本文主要研究内容
作者商景天（2019）在《泡菜中降解亚硝酸盐菌种筛选及其降解机理研究》一文中研究指出：亚硝酸盐（NIT）的安全控制一直是泡菜发酵过程中关键问题之一,本文从自然发酵的泡菜中筛选出一株有高效降解亚硝酸盐功能的乳酸菌,并对其降解亚硝酸盐的影响因素和降解机理进行研究,得到结果如下:1、从自然发酵萝卜中筛选出75株疑似乳酸菌菌株,通过亚硝酸盐降解能力的测试和实际发酵测试筛选出一株有高效降解亚硝酸盐能力的植物乳杆菌LP-7501。通过pH试验测定结果得出LP-7501具有较好的耐酸性,生长的最佳初始pH为6.5左右,通过温度试验表明在35℃时LP-7501生长代谢和降解亚硝酸盐最佳。2、通过碳源和氮源试验得出,LP-7501在单纯碳源培养基中生长代谢产酸和降解亚硝酸盐能力受到抑制,其对于单纯碳源的利用情况为单糖>双糖>多糖;LP-7501在以硝酸铵作为氮源时,生长代谢产酸和降解亚硝酸盐能力受到抑制,酵母抽提物、玉米浆膏和蛋白胨三种氮源对LP-7501的生长代谢产酸和降解亚硝酸盐能力都有促进作用,LP-7501在三种有机氮培养基中72h内的亚硝酸盐降解率均达99%以上,降解速率为酵母抽提物>玉米浆膏>蛋白胨。但是三种有机氮源培养基中LP-7501降解亚硝酸盐的速率要高于总酸增长速率,故推测LP-7501降解亚硝酸盐的途径中可能存在酶降解途径。通过碳氮源比例试验得出,葡萄糖加入量为3%时,酵母抽提物添加量越高LP-7501降解亚硝酸盐速率越快,但36h后碳氮源比例小于1的各组对于亚硝酸盐的降解效果相差不大。通过不同样品中有机酸种类的检测结果可知,LP-7501在单一碳源条件下都能生成乳酸,在含果糖、蔗糖和糊精条件下能生成少量的乙酸,在含酵母抽提物、玉米浆膏和蛋白胨三种有机氮源条件下能生成乳酸、乙酸、柠檬酸和丁二酸,而这些有机酸都能与亚硝酸盐反应生成NO和NO2,构成LP-7501降解亚硝酸盐的酸降解途径。3、通过粗提、DE-52层析和Sephadex G-150层析后得到2.1mg比酶活为36.72U/mg的NiRs,纯化产率为12.8%。对提纯的NiRs进行电泳、ICAP检测和性质分析后可以初步得出,该NiRs可能为三聚体Cu-NiRs,分子量为130kDa左右,蛋白中Cu2+和Fe2+浓度为413mg/kg和98.4mg/kg。该NiRs的最佳酶表达活性温度为35℃、pH为6.0,Cu2+、Fe2+、Fe3+都对其酶活有促进作用,Zn2+对其酶活有较大的抑制作用。通过检测铵态氮和N2O发现,LP-7501降解亚硝酸盐的产物中无NH4+而有N2O存在,故LP-7501酶降解亚硝酸盐的途径应为呼吸反硝化途径。MRS反应体系中亚硝酸盐的降解率曲线和N2O气体的浓度曲线基本重合,说明通过检测N2O气体浓度,基本可以检测亚硝酸盐的降解率。4、对发酵萝卜中有机酸的检测发现,LP-7501纯种发酵的泡菜较之自然发酵的泡菜中草酸和苹果酸含量降低,乳酸、柠檬酸和丁二酸含量增高。通过对蔗糖添加量、食盐添加量、氮源添加量、发酵时间和发酵温度进行单因素试验,在单因素试验的基础上,设计正交试验筛选LP-7501实际发酵过程中亚硝酸盐降解的最优发酵工艺为:蔗糖添加量0.9%、食盐添加量4%、氮源添加量0.7%、发酵时间84h、发酵温度30℃。在此发酵条件下,测得发酵萝卜中总酸含量为0.73g/100g,亚硝酸盐含量为0.432mg/kg,感官评分为75分。
Abstract
ya xiao suan yan （NIT）de an quan kong zhi yi zhi shi pao cai fa jiao guo cheng zhong guan jian wen ti zhi yi ,ben wen cong zi ran fa jiao de pao cai zhong shai shua chu yi zhu you gao xiao jiang jie ya xiao suan yan gong neng de ru suan jun ,bing dui ji jiang jie ya xiao suan yan de ying xiang yin su he jiang jie ji li jin hang yan jiu ,de dao jie guo ru xia :1、cong zi ran fa jiao luo bo zhong shai shua chu 75zhu yi shi ru suan jun jun zhu ,tong guo ya xiao suan yan jiang jie neng li de ce shi he shi ji fa jiao ce shi shai shua chu yi zhu you gao xiao jiang jie ya xiao suan yan neng li de zhi wu ru gan jun LP-7501。tong guo pHshi yan ce ding jie guo de chu LP-7501ju you jiao hao de nai suan xing ,sheng chang de zui jia chu shi pHwei 6.5zuo you ,tong guo wen du shi yan biao ming zai 35℃shi LP-7501sheng chang dai xie he jiang jie ya xiao suan yan zui jia 。2、tong guo tan yuan he dan yuan shi yan de chu ,LP-7501zai chan chun tan yuan pei yang ji zhong sheng chang dai xie chan suan he jiang jie ya xiao suan yan neng li shou dao yi zhi ,ji dui yu chan chun tan yuan de li yong qing kuang wei chan tang >shuang tang >duo tang ;LP-7501zai yi xiao suan an zuo wei dan yuan shi ,sheng chang dai xie chan suan he jiang jie ya xiao suan yan neng li shou dao yi zhi ,jiao mu chou di wu 、yu mi jiang gao he dan bai dong san chong dan yuan dui LP-7501de sheng chang dai xie chan suan he jiang jie ya xiao suan yan neng li dou you cu jin zuo yong ,LP-7501zai san chong you ji dan pei yang ji zhong 72hnei de ya xiao suan yan jiang jie lv jun da 99%yi shang ,jiang jie su lv wei jiao mu chou di wu >yu mi jiang gao >dan bai dong 。dan shi san chong you ji dan yuan pei yang ji zhong LP-7501jiang jie ya xiao suan yan de su lv yao gao yu zong suan zeng chang su lv ,gu tui ce LP-7501jiang jie ya xiao suan yan de tu jing zhong ke neng cun zai mei jiang jie tu jing 。tong guo tan dan yuan bi li shi yan de chu ,pu tao tang jia ru liang wei 3%shi ,jiao mu chou di wu tian jia liang yue gao LP-7501jiang jie ya xiao suan yan su lv yue kuai ,dan 36hhou tan dan yuan bi li xiao yu 1de ge zu dui yu ya xiao suan yan de jiang jie xiao guo xiang cha bu da 。tong guo bu tong yang pin zhong you ji suan chong lei de jian ce jie guo ke zhi ,LP-7501zai chan yi tan yuan tiao jian xia dou neng sheng cheng ru suan ,zai han guo tang 、zhe tang he hu jing tiao jian xia neng sheng cheng shao liang de yi suan ,zai han jiao mu chou di wu 、yu mi jiang gao he dan bai dong san chong you ji dan yuan tiao jian xia neng sheng cheng ru suan 、yi suan 、ning meng suan he ding er suan ,er zhe xie you ji suan dou neng yu ya xiao suan yan fan ying sheng cheng NOhe NO2,gou cheng LP-7501jiang jie ya xiao suan yan de suan jiang jie tu jing 。3、tong guo cu di 、DE-52ceng xi he Sephadex G-150ceng xi hou de dao 2.1mgbi mei huo wei 36.72U/mgde NiRs,chun hua chan lv wei 12.8%。dui di chun de NiRsjin hang dian yong 、ICAPjian ce he xing zhi fen xi hou ke yi chu bu de chu ,gai NiRske neng wei san ju ti Cu-NiRs,fen zi liang wei 130kDazuo you ,dan bai zhong Cu2+he Fe2+nong du wei 413mg/kghe 98.4mg/kg。gai NiRsde zui jia mei biao da huo xing wen du wei 35℃、pHwei 6.0,Cu2+、Fe2+、Fe3+dou dui ji mei huo you cu jin zuo yong ,Zn2+dui ji mei huo you jiao da de yi zhi zuo yong 。tong guo jian ce an tai dan he N2Ofa xian ,LP-7501jiang jie ya xiao suan yan de chan wu zhong mo NH4+er you N2Ocun zai ,gu LP-7501mei jiang jie ya xiao suan yan de tu jing ying wei hu xi fan xiao hua tu jing 。MRSfan ying ti ji zhong ya xiao suan yan de jiang jie lv qu xian he N2Oqi ti de nong du qu xian ji ben chong ge ,shui ming tong guo jian ce N2Oqi ti nong du ,ji ben ke yi jian ce ya xiao suan yan de jiang jie lv 。4、dui fa jiao luo bo zhong you ji suan de jian ce fa xian ,LP-7501chun chong fa jiao de pao cai jiao zhi zi ran fa jiao de pao cai zhong cao suan he ping guo suan han liang jiang di ,ru suan 、ning meng suan he ding er suan han liang zeng gao 。tong guo dui zhe tang tian jia liang 、shi yan tian jia liang 、dan yuan tian jia liang 、fa jiao shi jian he fa jiao wen du jin hang chan yin su shi yan ,zai chan yin su shi yan de ji chu shang ,she ji zheng jiao shi yan shai shua LP-7501shi ji fa jiao guo cheng zhong ya xiao suan yan jiang jie de zui you fa jiao gong yi wei :zhe tang tian jia liang 0.9%、shi yan tian jia liang 4%、dan yuan tian jia liang 0.7%、fa jiao shi jian 84h、fa jiao wen du 30℃。zai ci fa jiao tiao jian xia ,ce de fa jiao luo bo zhong zong suan han liang wei 0.73g/100g,ya xiao suan yan han liang wei 0.432mg/kg,gan guan ping fen wei 75fen 。
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论文作者分别是来自贵州大学的商景天，发表于刊物贵州大学2019-07-16论文，是一篇关于泡菜论文,乳酸菌论文,营养源论文,有机酸论文,亚硝酸盐还原酶论文,降解产物论文,贵州大学2019-07-16论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自贵州大学2019-07-16论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：泡菜论文; 乳酸菌论文; 营养源论文; 有机酸论文; 亚硝酸盐还原酶论文; 降解产物论文; 贵州大学2019-07-16论文;