Kinetics

1. Fermentation of Cucumis sativus with Lactobacillus delbrueckii
Natalie Dell, Karla Diviesti, Madison Dudley, Casey McCarroll
Kinetics and Reactor Modeling, Biosystems Engineering, Clemson University, Clemson, SC, 29631
Abstract
In this experiment the effect of salt brine concentration was observed in the
Lactobacillus delbrueckii fermentation of cucumbers. 5 jars were inoculated with L.
delbrueckii and contained 0%, 3.5%, 4%, and 5% salt concentration modeled after
commercially made pickle environments.A 6th jar was made with a starch/sugar
media and inoculated with L. delbrueckii. Our results confirmed the successful
fermentation of the cucumbers into pickles, as well as no significant effect on the
process by salt concentration.
Materials and Methods
(1)“Amount of Starch (or Amylum) in Cucumber, with Peel, Raw Natural.” Traditional Oven,
www.traditionaloven.com/foods/specific-nutrient/veggies/cucumber-peel-raw/starch-or-amylum.html
(2) Franco, Wendy, et al. “Cucumber Fermentation.” Lactic Acid Fermentation of Fruits and Vegetables,
Department of Food, Bioprocessing, and Nutrition Sciences at North Carolina State University.
(3) Chen, Lin-Lin et al. “Efficacy profiles for different concentrations of Lactobacillus acidophilus in
experimental colitis” World journal of gastroenterology vol. 19,32 (2013): 5347-56.
(4) Drapcho, C. 2018. Lab 6:Methods of Organic Substrate Determination. Unpublished Laboratory Notes,
BE 4101, Clemson University.
(5) Drapcho, C. 2018. Lecture 13: Batch Growth Kinetics. Unpublished Laboratory Notes, BE 4101,
Clemson University.
Initial Solution Characteristics
Jar
Mass of
Salt (g)
Water
(mL)
Mass of
Garlic (g)
Mass of
Dill (g)
Mass of
Bay
Leaves (g)
Control 0 400 6.17 5.8 0.353
3.5 %
Conc
14.01 400 5.14 5.2 0.332
4%
Conc
16.002 400 6.34 7.41 0.326
5%
Conc
20 400 5.62 5.2 0.531
Introduction
Fermentation has been an effective form of extending the shelf-life of foods for
thousands of years. In today’s society, fermentation plays four key roles; (i)
preservation of substantial amounts of otherwise perishable products; (ii)
biological enhancement of raw materials with protein, vitamins, essential amino
acids, and fatty acids; (iii) enrichment of human diets through improved texture,
appearance, flavor and aromas; and (iv) decreased energy requirements for
preservation (2). Many of the foods eaten today are products of fermentation.
Pickles for instance, result from the lactic acid fermentation of cucumbers.
Incorporating bacteria strains of Lactobacillus into the fermentation process help
facilitate the production of lactic acid. Additionally, Lactobacillus aids in healthy
digestion, provides a speedy recovery from yeast infections, and its anti-
inflammatory properties are thought to be useful in preventing certain kinds of
cancer (2). The objective of this laboratory design was to model a batch reactor
and analyze the effect salt concentration has on lactic acid formation.
Results Mathematical Modeling
Conclusions
References
Acknowledgements
We would like to thank Dr. Caye Drapcho and the Biosystems Engineering department for
providing equipment and guidance. We would also like to thank Ian Cummings for providing
us with L. delbrueckii.
Individual Pickle Characteristics
Length (L) [cm]
Diameter (d)
[cm] Radius (r) [cm]
Surface Area
(As) [cm2]
Volume (V)
[mL]
Initial Weight
(W) [g]
Final Weight
(W) [g]
Difference(W)
[g]
Control
(with
pickles)
4.9 2.6 1.3 38.06 13.01 11.805 13.48 1.675
5.5 2.6 1.3 42.07 14.6 17.664 18.781 1.117
5.8 2.4 1.2 40.31 13.12 16.15 17.095 0.945
4.5 2.7 1.35 36.96 12.88 13.687 14.772 1.085
5.7 2.5 1.25 41.54 13.99 13.702 15.257 1.555
3.6 2.5 1.25 28.05 8.84 13.323 14.127 0.804
3.5%
Conc
5.8 2.1 1.05 34.78 10.04 13.571 14.505 0.934
5.7 2.2 1.1 36.04 10.83 13.354 14.093 0.739
4.2 2 1 24.74 6.6 10.326 11.033 0.707
5.8 2.4 1.2 40.31 13.12 15.521 16.217 0.696
4.9 2.5 1.25 36.4 12.03 18.986 20.406 1.42
4.6 2.1 1.05 28.3 7.97 15.104 16.391 1.287
4% Conc
5.6 2.4 1.2 39.08 12.67 13.644 14.518 0.874
5.9 2.3 1.15 39.04 12.26 20.284 20.851 0.567
5.1 2.6 1.3 39.4 13.54 34.364 36.314 1.95
6 2.8 1.4 49.35 18.47 12.921 13.952 1.031
4.6 2.7 1.35 37.65 13.17 16.772 17.667 0.895
5.1 2.2 1.1 32.65 9.69 19.551 20.944 1.393
5% Conc
4.7 2.1 1.05 28.84 8.14 8.368 9.504 1.136
4.7 2.5 1.25 35.12 11.54 12.41 13.898 1.488
6 2.6 1.3 45.41 15.93 16.82 17.161 0.341
6 2.8 1.4 49.35 18.47 14.662 16.852 2.19
5.2 2.6 1.3 40.07 13.8 13.787 14.94 1.153
5.3 2.6 1.3 40.73 14.07 19.649 20.851 1.202
In conclusion, the salt concentration in the jars had little or no effect on the
pickling fermentation process, this was concluded through the COD test. The
COD, chemical oxygen demand, is an indicator of the amount of energy
present in a system. In our batch fermentation reactor with L. delbrueckii, as
the substrate (the starch and sugar media) is converted to lactic acid, less
energy becomes available, therefore less COD. It was observed in Figure 2 that
jar 4% maintained the highest COD and showed a consistent decreasing
relationship. Jar control no pickle also showed a decreasing relationship. The
rest of the jars showed a small spike in COD on the second day. This could be
due to the sugar initially being pulled from the pickle. A drop in COD should
then be observed as that sugar from the pickle is used. Qualitative visual
assessment showed similar qualities of the lab pickles to commercially made
pickles. Quantitative characteristics of the pickles made in lab agree with
commercially produced pickles. Commercially produced pickles are made at a
salt concentration of 5-8% and have a pH range of 3.2-3.8 (2).The lab grown
pickles showed similar conditions. Overall, the salt concentration of a reactor
has minimal effect on the Lactobacillus delbrueckii fermentation of Cucumis
sativus .
Materials: 16 oz. mason jars (5), cucumbers, Lactobacillus delbrueckii,
sugar/starch media, sea salt, flavorings (Dill, garlic, bay leaves) [table 1].
Methods: 5 jars were set up, 4 contained 6 pickles as well as each had a unique
salt concentration [0%(control), 3.5%, 4%, 5%] and was inoculated with L.
delbrueckii. The last jar was another control containing a calculated starch
concentration to replicate that of 6 pickles (calculation below(1)) as well as a
sugar media and L. delbrueckii. Fermentation was allowed to occur over the next
5 days and samples were taken every other day.
Table 1. Solution characteristics
Table 2. Pickle Characteristics
Figure 3 - 5. Stella models of Glucose Utilization, L. delbruecki
Growth, and Lactic Acid Growth, respectively
Figure 1. Graph of solution concentration vs Absorbance at 600 nm.
Figure 2. Graph of chemical oxygen demand (COD) with respect to time (in days) of each jar.
3.5%, 4%,
3.5%, 4%,