Kombucha sourdough as a novel biopreservative in bread: Characteristics and its effect on the quality and shelf-life of Lavash-bread

Sourdough is a complex biological system and a safe and well-known additive for improving different bread characteristics. Recently, the use of new starter cultures for sourdough fermentation, which can lead to creation of new characteristics in sourdough, has been considered. In this study, four herbal kombucha beverages were used as starter cultures to develop novel Black tea (BKS), Green tea (GKS), Lemon verbena (LKS), and Zataria multiflora (ZKS) kombucha sourdoughs. The traditional sourdough (TS) was compared with four kombucha sourdoughs (KS) for its chemical, microbiological, antioxidant, and antifungal activities. The results indicated that GKS had the highest phenolic content (164.36 mg/L), antioxidant activity (86.94 %), and considerable antifungal potential against Aspergillus niger and Aspergillus flavus . Whole-wheat Lavash breads containing GKS and TS were prepared, and their characteristics were compared with bread without sourdough (control). According to the results, the highest acidity, total phenol content, ash, ΔE, antioxidant activity and overall acceptance belonged to bread with GKS. Also, the GKS effectively reduced the phytic acid content of Lavash bread. The phytic acid contents of bread containing TS and GKS and control Lavash bread were 35.48, 32.46 and 39 mg/100 g, respectively. The bread's shelf-life after the addition of GKS was extended for one day. Therefore, GKS exhibited promising characteristics compared to TS, suggesting its potential as a natural preservative for bread, though industrial-scale studies are still required.