Identification of Dominant Microbes and Functional Analysis of Sourdough Starters Made of Dried Longan and Raisin

Abstract

Baking bread is currently experiencing a profound transformation, propelled by an escalating interest in health and wellness, global cuisines, and sustainability efforts. The surface of fruits harbors various microbes, such as yeasts and lactic acid bacteria (LAB). In contrast to Saccharomyces cerevisiae, a commercial yeast, the microbial flora present on the surface of fruits allows bread with greater flavor, texture, and health benefits as seen in sourdough starters. In this research, sourdough starters were created using dried longan and raisin. The microbial flora of the sourdough starters and the fermentation profile were examined, and possible bacteriocin genes were identified. The dried longan starter exhibited bubbling, stickiness, and a drop in pH value from 5.80 to 4.45 at the third day of fermentation. Meanwhile, the raisin starter began bubbling on the sixth day with no change in fluid viscosity, and a small pH value decreased from 4.00 to 3.82. The dried longan starter contained Weissella cibaria, W. paramesenteroides, S. cerevisiae, Pediococcus pentosaceus, Torulaspora delbrueckii and Leuconostoc citreum. On the other hand, raisin starter only contained Candida krusei and T. delbrueckii. To detect antibacterial property in W. paramesenteroides and P. pentosaceus, four bacteriocins, Gassericin A (gaaA), Lactacin F (lafA), Plantaricin S (pls) and Pediocin (ped) were explored. Polymerase chain reaction (PCR) results revealed that gaaA and lafA were present in W. paramesenteroides, which suggested that this strain possessed antimicrobial properties.

Keywords

• sourdough starters
• <i>Weissella paramesenteroides</i>
• bacteriocin gene