Date of Award
Animal, Dairy, and Veterinary Sciences
Dietary interventions with probiotic lactic acid bacteria (LAB) and prebiotics, complex dietary fibers that promote LAB growth, may favorably shift the gut microbiome to reduce colorectal cancer risk. Our primary hypothesis was that the LAB strains NCFM Lactobacillus acidophilus and HNO 19 Bifidobacterium lactis would thrive in the presence of agave, green banana, black raspberry, baobab fruit, or pomegranate peel whole food powders by fermenting their oligosaccharide (OS) components into lactic acid end products. LAB strains were cultured in media with no carbohydrate, purified OS, or one of the whole food powders. LAB strains cultured with agave appeared to grow better compared to the purified OS treatment as determined by the optical density measurement (p < 0.0001). Also, the medium pH for L. acidophilus cultured with agave or black raspberry decreased significantly more than with purified OS (p < 0.0001 ), indicating a greater rate of fermentation. For B. lactis cultured with agave, black raspberry, or baobab fruit the medium pH was not significantly different from the purified OS, suggesting that these foods are fermented at least as well as the purified OS. However, the effect of green banana, black raspberry, or pomegranate peel on bacteria growth could not be determined because the culture medium was too opaque for measurements. The medium pH of L. acidophilus cultured with baobab fruit was not significantly different than the no carbohydrate control. Optical density measurements suggested that baobab fruit did not support growth of L. acidophilus, though B. lactis grew in the presence of baobab as well as the purified OS. Lastly, neither green banana nor pomegranate peel appeared to be utilized by LAB strains as culture media pH was not changed. In conclusion, results of this study suggest that agave and black raspberry powders support lactic acid bacteria fermentation, while green banana and pomegranate peel did not under the culture conditions employed in this study. Additionally, the fermentation of baobab powder appeared to be dependent on the probiotic strain. Of the bioactive food powders tested, black raspberry appears to be the most promising candidate for future synbiotic colorectal cancer dietary intervention studies.
Brubaker, Michaela, "Fermentation of Prebiotics in Whole Food Powders by Probiotic Lactic-Acid Producing Bacterial Strains to Identify Synbiotic Combinations" (2019). Undergraduate Honors Capstone Projects. 517.
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Abby D. Benninghoff
Departmental Honors Advisor
Capstone Committee Member
Korry J. Hintze