Lactic acid bacteria can help plant-based fermented dairy alternative formulators overcome the sensorial, technological, and nutritional challenges posed by off-flavors and antinutrients, a study in Denmark reveals. The researchers say the findings are also relevant for other alt-protein sources, such as insects and microbial proteins with similar issues.

The study was led by the Technical University of Denmark (DTU) and biotech company Novonesis. The researchers analyzed existing literature to map how fermentation with seleced bacterial strains can “reduce off-flavors and degrade anti-nutrients” in alt-proteins. The process helps boost nutrient bioavailability, leading to improved consumer acceptance.

“Our review of the current research shows that fermentation with lactic acid bacteria can improve flavor perception and help make products more nutritionally complete,” says Claus Heiner Bang-Berthelsen, Senior Researcher at DTU National Food Institute.

The scientific review is published in Comprehensive Reviews in Food Science and Food Safety, and highlights how fermentation is emerging as a “vital tool” in developing more palatable and functional plant-based milk alternatives.

Overcoming sensory challenges

Many plant-based ingredients naturally contain flavor compounds that consumers perceive as unpleasant — such as bitter, earthy, or green notes. These compounds, often aldehydes, ketones, and tannins, are by-products of the plant’s metabolism and can be difficult to remove “without negatively affecting the rest of the product,” note the researchers.

Various antinutrients present in different plant-based proteins either decrease the digestibility of proteins (protease inhibitors), reduce the bioavailability of nutrients (as phytates, polyphenolic compounds, and saponins) or lead to health effects like flatulence.

Meanwhile, off-flavors like volatile compounds provide “green,” “grassy,” “earthy,” and “mushroom” notes, wheras non-volatile ones are “bitter” and “astringent.” The researchers highlight that alt-dairy manufacturers need to eliminate these compounds to produce high-quality plant-based fermented dairy substitutes.

The authors state that specific strains of lactic acid bacteria can convert these undesirable compounds into “neutral or less perceivable” flavor compounds. The resulting product more closely mirrors traditional fermented dairy products’ taste and aroma.

Selecting the right bacteria

The researchers point out that fermentation with lactic acid bacteria can help degrade several anti-nutritional compounds.

However, they emphasize that “not all lactic acid bacteria are equally suited for this task.”

“Bacteria originally isolated from milk are typically adapted to animal-based environments, wheras those derived from plants or plant-based foods have an evolutionary advantage in handling plant substrates,” explain the researchers.

Through natural selection, these strains have developed the ability to utilize plant sugars and degrade complex plant compounds. This makes them ideal starter cultures for plant-based fermented products.

“For industry stakeholders, the message is clear: existing microbial solutions can improve the quality and enhance the nutritional value of plant-based products — but success depends on knowledge of bacterial strains, raw materials, and fermentation processes.”

Last year, Food Ingredients First spoke with food tech company Armored Fresh to discuss how plant-based lactic acid bacteria can be used to formulate vegan cheese by mimicking the dairy cheese fermentation process.