نشا
S a ch
S a ch o amylum is a polyme ic ca bohyd a e co sis i g of ume ous glucose u i s joi ed by glycosidic bo ds. This polysaccha ide is p oduced by mos g ee pla s fo e e gy s o age. Wo ldwide, i is he mos commo ca bohyd a e i huma die s, a d is co ai ed i la ge amou s i s aple foods such as whea , po a oes, maize (co ), ice, a d cassava (ma ioc).
Pu e s a ch is a whi e, as eless a d odo less powde ha is i soluble i cold wa e o alcohol. I co sis s of wo ypes of molecules: he li ea a d helical amylose a d he b a ched amylopec i . Depe di g o he pla , s a ch ge e ally co ai s 20 o 25% amylose a d 75 o 80% amylopec i by weigh .4 Glycoge , he e e gy ese ve of a imals, is a mo e highly b a ched ve sio of amylopec i .
I i dus y, s a ch is of e co ve ed i o suga s, fo example by mal i g. These suga s may be fe me ed o p oduce e ha ol i he ma ufac u e of bee , whisky a d biofuel. I addi io , suga s p oduced f om p ocessed s a ch a e used i ma y p ocessed foods.
Mixi g mos s a ches i wa m wa e p oduces a pas e, such as whea pas e, which ca be used as a hicke i g, s iffe i g o glui g age . The p i cipal o -food, i dus ial use of s a ch is as a adhesive i he pape maki g p ocess. A simila pas e, clo hi g s a ch, ca be applied o ce ai ex ile goods befo e i o i g o s iffe hem.
E ymologyedi
The wo d s a ch is f om i s Ge ma ic oo wi h he mea i gs s o g, s iff, s e g he , s iffe .5 Mode Ge ma S ä ke (s e g h) is ela ed a d efe i g fo ce u ies mai applica io , he use i ex ile: sizi g ya fo weavi g a d s a chi g li e . The G eek e m fo s a ch, amylo (ἄμυλον), which mea s o milled, is also ela ed. I p ovides he oo amyl, which is used as a p efix fo seve al 5-ca bo compou ds ela ed o o de ived f om s a ch (e.g. amyl alcohol).
His o yedi
S a ch g ai s f om he hizomes of Typha (ca ails, bull ushes) as flou have bee ide ified f om g i di g s o es i Eu ope da i g back o 30,000 yea s ago.6 S a ch g ai s f om so ghum we e fou d o g i d s o es i caves i Ngalue, Mozambique da i g up o 100,000 yea s ago.7
Pu e ex ac ed whea s a ch pas e was used i A cie Egyp possibly o glue papy us.8 The ex ac io of s a ch is fi s desc ibed i he Na u al His o y of Pli y he Elde a ou d AD 77–79.9 Roma s used i also i cosme ic c eams, o powde he hai a d o hicke sauces. Pe sia s a d I dia s used i o make dishes simila o go humai whea halva. Rice s a ch as su face ea me of pape has bee used i pape p oduc io i Chi a si ce 700 CE.10
S a ch i dus yedi
I addi io o s a chy pla s co sumed di ec ly, by 2008 66 millio o es of s a ch we e bei g p oduced pe yea wo ldwide. I 2011, p oduc io was i c eased o 73 millio o .11
I he EU he s a ch i dus y p oduced abou 11 millio o es i 2011, wi h a ou d 40% bei g used fo i dus ial applica io s a d 60% fo food uses,12 mos of he la e as glucose sy ups.13 I 2017 EU p oduc io was 11 millio o of which 9,4 millio o was co sumed i he EU a d of which 54% we e s a ch swee e e s.14
The US p oduced abou 27.5 millio o s of s a ch i 2017, of which abou 8.2 millio o s was high f uc ose sy up, 6.2 millio o s was glucose sy ups, a d 2.5 millio o s we e s a ch p oduc s.cla ifica io eeded The es of he s a ch was used fo p oduci g e ha ol (1.6 billio gallo s).1516
E e gy s o e of pla sedi
Mos g ee pla s s o e e e gy as s a ch, which is packed i o semic ys alli e g a ules.17 The ex a glucose is cha ged i o s a ch which is mo e complex ha he glucose p oduced by pla s. You g pla s live o his s o ed e e gy i hei oo s, seeds, a d f ui s u il i ca fi d sui able soil i which o g ow.18 A excep io is he family As e aceae (as e s, daisies a d su flowe s), whe e s a ch is eplaced by he f uc a i uli . I uli -like f uc a s a e also p ese i g asses such as whea , i o io s a d ga lic, ba a as, a d aspa agus.19
I pho osy hesis, pla s use ligh e e gy o p oduce glucose f om ca bo dioxide. The glucose is used o ge e a e he chemical e e gy equi ed fo ge e al me abolism, o make o ga ic compou ds such as ucleic acids, lipids, p o ei s a d s uc u al polysaccha ides such as cellulose, o is s o ed i he fo m of s a ch g a ules, i amyloplas s. Towa d he e d of he g owi g seaso , s a ch accumula es i wigs of ees ea he buds. F ui , seeds, hizomes, a d ube s s o e s a ch o p epa e fo he ex g owi g seaso .
G ee algae a d la d-pla s s o e hei s a ch i he plas ids, while ed algae, glaucophy es, c yp omo ads, di oflagella es a d he pa asi ic apicomplexa s o e a simila ype of polysaccha ide called flo idea s a ch i hei cy osol o pe iplas .20
Glucose is soluble i wa e , hyd ophilic, bi ds wi h wa e a d he akes up much space a d is osmo ically ac ive; glucose i he fo m of s a ch, o he o he ha d, is o soluble, he efo e osmo ically i ac ive a d ca be s o ed much mo e compac ly. The semic ys alli e g a ules ge e ally co sis of co ce ic laye s of amylose a d amylopec i which ca be made bioavailable upo cellula dema d i he pla .21
Glucose molecules a e bou d i s a ch by he easily hyd olyzed alpha bo ds. The same ype of bo d is fou d i he a imal ese ve polysaccha ide glycoge . This is i co as o ma y s uc u al polysaccha ides such as chi i , cellulose a d pep idoglyca , which a e bou d by be a bo ds a d a e much mo e esis a o hyd olysis.22
Biosy hesisedi
Pla s p oduce s a ch by fi s co ve i g glucose 1-phospha e o ADP-glucose usi g he e zyme glucose-1-phospha e ade ylyl a sfe ase. This s ep equi es e e gy i he fo m of ATP. The e zyme s a ch sy hase he adds he ADP-glucose via a 1,4-alpha glycosidic bo d o a g owi g chai of glucose esidues, libe a i g ADP a d c ea i g amylose. The ADP-glucose is almos ce ai ly added o he o – educi g e d of he amylose polyme , as he UDP-glucose is added o he o – educi g e d of glycoge du i g glycoge sy hesis.23
S a ch b a chi g e zyme i oduces 1,6-alpha glycosidic bo ds be wee he amylose chai s, c ea i g he b a ched amylopec i . The s a ch deb a chi g e zyme isoamylase emoves some of hese b a ches. Seve al isofo ms of hese e zymes exis , leadi g o a highly complex sy hesis p ocess.24
Glycoge a d amylopec i have simila s uc u e, bu he fo me has abou o e b a ch poi pe e 1,4-alpha bo ds, compa ed o abou o e b a ch poi pe hi y 1,4-alpha bo ds i amylopec i .25 Amylopec i is sy hesized f om ADP-glucose while mammals a d fu gi sy hesize glycoge f om UDP-glucose; fo mos cases, bac e ia sy hesize glycoge f om ADP-glucose (a alogous o s a ch).26
I addi io o s a ch sy hesis i pla s, s a ch ca be sy hesized f om o -food s a ch media ed by a e zyme cock ail.27 I his cell-f ee biosys em, be a-1,4-glycosidic bo d-li ked cellulose is pa ially hyd olyzed o cellobiose. Cellobiose phospho ylase cleaves o glucose 1-phospha e a d glucose; he o he e zyme—po a o alpha-gluca phospho ylase ca add a glucose u i f om glucose 1-phospho ylase o he o – educi g e ds of s a ch. I i , phospha e is i e ally ecycled. The o he p oduc , glucose, ca be assimila ed by a yeas . This cell-f ee biop ocessi g does o eed a y cos ly chemical a d e e gy i pu , ca be co duc ed i aqueous solu io , a d does o have suga losses.282930
Deg ada io edi
S a ch is sy hesized i pla leaves du i g he day a d s o ed as g a ules; i se ves as a e e gy sou ce a igh . The i soluble, highly b a ched s a ch chai s have o be phospho yla ed i o de o be accessible fo deg adi g e zymes. The e zyme gluca , wa e diki ase (GWD) phospho yla es a he C-6 posi io of a glucose molecule, close o he chai s 1,6-alpha b a chi g bo ds. A seco d e zyme, phosphogluca , wa e diki ase (PWD) phospho yla es he glucose molecule a he C-3 posi io . A loss of hese e zymes, fo example a loss of he GWD, leads o a s a ch excess (***) phe o ype,31 a d because s a ch ca o be phospho yla ed, i accumula es i he plas ids.
Af e he phospho yla io , he fi s deg adi g e zyme, be a-amylase (BAM) ca a ack he glucose chai a i s o – educi g e d. Mal ose is eleased as he mai p oduc of s a ch deg ada io . If he glucose chai co sis s of h ee o fewe molecules, BAM ca o elease mal ose. A seco d e zyme, disp opo io a i g e zyme-1 (DPE1), combi es wo mal o iose molecules. F om his chai , a glucose molecule is eleased. Now, BAM ca elease a o he mal ose molecule f om he emai i g chai . This cycle epea s u il s a ch is deg aded comple ely. If BAM comes close o he phospho yla ed b a chi g poi of he glucose chai , i ca o lo ge elease mal ose. I o de fo he phospho yla ed chai o be deg aded, he e zyme isoamylase (ISA) is equi ed.32
The p oduc s of s a ch deg ada io a e p edomi a ly mal ose33 a d smalle amou s of glucose. These molecules a e expo ed f om he plas id o he cy osol, mal ose via he mal ose a spo e , which if mu a ed (MEX1-mu a ) esul s i mal ose accumula io i he plas id.34 Glucose is expo ed via he plas idic glucose a sloca o (pGlcT).35 These wo suga s ac as a p ecu so fo suc ose sy hesis. Suc ose ca he be used i he oxida ive pe ose phospha e pa hway i he mi ocho d ia, o ge e a e ATP a igh .32
P ope iesedi
S uc u eedi
While amylose was hough o be comple ely u b a ched, i is ow k ow ha some of i s molecules co ai a few b a ch poi s.36 Amylose is a much smalle molecule ha amylopec i . Abou o e qua e of he mass of s o ed s a ch i pla s co sis of amylose, al hough he e a e abou 150 imes mo e amylose ha amylopec i molecules.
Accumula ed s a ch wi hi pla s is s o ed i semi-c ys alli e g a ules. Each pla species has a u ique s a ch g a ula size: ice s a ch is ela ively small (abou 2 μm), po a o s a ches have la ge g a ules (up o 100 μm) a d whea a d apioca all i -be wee .37 U like o he bo a ical sou ces of s a ch, whea s a ch has a bimodal size dis ibu io , wi h bo h smalle a d la ge g a ules a gi g f om 2 o 55 μm.37
Some cul iva ed pla va ie ies have pu e amylopec i s a ch wi hou amylose, k ow as waxy s a ches. The mos used is waxy maize, o he s a e glu i ous ice a d waxy po a o s a ch. Waxy s a ches u de go less e og ada io , esul i g i a mo e s able pas e. A maize cul iva wi h a ela ively high p opo io of amylose s a ch, amylomaize, is cul iva ed fo he use of i s gel s e g h a d fo use as a esis a s a ch (a s a ch ha esis s diges io ) i food p oduc s.
Sy he ic amylose made f om cellulose has a well-co olled deg ee of polyme iza io . The efo e, i ca be used as a po e ial d ug delive ca ie .27
Dissolu io a d gela i iza io edi
Whe hea ed i abu da wa e , he g a ules of a ive s a ch swell a d bu s , he semi-c ys alli e s uc u e is los , a d he smalle amylose molecules s a leachi g ou of he g a ule, fo mi g a e wo k ha holds wa e a d i c easi g he mix u e’s viscosi y. This p ocess is called s a ch gela i iza io . The gela i iza io empe a u e of s a ch va ies depe di g o s a ch cul iva , amyloseamylopec i co e , a d wa e co e . S a ch wi h wa e could expe ie ce complex mul iphase a si io s du i g diffe e ial sca i g calo ime y (DSC) empe a u e sca i g.38 Fo s a ch wi h excess wa e , a si gle gela i isa io e do he m ca be usually obse ved i he low empe a u e a ge (54–73 °C).38 By educi g he wa e co e (
Du i g cooki g, he s a ch becomes a pas e a d i c eases fu he i viscosi y. Du i g cooli g o p olo ged s o age of he pas e, he semi-c ys alli e s uc u e pa ially ecove s, a d he s a ch pas e hicke s, expelli g wa e . This is mai ly caused by e og ada io of he amylose. This p ocess is espo sible fo he ha de i g of b ead o s ali g, a d fo he wa e laye o op of a s a ch gel (sy e esis).
Ce ai s a ches, whe mixed wi h wa e , will p oduce a o -New o ia fluid some imes ick amed oobleck.
S a ch ca also be dissolved o u de go gela io i io ic liquids o me al chlo ide sal solu io s. The he mal a si io of s a ch is la gely i flue ced by he a io of io ic liquidwa e . Aqueous io ic liquid wi h a ce ai io ic liquidwa e a io leads o he mos effec ive s uc u al diso ga isa io of some s a ches a sig ifica ly educed empe a u e (eve a oom empe a u e).4142 This phe ome o is ve y diffe e f om he dissolu io of cellulose, as he la e occu s mos efficie ly i pu e io ic liquids a d a y wa e co ai ed i he io ic liquids will hi de he dissolu io sig ifica ly.43 I is p oposed ha fo s a ches wi h g a ule su face po es (e.g. mille , waxy maize, o mal maize a d whea s a ches), he co osio by he aqueous IL follows a i side-ou pa e a d he des uc io o he g a ules is fas a d eve , whe eas fo s a ches wi h a ela ively smoo h su face (e.g. high-amylose maize, po a o, pu ple yam a d pea s a ches), he co osio ca o ly s a f om he su face a d hus he cha ge caused he aqueous IL is slow.44 A fu he s udy evealed ha while A- ype (cassava a d waxy maize) s a ches a e easie ha B- ype (po a o a d high-amylose maize) s a ches o be s uc u ally dis up ed due o su face weak poi s, mecha ically f ac u ed B- ype s a ch g a ules become oom- empe a u e-p ocessable, jus like A- ype s a ches.45 Besides, s a ch, eve high-amylose s a ch, ca be fully dissolved by aqueous me al chlo ide sal s (e.g., Z Cl2, CaCl2, a d MgCl2) a mode a e empe a u e (≤50 °C), a d s a ch a opa icles ca fo m du i g his dissolu io p ocess.4647 Resea ch has demo s a ed ha CaCl2 solu io -dissolved high-amylose s a ch ca fo m io -co duc ive a d s ai – espo sive ma e ials.4849 S a chCaCl2 gel ca also be used as a flame- e a da adhesive fo pape a d wood boa d.50
Hyd olysisedi
The e zymes ha b eak dow o hyd olyze s a ch i o he co s i ue suga s a e k ow as amylases.
Alpha-amylases a e fou d i pla s a d i a imals. Huma saliva is ich i amylase, a d he pa c eas also sec e es he e zyme. I dividuals f om popula io s wi h a high-s a ch die e d o have mo e amylase ge es ha hose wi h low-s a ch die s;51
Be a-amylase cu s s a ch i o mal ose u i s. This p ocess is impo a i he diges io of s a ch a d is also used i b ewi g, whe e amylase f om he ski of seed g ai s is espo sible fo co ve i g s a ch o mal ose (Mal i g, Mashi g).5253
Give a hea of combus io of glucose of 2,805 kilojoules pe mole (670 kcalmol) whe eas ha of s a ch is 2,835 kJ (678 kcal)2 pe mole of glucose mo ome , hyd olysis eleases abou 30 kJ (7.2 kcal) pe mole, o 166 J (40 cal) pe g am of glucose p oduc .
Dex i iza io edi
If s a ch is subjec ed o d y hea , i b eaks dow o fo m dex i s, also called py odex i s i his co ex . This b eak dow p ocess is k ow as dex i iza io . (Py o)dex i s a e mai ly yellow o b ow i colo a d dex i iza io is pa ially espo sible fo he b ow i g of oas ed b ead.54
Chemical es sedi
A iiodide (I3−) solu io fo med by mixi g iodi e a d iodide (usually f om po assium iodide) is used o es fo s a ch; a da k blue colo i dica es he p ese ce of s a ch. The de ails of his eac io a e o fully k ow , bu ece scie ific wo k usi g si gle c ys al X- ay c ys allog aphy a d compa a ive Rama spec oscopy sugges s ha he fi al s a ch-iodi e complex is simila o a i fi i e polyiodide chai like o e fou d i a py olope yle e-iodi e complex.55 The s e g h of he esul i g blue colo depe ds o he amou of amylose p ese . Waxy s a ches wi h li le o o amylose p ese will colo ed. Be edic ‘s es a d Fehli g’s es is also do e o i dica e he p ese ce of s a ch.
S a ch i dica o solu io co sis i g of wa e , s a ch a d iodide is of e used i edox i a io s: i he p ese ce of a oxidizi g age he solu io u s blue, i he p ese ce of educi g age he blue colo disappea s because iiodide (I3−) io s b eak up i o h ee iodide io s, disassembli g he s a ch-iodi e complex. S a ch solu io was used as i dica o fo visualizi g he pe iodic fo ma io a d co sump io of iiodide i e media e i he B iggs-Rausche oscilla i g eac io . The s a ch, howeve , cha ges he ki e ics of he eac io s eps i volvi g iiodide io .56 A 0.3% ww solu io is he s a da d co ce a io fo a s a ch i dica o . I is made by addi g 3 g ams of soluble s a ch o 1 li e of hea ed wa e ; he solu io is cooled befo e use (s a ch-iodi e complex becomes u s able a empe a u es above 35 °C).
Each species of pla has a u ique ype of s a ch g a ules i g a ula size, shape a d c ys alliza io pa e . U de he mic oscope, s a ch g ai s s ai ed wi h iodi e illumi a ed f om behi d wi h pola ized ligh show a dis i c ive Mal ese c oss effec (also k ow as ex i c io c oss a d bi ef i ge ce).
Foodedi
S a ch is he mos commo ca bohyd a e i he huma die a d is co ai ed i ma y s aple foods. The majo sou ces of s a ch i ake wo ldwide a e he ce eals ( ice, whea , a d maize) a d he oo vege ables (po a oes a d cassava).57 Ma y o he s a chy foods a e g ow , some o ly i specific clima es, i cludi g aco s, a ow oo , a acacha, ba a as, ba ley, b eadf ui , buckwhea , ca a, colocasia, ka aku i, kudzu, mala ga, mille , oa s, oca, poly esia a ow oo , sago, so ghum, swee po a oes, ye, a o, ches u s, wa e ches u s, a ow oo a d yams, a d ma y ki ds of bea s, such as favas, le ils, mu g bea s, peas, a d chickpeas.
Befo e p ocessed foods, people co sumed la ge amou s of u cooked a d u p ocessed s a ch-co ai i g pla s, which co ai ed high amou s of esis a s a ch. Mic obes wi hi he la ge i es i e fe me o co sume he s a ch, p oduci g sho -chai fa y acids, which a e used as e e gy, a d suppo he mai e a ce a d g ow h of he mic obes. Upo cooki g, s a ch is a sfo med f om a i soluble, difficul – o-diges g a ule i o eadily accessible glucose chai s wi h ve y diffe e u i io al a d fu c io al p ope ies.58
I cu e die s, highly p ocessed foods a e mo e easily diges ed a d elease mo e glucose i he small i es i e—less s a ch eaches he la ge i es i e a d mo e e e gy is abso bed by he body. I is hough ha his shif i e e gy delive y (as a esul of ea i g mo e p ocessed foods) may be o e of he co ibu i g fac o s o he developme of me abolic diso de s of mode life, i cludi g obesi y a d diabe es.59
The amyloseamylopec i a io, molecula weigh a d molecula fi e s uc u e i flue ces he physicochemical p ope ies as well as e e gy elease of diffe e ypes of s a ches.60 I addi io , cooki g a d food p ocessi g sig ifica ly impac s s a ch diges ibili y a d e e gy elease. S a ch has bee classified as apidly diges ible s a ch, slowly diges ible s a ch a d esis a s a ch, depe di g upo i s diges io p ofile.61 Raw s a ch g a ules esis diges io by huma e zymes a d do o b eak dow i o glucose i he small i es i e – hey each he la ge i es i e i s ead a d fu c io as p ebio ic die a y fibe .62 Whe s a ch g a ules a e fully gela i ized a d cooked, he s a ch becomes easily diges ible a d eleases glucose quickly wi hi he small i es i e. Whe s a chy foods a e cooked a d cooled, some of he glucose chai s e-c ys allize a d become esis a o diges io agai . Slowly diges ible s a ch ca be fou d i aw ce eals, whe e diges io is slow bu ela ively comple e wi hi he small i es i e.63 Widely used p epa ed foods co ai i g s a ch a e b ead, pa cakes, ce eals, oodles, pas a, po idge a d o illa.
Du i g cooki g wi h high hea , suga s eleased f om s a ch ca eac wi h ami o acids via he Mailla d eac io , fo mi g adva ced glyca io e d-p oduc s, (AGEs), co ibu i g a omas, flavo s a d ex u e o foods.64 O e example of a die a y AGE is ac ylamide. Rece evide ce sugges s ha he i es i al fe me a io of die a y AGEs may be associa ed wi h i suli esis a ce, a he oscle osis, diabe es a d o he i flamma o y diseases.6566 This may be due o he impac of AGEs o i es i al pe meabili y.67
S a ch gela i iza io du i g cake baki g ca be impai ed by suga compe i g fo wa e , p eve i g gela i iza io a d imp ovi g ex u e.
S a ch p oduc io edi
The s a ch i dus y ex ac s a d efi es s a ches f om seeds, oo s a d ube s, by we g i di g, washi g, sievi g a d d yi g. Today, he mai comme cial efi ed s a ches a e co s a ch, apioca, a ow oo ,68 a d whea , ice, a d po a o s a ches. To a lesse ex e , sou ces of efi ed s a ch a e swee po a o, sago a d mu g bea . To his day, s a ch is ex ac ed f om mo e ha 50 ypes of pla s.
U ea ed s a ch equi es hea o hicke o gela i ize. Whe a s a ch is p e-cooked, i ca he be used o hicke i s a ly i cold wa e . This is efe ed o as a p egela i ized s a ch.
S a ch suga sedi
S a ch ca be hyd olyzed i o simple ca bohyd a es by acids, va ious e zymes, o a combi a io of he wo. The esul i g f agme s a e k ow as dex i s. The ex e of co ve sio is ypically qua ified by dex ose equivale (DE), which is oughly he f ac io of he glycosidic bo ds i s a ch ha have bee b oke .
These s a ch suga s a e by fa he mos commo s a ch based food i g edie a d a e used as swee e e s i ma y d i ks a d foods. They i clude:
Modified s a chesedi
A modified s a ch is a s a ch ha has bee chemically modified o allow he s a ch o fu c io p ope ly u de co di io s f eque ly e cou e ed du i g p ocessi g o s o age, such as high hea , high shea , low pH, f eeze haw a d cooli g.
The modified food s a ches a e E coded acco di g o Eu opea Food Safe y Au ho i y a d INS coded Food Addi ives acco di g o he Codex Alime a ius:72
INS 1400, 1401, 1402, 1403 a d 1405 a e i he EU food i g edie s wi hou a E- umbe .73 Typical modified s a ches fo ech ical applica io s a e ca io ic s a ches, hyd oxye hyl s a ch a d ca boxyme hyla ed s a ches.
Use as food addi iveedi
As a addi ive fo food p ocessi g, food s a ches a e ypically used as hicke e s a d s abilize s i foods such as puddi gs, cus a ds, soups, sauces, g avies, pie filli gs, a d salad d essi gs, a d o make oodles a d pas as. They fu c io as hicke e s, ex e de s, emulsio s abilize s a d a e excep io al bi de s i p ocessed mea s.
Gummed swee s such as jelly bea s a d wi e gums a e o ma ufac u ed usi g a mold i he co ve io al se se. A ay is filled wi h a ive s a ch a d leveled. A posi ive mold is he p essed i o he s a ch leavi g a imp essio of 1,000 o so jelly bea s. The jelly mix is he pou ed i o he imp essio s a d pu o o a s ove o se . This me hod g ea ly educes he umbe of molds ha mus be ma ufac u ed.
Use i pha maceu ical i dus yedi
I he pha maceu ical i dus y, s a ch is also used as a excipie , as able disi eg a , a d as bi de .
Resis a s a chedi
Resis a s a ch is s a ch ha escapes diges io i he small i es i e of heal hy i dividuals. High-amylose s a ch f om whea o co has a highe gela i iza io empe a u e ha o he ypes of s a ch, a d e ai s i s esis a s a ch co e h ough baki g, mild ex usio a d o he food p ocessi g ech iques. I is used as a i soluble die a y fibe i p ocessed foods such as b ead, pas a, cookies, c acke s, p e zels a d o he low mois u e foods. I is also u ilized as a die a y suppleme fo i s heal h be efi s. Published s udies have show ha esis a s a ch helps o imp ove i suli se si ivi y,7475 educes p o-i flamma o y bioma ke s i e leuki 6 a d umo ec osis fac o alpha7677 a d imp oves ma ke s of colo ic fu c io .78 I has bee sugges ed ha esis a s a ch co ibu es o he heal h be efi s of i ac whole g ai s.79
Sy he ic s a chedi
I 2021, esea che s epo ed he wo ld’s fi s a ificial sy hesis of s a ch i he labo a o y. A cell-f ee chemoe zyma ic p ocess was used o sy hesize s a ch f om CO2 a d hyd oge . If he p ocess is viable a d ca be scaled, i could subs a ially educe la d-, pes icide- a d wa e -use as well as g ee house gas emissio s while i c easi g food secu i y. The chemical pa hway of 11 co e eac io s was d af ed by compu a io al pa hway desig a d co ve s CO2 o s a ch a a a e ha is ~8.5-fold highe ha s a ch sy hesis i maize.8081
No -food applica io sedi
Pape maki gedi
Pape maki g is he la ges o -food applica io fo s a ches globally, co sumi g ma y millio s of me ic o s a ually.12 I a ypical shee of copy pape fo i s a ce, he s a ch co e may be as high as 8%. Bo h chemically modified a d u modified s a ches a e used i pape maki g. I he we pa of he pape maki g p ocess, ge e ally called he we -e d, he s a ches used a e ca io ic a d have a posi ive cha ge bou d o he s a ch polyme . These s a ch de iva ives associa e wi h he a io ic o ega ively cha ged pape fibe s cellulose a d i o ga ic fille s. Ca io ic s a ches oge he wi h o he e e io a d i e al sizi g age s help o give he ecessa y s e g h p ope ies o he pape web fo med i he pape maki g p ocess (we s e g h), a d o p ovide s e g h o he fi al pape shee (d y s e g h).
I he d y e d of he pape maki g p ocess, he pape web is ewe ed wi h a s a ch based solu io . The p ocess is called su face sizi g. S a ches used have bee chemically, o e zyma ically depolyme ized a he pape mill o by he s a ch i dus y (oxidized s a ch). The sizes a ch solu io s a e applied o he pape web by mea s of va ious mecha ical p esses (size p esses). Toge he wi h su face sizi g age s he su face s a ches impa addi io al s e g h o he pape web a d addi io ally p ovide wa e hold ou o size fo supe io p i i g p ope ies. S a ch is also used i pape coa i gs as o e of he bi de s fo he coa i g fo mula io s which i clude a mix u e of pigme s, bi de s a d hicke e s. Coa ed pape has imp oved smoo h ess, ha d ess, whi e ess a d gloss a d hus imp oves p i i g cha ac e is ics.
Co uga ed boa d adhesivesedi
Co uga ed boa d adhesives a e he ex la ges applica io of o -food s a ches globally. S a ch glues a e mos ly based o u modified a ive s a ches, plus some addi ive such as bo ax a d caus ic soda. Pa of he s a ch is gela i ized o ca y he slu y of u cooked s a ches a d p eve sedime a io . This opaque glue is called a S ei Hall adhesive. The glue is applied o ips of he flu i g. The flu ed pape is p essed o pape called li e . This is he d ied u de high hea , which causes he es of he u cooked s a ch i glue o swellgela i ize. This gela i izi g makes he glue a fas a d s o g adhesive fo co uga ed boa d p oduc io .
Clo hi g s a chedi
Clo hi g o lau d y s a ch is a liquid p epa ed by mixi g a vege able s a ch i wa e (u modified s a ch o ly gels i wa e close o boili g poi , while comme cial p oduc s may o equi e hea ), a d is used i he lau de i g of clo hes. S a ch was widely used i Eu ope i he 16 h a d 17 h ce u ies o s iffe he wide colla s a d uffs of fi e li e which su ou ded he ecks of he well- o-do. Du i g he 19 h a d ea ly 20 h ce u y i was s ylish o s iffe he colla s a d sleeves of me ‘s shi s a d he uffles of wome ‘s pe icoa s by s a chi g hem befo e he clea clo hes we e i o ed. S a ch gave clo hi g smoo h, c isp edges, a d had a addi io al p ac ical pu pose: di a d swea f om a pe so ‘s eck a d w is s would s ick o he s a ch a he ha o he fibe s of he clo hi g. The di would wash away alo g wi h he s a ch; af e lau de i g, he s a ch would be eapplied. S a ch is available i sp ay ca s, i addi io o he usual g a ules o mix wi h wa e .
Bioplas icedi
S a ch is a impo a a u al polyme o make bioplas ics. Wi h wa e a d plas icise s such as glyce ol, s a ch ca be p ocessed i o so-called he moplas ic s a ch usi g co ve io al polyme p ocessi g ech iques such as ex usio , i jec io moldi g a d comp essio moldi g.82 Si ce ma e ials based o o ly a ive s a ch have poo p ocessibili y, mecha ical p ope ies a d s abili y, mo e commo ly modified s a ches (e.g. hyd oxyp opyl s a ch) a e used a d s a ch is combi ed wi h o he polyme s (p efe ably biodeg adable polyme s such as polycap olac o e), as some comme cial p oduc s (e.g. PLANTIC HP83 a d Ma e -Bi84) available o he ma ke .
O he edi
A o he la ge o -food s a ch applica io is i he co s uc io i dus y, whe e s a ch is used i he gypsum wall boa d ma ufac u i g p ocess. Chemically modified o u modified s a ches a e added o he s ucco co ai i g p ima ily gypsum. Top a d bo om heavyweigh shee s of pape a e applied o he fo mula io , a d he p ocess is allowed o hea a d cu e o fo m he eve ual igid wall boa d. The s a ches ac as a glue fo he cu ed gypsum ock wi h he pape cove i g, a d also p ovide igidi y o he boa d.
S a ch is used i he ma ufac u e of va ious adhesives o glues85 fo book-bi di g, wallpape adhesives, pape sack p oduc io , ube wi di g, gummed pape , e velope adhesives, school glues a d bo le labeli g. S a ch de iva ives, such as yellow dex i s, ca be modified by addi io of some chemicals o fo m a ha d glue fo pape wo k; some of hose fo ms use bo ax o soda ash, which a e mixed wi h he s a ch solu io a 50–70 °C (122–158 °F) o c ea e a ve y good adhesive. Sodium silica e ca be added o ei fo ce hese fo mula.
Occupa io al safe y a d heal hedi
I he US, he Occupa io al Safe y a d Heal h Admi is a io (OSHA) has se he legal limi (Pe missible exposu e limi ) fo s a ch exposu e i he wo kplace as 15 mgm3 o al exposu e a d 5 mgm3 espi a o y exposu e ove a eigh -hou wo kday. The Na io al I s i u e fo Occupa io al Safe y a d Heal h (NIOSH) has se a Recomme ded exposu e limi (REL) of 10 mgm3 o al exposu e a d 5 mgm3 espi a o y exposu e ove a eigh -hou wo kday.89
نشا
النشا23 (مقتضبه من نشاسته المعربه «نشاستج» من الفارسیه؛4 رقم CAS: 9005-25-8) هو خلیط عدید السکاری لکاربوهیدرات معقدین اثنین وهما الأمیلوز والأمیلوبیکتین، وکلاهما مکثور من الغلوکوز. تعمد النباتات لبناء النشا کطریقه لتخزین الغلوکوز الفائض لدیها.
الصیغه الکیمیائیه للنشا هی: (C6H10O5) ,5 حیث إنه بولیمر من الغلوکوز ذی الصیغه الکیمیائیه: C6H12O6. یتکون من تکاثف أکثر من 300 وحده من الألفا جلوکوز وهو یوجد مختزن فی النبات ویوجد فی حبیبات ذات غلاف سیلولوزی لا یتمزق إلا بالغلیان وعندما تتواجد حبه نشا فی الماء بإذابتها تتعکر المیاه ولکن بعد فتره یرسب النشا وذلک لوجود طبقه عازله بین النشا والماء تتمثل فی الحویصلات السیلولوزیه المحیطه بجزیئات النشا عند غلی الماء تتمزق الحویصلات السیللیوزیه ومن ثم ینتشر النشا فی المحلول وعندما تکون کمیه النشا کبیره یکون المحلول هلامی، وللعلم یعطی النشا لون أزرق مع الیود. یتحلل النشا بواسطه إنزیم الأمیلیز اللعابی إلى دیکسترینات عالیه تعطی لونا أزرقا برونزیاً أو بنیاً مع الیود تلیها مرحله ارثرو دیکسترینات الذی یعطی لونا أحمرا أو برتقالیا أحمرا مع الیود وتلیها مرحله الأکرو دیکسترینات الذی لا یعطی أی لون مع الیود ثم المرحله الأخیره وهی المالتوز.
وصف المادهعدل
هی عباره عن مسحوق ناعم جداً یتفتت بین الأصابع عند الضغط علیه، غیر منحل عملیاً فی الماء البارد والکحول، ویکون عدیم الرائحه وله طعم خفیف ممیز وله أنواع عدیده هی:
الاستعمالاتعدل
یستعمل النشا صیدلانیاً مزلقا وممددا ومفتتا للکبسولات والمضغوطات، وکذلک رابطا فی المضغوطات. کما قد یستخدم واقیا فی تحضیرات المراهم المطبقه على الجلد.
حفظ المادهعدل
یجب أن یحفظ فی عبوات محکمه الإغلاق فی أماکن جافه وبارده.