Ukusungula izinto ezisekelwe ku-bio, izikali kanye nokunye ukungcola kwemboni yezinhlanzi ukuze kwenziwe ipulasitiki ye-bio yokupakisha ukudla!

Ukukhiqizwa kwezinhlanzi emhlabeni wonke ngo-2019 kulinganiselwa kumathani ayizigidi ezingu-177.8 futhi kulindeleke ukuthi kukhule kakhulu esikhathini esizayo. Njengoba kuqashelwa kabanzi yi-United Nations 2030 Agenda for Sustainable Development kanye ne-FAO, ukudoba kanye nokufuywa kwezinhlanzi kudlala indima ebalulekile ekuphepheni kokudla kanye nokudla okunomsoco. Cishe ama-70% ezinhlanzi kanye nokudla kwasolwandle kuyacutshungulwa ngaphambi kokuba kuthengiswe, okuholela enanini elikhulu lemfucuza eqinile emisebenzini efana nokunqunywa kwekhanda, ukususwa kwegobolondo, ukususwa kwesisu, ukuhlukaniswa kwezicubu kanye nokukalwa kwezicubu, kanye nokususwa kwezicubu.

Imikhiqizo engaphansi kweyokudoba ivame ukufaka izitho zangaphakathi, izicubu zemisipha, izidumbu, amakhanda, amaphiko, isikhumba, amakala namathambo, okwenza cishe amaphesenti angama-50 kuya kwangu-75 esisindo esisha, kuye ngohlobo. Isibonelo, ukucutshungulwa kwezinhlanzi ezisanhlamvu kanye nezibopho kukhiqiza cishe u-50% no-75% (ngesisindo) wemfucuza. Cishe u-20% wemikhiqizo engaphansi kweyokudoba isetshenziswa njengezithako ezinenani eliphansi ekudleni kwezilwane, iningi lazo eligcwele umhlaba noma elishiswayo, okuholela ekulahlekelweni kwemvelo, impilo kanye nomnotho.

Ngakho-ke imfucuza yezinhlanzi iyinkinga ekhulayo edinga izindlela ezintsha nezixazululo. Ngenxa yalokhu, kuye kwamukelwa amaphrojekthi nezinyathelo eziningana emhlabeni wonke ukuvimbela imfucuza yokudla. Phakathi kwazo, imfucuza yezinhlanzi njengento entsha eluhlaza ye-bio-plastics iye yadonsela ukunaka okwengeziwe ezindaweni ezahlukene zokusetshenziswa (ikakhulukazi ukupakishwa kokudla), ngezinzuzo ezibalulekile zomnotho nezemvelo.

Zingenziwa zibe ukupakishwa kokudla ngokuphinda zisetshenziswe ama-molecule amaningana angaba usizo afaka phakathi amafutha, amaprotheni, imibala, ama-peptide asebenzayo, ama-amino acid, i-collagen, i-chitin, ne-gelatin. Ukupakishwa kusabhekwa njengengxenye enkulu yeukukhiqizwa kwe-bio-plastics, okubalwa u-47% (amathani angu-990,000) wemakethe ye-bio-plastics ngo-2020. Phakathi kwalezi zinto ezintsha eziluhlaza, amafilimu adliwayo/abolayo ezicelo zokupakisha ukudla adonsele ukunaka kwabacwaningi kwezemfundo kanye nezimboni.

UFrancesca Rioneto, ovela eMnyangweni Wezobunjiniyela Bokusungula Izinto Ezintsha eNyuvesi yaseSalento, eyanyatheliswa ku-Polymers. Isihloko esifingqiwe, esinesihloko esithi 'Izicelo Zamuva Zama-Bio-polymers Ezivela Kumfucuza Wezimboni Zezinhlanzi Ekupakisheni Ukudla', sifingqa intuthuko yakamuva ekulinganisweni kwemfucuza evela embonini yezinhlanzi kanye nethuba lokusebenzisa kabusha le mikhiqizo engaphansi kwezinye izindlela zomnotho ezijikelezayo zokulungiselela amapulasitiki e-bio ukuze kupakishwe ukudla.

1. Iphrotheni yemisipha
Amaprotheni emisipha ahlukaniswe ngezigaba ezintathu ezibanzi ngokuya ngokuncibilika kwawo: i-myogenic fibrin, amaprotheni e-sarcoplasmic, kanye namaprotheni e-matrix. I-Myoffibrin iyisakhi esiyinhloko semisipha yamathambo, equkethe cishe u-65-75% weprotheni iyonke yemisipha. I-Myoffibrin ihlanganisa amanye amaprotheni athambile, njenge-myosin ne-actin, amaprotheni alawulayo njenge-protomyosin ne-troponin, kanye namanye amaprotheni esibili. Ngenxa yesakhiwo sawo kanye nendawo atholakala kuyo, ama-myoffibrin adinga izimo ezishintsha umbala, njengezixazululo zamandla aphezulu ukuze zincibilikiswe futhi zikhishwe.

Amaprotheni angenye yezinto eziphilayo ezisetshenziswa kakhulu embonini yokudla ngenxa yenani lawo lokudla okunomsoco, ikhono lokungabi nobuthi, ukubola kanye nekhono lokwenza ijeli. Eminyakeni yamuva nje, amaprotheni e-fish matrix kanye ne-myogen fibrin athole ukunakwa okukhulu ngekhono lawo lokwenza amafilimu abolayo, adliwayo anegesi ezinhle zokuvimbela, ama-volatiles e-organic kanye nezakhiwo ze-lipid ezingancibiliki emanzini kodwa ezingancibilika ngokulungisa i-pH yesisombululo. Lawa mafilimu enziwe ngama-fibrils emisipha yezinhlanzi noma amaprotheni emisipha anezinzuzo eziningana: (i) Isithiyo se-UV esihle kakhulu uma siqhathaniswa namafilimu okupakisha ezentengiselwano enziwe nge-PVC; (ii) izithiyo ezinhle ze-oxygen kanye ne-carbon dioxide; (iii) ukucaca okuncane; (iv) amandla okukhiqizwa kokupakisha okusebenzayo.

Izinkinga ezinkulu ezivimbela ukusetshenziswa kabanzi kwala mafilimu kwezentengiselwano ukuqina kanye namandla aphansi okusebenza, okuthuthukiswa kakhulu yizibopho ze-disulfide, izibopho ze-hydrogen, kanye/noma ukusebenzisana kwe-electrostatic ngenxa yokusebenzisana okukhulu kweketanga le-protein-protein kunethiwekhi yefilimu encane. Ukuze kunqotshwe le nkinga, amazinga aphezulu e-plasticizers (cishe ama-40-60%) angangezwa kumafilimu abolayo ukuze kuncishiswe ukuphuka nokwandisa ukuqina nokuqina ngokunciphisa amandla phakathi kwamaketanga e-protein-protein. Omunye umkhawulo we-fish fibrin membranes ukuvinjelwa komusi wamanzi ompofu, okubangelwa ukunamathela okuphezulu kwama-amino acid kumaprotheni kanye nokwengezwa kwenani elikhulu le-hydrophilic plasticizers (njenge-glycerol kanye ne-sorbitol) ukuze kunikezwe ulwelwesi ukuguquguquka okwanele. Ukuxhumanisa kwamakhemikhali, imisebe ye-electron, kanye nemisebe ye-gamma kubikwe njengezindlela ezisebenzayo zokuthola amafilimu aqinile futhi angangeni kakhulu.

2. I-collagen yasolwandle

I-Collagen yiprotheni yesilwane evame kakhulu ngoba itholakala kuzo zonke izicubu ezixhumene (okungukuthi, isikhumba, amathambo, imisipha, imisipha kanye ne-cartilage) kanye nezicubu ezingaphakathi kwezitho ze-parenchymal.

I-colagen yasolwandle ikhishwa kakhulu ezikhumbeni zezinhlanzi, emathanjeni ezinhlanzi, emaphinini, emaqolweni noma ezicutshini ezixhumanisayo ze-jellyfish, ama-sea urchins, i-starfish noma ama-sea cucumber. Izikhumba zezinhlanzi zisetshenziswe ukukhipha i-collagen ngoba u-70-80% wezinto zayo ezomile yi-collagen. Ngaphezu kwalokho, amaqolweni ezinhlanzi angomunye umthombo othembisayo futhi ongabizi we-colagen yasolwandle, ohlanganisa cishe u-4% wesisindo sonyaka se-fish offal, cishe amathani ayizigidi ezingu-18-30. Amaqolweni ezinhlanzi aqukethe kokubili izingxenye eziphilayo (i-collagen, amafutha, i-lecithin, iphrotheni eqinile, amavithamini ahlukahlukene, njll.) kanye nezingxenye ezingaphili (i-hydroxyapatite, i-calcium phosphate, njll.).

Uma kuqhathaniswa ne-collagen yezilwane ezincelisayo, i-collagen yasolwandle inesisindo sama-molecule esifanayo noma esiphansi kancane kanye nokushisa okuphansi kokushintshashintsha (ukuncibilika), okungaba ngu-20-35°C ezinhlanzini eziningi, kuyilapho amanani e-collagen avela ezinhlotsheni zamanzi afudumele ephakeme. Ukuze kuthuthukiswe ukuzinza kokushisa, kuye kwafundwa izindlela zokwelapha ezihambisanayo zokuxhumanisa.

Ngokusho kukaCoppola njll., isisindo esomile se-collagen ekhishwe emikhiqizweni yezinhlanzi singafinyelela ngaphezu kuka-50%. Ngaphezu kwalokho, ukuhlanza amafutha ngesikhathi sokucubungula izinhlanzi akuqinisekisi iphunga noma ukunambitheka. Ngokuvamile kuthatha isikhathi eside ukukhipha i-collagen ezikalini zezinhlanzi ngezindlela zamakhemikhali. Ngenxa yalokho, abacwaningi banesithakazelo esikhulu enqubweni efanelekile yokukhipha i-collagen ezikalini zezinhlanzi.

Uma kuqhathaniswa ne-collagen yezilwane ezincelisayo, i-collagen yasolwandle ayinayo imikhawulo yokusetshenziswa ngezizathu zenkolo kanye nezifo ezithathelwanayo ezingaba khona, futhi ngesikhathi esifanayo inamandla amahle okwakha ifilimu, ukuhambisana kwe-bio, i-antigen ephansi, ukubola okuphezulu kanye nekhono lokukhula kwamaseli. Lo mfucuza unamandla okuthuthukiswa njengomthombo we-collagen onobungani nemvelo futhi ongabizi kakhulu onezinhlelo eziningi ezingaba khona njengomthwali wemithi/wokulethwa noma ukubopha amanxeba emikhakheni ehlukahlukene njengokudla okunempilo, izimonyo kanye nemithi ye-bio. Ngenxa yamandla ayo aphezulu okumunca amanzi, i-collagen iyindlela enhle yokwenza i-texturization, ukuqina, kanye nokwakheka kwejeli. Ngaphezu kwalokho, inezakhiwo ezithakazelisayo ezihlobene nokuziphatha kwendawo, okuhlanganisa i-emulsion, ukwakheka kwe-foam, ukuzinza, ukunamathela kanye nokuhlangana, umsebenzi wokuvikela we-colloidal kanye nekhono lokwakha ifilimu. Nakuba isetshenziswe njengesithasiselo sokudla ukuthuthukisa izakhiwo zokudla ze-rheological, i-collagen yasolwandle ayikasetshenziswa ngokugcwele futhi ukusetshenziswa kwayo kuphansi kakhulu kune-collagen yezilwane ezincelisayo.

Ukusetshenziswa kwefilimu ye-collagen yezinhlanzi embonini yokupakisha kunqunyelwe ezinye izinkinga, njengokuqina okuphansi kokushisa kanye nezakhiwo zemishini ezingezinhle. Ngaphezu kwalokho, i-collagen iyi-polymer ephilizayo enamaqembu e-hydroxyl. Ngakho-ke, umhwamuko wamanzi udlula kalula efilimini. Ukuze kunqotshwe lokhu kulinganiselwa, kuye kwenziwa imizamo ehlukahlukene, okuhlanganisa ukuxuba i-collagen namanye ama-biopolymer kanye nezinqubo eziningana zamakhemikhali nezama-enzyme. Isibonelo, u-Ahmed nabanye. besebenzisa ingxube ye-collagen ne-chitosan ekhishwe ezikhumbeni zejazi lesikhumba, amandla e-bacteriostatic kanye nomsebenzi we-bacteriostatic wefilimu kuyathuthukiswa, kodwa ukuqina noma ubuthakathaka befilimu kuyathinteka.

3. Inhlaka yenhlanzi

I-Gelatin iyiprotheni ephukile etholakala ku-hydrolysis engaphelele kanye nokwelashwa kokushisa kwe-collagen. Yakhiwa yiqoqo lamaprotheni nama-poly-peptide anesisindo sama-molecule ahlukene, ukwakheka kwawo kuncike kakhulu ku-collagen engumzali kanye nenqubo yokukhipha. Ngesikhathi se-hydrolysis, izibopho zemvelo zama-molecule phakathi kwamaketanga e-collagen ngamanye ziyahlukaniswa, okushiya ingxube yama-poly-peptides anombala owodwa noma amaningi, ngalinye linokwakheka kwe-left-helix enwetshiwe futhi liqukethe ama-amino acid angu-50-1000. Izinhlobo ezimbili ze-gelatin zitholakala nge-acid hydrolysis kanye ne-alkali hydrolysis, okungukuthi uhlobo A kanye nohlobo B.

Ngenxa yezinkinga zenkolo kanye nokukhathazeka mayelana nempilo yokusabalala kwezifo kubantu, ukukhishwa nokusetshenziswa kwe-gelatin endle yezinhlanzi kuye kwavusa isithakazelo esikhulu. I-Gelatin iyi-bio-polymer ebalulekile yezimboni enezakhiwo ezibalulekile ze-gelling kanye ne-film-forming ezingasetshenziswa ekudleni, emithini nakwezinye izinkambu ezihlobene.

Ngenxa yezakhiwo zayo ezinhle zokwakha ifilimu, izindleko eziphansi, ukuhambisana kwezinto eziphilayo kanye nokubola kwazo, i-fish gelatin isanda kunconywa ekulungiseleleni amafilimu abolayo ekupakisheni kokudla okusebenzayo ukuze ithathe indawo yama-polymers avamile angaboli kanye namanye ama-gelatin asekelwe ezincelisayo. Ngokusebenzisa ukushisa kanye nokucindezeleka komshini kubuchwepheshe obusekelwe ekukhipheni, i-gelatin kulula ukuyicubungula. Ukuze kwandiswe ukuguquguquka, ama-plasticizer asetshenziswa njengezinto zokugcoba zangaphakathi, ezithuthukisa ukugeleza kwama-molecule. Isixazululo samanzi se-Gelatin singatholakala ngokufaka ifilimu ye-gelatin. Ayinaphunga, ayinambala, iyabonakala, ayincibiliki emanzini, futhi iguquguquka kakhulu kunezinye amafilimu asekelwe ezintweni eziphilayo asetshenziswa ekupakisheni kokudla. Njengoba indawo yokuncibilika kwe-gelatin iseduze nokushisa komzimba, amafilimu asekelwe ku-gelatin angasetshenziswa ukulungiselela amafilimu adliwayo. Ngaphezu kwalokho, i-fish gelatin ibonise amandla amakhulu njenge-matrix enhle kakhulu yamakhemikhali asebenzayo ngezinto eziphilayo anemisebenzi ethuthukisayo, njenge-antioxidants/ama-antibacterial agents.

Ukumelana namanzi kuthuthukiswa ngokufaka ifilimu ye-gelatin yenhlanzi nge-polymer engaboliyo yomswakama efilimu enezingqimba eziningi enesendlalelo sokuvimbela umswakama nomoya-mpilo esilungiselelwe ukupakishwa nezimo ezithile. I-Matutsch njll. Nge-montmorillonite sodium plasticizing gelatin njengesendlalelo sangaphakathi, isitashi se-dialdehyde esixhumene ne-cross-linked kanye nefilimu ye-gelatin epulasitiki njengesendlalelo sangaphandle, izendlalelo ezintathu zefilimu ye-gelatin zacindezelwa ngokushisa. Njengoba izendlalelo ngazinye zingasebenzisana ngezibopho ze-hydrogen eziqinile, ama-membrane anezingqimba eziningi abonisa izakhiwo ezincane ezihlangene nezifanayo. Ababhali abafanayo baphinde balungiselela isakhiwo esinezingqimba eziningi lapho ifilimu ye-poly-lactic acid isebenza njengesendlalelo sangaphandle esinokungena kwamanzi okuphezulu kunamanye ama-polymer ezentengiselwano njenge-polyethylene ephezulu noma i-polyvinyl chloride.

Enye indlela ethembisayo yokuthuthukisa izakhiwo zokuvimbela, izakhiwo zemishini kanye nezakhiwo zokushisa zeglue yezinhlanzi zokupakisha ukudla isekelwe ekuhlanganiseni okuhlanganisiwe. Ikakhulukazi, njengoba iGaravand njll. ibukezile, ama-crosslinkers asekelwe ngokwemvelo adonsele ukunaka okwengeziwe ukuze kucatshangelwe izinkinga zemvelo nezempilo kanye nezinkinga zomnotho. I-Liguori njll. yasungula inqubo yokuxhumanisa i-gelatin yezinhlanzi ne-citric acid. Ukwelashwa ngokushisa lapho kukhona ushukela oncishisiwe (okubizwa ngokuthi i-Maillard reaction) kuboniswe ukuthi kuholela ezinqubweni zokuxhumanisa okuhlanganisiwe kanye nezakhiwo zenethiwekhi ezishintshiwe. Muva nje, i-Maroufi njll. ibonise ukuxhumanisa kwamakhemikhali kwe-gelatin yezinhlanzi neqembu le-aldehyde le-K-carrageenan.

4. Ukusetshenziswa kwe-chitosan emaphaketheni okudla

I-Chitin, i-bio-polymer yesibili etholakala kakhulu ngokwemvelo ngemuva kwe-cellulose, iyi-polymer eqondile, i-polysaccharide, etholakala odongeni lweseli lesikhunta kanye nase-plankton, ama-crustaceans kanye ne-exoskeleton yezinambuzane, ngesimo se-microfibers e-crystalline ehlelekile ekhiqiza amathani angaba yizigidi eziyi-100 ze-chitin ngonyaka.

Izakhiwo ze-bio-polymers ze-chitin kanye ne-chitosan ezihambisana ne-bio, ezingenabo ubuthi kanye nokusebenza kwe-bio zenza ukuthi zifaneleke kakhulu ekufakweni kokudla. Ikakhulukazi, ama-bio-polymers e-chitosan akhishwe kuma-shrimp anqunywa kusengaphambili njenge-Safe (GRAS). Ngakolunye uhlangothi, i-chitosan ishibhile kakhulu uma iqhathaniswa namanye ama-bio-polymers. Noma kunjalo, izakhiwo ezinhle kakhulu ze-chitosan zenza ukuthi ifaneleke kakhulu ekufakweni kokudla. Isibonelo, kwaphakanyiswa ngempumelelo ukwandisa impilo yeshelufu yesinkwa ngoba kwabonakala ukuthi ibambezela ukubuya kwesitashi ngokuvimbela ukukhula kwamagciwane.

I-Tyliszczak njll. ikhombisile ukuthi amafilimu e-chitosan angagcina nama-strawberry. Ngaphezu kwalokho, i-Zakaria njll. ikhombisile ukuthi ulwelwesi lwe-chitosan luvimbela izinguquko ezakhiweni zomzimba zemifino. I-Chitosan ingasetshenziswa futhi ukukhiqiza isimbozo sokudla esimbozwe yiso, ngaleyo ndlela ibambezele ukukhula kwamagciwane. Isu lokuthuthukisa ukusebenza kwamafilimu e-chitosan okupakisha ukudla licishe lifane nalelo elisetshenziselwa amafilimu e-gelatin enhlanzi. Eqinisweni, ukuthuthukiswa kwezingxube ze-polymer kumelela indlela ephumelelayo yokuthuthukisa izakhiwo zemishini nokunciphisa ukuncibilika kwamanzi kanye nokuvuleka komhwamuko wamanzi. Ama-polysaccharide amaningana aye engezwa ku-chitosan ukuze kukhiqizwe amafilimu axubile anezakhiwo zokugcina ezithuthukisiwe zokusetshenziswa kokudla. Phakathi kwawo, ngenxa yezindleko zayo eziphansi, ukutholakala kabanzi kanye nokubola kwezinto eziphilayo, isitashi singenye yama-polysaccharide avame kakhulu ahlongozwayo ekukhiqizweni kwama-biofilm asekelwe ku-chitosan.

Amafilimu e-Chitosan/starch abonisa ukunamathela okunciphile kwamagciwane, umsebenzi omuhle kakhulu we-antioxidant kanye nezakhiwo zokuvimbela umhwamuko wamanzi ezandayo ekupakishweni, ngaleyo ndlela ekhombisa ukufaneleka kwawo ekusetshenzisweni okuthile. Ososayensi abaningana baye bafunda ukuthi kungenzeka yini ukulungiselela ingxube ye-cellulose/chitosan ukuze kuthuthukiswe izakhiwo ze-chitosan emsulwa.

Imfucuza yezimboni zezinhlanzi ikhombisa amandla amakhulu njengezinto ezintsha zokusetshenziswa kwe-bio-polymer futhi ingasetshenziswa ezindaweni ezahlukene zokusetshenziswa, ikakhulukazi ekupakisheni ukudla. Ukusetshenziswa kwemfucuza yezinhlanzi okunenani elongeziwe kunezinzuzo zomnotho ngoba kusiza ukunciphisa izindleko zokulahla imfucuza ephephile futhi kukhiqiza inani elengeziwe ngokuphinda kusetshenziswe ama-molecule amaningana angaba yigugu. Ngaphezu kwalokho, inani elengeziwe lemikhiqizo yezinhlanzi engaphansi kwemikhiqizo liletha izinzuzo eziningana zemvelo ezivela ekunciphiseni ukugcwaliswa komhlaba, ukushiswa kanye nokulahlwa, okwakha ukulahlwa okukhulu kwezinsizakusebenza, kanye nokufakwa esikhundleni sama-polymer asekelwe ezinsaleleni. Ngale ndlela, ukuphinda kusetshenziswe imfucuza yezinhlanzi kungaba nomthelela omuhle ezindaweni zemvelo kanye nokusebenza kahle kwezezimali kwezindawo zokudoba. Umthelela wayo kulindeleke ukuthi wande eminyakeni ezayo.

Umnikelo oyinhloko walokhu kubuyekezwa ukukhombisa ukuthi yonke imikhiqizo yokudoba engasetshenziswa ukuthuthukisa ubuchwepheshe bokucwenga i-bio uma kuqhathaniswa nezindawo zokuhlanza i-petroleum zakudala ezihlotshaniswa nokukhishwa kwegesi ebamba ukushisa esuselwe ku-carbon. Njengoba kubonisiwe, i-fibro-fibrin, i-collagen, i-gelatin, i-chitin, i-chitosan evela emisipheni, i-visceral, isikhumba, izikali, amaphiko noma amagobolondo e-crustacean kuye kwabonakala kuhlangabezana nezidingo zobuchwepheshe zesizukulwane esisha sokupakisha, okubizwa ngokuthi ukupakisha okuhlakaniphile, okubandakanya ukusebenzisana phakathi kokupakisha nokudla noma ukudla ngaphakathi kwesimo sokupakisha. Amathemba emakethe esikhathi esizayo angalindelwa!