Xanthan cov pos hniav tam sim no suav hais tias yog qhov zoo tshaj plaws bio- cov pos hniav thoob ntiaj teb, sib txuas cov thickening, suspending, emulsifying, thiab stabilizing zog. Tus nqi ntawm pyruvate pawg ntawm qhov kawg ntawm xanthan cov pos hniav molecular sab chains cuam tshuam rau nws cov kev ua tau zoo. Thaum muaj cov khoom siv dav dav ntawm ntev - cov saw hlau polymers, xanthan cov pos hniav muaj ntau pab pawg ua haujlwm tshaj li cov polymers, nthuav tawm cov khoom tshwj xeeb hauv cov xwm txheej tshwj xeeb. Nws conformation nyob rau hauv aqueous daws yog ntau haiv neeg, displaying txawv cov yam ntxwv nyob rau hauv txawv tej yam kev mob.
1. Suspension thiab Emulsifying Properties: Xanthan cov pos hniav nthuav tawm cov khoom ncua kev kawm zoo rau cov khoom tsis sib haum thiab cov roj tee. Xanthan gum sol molecules tuaj yeem tsim super-bound, ribbon-zoo li helical copolymer, ua rau tsis yooj yim, gel-zoo li cov qauv network. Yog li ntawd, nws muaj peev xwm txhawb nqa lub morphology ntawm cov khoom hais, tee, thiab npuas, nthuav tawm muaj zog emulsifying stabilizing teebmeem thiab muaj peev xwm raug ncua.
2. Dej Solubility zoo: Xanthan cov pos hniav dissolves sai sai hauv dej, nthuav tawm cov dej solubility zoo heev. Nws dissolves txawm nyob rau hauv dej txias, tshem tawm cov txheej txheem complex thiab ua kom yooj yim rau siv. Txawm li cas los xij, vim nws muaj zog hydrophilicity, yog ntxiv ncaj qha rau hauv dej yam tsis muaj qhov sib tov txaus, txheej txheej sab nrauv yuav nqus dej thiab o mus rau hauv gel-zoo li huab hwm coj, tiv thaiv dej los ntawm kev nkag mus rau hauv txheej txheej thiab yog li cuam tshuam rau nws cov txiaj ntsig. Yog li ntawd, kev siv kom zoo yog qhov tseem ceeb. Xanthan pos hniav hmoov, los yog sib tov ntawm xanthan pos hniav hmoov thiab qhuav hmoov additives xws li ntsev los yog qab zib, yuav tsum tau maj mam ntxiv rau dej thaum stirring los tsim ib tug tov.
3. Thickening Properties: Xanthan gum tov muaj viscosity siab nyob rau hauv tsawg concentrations (ib 1% aqueous tov muaj ib tug viscosity sib npaug rau 100 npaug ntawm gelatin), ua rau nws yog ib tug zoo thickener.
4. Pseudoplasticity: Xanthan cov pos hniav aqueous daws muaj viscosity siab nyob rau hauv zoo li qub lossis tsis tshua muaj shear. Nyob rau hauv siab shear tej yam kev mob, lub viscosity txo sharply, tab sis cov qauv molecular tseem tsis hloov. Thaum lub zog shear raug tshem tawm, qhov qub viscosity yog tam sim ntawd rov qab los. Kev sib raug zoo ntawm shear quab yuam thiab viscosity yog tag nrho cov yas. Xanthan cov pos hniav nthuav tawm cov pseudoplasticity tseem ceeb heev, uas yog qhov ua tau zoo heev hauv kev ruaj ntseg tshem tawm thiab emulsions.
5. Thermal Stability: Lub viscosity ntawm xanthan gum tov tsis hloov pauv nrog kub. Thaum cov polysaccharides feem ntau muaj viscosity hloov thaum cua sov, viscosity ntawm xanthan gum aqueous daws tseem yuav luag tsis hloov ntawm 10-80℃. Txawm tias tsis tshua muaj siab aqueous daws teeb meem muaj qhov ruaj khov siab viscosity dhau qhov kub ntau. Cov pos hniav 1% xanthan (muaj 1% poov tshuaj chloride) rhuab ntawm 25℃mus rau 120℃qhia tau hais tias tsuas yog 3% txo qis hauv viscosity.
6. Acid thiab Alkali Stability: Xanthan gum tov yog ruaj khov rau cov kua qaub thiab alkalis. Nws viscosity tsis cuam tshuam ntawm pH 5-10, nrog kev hloov me ntsis ntawm pH qhov tseem ceeb hauv qab no 4 thiab siab dua 11. Nyob rau hauv qhov pH ntau ntawm 3-11, qhov sib txawv ntawm qhov siab tshaj plaws thiab qhov tsawg kawg nkaus viscosity yog tsawg dua 10%. Xanthan cov pos hniav yog soluble hauv ntau cov kua qaub, xws li 5% sulfuric acid, 5% nitric acid, 5% acetic acid, 10% hydrochloric acid, thiab 25% phosphoric acid. Cov xanthan cov pos hniav cov kua qaub no ruaj khov heev ntawm chav tsev kub, thiab lawv cov khoom tseem tsis hloov txawm tias tom qab ob peb lub hlis. Xanthan cov pos hniav kuj yog soluble hauv sodium hydroxide tov thiab muaj cov khoom thickening. Cov txiaj ntsig daws tau ruaj khov heev ntawm chav tsev kub. Xanthan cov pos hniav tuaj yeem degraded los ntawm cov oxidizing muaj zog, xws li perchloric acid thiab persulfate, thiab degradation accelerates nrog nce kub.
