Four isolated lactic acid bacteria LAB strains Lactobacillus brevis, Lactobacillus plantarum, Pediococcus pentoseus, and Pediococcus acidilactici were selected and used to inoculate sourdough in order to reduce acrylamide content. After fermentation for 16 h, all of the inoculated sourdoughs showed lower pH values compared to the spontaneous sourdough. This acidification was accompanied by a significant (p<0.05) increase in the concentration of reducing sugars. The baked bread samples made with the tested LAB strains showed significantly reduced acrylamide content, in particular for the sample inoculated with P.acidilactici (5.64 µg/kg), compared to the bread sample prepared with baker's yeast (35.6 µg/kg). The resulting breads were also evaluated for several other quality parameters. The highest softness was registered for the breads obtained from the fermentation by P.acidilactici (2704 g). The different tested strains also influenced the color, the void fraction, and the cell density of the breads. The sensory evaluation indicated that the crust color, crumb aeration, as well as the salty and acidic tastes were not significantly affected by sourdough incorporation. However, breads made from LAB sourdoughs were more appreciated by the tasters. This study proved the suitability use of the selected P.acidilactici strain for industrial-scale bread production.
The aim of this work was the optimization of the enzyme hydrolysis of potato peel residues (PPR) for bioethanol production. The process included a pretreatment step followed by an enzyme hydrolysis using crude enzyme system composed of cellulase, amylase and hemicellulase, produced by a mixed culture of Aspergillus niger and Trichoderma reesei. Hydrothermal, alkali and acid pretreatments were considered with regards to the enhancement of enzyme hydrolysis of potato peel residues. The obtained results showed that hydrothermal pretreatment lead to a higher enzyme hydrolysis yield compared to both acid and alkali pretreatments. Enzyme hydrolysis was also optimized for parameters such as temperature, pH, substrate loading and surfactant loading using a response surface methodology. Under optimized conditions, 77 g/L of reducing sugars were obtained. Yeast fermentation of the released reducing sugars led to an ethanol titer of 30g/L after supplementation of the culture medium with ammonium sulfate. Moreover, a comparative study between acid and enzyme hydrolysis of potato peel residues was investigated. Results showed that enzyme hydrolysis offers higher yield of bioethanol production than acid hydrolysis. These results highlight the potential of second generation bioethanol production from potato peel residues treated with onsite produced hydrolytic enzymes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.