Lactic acid bacteria and yeasts isolated from the starter doughs for Chinese steamed buns in Thailand

• Published in: Food science & technology 2009-10, Vol.42 (8), p.1404-1412
• Main Authors: Luangsakul, Naphatrapi, Keeratipibul, Suwimon, Jindamorakot, Sasitorn, Tanasupawat, Somboon
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cereal and baking product industries; Chinese steamed bun; Fermented food; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; Lactic acid bacteria; Sourdough; Yeasts
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2009.03.007

Isolation of lactic acid bacteria (LAB) and yeasts from the starter dough of Chinese steamed buns from four different commercial sources in Thailand was carried out. Thirty-one lactic acid bacteria and eight yeast strains were isolated. Total counts of LAB were from 1.8 × 10 4 to 10 8 colonies/g sample, whilst yeasts were very low from 10 to 2.3 × 10 2 colonies/g sample. The pH values of all starter doughs ranged from 3.36 to 3.52 and the Total Titratable Acidity (TTA) varied from 11.1 to 17.0 ml of 0.1 N NaOH/10 g dough. All LAB isolates were identified as Lactobacillus. The phenotypic characteristics were used to cluster all the LAB isolates into two major groups (Group A and Group B), with the B group subdivided into four groups. Phylogenetic analysis, based upon partial 16S rRNA gene sequences, showed that isolates of Group A, which all contained meso-diaminopimelic acid in their cell wall and produced dl-lactic acid, were closely related to Lactobacillus plantarum, whilst the strains of Group B that produced l-lactic acid were closely related to Lactobacillus casei. For yeasts, eight isolates based on the D1/D2 domain sequences of 26S rRNA were identified as Candida tropicalis, Pichia stipitis, Candida parapsilosis, Issatchenkia orientalis and Saccharomyces cerevisiae.