Applying a novel jujube-based sourdough as starter culture to enhance the flavor complexity and rheological structure of bread

CICC 23121 as starter culture for improving the aromatic profiles and rheological properties of bread. It was noted that use of the JS significantly increased varieties and concentrations of VOCs in jujube dough samples compared to wheat dough by improving the viability and acidogenesis activity of strain CICC 23121. The JS-incorporated bread developed multiple fruit- and floral-characteristic VOCs, which consists of 2-heptanone, acetaldehyde and octyl formate as key discriminant aroma compounds compared to the other three bread varieties. Selecting a 24h fermented JS as starter culture increased the level of lactic acid from 2.94 ± 0.11 mg/mL to 13.05 ± 0.96 mg/mL, and acetic acid from 0.02 ± 0.002 mg/mL to 0.13 ± 0.01 mg/mL, directly serving as precursors for fruity ethyl acetate esters of bread. Use of the JS accumulated the free amino acids of excessive 0.11 μg/mg (proline, serine, and lysine) in the fermented dough, thereby generating the aromatic VOCs of ethyl octanoate and isopentyl alcohol which contribute to the complex aroma profile. Currently, a 20% incorporation ratio of the JS to wheat dough was confirmed to be the optimal for bread making. The resulting bread not only produces strong jujube fruit-like flavor but has an ideal viscoelasticity and well-developed gluten network structure as well.