Degradation of β-Lactoglobulin during sourdough bread production

The research featured various types and strains of lactic acid bacteria (LAB) and yeast. The research objective was to study their ability to utilize beta-lactoglobulin during sourdough fermentation. The present paper also described the effect of sourdough fermentation and baking on beta-lactoglobulin degradation. A set of experiments with various types and strains of LAB showed that beta-lactoglobulin decreased in gluten-free sourdough with 30%, 60%, and 90% of skimmed milk powder (SMP). L.plantarum E36 demonstrated the highest biodegradation of beta-lactoglobulin (by 53%) with SMP = 30%. L.helveticus ATCC8018T showed the lowest content of beta-lactoglobulin with SMP = 60% and 90%: the content fell by 48% and 40%, respectively. The largest decrease in the content of beta-lactoglobulin was observed in the sourdough with Saccharomyces cerevisiae 17 (by 28-42%) and Candida milleri Pushkinsky (by 25-41%). The content of total protein increased, which was not associated with yeast biomass growth. The content was determined after fermentation in sourdoughs with SMP = 60% and 90% using a bicinchoninic acid reagent kit. The content of beta-lactoglobulin in the control and experimental samples did not exceed 1 mu g/g in the finished bakery products. This fact indicated a significant effect of thermal treatment on beta-lactoglobulin degradation in baking. Thus, temperature processing (baking) had a greater impact on the destruction of beta-lactoglobulin than enzymatic processing (fermentation).