Tiu lun ph gia GVHD: L Vn Nht HoiB CNG THNGTRNG I HC CNG NGHIP TP H CH MINH VIN CNG NGH THC PHM SINH HC------1 1 -------Tiu lun mn: ti:GVHD: Th.S L Vn Nht Hoi Lp : HTP2Sinh vin: Trn Th Ngc DiuPhm Th Bch LoanNguyn Th HoPhm Th Hong YnTp.H Ch Minh. Thng 4 nm 2009Lp DHTP2Trang 1Tiu lun ph gia GVHD: L Vn Nht Hoi----- ' ------Lp DHTP2Trang 2Tiu lun ph gia GVHD: L Vn Nht Hoi

Nc ta l nc nng nghip, do nguyn liu trong ngnh cng ngh thc phm v cng a dng. Nhng vic tn dng cc nguyn liu trong sn xut cn hn ch, a s nc ta ch sn xut nguyn liu th.V vy, victmhngpht trinmi chongnhcngnghipchbin ngy cng tr nn cp thit hn, mt trong nhng gii php l vic s dng cc cht ph gia trong sn xut, chng ngy cng tr nn ph bin, a dng v hon thin hn bi nhng c tnh u vit nh tng thi gian bo qun, to cu trc v c gi tr cm quan. Cho nn s dng cht ph gia thc phm ngy nay tr thnh mt vn ht sc quan trng v cn thit. Ph gia th rt a dng, vic s dng ph gia thch hp s lm tng gi tr cm quan thc phm. y, chng em xin nghin cu v ph gia to cu trc, m trong ng quan tm nht l pectin.Thi tin s,pectin l thnh phn quan trng trong khu phn thc n ca con ngi. Nhng ch mi trong na th k trc ngnh thc phm mi nhn bit c vai tr quan trng ca ph gia pectintrong vic a dng ha cc sn phm thc phm.Trong cng nghip pectin c thu nhn t dch chit ca cc nguyn liu thc vt, thng l to hay cc qu c mi. Phn ln cc quc gia xem pectin l ph gia qu v v hi, c s dng vi liu lng ph thuc vo quy trnh cng ngh.Do kin thc cng nh thi gian cn hn ch v vi quy m l mt bi tiu lun. V vy khng th trnh khi nhng thiu xt v khng y . Knh mong Thy v qu bn c gp cho nhm nhng bi tiu lun sau hon thin hn. Nhm chng em xin gi li cm n chn thnh n thy L Vn Nht Hoi hng dn tn tnh nhm chng em hon thnh tt bi tiu lun ny.Lp DHTP2Trang 3Tiu lun ph gia GVHD: L Vn Nht Hoi1. Gii thiu chung v pectin: 1.1 .Ngun gc- Pectin l mt polymer ca polygalacturonic v cc ester methyl ca chng. Pectin c nhiu qu, c hoc thn cy. Trong thc vt, pectin tn ti di hai dng: dng protopectin khng tan, tn ti ch yu thnh t bo di dng kt hp vi polysaccharide araban, dng ha tan ca pectin tn ti ch yu dch t bo.- Pectin nh mt loi keo gn cht cc t bo thc vt vi nhau, v th ngi ta thung gi chng l cht ciment l protopectin, protopectin chim t l kh1 cao, protopectin khng ha tan trong nc gip qu c cng.- Khi qu chn dn protopectin s chuyn sang pectin ha tan (pectin) v araban, lm gim s lin kt gia t bo, qu tr nn mm hn. Qu trnh ny cng xy ra di tc dng ca acid v nhit trong qu trnh chn 60-850C.- Trong thc vt cc pectin thng lin kt vi cellulose vch t bo dng phc hp cha bit r (hnh 1)Hnh 1: pectin trong cu to ca thnh t bo thc vtLp DHTP2Trang 4Tiu lun ph gia GVHD: L Vn Nht Hoi1.2 .Cu to phn t pectin:Cc cht pectin l cc polysaccharide, mch thng, cu to t s lin kt gia cc mch ca phn t acid D-galacturonic C6H10O7, lin kt vi nhau bng lin kt 1,4-glucoside. Trong mt s gc acid c cha nhm th methoxyl (-OCH3). Chiu di ca chui acid polygalacturonic c th bin i t vi n v ti hng trm n v acid galacturonic.Cu to 1 n v ca chui pectin:Hnh 2: Cu to mt n v chui pectin1.3 .Tnh cht ca pectin: Pectin thuc nhm cc cht lm ng t. Pectin uc xem l mt trong nhng ph gia thc phm an ton v uc chp nhn nhiu nht, v iu ny c chng minh bi hm lng ADI cho php l khng xc nh uc ban hnh bi t chc JECFA(Joint Food Experts Committee), SCF (Scientific Committee for Food) lin minh Chu u, v GRAS (Generally Regarded).M hiu quc t ca pectin l E40.Lp DHTP2Trang 5Tiu lun ph gia GVHD: L Vn Nht HoiPectin tinh ch c dng bt trng mu xm nht.L mt cht keo ht nc v rt d tan trong nc, khng tan trong ethanol. ctnhquantrongcapectinlkhi cmt caacidv ng n c kh nng to ng (to gel). V vy, n c ng dng ph bin trong k ngh sn xut bnh ko. Dung dch pectin c nht cao. Nu mun thu dch qu p th dungdchnybtli, ngi taphidngenzymespectinasethyphn pectin,gim nht. V d nc c chua 90-92% H2O nhng v % pectin cao nn sn phm c dng st. Nc da t pectin d p, lc.2. Cc yu t nh hng n kh nng to gel: Gm 4 yu t: cht lng pectin, ng, nc v acid.+ Pectin: - Mch phn t pectin l c cu chnh ca hin tng to gel. V th, lng pectin c trong dch ng phi t mt lng ti thiu no mi to c s keo t. Nng pectin c trong dung dch cng ln th s lin hp gia cc phn t xy ra cng nhanh, h keo t cng bn. Thng lng pectin s dng khong t 0.5-1%. Khi dng lng pectin vt qu lng thch hp s thu c gel qu cng, v vy i vi loi qu cha d pectin ngi ta cn tin hnh phn gii bt chng bng cch un lu hn.- Tuy nhin, cht lng ca h keo pectin li ph thuc rt ln vo tnh cht ca pectin ch khng n thun hm lng pectin c s dng. Hai yu t quan trng hng u l chiu di mch phn t pectin v mc methoxyl ha trong phn t ca chng.- Chiu di phn t pectin quyt nh cng ca gel:- Nu phn t pectin qu ngn th n s khng to c gel mc d s dng vi liu lng cao.- Nu phn t pectin qu di th gel to thnh qu cng.Lp DHTP2Trang 6Tiu lun ph gia GVHD: L Vn Nht Hoi- Mc methoxyl ha qui nh c ch to gel:- Kh nng keo ha ca pectin ph thuc tong i vo mc hin din ca cc nhm methoxyl. Ty thuc vo ch s methoxyl cao (>7%) hoc thp (3-5%) phn t pectin m cc kiu kt hp gia chng s khc nhau trong vic to gel.Bng 2.1 : Tc dng ca DE ca pectin ln s to gelDE(%) iu kin to gel>70 pH ng (%)Ion ha tr IITc to gel59-70 2.8-3.4 65 Khng Nhanh