Unpleasant odors have been a barrier for many consumers considering plant-based proteins, despite their health benefits. Researchers at The Ohio State University have developed a two-step fermentation process aimed at making these proteins more appealing by removing undesirable smells.
The study, published in the journal Foods, demonstrated that this new method could eliminate between 95 to 99% of key odor compounds from various plant-based proteins. This performance was significantly better than what is achieved with single-stage fermentation.
Sheryl Barringer, senior author and professor in food science and technology at Ohio State, explained the motivation behind the research: "Plant-based proteins are becoming more and more popular, either as people become vegetarians or just want to reduce their meat consumption. Consumers want that option, but they don't want to give up on the taste."
Many plant-based protein products emit natural odors—often described as beany, grassy, earthy, sulfurous or cereal-like—that can deter potential consumers. Since smell is closely linked to flavor perception, overcoming these sensory challenges is important for wider adoption of alternative proteins.
"Lots of factors all contribute to food preference, but it's really hard to say I'm going to force myself to eat a product because it's good for me, even if it tastes bad," Barringer said.
As demand grows for sustainable and allergen-friendly foods compatible with vegan and lactose-intolerant diets, scientists are seeking ways to improve consumer acceptance of plant-based options. These alternatives may also support global food security and help lower the environmental impact associated with traditional animal agriculture.
Lead author Manpreet Kaur, a PhD student in food science and technology at Ohio State, emphasized that the improved process does not add complexity or cost for future production: "We are using the same things that are used in the normal fermentation process. The only thing changed is how we utilize the bacteria."
In their experiments, researchers first introduced Lactobacillus plantarum—a beneficial bacterium—to break down odor-causing compounds during initial fermentation. A second stage involved a traditional yogurt culture containing common bacteria known for creating desirable aromas.
This approach was tested on eight different plant protein solutions: soy (9%), pea, chickpea, mung bean, faba bean, rice, barley-rice and hemp. Human sensory evaluations showed consistent reductions in unwanted smells across all samples.
The team also found that certain ingredients could influence results. Natural sugar allulose enhanced bacterial activity in one stage; strawberry preserves supported bacteria performance in another; non-fermentable additives like pectin or xanthan gum had minimal effect on odor reduction.
Researchers believe their findings offer practical steps toward developing flavorful plant-based dairy snack alternatives while expanding understanding of fermentation’s role in addressing sensory issues.
"There's a real focus on people wanting to be healthier and more environmentally conscious, and a push for plant-based products instead of meat and dairy products," Barringer said. "So I expect this area of research will absolutely continue to grow in the next many years."
