Optimizing Sourdough Process for the Production of Honey and Rose-Like Aromas in Breads

Fermentation is one of the best methods for in-situ generation of aromas in breads. However, generating desirable flavors needs controlling several effective factors. In this study, optimal conditions for the production of honey and rose-like aromas were investigated by fitting a quadratic model using response surface method. To the best of the authors’ knowledge, no study has used this method for the high-efficiency production of flavor compounds in sourdough. Material and Methods: In the present study, headspace solid-phase microextraction-gas chromatography mass spectrometry was used to demonstrate ability of Kluyvero- myces marxianus and Leuconostoc mesenteroides co-culture to produce 2-phenyl ethyl acetate and 2-phenyl ethyl alcohol in sourdough. Therefore, experiments were developed using response surface method and six parameters of dough yield, temperature, time, fructose, phenylalanine and bran proportions. Volatiles were collected from sourdough using headspace solid-phase microextraction method, followed by measuring the extracted volatile compounds using gas chromatograph connected to a mass selective detector. Results and Conclusion: Results suggested that fermentation was optimum at 25 ℃ for 66.5 h with dough yield, 400; fructose, 6%w v-1; phenylalanine, 0.3% w v-1 and bran, 20% w w-1 for the production of rose and honey-like aromas with high efficiency (2-phenyl ethyl alcohol 127.1 mg l-1 and 2-phenyl ethyl acetate 70.7 mg l-1). Assessment of the baking and storage effects on the selected aroma compounds showed that although sharp decreases occurred in their concentrations due to the oven temperature, they were still detectable in the bread after 3 days of storage. Based on the optimized model, it can be concluded that increasing time and decreasing fermentation temperature led to the strengthening of aroma production. Furthermore, phenylalanine and fructose strongly affected development of the target aromas.