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1、摘要半纖緞索生物降解后得到的低聚木糖是高附加值的功能性生理活性物質(zhì)。近年來,在翻際土已經(jīng)掀怒了一段功能一陡食鑫麴磅究生產(chǎn)熱瀑,功姥經(jīng)低聚耱瓣具有獨特的生理功能而成為一種踅要的功能性食品基料,低聚術(shù)糖(xylo.oligosaccharide)也怒功能性低聚糖的一種,而通過酶解法制取木低聚糖怒目蘸工業(yè)上,“泛采用的方法。本文以稻殼為原料,對如何提高術(shù)聚糖得率、照曲霉誘變條件、誘變后酶的性質(zhì)和木聚糖酶降解條件進(jìn)行了研究,主要是木聚糖提取條件的優(yōu)化和木聚糖酶降解本聚糠。疆究縫暴凌弭:稻殼中本聚糖的含綴占絕干原料的19.9%,程堿法提取過程中,通過調(diào)節(jié)堿濃度、固液比、
2、抽提溫度和抽提時間因素的影響,確定了較佳的提取條件:堿濃度10%,固波魄1:lO,抽援時聞3h,獺提溢度60~95℃。本聚糖艙提取率可達(dá)到67.50%以上。根據(jù)黑曲霉的誘變條件,致死率猩85%左右,誘變效果最好。實驗采用紫外燈40瓦,紫外燈和及廢池的距離(照射距離)28cm,紫外誘交的最佳時閥為2.5min。瓣辯氌對誘交囂爨魏霉產(chǎn)璽三術(shù)聚糖酶的僚矮進(jìn)行了蔫定,最佳反庭滋度為50。C,娥佳pH值為4.2。并研究了術(shù)聚糖酶對溫度和對pH德的穩(wěn)定性。影響術(shù)漿糖酶解的主要因素包括木聚糖底物濃度,加酶量,pH值,溫度,時闋等。主黌磅究了本聚耱癮麓濃凌,麓酶量對酶鱗靜影璃
3、。采用3,5一二硝基水楊酸法(DNS法)來測定酶活和木聚糖含量。利用紫外可見光度計,在主波長480nm處測定提取液的吸光度,通過特征峰的存在,測定它夔有效羧分熬含量。本論文的研究結(jié)果為提高稻殼的利用開辟了一條新的途徑,既處理了農(nóng)林廢棄物,又解決了環(huán)境污染問題,有很好的經(jīng)濟(jì)效益和社會效益。關(guān)鍵落:疆殼,本低象糖,黑蕊霉,誘交,本聚糖酶AbstractXylo—oligosaccharide,theproductofbiodegradationofhemicellulose,istheUghadditionalvaluesubstance.Nowadays,the
4、reisaresearchupsurgeofthefimctionalfoodintheworld.Thefenetionalligosaecharideshavebeenakindofimportantfunctionalfoodadditivebecausetheyhavespecialphysiologicalfunction,Xylo-oligosaccharideisoneofthefunctionalligosaccharides.Thebiodegradationofxylantopreparexylo-oligosaccharideisstil
5、lthemainmethodatpresent.Thispapermainlystudiedxylanextractionfrompaddyhull,aspergillusnigermutationbyultravioletray,xylanasecharacteristicandtheconditionofxylanbiodegradation。Thecontentofxylanfrompaddyhullwas19.9%.Thevariableswhichaffectextraction:alkaline(NaOU)concentration,therati
6、oofsolidtoliquid,extractiontemperatureandextractiontime.Thebetterextractiveconditionswasobtained:alkalineconcentrationwas10%,therationofsolidtoliquidl:i0,extractiontimewas3h,temperaturewas60--956C.Theyieldofxylanfrompaddyhullwas67。50%.Ahighaspergillusnigerstrainwasobtainedbyusingult
7、ravioletray.Mutationeffectisbestwhenlethalwas85%orso.Thebestmutationconditionsofaspergillusnigerwereasfollows:UVwattwas40,irradiantdistancewas28cm,irradianttimewas2.5min.Xylanaseactivitiesproducedbymutationaspergilusnigerweredetermined.Theoptimumreactiontemperaturewas50。C,theoptimum
8、reactionpHwas4.2.Th