Microencapsulation in food science and biotechnologyFilomena Nazzaro1 , Pierangelo Orlando2 , Florinda Fratianni1 and Raffaele Coppola1

Microencapsulation c th i din cho mt v d tuyt vi ca cng ngh vi p dng i vi khoa hc thc phm v cng ngh sinh hc. Microencapsulation c th c p dng thnh cng chit xut cc hp cht t nhin, ging nh cc loi tinh du chit xut t thc vt hoc c cha polyphenol vi khng sinh cng c bit n thuc tnh c s dng trong bao b thc phm. Microencapsulation lu gi vi khun axit lactic, c hai mi bt u v ch phm sinh hc, trong thc phm v trong thi gian qua thng qua ng tiu ha, v c th ng gp vo s pht trin ca cc chc nng mi thc phm.Microencapsulation: nguyn tc v s dng vi thnh phn t nhinMicroencapsulation (ME) l s bao nh cc ht rn, git cht lng hoc cht kh trong mt lp ph (1-1000 m). Ni chung, ngi ta c th phn bit gia vin nang bch cu n nhn, trong c mt li bao bc bi mt v, v ct liu, trong c nhiu li nhng trong mt ma trn, thng l polyme (Hnh 1). S pht trin thnh cng h thng ng gi cho mc tiu ng dng l c s trn nhu cu ca s hiu bit tt v s n nh chn thnh phn, phn t sinh hc hoc t bo, c ng gi (core), thuc tnh ca cc vt liu dng cho ng gi (ma trn encapsulant) v s ph hp ca cc h thng phn phi (microcapsule) cho ng dng cui cng ca n. Cc cng ngh c sn nht cho microencapsulation s dng mt cht lng (phc h t git, b mt v ti ch trng hp hay bc hi dung mi t nh tng) hoc kh gas nh nh ch trung bnh (sy phun hoc phun lm mt, tng si sn hoc ng n). Vi bao (ME) c tc ng r rt trn cc ngnh cng nghip thc phm. polyphenols, cc cht ph gia d bay hi, enzyme, vi khun (tc l vi khun lactic bt u lm mi hoc probiotics) trong vin nang nh, cho n kh nng c n nh, bo v v bo qun chng li s mt dinh dng v mt mt sc khe v cui cng lm trung tm khng khun. Cht kt dnh tip xc vi thc phm ni chung l thnh phn t nhin, nhng ch yu h phi c cng nhn An Safe (Generally Recognised As Safe (GRAS)) cho con ngi.Vi bao ca cc thnh phn hot tnh sinh hc c thc hin thng qua vic s dng cc vt liu khc nhau, v d nc v du. Mt nh tng nc-du-nc thng c hnh thnh vi nhng git nc nh, phn tn trong cc git du ln, t phn tn trong mt pha nc ngoi. Cc thnh phn chc nng c th c gi gn trong phm vi giai on bn trong, pha du hoc pha nc ngoi sau khi lm kh; do , mt h thng phn phi duy nht c th cha nhiu thnh phn chc nng.Vi nh tng, vi nhng git c ng knh nh hn 500nm, c to ra bi k thut hnh thnh vi tng si hoc mixen, vi bao c th c p dng thnh cng cho bao bc cc hp cht t nhin, ging nh cc loi du thit yu (EOs) hoc chit xut t thc vt c cha polyphenol c c tnh khng khun. Kha cnh ny i din cho mt im khi u quan trng cho ngnh cng nghip, trong c th th trn vt liu t nhin mi v vt liu an ton hoc cc h thng bao b c kh nng ko di tui th ca cc loi thc phm, chng hn nh cc loi thc phm d b h hng rt ti (rau, qu, tht, vv), m khng lm gim tnh cht ca h v cht lng v v sinh. ME c th c coi thc s l mt ngun lc ng gi thc phm cng che du hng v v mi hi kh chu, hoc l cc ro cn gia cc vt liu hot tnh sinh hc v mi trng nhy cm (v d bi thc n v oxy). Nhiu loi du thit yu (essential oils EOs) c c tnh khng khun chng li nhiu tc nhn gy bnh do thc phm v c th c kh nng c s dng trong thc phm khc nhau matrices, bao gm c cc sn phm tht [3,4]. Tuy nhin, gii hn s dng c lin kt vi cc mi hng c th l kh chu cho ngi tiu dng, hoc c kh nng ha tan nc km v bt n. Tuy nhin, gii hn s dng ca h nh hng n c th l gy mi hng kh chu cho ngi tiu dng, hoc ha tan nc km v bt n. bao bc lm c th lm tng hiu qu cc loi du thit yu v gim tc ng cm gic ca n trn thc phm. Vi bao ca loi du thit yu thng c biu t trong hai bc. Th nht, mt nh tng ca cc hp cht d bay hi thc hin trong mt dung dch nc phn tn mt loi vt liu c vch m cng c chc nng nh cc cht nh ha. Sau , cc vi bao nh tng phi c sy kh trong iu kin kim sot gim bt s mt mt ca cc ng gi.

Bao bc du nguyn cht cy hng tho chng t c hot tnh khng khun hiu qu hn so vi cy hng tho du nguyn cht chng li vi L. monocytogenes trong xc xch gan ln. Eugenol v Carvacrol gi gn trong cc mixen ca b mt khng ion c hiu qu cao i vi L. monocytogenes v E. coli O157: H7, nh vo lng ln hn ca hp cht khng khun tip xc vi b mt ca vi khun khi c trnh by theo hnh thc ny, vi bao du nguyn cht cng c nhn nh thnh cng chng li E. coli O157: H7 c cy trong t lnh, tht b bm nh ng gi bng nit.Polyphenols ng mt vai tr thit yu trong thc phm cng c bit n cht lng v an ton, cng nh i vi sc khe con ngi. trong khoa hc thc phm, n nh ca h c th c ci thin bng cch s dng ng gi v sy phun, c th bo v h chng li oxy, nc hay bt k iu kin c th nh hng s n nh ca h. i l ng gi khc nhau c s dng sy phun: polysaccharides (tinh bt, maltodextrins, syrups ng v gum arabic), cht bo (acid stearic, mono v diglycerides), v cc protein (gelatin, casein, huyt thanh sa, u nnh v la m). Maltodextrins, cc vt liu thng c s dng nht cho ME, thu c bng cch mt thy phn axit ca mt s loi tinh bt (ng, khoai ty hoc nhng ngi khc). Ni chung, maltodextrins c tnh ha tan cao trong nc, nht thp, hng v nht v khng mu. iu th v c th l ng gi inulin, tnh cht dinh dng v prebiotic (cht x) s lm cho vi bao hu ch trong vic to ra tng v s pht trin ca thc phm chc nng.Hn ch l vt liu ph hp encapsulant c php s dng thc phm vn l thch thc chnh trong nguyn liu la chn, c bit l khi tnh cht phc tp hn l theo yu cu ca cc nh sn xut thc phm v ngi tiu dng. Tin mi ca h thng ng gi l lin tc mi ni cho cc ng dng thc phm. Polyvinyl alcohol (PVA) c th l mt trong nhng vt liu y ha hn nht. PVA, mt cht phn cc cao, khng c hi, polime tng hp tan trong nc chun b bng cch thy phn polyvinyl acetate, c s dng trong polymer pha trn vi cc vt liu polyme t nhin. Hn na n c s dng cho mt lot cc ng dng y sinh hc, v phi c tnh ca n vn c, khng gy ung th, tnh tng hp sinh hc tt v tnh cht vt l mong mun, ngoi mng hnh thnh c tnh tuyt vi. PVA gn y c s dng bao bc bi mt chit xut hydroalcoholic (hn hp ru v nc) thu c t cy hng tho c s dng nh mt tc nhn khng khun chng li nhng mm bnh khc nhau nh E. coli. Cc kt qu xut sc ngh ph hp ca n s dng trong bao b thc phm, ko di tui th ca cc loi thc phm ti rt d b h hng, do nng cao cht lng v an ton (Nazzaro et al., unpublished data).Microencapsulation ca vi khun