Smartphone wireless pH electrodes for at-home fermentation experiments for CHM/CPD/MBI 436A

Project Title: Smartphone wireless pH electrodes for at-home fermentation experiments for CHM/CPD/MBI 436A

Project Lead’s Name: Neil Danielson


Phone: (513) 529-2872

Please Choose the Primary Affiliation: CAS

Are There Other Project Team Members?: No

Brief description of project: This past Fall 2016, Principles of Fermentation, CHM/CPD/MBI 436A (three credits), was offered for the first time. It was team taught by Luis Actis (MBI), Jason Berberich (CPD), Mike Crowder (CHM), Neil Danielson (CHM), Andor Kiss (MBI), and Rob McCarrick (CHM). The course objectives and learning outcomes follow.

Course Objectives: Through a combination of lectures from faculty and experts in the fermentation industry, hands-on laboratory experiences, and site visits, students will develop an understanding of the importance of fermentation in the food, beverage, and drug industry. Students will have the opportunity to learn how microbiology, biology, chemistry/biochemistry, engineering, psychology, and business are interrelated in the fermentation industry. Students will have a basic understanding of biological processes involved in fermentation, the theory and design principles behind the equipment and facilities used in different fermentation/distillation processes, analysis and preservation of yeast strains and quality control of fermentation products, legal and regulatory issues related to the production of fermentation products, packaging development and critical business aspects related to the commercialization of fermentation products. It is expected that students who successfully complete this course will be well-positioned to enter the fermentation industry and make relevant contributions to the different aspects and steps involved in this complex process that provides critical products for human consumption.

Course Learning Outcomes: Students will be able to: 1.Describe and discuss the biological, chemical/biochemical and engineering factors involved in the fermentation process as it relates to food, beverage, and drug industry. 2. Explain how fermentation products are produced and characterized physically and chemically. 3. Compare and evaluate issues related to up-scaling fermentation processes from small to large commercial endeavors. 

Assignments were a combination of weekly readings and homework, laboratory exercises and lab reports, midterm and final exams, and a final project oral presentation on some focused aspect of fermentation. My major contribution to the course was the development of six quality control type laboratory experiments entitled: 1. Beer color/turbidity, 2. Beer bitterness by extraction, 3. Determination of lactic acid in beer by titration, 4. Ethanol in beer by gas chromatography, 5. Calcium in beer using atomic absorption spectroscopy, and 6. Determination of alpha- and beta-acids in hops using liquid chromatography. One other lab, developed by Jason Berberich, followed amylase enzyme activity, derived from malt using triiodide as the indicator for the starch substrate. Although the lecture aspect of the course emphasized the microbiology, biochemistry, and engineering in the fermentation industry, no actual fermentation lab was done. This was mainly due to the lack of time; the fermentation process takes much longer than a three hour laboratory period.

The intent of this proposal is to have students carry out a fermentation process at home and monitor its progress by measuring pH due to the gradual production of lactic/acetic acid from glucose. In particular, we propose that student make yogurt and kimchi, two very different types of fermentation processes, and use pH as a measure of quality control. The measurement of pH will be done using a pH electrode and the student's smartphone as a wireless meter permitting both temperature and pH to be recorded as a function of time. The importance of monitoring pH and temperature is described in the Approach to Solving the Problem section.

Does this project focus on graduate student education or graduate student life?: No

If yes, please explain: To run the labs effectively this first time, we did have a chemistry graduate student from Danielson's research group volunteer to be the teaching assistant. We expect we can continue to attract an analytical chemistry graduate student for future course offerings. Teaching experience in this course will give the student analytical chemistry expertise in an important fast-growing industry and widen their employment opportunities.

Describe the problem you are attempting to solve and your approach for solving that problem.: Fermentation quality control

Summary of fermentation studies to produce yogurt and kimchi. 

The pH profile as a function of time for the production of yogurt does vary somewhat based on experimental conditions such as the type of milk and microbial starter culture. For one study, the pH remained constant at 6.5 for 3 hr and then decreased to a pH of 4.5 in about 8 hr [1]. Skim milk yogurt as compared to whole milk had a slower incubation rate but better firmness and was somewhat more acidic [2]. The pH profile showed no initial plateau at 6.5 but decreased steadily to 4.0 in about 5-6 hr. Both these studies used commercial microbial cultures not active yogurt and so the time profiles are quite rapid. 

Kimchi is produced through hetero-fermentative bacteria, converting one molecule of sugar to one molecule of lactic acid and the rest of the sugar molecule goes to CO2 or acetic acid/ethanol [3]. The lactic acid bacteria such as lactobacillus on the surface of a vegetable like cabbage will produce lactic/acetic acid from glucose lowering the pH from near pH 6 to about 4. The anaerobic environment is maintained by keeping the cabbage underneath a 3% salt solution. At 20 oC, using a 3% salt solution, the pH changes from just under 6 to about 3.5 in 14 days, after which the pH remains stable. Using a lower salt concentration of 2%, maximum acidity is reached in a slightly shorter time [4]. Using a higher temperature of 25 oC and a 10% salt brine for initial soaking of the cabbage, the optimum pH of 4 is reached in only 3 days but the pH does not level out at 3.5 until about 7 days [5]. 

Student experiments 

Yogurt is easy to make, requiring only milk, commercial yogurt with active cultures, and common kitchen utensils. Milk is heated to about 180 oF and then added to mason jars for cooling to about 115 oF. Approximately two tablespoons of active yogurt are added to each jar and thoroughly mixed. The jar should be placed under a desk lamp to provide some heat. Initially, both pH and temperature are measured and both are monitored approximately every hour, for about 16 hr. For the last 6 hr, tasting should be done. The reaction can be stopped by placing the jars in the refrigerator. It is important to clean the pH electrode after each measurement with the commercial solution intended for protein removal.

Kimchi is in principle easier to make than yogurt because no starter culture is necessary. The primary ingredients are cabbage or bok choy, salt, and various vegetables and spices (such as Korean red flakes or gochugaru) to add flavor. The cabbage is rinsed and cut into strips. Salt is massaged into the strips; the cabbage is covered with water to make a brine solution and allowed to wilt for at least 3 hr or even overnight. The cabbage is then drained and set aside. A mix of chopped vegetables and spices (carrots, chili peppers, garlic, onions, and ginger) is made and is coated/mixed with the cabbage. The cabbage is placed in a jar and covered with a 2 or 3% brine salt solution leaving an inch of air space (headspace). The initial pH and temperature is measured before sealing the jar loosely. The jar should be allowed to stand at room temperature for at least three days. Evidence of any bubbles due to CO2 should be noted. The pH and temperature should be measured every 6 or 7 hr to generate at least 12 points. Tasting (and smelling!) should be done during the last day.

For both the yogurt and kimchi experiments, pH and temperature should be plotted as a function of time. The optimum pH based on tasting should be determined. Discussion of the shape of the pH/temperature - time plots is an appropriate part of the report. Variations of the yogurt experiment could involve use of different brands and amounts of the active yogurt and varying the starting temperature. Variations of the kimchi experiment could involve different vegetables such as Asian white radish and temperature.

Future experiments could involve the fermentation of sweetened black tea to make kombucha, a process that takes several weeks. In this case, sugar is converted by yeast to alcohol which through bacterial action forms acetic acid [6].

1. A. G. De Brabandere, J. G. De Baerdemaeker, J. Food Eng. 41 (1999) 221-227.
2. C. Soukoulis, P. Panagiotidis, R. Kourell, C. Tzia, J. Dairy Sci. 90 (2007) 2641-2654.
3. J. C. Oberg, R. J. Brown, J. Chem. Ed. 70 (1993) 653-656.
4. T-I. Mheen, T-W. Kwon, Korean J. Food Sci. Technol. 16 (1984) 443-450.
5. C-H. Lee, Food Control 8 (1997) 259-269.
6. B. Miranda, N.M. Lawton, S.R. Tachibana, N.A. Swartz, W.P. Hall, J Chem. Ed. 93 (2016) 1770-1775.

The criteria state that technology fee projects should benefit students in innovative and/or significant ways. How would you describe the innovation and/or significance of your project?: The innovation of this project is the introduction of at-home lab experiments to extend the limited in-class lab time and permit experiments to be done that take too long for completion in a normal lab period. In addition, the use of smartphones to facilitate taking laboratory data likely represents the future in teaching lab courses and this is good way to try out this innovative approach.

The significance of this project specifically to a course such as Principles of Fermentation that could truly impact a student's career path, is to provide an hands-on experience with what goes on during the fermentation of food. I have talked informally with several chemistry/biochemistry majors after completing this course and they definitely indicate they learned a lot but doing an actual fermentation process would be a plus.

How will you assess the project?: As part of the yogurt and kimchi fermentation report, we will ask students to critique the success of this experiment and how it impacted their overall learning of the fermentation process. 

There are a few reports of fermentation lab experiments in the chemical education literature (see references cited above). However, this novel approach for an at-home lab experiment, made possible by application of a wireless smartphone pH electrode, has not been explored in the literature and could definitely lead to publication in the Journal of Chemical Education or The Chemical Educator.

Have you applied for and/or received Tech Fee awards in past years?: Yes

If funded, what results did you achieve?: FY09 Student Laboratory Data Collection Network (with T. L. Riechel). One 12-station MeasureNet network for each of our two teaching labs on the third floor of Hughes were purchased. This system has revolutionized the way we teach our first year chemistry/biochemistry majors and honors students (CHM 144M/H and CHM 145M/H and has also been heavily used for CHM 375. A final report was submitted.

FY11 Student Laboratory Data Collection Network (with T. L. Riechel). Addition of three MeasureNet stations to each of our two networks, along with five probes/devices for use at each station, due to increased enrollment. With 15 stations in each lab room, we can accommodate 30 students working as pairs. A final report was submitted.

FY 13 Gas Chromatography - Mass Spectrometry (GC-MS) Instrumentation for the Analytical Chemistry Teaching Laboratory. The computer control and data acquisition upgrade for two GC-MS instruments and one GC flame ionization instrument was critical to allow effective teaching of not only GC but also mass spectrometry. A final report has been submitted. These instruments continue to get heavy use in CHM 375.

FY14 Low-Cost Liquid Chromatography Instruments for the Chemistry Teaching Laboratory. I have constructed and characterized four isocratic HPLC instruments to be used with MeasureNet data acquisition. Two are used as flow injection analysis experiments for CHM 375 in the first half of the course and then can be easily converted to HPLC instruments for the second half. The flow injection analysis experiment involving the determination of iron in Cheerios was done for the first time Fall 2014 and the HPLC experiment for the determination of caffeine was also markedly improved that semester. The final report was submitted March 2015. These instruments still get heavy use each semester in CHM 375.

FY15 Student Laptop Interfaced Electrochemical Instruments for the Analytical Chemistry Laboratory Courses (with S. Zou). These electrochemical instruments were tested for the cyclic voltammetry experiment Fall 2014 and have continued to work very well in subsequent semesters. Fundamentals of oxidation-reduction using ferricyanide/ferrocyanide are emphasized. The constant current sources for coulometry were tested Spring 2015 for the determination of ascorbic acid in fruit drinks and the precision and accuracy was found to be excellent. Photodiode detection of the titration triiodide-starch endpoint is being investigated by undergraduate student Eri Coombs and graduate students Jenny DeJesus and Jeralyne Padilla Mercado; a presentation at the ACS Central Regional meeting was in May 2016. The final report for this project has been submitted. These instruments are used every semester in CHM 375.

FY16 Computer upgrade for Hitachi HPLC instrument for CHM375. The computer upgrade for the Hitachi high performance liquid chromatography (HPLC) instrument was carried out August 2015 and came in under budget. The instrument was used that Fall semester for the unattended determination of caffeine in soda. This permitted the students to work on the comparison of solvent strength for methanol, acetonitrile, and tetrahydrofuran for HPLC using cartridge columns. This HPLC instrument is also used for the estimation of capsaicin in arthritis pain relief topical cream. The final report was submitted in February 2016.

FY17 Raman Spectroscopy Instrument for Instrumental Analysis (CHM375) (with A. Sommer). The components for the Raman instrument have been ordered from Andor Instruments, as specified in the quote attached to the grant proposal. We expect to build and test this Raman instrument with a microscope late this spring semester. Students in my Fall 2017 CHM 375 class will definitely compare standard Raman spectroscopy and Raman micro-spectroscopy as one of the lab experiments. We plan to submit a final report by December of 2017.

Did you submit a final report?: Yes

What happens to the project in year two and beyond? Will there be any ongoing costs such as software or hardware maintenance, supplies, staffing, etc.? How will these be funded?: We expect to offer this course to 36 students in Fall 2017 and continue offering this course every Fall. The student demand for this course is high and students who take this course are chosen in part based on instructor recommendation. We expect they will take good care of these electrodes. However, students will need to sign a form indicating their Bursar account will be charged in case of electrode breakage or loss. Therefore do not expect there will be any major on-going costs such as software or hardware maintenance.

Budget: Hardware

Hardware Title(s) & Vendor(s): Hanna Instruments

Hardware Costs: $6,496.00

What is the total budget amount requested?: $6,496.00

Comments: The requested combination pH-reference electrode is the HALO PEI body gel filled type with Bluetooth capability (Hanna Instruments). The Hanna Lab App is loaded into a compatible Apple or Android device such as a smartphone to allow pH and temperature readings to be made in the wireless mode. We have also requested several cleaning solution kits from Hanna Instruments. They are recommended when measuring pH of high protein containing samples such as yogurt. Based on the high student demand for taking the Principles of Fermentation course last Fall, the instructors have decided to raise the enrollment limit to 36 for this coming Fall 2017. Therefore 40 pH electrodes are requested, a number providing insurance with a few spares.