Identification of Key Aroma Contributors Responsible for Producing Grilled Aromas of Plant-Based Burgers

Dr. LiLi Zyzak 

The growing trend for healthier diets that are lower in red meat, as well as the concern about the environmental impact of farmed meats has created a high demand for meat substitute products. The growth of plant-based meat substitutes is readily apparent as one can see from the number of new products being introduced to the market. In addition to the startup and mid-size manufacturers in the market, traditional food manufacturers such as Nestle and Tyson Foods are now selling plant-based hamburger substitutes. To create the most realistic meat substitute for consumers, manufacturers rely on food scientists to help create the products that provide the most realistic sensory experience when creating plant-based hamburger substitutes.

Key to the overall experience of a food is the aroma that is perceived while cooking and consuming the product. The challenge with meat substitutes is that the plant protein sources often produce flavors and aromas not traditionally associated with hamburger when cooked. For example, pea and soy protein can produce beany, nutty, and earthy aromas which are not exactly desirable in a hamburger. Some manufacturers are combining ingredients such as canola or safflower oils with the plant protein in specific ratios to produce burger substitutes that when cooked, release similar fatty aromas as real meat. Others are using a more traditional method of adding spices that mask the plant-based taste and produce a flavor profile that customers would associate with a hamburger.

One scientist that is trying to identify and compare the key aroma components of plant-based substitutes with real hamburgers is Dr. LiLi Zyzak from Eastern Kentucky University. Dr. Zyzak’s research is primarily focused on classifying the aromas of different manufacturer’s products to determine the most desirable aromas that best replicate real beef. Dr. Zyzak’s team is using a technique known as gas chromatography-mass spectrometry with olfactometry (GC-O/MS) to smell individual odors in a product and simultaneously determine the identity of the compound by mass spectrometry. Using this technique on real cooked beef and beef substitutes, they were able to identify over 100 compounds, 30 of which were odor active.

Using the GERSTEL Olfactory Detection Port (ODP 4), Dr. Zyzak’s team has compared various meat substitutes on the market and analyzed the data using principal component analysis (PCA). With PCA analysis, they were able to show in a 2-dimensional plot how close or far away products were in comparison to a real beef hamburger used as the control sample (Figure 1). With this data, the researchers were then able to determine what key odor compounds were driving the aroma of the product closer or further away from the beef hamburger control and identify these compounds with mass spectrometry. Some of the products analyzed have a more authentic meaty, buttery, and fatty aroma created from lipid oxidation products, while others were further away and had a barbeque, caramel, or onion-type odor. With GC-O/MS, the team was able to identify some of the compounds that are responsible for these aromas.

Figure 1

The next phase of Dr. Zyzak’s research will focus on developing formulations that behave like real hamburger when cooked. The compounds identified as key aroma contributors from her preliminary work will be used as a starting point to determine which precursors are responsible for producing these aromas during cooking.