Date of Award

Summer 8-21-2020

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Jennifer Perry

Second Committee Member

L. Brian Perkins

Third Committee Member

Beth Calder

Abstract

Fermentation is the process by which primarily lactic acid bacteria (LAB), an environmentally ubiquitous group of organisms, convert carbohydrates into several byproducts, including acid, ethanol and/or gas. Often these resulting byproducts create desirable foods with unique flavor attributes and an increased inherent safety due to acidification. Vegetables such as red beetroot are suitable commodities for fermentation, due to abundant nutrient sources to sustain the LAB population. However, sufficient growth of LAB may lead to the production of harmful biogenic amines, specifically histamine and tyramine which can cause an allergic reaction and poisoning at high levels. Additionally, red beetroot is grown in direct contact with soil, a known fomite for foodborne pathogens. Thus, the objectives of this study are to determine the effects of three different salt (0.5%, 1.5%, and 2.5% NaCl (w/w)) and garlic (0%, 0.5%, and 1.0% (w/w)) concentrations on bacterial pathogen (STEC, Salmonella, and L. monocytogenes) survival and biochemical properties (biogenic amines, organic acids, sugars, and alcohol), during both spontaneous fermentation and storage of beet kvass. The sensory perception of fermented beet kvass at two different salt (1.5% and 2.5% NaCl (w/w)) and garlic (0% and 0.5% (w/w)) concentrations and the impact of health-related messaging on product consumer acceptability were also assessed. Results indicate that neither the salt or garlic concentrations tested had a significant effect on pathogen survival. Although there was a decrease in Salmonella and L. monocytogenes survival after storage, neither pathogen was completely eradicated in all samples. Therefore, to better ensure consumer safety, it is important for fermenters to maintain cleanliness and avoid cross-contamination during production. Salt and garlic concentration, however had a significant effect on organic acid and fructose content. Specifically, beet kvass produced with garlic had significantly reduced lactic and acetic acid, glucose, and fructose content, but significantly increased ethanol levels, when compared with samples without garlic. This biochemical profile suggests that garlic favors the growth of yeast in beet kvass. These observations suggest that formula development has considerable impacts on microbial diversity in this product. Biogenic amine analysis determined that low accumulation of these compounds in the production and storage of kvass are insufficient to pose obvious safety risks to consumers. Sensory evaluation revealed that salt concentration is a significant deciding factor on overall product acceptance, with consumers generally preferring lower salt levels. Inclusion of information on the potential health benefits of the product increased panelists’ interest in consuming the product, indicating that participants may be willing to compromise sensory characteristics for health benefits. Therefore, producers may formulate beet kvass with lower salt and with or without garlic, without adversely effecting product acceptability.

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