CommonFoodAdditives:Preservatives,Thickeners,and Sweeteners
Foodadditiveshavethefollowingthreecharacteristics:
Itisthesubstanceaddedtofood,soitisgenerallynoteatenas foodalone.
Itincludesbothartificiallysynthesizedsubstancesandnatural substances.
Thepurposeofaddingadditivestofoodistoimprovefoodquality andcolor,aroma,andtaste,aswellastomeettheneedsof antisepsis,preservation,andprocessingtechnology.
Preservatives
Preservativesrefertonaturalorsyntheticchemicalcomponents addedtofood,medicines,pigments,andbiologicalspecimens,to delaythespoilagecausedbymicrobialgrowthorchemicalchanges. Nitriteandsulfurdioxidearecommonlyusedpreservatives.Food preservativescaninhibitmicrobialactivity,preventfoodspoilage,and prolongtheshelflifeoffood.
Thickeners
Thickenersarehydrophilicpolymercompounds,alsoknownas hydrosols.Itismainlyusedtoimproveandincreasetheviscosityof food,maintainthecolor,aroma,taste,andstabilityofliquidfoodand jellyfood,improvethephysicalpropertiesoffood,andmakefoodfeel lubricatedandpalatable.Thickenersarewidelyusedinfood,coatings, adhesives,cosmetics,detergents,printinganddyeing,rubber, medicineandotherfields.Thickenerscanbedividedintotwo categories:naturalandchemicalsynthesis(includingsemi-synthetic) accordingtotheirsources.
Mostnaturalthickenersareproducedfromplantsandseaweeds containingpolysaccharideviscoussubstances,suchasstarch,pectin, agar,gelatin,seaweedfat,carrageenan,dextrin,tragacanthgum, andpolysaccharidederivatives.Syntheticthickenersincludecellulose derivativessuchasmethylcelluloseandcarboxymethylcellulose, starchderivatives,casein,sodiumpolyacrylate,polyethyleneoxide, polyvinylpyrrolidone,polyvinylalcohol,lowmolecularweight polyethylenewax,andpolypropyleneamides.Thickenersthatare commonlyusedinbeverageproductionasemulsionstabilizersare: sodiumcarboxymethylcellulose,propyleneglycolalginate, carrageenan,xanthangum,pectin,andlocustbeangum.
Sweeteners
Sweetenersrefertofoodadditivesthatimpartsweetnesstofoodor feed.Therearemanysweetenersusedintheworld.Sugaralcohol sweetenersaremostlyartificiallysynthesized,andtheirsweetnessis similartothatofsucrose.Becauseofitslowcalorificvalue,orbecause ofitsdifferentmetabolicprocessfromglucose,itcanstillhavesome specialuses.Non-sugarsweetenershavehighsweetness,lowdosage, smallcalorificvalue,andmostlydonotparticipateinthemetabolic process.
Becauseartificialsyntheticsweetenersproducefewercalories,they arebeneficialtopatientswithobesity,hypertension,ordiabetesand arewidelyusedinthefoodindustry,especiallythesoftdrinkindustry. Thesafetyofartificialsyntheticsweetenershasbeenprovedbymany studies.Aslongasthemanufacturersusethemstrictlyinaccordance withrelevantstandardsandlabelthemcorrectlyonthefoodlabels, theywillnotcauseharmtothehealthofconsumers.
Leaveningagents
Leavingagentreferstotheadditionofaclassofsubstancestowheat flour,themainrawmaterialfortheproductionofbakedfood,infood processing,anditisdecomposedbyheatduringprocessing, producinggas,makingthedoughriseandformingadenseporous structure,sothattheproducthasabulky,softorcrispytexture.
Leavingagentsplayanimportantroleinfoodmanufacturing.Foods suchasbread,cakes,andsteamedbunsarecharacterizedby sponge-likeporoustissues,sothetasteissoft.Inordertoachieve thispurposeinproduction,itisnecessarytomaintainasufficient amountofgasinthedough.Theairmixedinthematerialmixing processandthewatervaporproducedbytheheatingofthemoisture containedinthematerialcanmaketheproductproducesome sponge-liketexture,buttoachievetheidealeffectoftheproduct,the amountofgasisfarfromenough.Thevastmajorityoftherequired gasisprovidedbyleaveningagents.