Effect of drying method on the Antioxidant properties of some local spices

Abstract

Introduction Spicesarealargegroupofnaturalingredientssuchasdriedseeds,fruits,roots, rhizomes,barks,leaves,flowersandothervegetativesubstancesusedinavery smallquantityasfoodadditiveseitherascolor,aroma,flavororpreservative[1]. Theyaremainlyusedtoimprovethepalatability/tasteandthevisualappearanceof diets.MostSpicescontainphenoliccompoundthatisresponsiblefortheirmedicinal, antioxidantandpreservativeproperties[2].Thethreespicesstudiedincludeginger leaf,curryleafandscentleafdriedusingtraditionalsundriedmethodandovendried method.Theobjectiveofthisstudyistodeterminetheantioxidantpropertiesofthe selectedspice. MaterialsandMethod Thespices(ginger,curryandscentleaf)werepurchasedfrom alocalmarketin Minna,NigerState.Thespicesweresundried5hdailyfor2consecutivedaysand turnedoverat1hintervaltoachieveuniform drying.Aftersundrying,thesample wasmilledtopowderform.Thesecondsamplewasovendriedatatemperatureof 50ºcfor5handturnedoverperiodicallytoaiduniform dryingandmilledtopowder form.The results obtained from analysis ofthe antioxidantproperties were subjectedtoone-wayANOVAandthemeanswereseparatedbyDuncanMultiple RangeTestusingSPSSversion20. ResultsandDiscussion TheantioxidantpropertiesofthespicesispresentedinTable1.Totalphenolwasin therangeof185to290mg/100g.Therewasasignificantdifferenceacrossthe samples.Totalflavonoidrangedfrom 19to27mg/100.Therewassignificant differenceinthevalueswithsampleovendriedhavingthehighestvalue.The decreaseinthevaluesofthesundriedsamplemaybeduetorapidlossofphenolic compoundwhenthespiceswereexposedtouncontrolledsundryingtemperature[3]. Totalflavonoidandphenol havetheabilitytoactasantioxidant,ameliorate inflammation,modulateenzymeactivityandregulategeneexpression[3].Table1Antioxidantpropertiesofthesamples Parameters(mg/100g) Samples Totalphenol Totalflavonoid ScentleafSD 185.0d1±0.06 25.96b±1.15 ScentleafOD 290.52a±4.60 27.56ab±0.40 GingerSD 222.58c±0.13 19.06d±1.00 GingerOD 249.31b±3.46 21.12c±0.09 CurryleafSD 247.65b±0.16 27.96a±0.23 CurryleafOD 221.97c±1.57 19.85d±0.35 Valuesaremeans±standarddeviationofduplicatedetermination.Meansinthesame columnfollowedbydifferentsuperscriptsaresignificantlydifferent(p<0.05). Key: SD=Sundriedsamples OD=Ovendriedsamples Conclusion Theresultshowsthatsundryingandovendryingmethodsareeffectiveinthe processingofspicesaswellasaffectthefunctionalityofthespicesinfoodsystem. Ovendriedsampleswerefoundtoexhibitabetterpropertiesintheparameter investigated.Therefore,theuseofovendryingmethodisrecommendedinthedrying ofspicesduetoitscontroltemperatureofdryingtominimizethedestructionofthe antioxidantpropertiesofthespicesandalsotoreduceincidenceofcontamination ofthespiceswhenexposedtoopenenvironmentforsundrying. References 1.Birt,D.A.(2006).Phytochemicalsandcancerprevention:fromepidemiologyto mechanism ofaction.JournaloftheAmericanDieteticAssociation106:20 –24. 2.Burt,S.(2004).Essentialoils:Theirantibacterialproperties and potential applicationsin foods–Areview.InternationalJournalofFoodMicrobiology94(3):223–253. 3.Mueller-Harvey,I.(2001).Analysisofhydrolysabletannins.Anim,Feed Sci, Technol,9,3-20Podsedek,A.(2007).Naturalantioxidantsandantioxidant capacityofBrassicavegetables:Areview.FoodScienceandTechnology,40,1-11