Source: UNIVERSITY OF CALIFORNIA, DAVIS submitted to NRP
CLOSED-LOOP ELECTROFERMENTATION FOR IMPROVED FERMENTED FRUITS AND VEGETABLES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1032348
Grant No.
2024-67017-42816
Cumulative Award Amt.
$595,400.00
Proposal No.
2023-10631
Multistate No.
(N/A)
Project Start Date
Sep 1, 2024
Project End Date
Aug 31, 2028
Grant Year
2024
Program Code
[A1364]- Novel Foods and Innovative Manufacturing Technologies
Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Performing Department
(N/A)
Non Technical Summary
This project supports the mission of the Agricultural Experiment Station by addressing the Hatch Act areas(s) of processing, distribution, safety, marketing, and utilization of food and agricultural products. Specifically, this project will focus on the pressing issue that healthy, fermented fruits and vegetables are difficult to make at industrial scales and are frequently subject to quality defects and inconsistent products with variable sensory profiles. Specifically, the project will assess the use of electrochemically driven methods and selected safe microorganisms to improve the control over fruit and vegetable fermentations. We expect that the results from this project will eventually lead to an expansion in low-cost, commercially-produced fermented fruit and vegetable foods with optimized sensory and nutritional characteristics. Increased availability of these foods will improve consumer access to fruits and vegetables, thereby lead to increasing daily intakes across the US population. The project specifically addresses the need for US manufacturing technologies to ensure a more sustainable, resilient, and healthy food supply. Broadly, we aim to develop innovative manufacturing technologies that increase improve food quality and nutritional value and that advance sciences and technologies to yield improved shelf life while minimizing food waste and loss throughout the food supply chain. The project also contributes to on-going efforts to provide all Americans with safe, nutritious food.
Animal Health Component
(N/A)
Research Effort Categories
Basic
100%
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
5015310202050%
5015310110050%
Knowledge Area
501 - New and Improved Food Processing Technologies;

Subject Of Investigation
5310 - Machinery and equipment;

Field Of Science
2020 - Engineering; 1100 - Bacteriology;
Goals / Objectives
The over-arching goal of this project is to develop a novel, controllable, fermentation technology, termed Electro-Fermentation (EF) for precision production of fermented fruit and vegetables. EF is defined as electrochemically controlling microbial fermentation metabolism with polarizable electrodes. This technology takes advantage of our discovery that lactic acid bacteria (LAB), microorganisms essential for many food fermentations, possess a metabolism amenable to manipulation by EF. Our interdisciplinary team will use EF and LAB to modify fruit and vegetable fermentations with the following three objectives: (1) develop a closed-loop EF system for LAB fermentations controlled with a polarized anode that is monitored using real-time, oxidation reduction potential, pH, temperature, and electrochemical current read-outs; (2) apply EF and LAB starter cultures to modify juice and sauerkraut fermentations; (3) modulate EF using EF-guided starter culture selection.
Project Methods
In order to reach our goal of developing a closed-loop electro-fermentation (EF) system for the manufacture of fermented fruits and vegetables, we will test the overarching hypothesis that by modulating anode polarization based on real-time redox and pH measurements in a closed-loop configuration, it will be possible to control and improve fermentation outputs. To investigate this hypothesis, we will first build electrochemical cells and measure and modulate conditions to understand the range of anodic EF with a strain of Lactiplantibacillus plantarum, a species that is required for many fruit and vegetable fermentations. The studies will result in increasing the fermentation complexity in open and then subsequently closed-loop settings, with the latter defined by automatically varying the applied potential to track optimal redox, pH, current readings (Objective 1). Next, we will apply EF to modify juice and sauerkraut L. plantarum fermentations, with the goal of demonstrating the range of EF in simple and increasingly complex nutritive and microbial conditions (Objective 2). Lastly, we will aim to improve EF outputs by isolating and identifying EF-optimized L. plantarum and other bacteria from fruit and vegetable fermentations for use as starter cultures (Objective 3). Data collected from the three objectives will be analyzed with the appropriate controls and statistical tests. The results will be evaluated and interpreted in manuscripts and student theses. Efforts will be taken to share the results and interpretations with stakeholders at scientific conferences, at industry-directed meetings and events, and with the public via websites and national speaking opportunities. Evaluation of the outputs will encompass the timely publication of the experimental findings in high-tier microbiology and engineering journals and by documented industrial interest in adoption of the EF fermentation technology.

Progress 09/01/24 to 08/31/25

Outputs
Target Audience:The target audiences include individuals, groups, market segments, and communities interested in improving fruit and vegetable fermentations and preservation methods. These groups encompass research, agricultural, and industrial sectors. Reaching these audiences is needed because modifying food fermentation practices will result in more cost-effective ways to deliver healthy, preserved foods where access to fresh fruits and vegetables is limited while also minimizing food waste. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project thus far has provided training to graduate and undergraduate students. Besides training on scientific methods and scientific writing, this project has also resulted in professional development opportunities including mentorship on grant writing and scientific presentations. How have the results been disseminated to communities of interest?Dissemination events so far include conference presentations and consultations with local and international food processors and members of the media. Dissemination of knowledge beyond a scientific audience has included on-site tours of the research laboratory and descriptions of the research program to university students, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science, nutrition, and health). What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we will perform Electro-Fermentation (EF) cyclic voltammetry and chronoamperometry measurements using lactic acid bacteria (LAB) in increasingly complex food media. These tests will help to characterize critical fermentation metabolic pathways and monitor fermentation in real-time. This will be initiated with open-circuit conditions --no electrical signals applied --to establish baseline datasets. These baselines will be used to evaluate how effectively electrical signals can control fermentation metabolism. During this phase, we will monitor several parameters: temperature, pH, oxidation reduction potential, bacterial cell numbers, and metabolite output. These data will help us identify what constitutes a "healthy, nutritious" fermentation batch. To analyze the results, single-variable T-tests and multi-variable machine learning models will be used. These statistical tools will identify the most critical characteristics of successful fermentation, which our control algorithm will subsequently target during electrically-driven control. In parallel, we will continue developing our electrical signal automation and user interfaces. We expect to complete these goals near the end of the next period. Concurrently with these activities we will continue to characterize existing strains and isolate and identify LAB enriched in juice and sauerkraut fermentations and to study their capacity to improve EF. This work includes examining LAB with EF capabilities together with helper strains. Strains will be incubated in fruit and vegetable juices to quantify growth and to measure EF activity. The most promising strain candidates will be tested for compatibility in coculture.

Impacts
What was accomplished under these goals? The over-arching goal of this project is to develop a novel, controllable, fermentation technology, termed Electro-Fermentation (EF) for precision production of fermented fruit and vegetables. EF is defined as electrochemically controlling microbial fermentation metabolism with polarizable electrodes. This technology takes advantage of our discovery that lactic acid bacteria (LAB), microorganisms essential for many food fermentations, possess a metabolism amenable to manipulation by EF. This project year, we first designed a custom nested dual-chamber BioElectrochemical System (BES) for EF. Off-the-shelf components were combined with 3D resin printing to create the first prototype. This design is a low-cost alternative to standard electrochemistry equipment, and it is simple to assemble. These advantages will allow us to quickly scale up experiments at minimal expense with more biological replicates. This system also lays the groundwork for cost-effective fermentation vessels that could eventually be used in food manufacturing. Next, the dual-chamber system was integrated with programmable electrical equipment. To test the setup, signals from our potentiostat (an electronic device that controls voltage (or potential)) were successfully applied to split DI water into hydrogen and oxygen through electrolysis. This proves our system can perform cyclic voltammetry, a capability needed to identify key electrical inflection points in metabolic pathways. These measurements are essential for characterizing and confirming that EF is truly electrochemically driven. Finally, real-time monitoring of critical parameters like ORP and pH was performed while controlling the electrical signals sent to the BES. This automation is a crucial step toward our ultimate goal: a closed-loop fermentation control system. Also, this year we initiated LAB strain isolations from fermented plant foods to test in the EF system. These isolates were identified to the species levels and confirmed to grow in media appropriate for EF. Thus, this year we were highly successful in meeting the initial milestones of the project.

Publications

  • Type: Conference Papers and Presentations Status: Other Year Published: 2024 Citation: Connecting food, microbes, and gut health with lacto-fermentation, Invited Speaker, University of Florida Departmental Seminar Series. September 2024.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Fermented foods and health. Invited Speaker, Bridge2Food Online Seminar Series. April 2025
  • Type: Conference Papers and Presentations Status: Other Year Published: 2025 Citation: Should we be eating more lactic acid bacteria? Invited speaker, Gordon Research Conference on Lactic Acid Bacteria, Ventura, California. July 2025.