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Published on: June 3, 2020
A fermentor for study of sauerkraut fermentation
H P Fleming1, R F McFeeters, E G Humphries
1Food Fermentation Laboratory, U.S. Department of Agriculture, Agricultural Research Service, and North Carolina Agricultural Research Service, Department of Food Science, North Carolina State University, Raleigh, North Carolina 27695-7624.
Biotechnology and Bioengineering
|February 20, 1988
Summary
This study details a novel fermentor for sauerkraut, revealing two distinct fermentation stages: a gaseous phase with rapid CO2 and acid production, followed by a non-gaseous phase. Nitrogen purging offers benefits like brine circulation and nutrient retention.
Area of Science:
- Food Science and Technology
- Microbiology
- Chemical Engineering
Background:
- Sauerkraut fermentation involves complex physical, microbiological, and chemical changes.
- Understanding these changes is crucial for optimizing sauerkraut production and quality.
Purpose of the Study:
- To design and construct a specialized fermentor for studying sauerkraut fermentation.
- To investigate the distinct stages and microbial dynamics during sauerkraut fermentation.
- To evaluate the impact of nitrogen purging on the fermentation process.
Main Methods:
- A custom fermentor was built with features for volume restriction, visual liquid level monitoring, and nitrogen purging.
- Fermentation processes were monitored for physical, microbiological, and chemical changes.
- The effects of nitrogen purging on brine circulation, CO2 removal, and anaerobiosis were assessed.
Main Results:
- Sauerkraut fermentation exhibited two distinct stages: a gaseous stage (hetero-fermentative bacteria, CO2 production, fructose to mannitol conversion) and a non-gaseous stage (homo-fermentative bacteria, increased lactic acid).
- Gas entrapment caused liquid level rises during the gaseous stage.
- Nitrogen purging facilitated brine circulation, CO2 removal, and maintained anaerobiosis, preserving ascorbic acid and color.
Conclusions:
- The designed fermentor effectively facilitates the study of sauerkraut fermentation dynamics.
- The two-stage fermentation process is characterized by specific microbial activities and chemical transformations.
- Nitrogen purging is a valuable technique for enhancing sauerkraut quality and process control.
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