Soy has been a kitchen hero in Asia for centuries. It's packed with nutrition and health perks and contains all the essential amino acids, like those found in meat. But when it crossed over to Western plates, it hit a flavor roadblock. Despite its nutritional benefits, many Western eaters shy away from soy foods due to their "beany" taste, perceiving them as grassy, green, and a bit too earthy.
The culprit? A compound called hexanal, which smells like freshly cut grass and is super potent even in tiny amounts. It's one of over 20 flavor compounds that make soy taste ... well, not so appetizing to some.
Soy's funky flavors, like that grassy hexanal note, come from a breakdown of healthy fats inside the bean. This breakdown is triggered by special enzymes called lipoxygenases (LOX) – soybeans carry three types: LOX-1, LOX-2, and LOX-3. Though they make up just 1–2% of the bean's protein, each one plays a different role in shaping how soy tastes.
Scientists have tried tweaking soybeans, breeding some for better oil and stripping others of flavor-triggering enzymes, to make them tastier and healthier. Sounds promising. But up to now no one's fully explored what happens when you combine all these traits.
Prior studies have focused on processed soy products, overlooking the raw beans. That means we still don't know how these new super-soybeans actually smell or taste at the source.
At the University of Missouri, researchers stirred up a science smoothie (raw soy slurries) to determine how different soybean varieties affect taste and aroma. Their mission? Make soy foods tastier, healthier, and loved by more people.
Researchers compared the taste and aroma of four soybean varieties: Patriot (a commodity strain often used in research), high oleic/low linolenic acid oil (HOLL), and two HOLL soybean types with reduced anti-nutrient carbohydrates, Tiger and Super (lipoxygenase-free).
All were grown side-by-side and blended into uncooked soy-milk-style slurries. They soaked, ground, strained, and chilled the beans, then ran a complete nutritional checkup: protein, fat, fiber, moisture, and ash.
Using high-tech tools like gas and ion chromatography, they mapped out fat types and sugars like sucrose. Then came the sniff test: nine expert panelists rated each slurry on 12 traits, from color to aroma to flavor.
The HS-SPME-GC-MS/MS analysis (a powerful method for spotting volatile compounds, additives, and breakdown products) revealed 21 key smell compounds in raw soy slurries. The Patriot variety was found to be loaded with the most off flavors. Meanwhile, Super showed the lowest concentrations and came out smelling fresh.
Sensory analysis confirmed Patriot was the loudest in the "painty" department, while HOLL, Tiger, and Super kept those funky flavors in check.
Among all the varieties tested, Super soybeans stole the spotlight. With their mild, pea-like aroma and smooth flavor, they're the most likely to win over taste buds and boost soy's popularity on the plate. The Super soy subtype was engineered by the researchers giving it a heart-friendly fat profile, trimming out non-nutritive sugars, and ditching the flavor-spiking enzyme lipoxygenase. The result? A smoother, tastier, and healthier soy.
"There's a clear need for soybeans with a milder or even neutral flavor profile – beans that can be added to a variety of products without announcing themselves on the palate," explained Bongkosh Vardhanabhutisaid, a researcher working on the project.
This study marks the first step in a flavor-forward journey led by Vardhanabhuti's team. Next up: cracking the taste code in tofu, soy milk, and soy protein.
By understanding how different soybean types behave before processing, researchers can better predict how flavors evolve after. These insights could lead to tastier soy products, higher quality, and broader appeal, from health-conscious eaters to flavor-focused foodies.
This study was published in the journal Food Chemistry.
Source: University of Missouri
