一株强化发酵甜瓣子的乳酸片球菌特性及应用效果评价

甜瓣子是以蚕豆制曲后加盐水发酵而成的,是郫县豆瓣风味形成的关键阶段。筛选适用于强化甜瓣子发酵的专用乳酸菌,以期应用于强化甜瓣子发酵。以甜瓣子为原料筛选生长速度快、产酸能力强的高效乳酸菌,研究其生长特性。利用筛选得到的高效乳酸菌制备菌剂并用于强化甜瓣子发酵,分析甜瓣子品质。该研究筛选得到1株乳酸片球菌ND1,37℃培养6 h、OD610达1.375,培养24 h发酵液中乳酸含量达到1.296 g/100 g。ND1在4~50℃条件生长良好,高温更利于其生长,在37~45℃生长速度最快;能耐受10%的盐,在盐含量(质量分数)为0%~8%的条件生长良好;在pH 3.5~6生长速度快。利用菌株ND1发酵得到的乳酸菌剂活菌数可达1.07×10^12CFU/g,利用该菌剂发酵甜瓣子,可有效提高甜瓣子中有机酸(尤其是乙酸、苹果酸、乳酸)含量,强化甜瓣子风味。该研究筛选的乳酸片球菌ND1具有良好的温度、酸度、盐度适应性,能改善甜瓣子中有机酸含量,有望被用作强化甜瓣子发酵增香的乳酸菌,改善郫县豆瓣品质。

The characteristics and application of a Pediococcus acidilactici for improving broad bean mash fermentation

Broad bean mash is fermented by mixing broad bean koji with salt solution for six months.The fermentation of broad bean mash is the key process for the flavor generation of Pixian broad bean paste.This study was to screen lactic acid bacteria specialty for improving the fermentation of broad bean mash.The growth characteristics of the lactic acid bacteria at different culture conditions was analyzed.The freeze-dried lactic acid bacteria powder was added in the broad bean mash fermentation system to strengthen the fermentation.A high efficiency Pediococcus acidilactici ND1 was screened out and could grow up to OD6101.375 after 6 h cultivation at 37℃.The total acid in the fermentation broth of ND1(cultivated 24 h)reached 1.296 g/100 g.Strain ND1 growed well between 4℃and 50℃,the optimum temperature was between 37℃and 45℃.It could stand 10%salt and grow well in the concentration of less than 8%.Strain ND1 grows well under acidic conditions at pH from 3.5 to 6.The living Pediococcus acidilactici count of vacuum freeze-dried powder reached 1.07×10^12 CFU/g and could enhance the content of organic acid,especially acetic acid,malic acid,lactic acid in the broad bean mash fermentation system.Strain ND1 could improve the flavor of broad bean mash and tolerance high range of temperature,pH and salt concentration.These characteristics made this strain to be a potential lactic acid bacterial for flavoring broad bean mash,improving the quality of pixian broad bean paste furthermore.