高粘度低后酸酸奶发酵剂的研究与应用

《高粘度低后酸酸奶发酵剂的研究与应用》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、摘要随着我国乳制品工业的迅猛发展，积极研究和开发不同种类的酸奶发酵剂，对提高酸奶的品质和酸奶发酵剂的生产水平具有重要的意义。本文针对市售酸奶易出现粘度低和后酸化严重的两个问题，通过单发酵酸奶和复配发酵酸奶试验，筛选出一对具有产粘高和后酸化度低特性的球杆菌组合：PZST4-PZLB5。具体结果如下：（1）从商业发酵剂中运用分离纯化的方法初选出六株嗜热链球菌和五株保加利亚乳杆菌，通过单发酵酸奶试验和复配发酵酸奶试验筛选出一组菌株，与对照组G027相比，具有粘度高和后酸化度低的特性。（2）对PZST4进行培养基和培养条件

2、的优化，结果为：葡萄糖13.3g/L、大豆蛋白胨8.9g/L、酵母浸粉8.9g/L、牛肉粉8.9g/L、Na2HPO46.75g/L、NaH2PO416.75g/L和MgSO4²7H2O100mg/L。培养温度为37℃、接种量为5%、起始pH为6.8，培养16h达到最大菌体干重。（3）对PZLB5进行培养基和培养条件的优化，结果为：蔗糖13.3g/L、大豆蛋白胨8.9g/L、酵母浸粉8.9g/L、牛肉粉8.9g/L、柠檬酸钠1.25g/L、乙酸钠3.125g/L、K2HPO41.25g/L、MgSO4²7H2O20

3、0mg/L和MnSO4²5H2O50mg/L。培养温度为37℃、接种量为2%、起始pH为6.5，培养18h达到最大菌体干重。（4）对球杆菌比例进行试验，可知酸奶发酵剂中PZST4：PZLB5的比例为50:1时能更好地达到产粘高后酸化低的效果。关键字：后酸化；粘度；嗜热链球菌；保加利亚乳杆菌；发酵剂；酸奶HighviscosityandlowpostacidificationofyoghurtcultureanditsapplicationAbstractTheactiveresearchanddevelopment

4、oftheyoghurtstartershadgreatsignificanceinimprovingthequalityofyogurtandthelevelofstarterswiththerapiddevelopmentofdairyindustryinChina.Inthispaper,AcomposeofPZST4-PZLB5withcharacteristicsofhighviscosityandlowacidificationwerepickedoutbyfermentingmilkwithasing

5、lestrainortwostrainsofstarter,inordertosolvetwomajorproblems(lowviscosityandseriouspostacidification)ofcommercialyogurtinshelf.Specificconclusionswereasfollows:(1)SixstrainsofS.thermophilusandFivestrainsofL.bulgaricuswereisolatedandpurifiedfromcommercialstarte

6、rs.AcomposeofPZST4-PZLB5wasselectedbyfermentingmilkwithasinglestrainortwostrainsofstarter,withG027asthecontrol.Theproductshoweditsspecialproperties:highviscosityandlowacidification.(2)ThemediaandcultureconditionforPZST4wereoptimized.Theoptimummediumwas:glucose

7、13.3g/L,soypeptone8.9g/L,yeastextract8.9g/L,beefpowder8.9g/L,Na2HPO46.75g/L,NaH2PO416.75g/LandMgSO47H2O100mg/L.Theoptimumcultureconditionwere:temperature37℃,inoculums5%,initialpH6.8,cultivationtime16h.(3)ThemediaandcultureconditionforPZLB5wereoptimized.Theopt

8、imummediumwas:glucose13.3g/L,soypeptone8.9g/L,yeastextract8.9g/L,beefpowder8.9g/L,sodiumcitrate1.25g/L,sodiumacetate3.125g/L,K2HPO41.25g/L,MgSO47H2O200mg/LandMnSO45H2O50mg/L.Theo