小麥粉水分活度及其與儲(chǔ)藏品質(zhì)的關(guān)系.pdf

1、南京財(cái)經(jīng)大學(xué)碩士學(xué)位論文小麥粉水分活度及其與儲(chǔ)藏品質(zhì)的關(guān)系姓名：吳小麗申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：農(nóng)產(chǎn)品加工及貯藏工程指導(dǎo)教師：王明潔201101IIABSTRACTAdsptiondesptionequilibriummoisturecontent(EMC)fwheatflour(highglutenwheatflour、dleglutenwheatflour、lowglutenwheatflour)wereexperimrntallyd

2、eterminedusingthestaticgravimetricmethodovertherangeoftemperature(10–40℃)relativehuity(11%–87%).Theadsptiondesptionisothermsweredeterminedusingtheexperimentaldate.Inthispapertherelationshipbetweenwateractivity(Aw)EMCwasd

3、iscussed.Theresultswereasfollows:MetimewererequiredtoreachtheEMCfadsption.Equilibriumtimewasshtenedwithincreasingtemperature.Thetimeappeareddifferentlyasthevarietiesofwheatflour:thelongesttimeneededbyhighglutenwheatflour

4、theleasttimeneededbydleglutenwheatflour.TherateoftheEMCchangewasquickatlowAwsloweratdleAwthenbecomequickerathighAw.Atthesametemperaturetheresultsshowedthattheisothermsbetweenthedifferentvarietiesofwheatflourwerenotsignif

5、icantlydifferentbutweresignificantlyaffectedbyAw.TheEMCdecreasedwiththeincreasingtemperatureatanygivenwateractivity.Itcouldalsobeseenfromtheadsptiondesptionisothermsthattheyexhibitthephenomenonofhysteresis.Allhysteresisp

6、lotsshowedatendencyofexecutingaclosedloopbetweentheupperlowerboundsofAw.Thesizeofthetotalhysteresisappearedtoreduceasthetemperatureincreased(from10to30℃).Whenthetemperaturereachedto40℃thehysteresiswasdisappeared.TheScurv

7、ewasidentifiedasthemostappropriateequationfrepresentingtheadsptiondesptionisothermsofwheatflour.Thedleglutenwheatflourwasstedatcombinedconditionsoftwolevelsoftemperature(20、35℃)fivelevelsofwateractivity(0.43~0.87).Whenth

8、eAwwasaround0.70thewheatflourstedinroomtemperaturewassaferHoweverwhentheAwwasaround0.50thewheatflourinthehightemperatureconditionswassafer.Themainresultswereasfollows：ThefattyacidvalueincreasedslowlywhentheAwunder0.6990i