Screening and co-fermentation of lactic acid bacteria and yeasts for low-acid paocai
In this study,heterofermentative lactic acid bacteria(numbered as L1-L6)and yeasts(numbered as M1-M6)isolated from different fermented vegetables were used as research objects.Superior strains were screened through acid and salt tolerance and fermentation performance studies.Mus-tard was fermented with the combination of superior strains with naturally fermented mustard as a control.The physicochemical properties and sensory properties of fermented mustard were investigated for the screening of mixed starter suitable for low-acid paocai.The results showed that Leuconos-toc mesenteroides L5 tolerated well at pH 4.5 and salt concentration 4％and produced less acid in 24 h;Kazachstania exigua M1,Pichia kudriavzevii M2,and Zygosaccharomyces bisporus M4 tolerated well at pH 4.0 and salt concentration 4％and did not produce gas or film.Mustard was inoculated with strain L5 combined with M1,M2 andM4,respectively.Strain M1 grew better in paocai system,and the viable counts was(2.41±0.06)lg(CFU/ml)after 10 d,while strain M2 and M4 were not detected after 4 d.After fermentation,the viable count[(5.71±0.02)lg(CFU/ml)]of lactic acid bacteria in L5 and M1 co-fermentation group was significantly lower than that of other groups(P＜0.05).The total acid(2.30±0.03 g/kg)and nitrite content(1.35±0.02 mg/kg)were also lower than the other two inoculated groups,with the highest sensory score(85.00±2.12)and a unique fragrance.The natural fermentation group was immature and had an obvious raw astringent taste.
万方数据
维普
