Antioxidant, flavor profile and quality of wheat dough bread incorporated with kiwifruit fermented by β-glucosidase producing lactic acid bacteria strains

This study aimed to investigate the effect of incorporation of kiwifruit substrate fermented by 3 high β-glucosidase producing lactic acid bacteria (LAB) of Lactobacillus harbinensis (M12, M24) and Pediococcus pentosaceus (J28) on physicochemical and rheo-fermentation properties during proofing of wheat dough. Quality, sensory evaluation, antioxidant content and activity, and flavor profiles of bread was evaluated. Results revealed that LAB strains adequately adapted (J28>M12>M24) and produced enzymes during substrate fermentation. In dough, incorporation of fermented substrate increased acidity, soluble dietary fiber, β-glucosidase and α-amylase activity and gas retention during proofing, in a strain dependent manner (J28>M12>M24). The subsequent breads exhibited higher specific volume and had softer crumbs. Furthermore, total flavonoid, total phenolic, antioxidant activity, flavor content and intensity increased in breads incorporated with fermented substrate. Overall sensory acceptance was in order, bread containing substrates fermented by J28 (KFB-J28)> M12 (KFB-M12)> M24 (KFB-M24)> wheat bread (WB)> bread containing unfermented substrate (KFB). Changes observed were attributed to biotransformation by β-glucosidase which increasingly degraded dietary fibers into soluble dietary fiber, increased acidity, released glycosylated aroma compounds and phenolic compounds in substrate. When incorporated in dough, fermented kiwifruit substrates stabilized gluten network, increased yeast metabolism and gas retention during proofing. Subsequently, KFB-J28, KFB-M12, and KFB-M24 had higher antioxidant content and activity, higher flavor content and intensity, better quality and were more accepted compared to WB and KFB. This suggested the potential role played by β-glucosidases through LAB fermentation on functionally enriching and adding value to kiwifruit substrate as a novel functional ingredient in bakery industry.