乳酸菌分离鉴定及其条斑紫菜乳酸菌混合发酵理化因子的变化

Isolation and identification of lactic acid bacteria and changes of physical and chemical factors in the process of Pyropia yezoensis mixed fermentation

对泡菜老坛水中的乳酸菌进行分离鉴定,获得3株乳酸菌,确定为短乳杆菌(Lactobacillus brevis)、植物乳杆菌(Lactobacillus plantarum)、干酪乳杆菌(Lactobacillus casei)。以条斑紫菜(Porphyra yezoensis)为原料,以4种不同配比的上述乳酸菌对条斑紫菜进行直投式发酵,探讨发酵过程中发酵液部分理化因子的变化规律。结果显示,4种发酵液的pH下降趋势相似,从开始的4.51下降到2.90;1∶1∶2(体积比)混合乳酸菌发酵液的产酸能力最强,发酵终点总酸含量为13.75 g/L,为发酵开始的6倍;1∶1∶2混合乳酸菌发酵液的总糖含量由开始的29.95 g/L下降为发酵终点的18.97 g/L;1∶1∶2混合乳酸菌发酵液亚硝酸盐含量的峰值最小,为3.75 mg/kg;1∶1∶1混合乳酸菌发酵液氨基酸含量较高,最大值为58.16μmol/mL;蛋白质含量下降幅度最大的是1∶1∶3混合乳酸菌发酵液。

Three strains of lactobacillus were isolated and identified from fermented liquid of pickle after isolation and identification.They were identified as Lactobacillus brevis,Lactobacillus plantarum and Lactobacillus casei.Then these lactic acid bacteria were used to directly ferment Pyropia yezoensis with four different ratios,and some physical and chemical changes in the fermentation process was discussed.The results showed that all four kind of mixed lactobacillus fermentation broth had similar pH decline trends,from 4.51 to 2.90;1∶1∶2(V∶V∶V)mixed lactobacillus fermentation broth had the strongest acid production capacity,and at the end point of fermentation,the total acid content was 13.75 g/L,which was 6 times of the beginning;the total sugar content of 1∶1∶2 mixed lactobacillus fermentation broth was from the initial 29.95 g/L to 18.97 g/L at the fermentation end point;the minimum peak of nitrite content of 1∶1∶2 mixed lactobacillus fermentation broth was 3.75 mg/kg;the higher amino acid content occurred in 1∶1∶1 mixed lactobacillus fermentation broth,with the maximum value of 58.16μmol/mL;the 1∶1∶3 mixed lactobacillus fermentation broth had the largest decrease of protein content.