Exploring the role of lactic acid bacteria involved in bread fermentation in improving flavor via intelligent sensory technologies and GC×GC-ToF-MS

The effect of individually mixing Lactobacillus paracasei C5 and Lactobacillus pentosus D1 with yeast as starter cultures on bread flavor was investigated via electronic-nose, electronic-tongue, and GC × GC-ToF-MS methods The electronic-nose results showed that the bread smell could be completely distinguished. Electronic-tongue analysis revealed that the taste of mixed-fermented bread was positively correlated with sourness, sweetness, saltiness, and umami, while the taste of yeast-fermented bread was positively correlated with bitterness and astringency. GC × GC-TOF-MS was used to further detect volatile organic compounds, from which 15 ( L. paracasei bread) and 18 ( L. pentosus bread) major contributing aroma compounds were screened (ROAV ≥1 and VIP >1). Additionally, Lactobacillus was found to be positively correlated with 35 flavor substances and positively regulated the aroma profile of the bread, especially sweet-caramel, coffee-like, and roasted aromas. In conclusion, LAB involved in fermentation can improve the flavor of bread.