Powering the Evolution of Fermentation Processing
Fermentation has a long history, beginning with the spontaneous fermentation of dairy in North Africa in 10,000 BC. So began Paulo de Boer, Ph.D., Scientist And Project Manager, Wageningen Food & Biobased Research, in his Global Food Forums’ 2022 Clean Label Conference presentation titled “Powering the Evolution of Fermentation Processing.” De Boer went on to discuss current and emerging applications.
There is a strong revival of interest in fermentation. This is partly because consumers perceive fermentation as natural; some fermentation products contain healthful probiotic cultures; and due to of the popularity of home fermentation.
Technically, fermentation is the process where sugar is converted into several components, and energy is released. This takes place in the absence of oxygen. Different types of fermentation are distinguished, e.g., lactic acid homo-fermentation, lactic acid hetero-fermentation (other acids produced) and alcohol fermentation. However, fermentation is a term widely used nowadays to describe processes where microorganisms are involved, irrespective of the presence of oxygen.
Evolving Industrial Fermentation Uses
Industrially, there are two major fermentation styles: submerged or liquid fermentation and solid-state fermentation (SSF). Mushrooms are an example of SSF. Soybeans can be fermented to create soy sauce, a liquid fermentation process. Fermentation is widely used to produce ethanol, enzymes, secondary metabolites (e.g., penicillin, statins), organic acids, flavors and amino acids.
Environmentally, fermentation is used for wastewater management, bioremediation and air filtration. Side streams of industrial processes can be used as substrates for further fermentation or production of biogas.
In food, fermentation produces a wide range of products. Examples are provided below in the form of production of flavors or low-caloric sweeteners. Moreover, precision fermentation is being looked into to make alternatives for animal-derived proteins, such as casein. Fermentation can also be used for shelflife extension and production of vitamin B12, an essential vitamin lacking in plant-based foods.
Currently, many ingredients are being used to improve the flavor of and mask plant-based foods’ off-flavor. Fermentation can improve the quality of plant-based alternative protein sources using fewer ingredients.
For example, ingredients used in the production of plant-based yogurt are often associated with a beany flavor. The source of this off-flavor is aldehydes and ketones. One way to remove off-flavor is to convert the aldehydes to alcohols. Soy yogurt base can be fermented to lower hexanal levels and to convert beany flavor to fruity flavor.
Vitamin B12 is an essential vitamin that is lacking in plant-based foods. Tempeh is produced by fermenting chickpeas with a fungus. Specific bacterial strains can be added to the fermentation to produce B12 at similar levels to meat products.
Stevia low-caloric sweeteners are derived from the plant Stevia rebaudiana. Various stevia glycosides [NOTE: In the U.S. FDA GRAS petition, the term “steviol glycosides” is used] are produced via precision fermentation using a modified yeast. The resulting sweetener is free of the production organisms, so GMO-free and can be labeled as “steviol glycosides.”
Erythritol is a sugar alcohol with close to zero calories; it does not affect blood glucose or cause tooth decay. It has 60-70% of the sweetness of sucrose. The fermentation from glucose to erythritol may be done by Moniliella pollinis or Yarrowia lipolytica in highly osmotic media.
Microbial biomass as a protein source is commonly referred to as mycoprotein. Quorn is a commercial brand of such a mycoprotein. Protein can be extracted from fungal biomass to produce meat alternatives, but the microbial biomass can also be used as a protein source. These microorganisms can also be grown on various side streams. The textural properties of such microorganisms can also be used to produce a microbial fabric, explained De Boer.
A major challenge in the current protein transition is that the novel plant-based substrates often have unwanted properties, such as undesirable flavor components. Fermentation is a very attractive method to assist in the development of novel plant-based meat alternatives, but finding the best combination of microorganisms and substrates is difficult to predict. Therefore, efficient screening of microorganisms-substrates is necessary to cost-effectively develop products that taste similar to traditional food products.
Wageningen has developed a highly efficient screening platform, “MINIScreen,” that is based on matrix interaction and can predict, design and develop natural solutions and optimal fermentation strategies. This platform allows the scientist to screen many more combinations than conventional screening, offered De Boer.
“Powering the Evolution of Fermentation Processing,” Paulo de Boer, Ph.D., Scientist And Project Manager, Wageningen Food & Biobased Research.
