Lactic acid bacteria can improve plant-based dairy alternatives

Plant-based dairy alternatives -- such as soy, oat, and almond drinks -- are produced without animal ingredients for consumers seeking plant-based substitutes for milk and yoghurt. However, many of these products have the similar shortcomings: flavours that do not always appeal to consumers, and nutritional profiles that may fall short of those of cow's milk.

A new review, led by DTU and Novonesis researchers, explores how lactic acid bacteria may help address these challenges. By analysing existing literature, the authors map how fermentation with selected bacterial strains can reduce so-called off-flavours and degrade anti-nutrients. The latter enhancing the nutrient bioavailability in plant-based dairy alternatives.

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

Perspectives for more foodsa

While the study focuses specifically on plant-based dairy alternatives, the researchers believe the findings are also relevant for other food products facing similar issues. Products based on alternative protein sources such as insects, microbial proteins (e.g. mycoprotein or fermented yeast), and ingredients derived from food production side streams often face the same sensory and nutritional challenges. Fermentation with selected lactic acid bacteria may therefore prove to be a key technology in developing a wide range of sustainable foods.

"We see food fermentation as a platform technology that can support the creation of alternative foods which taste better and have higher nutritional value, allowing the use of more sustainable raw materials, says Guillermo-Eduardo Sedó Molina, PhD student at DTU National Food Institute.

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.

Fermentation as a key technology

Fermentation has been used for millennia to preserve and enhance foods -- from sauerkraut and kefir to cheese and yoghurt. Today, it also emerges as a vital tool in developing more palatable and functional plant-based alternatives to milk.

In the new review, the researchers highlight how lactic acid bacteria -- particularly those naturally adapted to plant-based raw materials -- can play a pivotal role in developing plant-based fermented dairy alternatives (PBFDA).

Many plant-based ingredients naturally contain flavour 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. According to the researchers, specific strains of lactic acid bacteria can convert these unwanted compounds into neutral or less perceivable flavor compounds. The result is a product that more closely resembles traditional fermented dairy products in both taste and aroma.

Key findings

• Lactic acid bacteria can reduce off-flavours in plant-based fermented products.
• They can degrade anti-nutritional compounds and enhance the absorption of minerals such as iron and zinc.
• Lactic acid bacteria found in plants are especially well-suited to ferment plant-based milks because they have been genetically adapted to grow in plant environments.
• The findings are also relevant for other alternative foods where off-flavours influence consumer acceptance, e.g. insect-based products.

Anti nutrients and mineral absorption

Another challenge with plant-based dairy alternatives is their anti-nutrient content, which negatively influences the body's absorption of essential minerals like iron, zinc, and calcium or affects protein digestibility. Anti-nutrients bind to these minerals, making them inaccessible to the body. As a result, products may contain iron or zinc on paper but still fail to meet nutritional needs.

The researchers point out that fermentation with lactic acid bacteria can help degrade several anti-nutritional compounds. Certain bacterial strains produce enzymes that can break down these complex molecules, thereby increasing the bioavailability of nutrients in the final product.

Plant-adapted bacteria

The researchers emphasise that not all lactic acid bacteria are equally suited for this task. Bacteria originally isolated from milk are typically adapted to animal-based environments, whereas those derived from plants or plant-based foods have an evolutionary advantage in handling plant substrates. Through natural selection, these strains have developed the ability to utilise plant sugars and degrade complex plant compounds -- making them ideal starter cultures for plant-based fermented products.

Therefore, the choice of bacterial strain and fermentation conditions will be crucial for developing products that are not only palatable and aromatic but also of high nutritional quality.