Editor’s note: Every year, hundreds of undergraduates at the University of Delaware pursue research under the guidance of a faculty mentor, especially during the summer months. Such experiences provided by UD — a nationally recognized research university — can be life-changing, introducing young scholars to a new field, perhaps even the path to a future career, as they uncover new knowledge. These spotlights offer a glimpse into their world. 

When you’re hungry for a snack, what do you reach for? While cookies are most popular with Americans, followed by chips and ice cream, the market for savory snacks is growing in the U.S., according to a 2024 report by Statista.  

In 2023, more than $70 billion dollars’ worth of potato chips and other savory snacks were sold in the U.S., with sales expected to exceed $88 billion by 2027. The puffed snack market — think Cheetos, Pirate’s Booty, corn puffs and chickpea puffs — is part of the trend, with more “protein puffs” expected to enter the arena, driven by health-conscious consumers and followers of plant-based diets. 

In the quest to develop innovative, new puffed snack products, researchers at the University of Delaware are experimenting with a nutritious, protein-packed, fiber-rich vegetable — lima beans (also known as butter beans). Delaware farmers plant more lima beans for commercial freezing and canning than any other state in the U.S. 

This summer, Brandon Tang, a UD junior majoring in mechanical engineering from Wilmington, Delaware, has been working to optimize the process that transforms small lima beans into puffed snacks. He works with an extruder machine that subjects the “dough” made from lima beans, spices and water to high temperature and pressure. When the mixture gets extruded, the sudden drop in pressure causes the water in the dough to turn into steam, creating air cells that cause the dough to puff up. His adviser is Dr. Hui Ru Tan, postdoctoral researcher in UD’s College of Agriculture and Natural Resources.

Q: Why did you want to pursue this? What intrigues you about the topic? 

Tang: This internship is an interdisciplinary opportunity to apply concepts I learned in mechanical engineering courses to food processing. Gaining first-time experience in using the pilot-scale equipment in the lab and an understanding of how an intricate process such as extrusion works are both interesting aspects.

Q: Why does research like this matter? 

Tang: While lima beans are a cornerstone crop for Delaware and the leading vegetable crop for processing, more economic gains for both the state and its farmers could be experienced by creating more applications for lima beans, such as a food ingredient in a commercially sold, puffed snack.

Q: What does your daily research entail? 

Tang: Together in the lab when everything goes smoothly, we first measure the moisture content of the raw lima beans, grind and sieve the beans into flour, run an extrusion with the resulting samples, then measure the moisture content again. Additionally, the extrudate, or “puff,” is sometimes freeze-dried.

Q: What’s the coolest thing about being involved in this project? Have you had any surprising or especially memorable experiences? 

Tang: Observing and setting up the complex process from which raw lima beans are transformed from their inedible state into a puffed snack was interesting. While we would prefer the extruder’s output to remain relatively calm and constant, sometimes certain changes (or mistakes during setup) can cause the product to sporadically explode outwards across the room with an abrupt pop. The latter scenarios were typically the types which were harder to clean, as the material’s hardness would become closer to that of a rock as it cooled inside of the machine’s various parts. 

Q: Is there anything you've discovered about yourself and your career goals as you've worked on the project? 

Tang: This internship has helped me realize the value in automating the tedious aspects of taking care of the extruder, such as cleaning out the burnt and hardened material that accumulated on the inside, which aligns with my future goal to hopefully pursue robotics and apply automation to real-world context (e.g., in a food production plant).

Q: What do you enjoy doing in your spare time? 

Tang: When I have enough time, what I usually enjoy most involves some degree of creativity, such as making basic clay figures, assembling crafts from kits, sketching, or attempting to code and create assets for a game I’m trying to make.