مجله پژوهشهای علوم و صنایع غذایی ایران (Feb 2024)
Effect of the Controlled Fermented Sprouted Lentil Containing Fennel Extract on the Characteristics of Wheat Bread
Abstract
IntroductionWheat bread is a staple food worldwide, and bread making using sourdough is one of the oldest technologies. In this regard, the use of legume sourdough is important in improving the quality of wheat bread. Sprouted legumes are also proper substrates rich in bioactive compounds for sourdough fermentation to produce enriched products. Furthermore, application of herbal extracts in sourdough formulation is a simple way to enhance organoleptic properties and mold-free shelf-life of the produced sourdough bread. Considering positive effects of sourdough on techno-functional properties of the produced bread, the aim of the present study was to enhance quality parameters of wheat bread using controlled fermented sprouted lentil containing fennel extract. Materials and MethodsIn the present study, predominant lactic acid bacteria (LAB) were isolated using the sequential back-slopping process from fermented sprouted lentil containing fennel extract. The isolates were screened based on their antifungal activities against Aspergillus niger. The selected isolates were identified through amplification of the target sequence with 1500 bp from its 16S rDNA gene and sequencing of the PCR products. After that, controlled fermentation containing selected LAB isolates (as a starter culture) was performed in processing of wheat bread. Crumb hardness, specific volume, water activity, overall acceptability and surface growth rate of the target fungus were compared in the produced breads. In order to determine the effects of the substrate, fermentation and germination, suitable samples were produced. The results of the present study were also analyzed in a completely randomized design with three replications, and Duncan test at P<0.05 significant difference was used to compare the mean. Results and DiscussionSequencing results of the PCR products (amplicons) led to the identification of Pediococcus acidilactici as the selected LAB isolate. Addition of lentil sourdough to wheat bread significantly (P<0.05) reduced the weight loss and crumb hardness of wheat bread and also increased its specific volume without significant effect. Among the produced breads, the lowest specific volume was belonged to the sample containing lentil and the highest specific volume was observed in the control sample. Moreover, fermentation and sprouting reduced the surface growth of A. niger in the produced breads. The surface growth rate of the fungus in the bread containing fermented sprouted lentil was also significantly lower than those of the control sample. In addition, wheat bread containing fermented sprouted lentil received the highest overall acceptability score among the produced enriched breads. It is reported that the positive effects of controlled sourdough on textural features of the produced bread are mainly associated with the acidification activity of the starter culture used. Production of organic acids and other inhibitory metabolites by the sourdough starter culture is also involved in its antifungal activity in the product. Moreover, production of volatile and non-volatile aroma precursors during sourdough fermentation affect sensory attributes of the sourdough bread. ConclusionNowadays, consumer demand for healthy products with minimal processing and with no synthetic additives such as clean-label foods, and the use of bio-preservatives (application of microorganisms and their metabolites to prevent spoilage and increase the shelf-life of the product) has become a growing trend. Application of legumes as a good source of protein, other nutrients and essential components in bread formulation is important for their use in the daily diet. According to the results of the present study, controlled fermented sprouted lentil containing fennel extract can be used as an antifungal compound and texture improver in bakery industries. Overall, the use of plant extracts with antifungal effects as well as controlled fermentation of sourdough with selected LAB as protective/starter culture can reduce the use of chemical preservatives in bread.
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