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2012 - 11th Annual NC State Summer Undergraduate Research Symposium
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Session Time :
8/1/12 1:30 PM - 8/1/12 2:45 PM
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Content Area : NC State Independent Researchers
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Lead Student Presenters : Rickey Earl Smith
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Co-Presenters :
Jeannette Theora
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Co-Presenters :
Erin McMurtrie
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Co-Presenters :
Meredith Levi
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Co-Presenters :
Sae Iwata
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Co-Presenters :
Susan Dieck
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Co-Presenters :
Katheryne Daughtry
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Abstract Title : Selection of Starter Culture(s) for Commercial Cucumber Preservation Using a Screening Design for Fermentation Potential and Antimicrobial Activity
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Abstract :
Without the use of a starter culture, the cucumber pickling industry currently relies on 6% sodium chloride (NaCl) brine solutions to aid in selection of lactic acid bacteria to carry out the fermentations. Cucumbers can be fermented without NaCl if a starter culture is added and natural preservatives are supplemented after the primary fermentation is completed, eliminating the cost of treating high salt cover brines post-processing. A commercially viable starter culture must be effective in a variety of conditions. Potential starter cultures were tested under varied initial pH, salt concentration, and temperature. In this experiment, 233 bacterial isolates from commercial cucumber fermentations (70:30 Lactobacillus plantarum: Lactobacillus brevis) were evaluated for the ability to rapidly decrease pH. Each isolate was tested in duplicate for the ability to ferment cucumber juice under 0% and 6% NaCl, pH 4.0 and 5.4, and at incubation temperatures of 15ºC and 30ºC using a fractional factorial screening design. Based on the magnitude of the pH drops in each treatment combination, 143 isolates were eliminated. Remaining isolates were screened for antimicrobial activity against two fermented cucumber spoilage yeasts, Pichia manshurica and Issatchenkia occidentalis, two Lactobacillus buchneri strains associated with fermented cucumber spoilage, and Lactobacillus plantarum and Lactobacillus brevis. The selected Lactobacillus plantarum and Lactobacillus brevis strains will be further evaluated in commercial fermentations to determine their potential as starter cultures. Identification of suitable starter cultures for commercial scale cucumber fermentations will allow processors to reduce high salt waste, implement a more sustainable operation, and reduce processing costs.
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Mentor and/or Co-Author : Ilenys Muniz Perez-Diaz
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