcoplasmic proteins shrank the myofilamental lattice spacing by 6.3%, compared to protein-free sarcoplasm, during post-rigor incubation at 44 ˚C, shown by X-ray diffraction. These results challenge the current understanding of the role of the denaturation of different proteins in water-holding, and therefore, a new hypothesis is proposed in this thesis: 1) in the intramyofibrillar space, the presence of precipitating sarcoplasmic proteins is associated with the filamental lattice compression that expels water; 2) in the space outside the myofibrils (intermyofibrillar space) within fiber and up to the extracellular space, the coagulated sarcoplasmic proteins form a network that traps water expelled from the intramyofibrillar space.","Tutkimuksen tarkoitus oli tutkia sarkoplasman proteiinien ja myofibrilliproteiinien välistä vuorovaikutusta lihan vedenpidätyskyvyn suhteen tilanteessa, jossa proteiinit denaturoituvat miedon lämmön vaikutuksesta PSE-tyyppisessä (Pale, Soft, Exudative) tilanteessa. Sian longissimus thoracis et lumborum -lihakset inkuboitiin lämpötiloissa 0, 10, 20, 30 tai 40 ˚C kuusi tuntia post mortem. Inkubointi 40 ˚C:ssa alensi vedenpidätyskykyä verrattuna alempiin lämpötiloihin (P < 0.001). SDS-PAGE- ja Western blot -tulokset osoittivat, että glykogeenifosforylaasi ja kreatiinikinaasi saostuivat myofilamenttien pinnalle kuuden inkubointitunnin aikana. Merkittävä mureutuminen ja samanaikainen liukoisten μ- and m-kalpaiinien aktiivisuuden väheneminen havaittiin 40 ˚C:ssa tapahtuneen inkuboinnin jälkeen verrattuna alempiin lämpötiloihin (P < 0.001). Tämä viittaa siihen, että kalpaiinien aktivoituminen korkeassa lämpötilassa tapahtuvan inkuboinnin alkuvaiheessa on saattanut olla mureutumisen syy. Myofilamenttien pinnan hydrofobisuus oli korkeampi 40 ˚C:ssa suoritetun pre rigor -inkubaation jälkeen kuin alemmissa inkubaatiolämpötiloissa (P < 0.001). Samaten kymotrypsiini vapautti vähemmän myosiinin subfragmentti 1:ä ja Ca2+ ATPaasiaktiivisuus laski enemmän inkuboitaessa 40 ˚C:ssa kuin alemmissa lämpötiloissa (P < 0.001). Tulokset siten viittavat siihen, että korkeassa lämpötilassa suoritettu inkubaatio aiheuttaa muutoksia myosiinimolekyylien pään (S1-osa) alueella, mikä on saattanut olla yhteydessä vedenpidätyskyvyn laskuun. Tutkimuksessa verrattiin myös sarkoplasman proteiinien ja myofibrilliproteiinien denaturoitumisen vaikutuksia. Myofibrillit, joihin oli lisätty sarkolasmaa tai proteiinivapaata sarkoplasmaa eri suhteissa, asetettiin PSE-tyyppisin olosuhteisiin (pH 5,6/44 ˚C). Veden pidättyminen oli heikointa, kun inkuboituja sarkoplasman proteiineja ei ollut läsnä. X-sädedifraktiomittaukset osoittivat, että saostuvat sarkoplasman proteiinit supistivat myofilamenttien välisiä etäisyyksiä 6,3 % poikkisuunnassa 44 ˚C:ssa suoritetun post-rigor -inkubaation seurauksena. Nämä tulokset kyseenalaistavat nykyiset käsitykset eri proteiinien denaturaation vaikutuksista vedensidontakykyyn. Tässä väitöskirjassa esitetään siten uusi hypoteesi: 1) myofibrillien sisällä koaguloituvat sarkoplasman proteiinit ovat yhteydessä filamenttiverkoston kutistumiseen, jossa vettä puristuu niiden sisältä; 2) myofibrillien välissä ja lihassyyn ulkopuolella koaguloituvat sarkoplasman proteiinit muodostavat verkoston, joka sulkee sisäänsä myofibrillien sisältä puristunutta vettä."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Denaturation of myofibrillar and sarcoplasmic proteins in pale, soft and exudative-like meat : effects on water-holding"]}]}],"canonical_facts":{"dc:creator":["Liu, Jiao"],"dc:date.accessioned":["2016-06-09T13:26:32Z"],"dc:date.available":["2016-06-19","2016-06-09T13:26:32Z"],"dc:date.issued":["2016-06-29"],"dc:description.abstract":["The aim of the thesis was to investigate the interaction between sarcoplasmic proteins and myofibrillar proteins, considering the effects on the loss of water-holding in mild heat induced denaturation such as occurring in pale, soft and exudative (PSE) condition. Porcine longissimus thoracis et lumborum muscles were incubated at temperature 0, 10, 20, 30 or 40 ˚C to 6 h post mortem. Incubation at 40 ˚C reduced the water-holding of meat compared to the lower temperatures (P < 0.001). SDS-PAGE and Western blot analyses indicated that glycogen phosphorylase and creatine kinase precipitated with the myofilaments, which was already accomplished at 6 h post mortem. Substantial meat tenderization was measured after incubation at 40 ˚C, but with less activity of extracted μ- and m- calpains compared to lower temperatures (P < 0.001), which suggests that an early activation of calpains at the highest incubation temperature could have been the reason for the tenderization. Surface hydrophobicity of myofilanments was higher after the pre-rigor incubation at 40 ˚C compared to lower temperatures (P < 0.001). Less myosin subfragment-1 (S1) units were released by chymotryptic cleavage simultaneously with the loss of Ca2+ ATPase activity after incubation at 40 ˚C than at lower incubation temperatures (P < 0.001). The results suggest that the high temperature incubation induce microstructural alterations on the myosin head (S1) region, which may in turn have been related to the loss of water-holding. The roles of the denaturation of sarcoplasmic proteins and myofibrillar proteins were compared. Sarcoplasm not-incubated or incubated at 44 ˚C were mixed with protein-depleted sarcoplasm in different rations and the mixtures were combined with myofibrils and subjected to PSE-like condition pH 5.6/44 ˚C for 1 h . Water-holding was the poorest without the incubated sarcoplasmic proteins. Precipitated sarcoplasmic proteins shrank the myofilamental lattice spacing by 6.3%, compared to protein-free sarcoplasm, during post-rigor incubation at 44 ˚C, shown by X-ray diffraction. These results challenge the current understanding of the role of the denaturation of different proteins in water-holding, and therefore, a new hypothesis is proposed in this thesis: 1) in the intramyofibrillar space, the presence of precipitating sarcoplasmic proteins is associated with the filamental lattice compression that expels water; 2) in the space outside the myofibrils (intermyofibrillar space) within fiber and up to the extracellular space, the coagulated sarcoplasmic proteins form a network that traps water expelled from the intramyofibrillar space.","Tutkimuksen tarkoitus oli tutkia sarkoplasman proteiinien ja myofibrilliproteiinien välistä vuorovaikutusta lihan vedenpidätyskyvyn suhteen tilanteessa, jossa proteiinit denaturoituvat miedon lämmön vaikutuksesta PSE-tyyppisessä (Pale, Soft, Exudative) tilanteessa. Sian longissimus thoracis et lumborum -lihakset inkuboitiin lämpötiloissa 0, 10, 20, 30 tai 40 ˚C kuusi tuntia post mortem. Inkubointi 40 ˚C:ssa alensi vedenpidätyskykyä verrattuna alempiin lämpötiloihin (P < 0.001). SDS-PAGE- ja Western blot -tulokset osoittivat, että glykogeenifosforylaasi ja kreatiinikinaasi saostuivat myofilamenttien pinnalle kuuden inkubointitunnin aikana. Merkittävä mureutuminen ja samanaikainen liukoisten μ- and m-kalpaiinien aktiivisuuden väheneminen havaittiin 40 ˚C:ssa tapahtuneen inkuboinnin jälkeen verrattuna alempiin lämpötiloihin (P < 0.001). Tämä viittaa siihen, että kalpaiinien aktivoituminen korkeassa lämpötilassa tapahtuvan inkuboinnin alkuvaiheessa on saattanut olla mureutumisen syy. Myofilamenttien pinnan hydrofobisuus oli korkeampi 40 ˚C:ssa suoritetun pre rigor -inkubaation jälkeen kuin alemmissa inkubaatiolämpötiloissa (P < 0.001). Samaten kymotrypsiini vapautti vähemmän myosiinin subfragmentti 1:ä ja Ca2+ ATPaasiaktiivisuus laski enemmän inkuboitaessa 40 ˚C:ssa kuin alemmissa lämpötiloissa (P < 0.001). Tulokset siten viittavat siihen, että korkeassa lämpötilassa suoritettu inkubaatio aiheuttaa muutoksia myosiinimolekyylien pään (S1-osa) alueella, mikä on saattanut olla yhteydessä vedenpidätyskyvyn laskuun. Tutkimuksessa verrattiin myös sarkoplasman proteiinien ja myofibrilliproteiinien denaturoitumisen vaikutuksia. Myofibrillit, joihin oli lisätty sarkolasmaa tai proteiinivapaata sarkoplasmaa eri suhteissa, asetettiin PSE-tyyppisin olosuhteisiin (pH 5,6/44 ˚C). Veden pidättyminen oli heikointa, kun inkuboituja sarkoplasman proteiineja ei ollut läsnä. X-sädedifraktiomittaukset osoittivat, että saostuvat sarkoplasman proteiinit supistivat myofilamenttien välisiä etäisyyksiä 6,3 % poikkisuunnassa 44 ˚C:ssa suoritetun post-rigor -inkubaation seurauksena. Nämä tulokset kyseenalaistavat nykyiset käsitykset eri proteiinien denaturaation vaikutuksista vedensidontakykyyn. Tässä väitöskirjassa esitetään siten uusi hypoteesi: 1) myofibrillien sisällä koaguloituvat sarkoplasman proteiinit ovat yhteydessä filamenttiverkoston kutistumiseen, jossa vettä puristuu niiden sisältä; 2) myofibrillien välissä ja lihassyyn ulkopuolella koaguloituvat sarkoplasman proteiinit muodostavat verkoston, joka sulkee sisäänsä myofibrillien sisältä puristunutta vettä."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10138/163547"],"dc:language.iso":["eng"],"dc:publisher":["Helsingin yliopisto","Helsingfors universitet","University of Helsinki"],"dc:rights":["Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.","This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.","Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden."],"dc:subject":["Meat Science"],"dc:title":["Denaturation of myofibrillar and sarcoplasmic proteins in pale, soft and exudative-like meat : effects on water-holding"],"dc:type.dcmitype":["Text"]},"updated_at":"2026-08-21T22:21:56Z"}