Scientists are exploring whether protein recovered from pumpkin seeds could be transformed into a higher-value ingredient for coffee and other beverages, including beer.
Pumpkin seeds that might otherwise become a food-processing byproduct could someday find their way into consumers' morning coffee.
Researchers have developed a prototype plant-based coffee creamer using protein extracted from pumpkin seeds, creating another potential use for material that may be discarded or left behind after pumpkin seed oil production.
The work, published in the Journal of Agricultural and Food Chemistry, examined whether pumpkin seed protein could be modified to produce the smooth and stable emulsion needed in a nondairy creamer.
For agriculture and the food industry, the research is noteworthy because it demonstrates another potential pathway for turning an underused agricultural material into a value-added food ingredient.
Turning seed protein into an ingredient
Pumpkin seeds contain substantial amounts of protein. While some seeds are consumed as food, others are discarded or processed for oil. After oil extraction, the remaining material is largely protein, according to the American Chemical Society.
There is a challenge, however.
Pumpkin seed protein tends to clump when mixed with water, making it difficult to incorporate into plant-based beverages.
Researchers Jicheng Chen, Jianyu Huang and their colleagues investigated whether food-grade phosphate salts could improve the protein's ability to create stable oil-and-water emulsions.
They experimented with different proportions of sodium tripolyphosphate and sodium trimetaphosphate, two food texture modifiers and thickeners. A ratio of four parts sodium tripolyphosphate to one part sodium trimetaphosphate produced the best overall results.
The modified pumpkin seed protein was then mixed with water and camellia oil, also known as tea seed oil, to produce the prototype nondairy creamer.
Putting the pumpkin creamer to the taste test
Researchers added the prototype to instant black coffee prepared with room-temperature water.
For the sensory evaluation, they selected a concentration of 10% creamer. At that level, the pumpkin seed product slightly lightened the coffee without substantially changing its aroma.
Then came the taste test.
A panel of 12 people compared coffee containing the pumpkin seed protein creamer with coffee made using a commercial nondairy creamer. Participants preferred the pumpkin seed version.
The commercial product improved the coffee's texture, but testers indicated it was less successful at reducing bitterness and could introduce off-flavors. The pumpkin seed creamer improved appearance, body and smoothness while maintaining the flavor and aroma consumers expected from coffee.
"A plant-based coffee creamer can improve mouthfeel without sacrificing the coffee's own flavor," Jicheng Chen said.
A potential value-added opportunity
The research could eventually have implications beyond coffee.
Finding food uses for pumpkin seed protein could add value to a material that might otherwise have limited markets, particularly following oil extraction. It fits into a broader food-industry effort to find higher-value uses for processing byproducts and reduce waste.
However, consumers shouldn't expect pumpkin seed creamer in the dairy aisle just yet.
The initial sensory test involved only 12 people, and further work is needed before the prototype could become a commercial product. Researchers plan to investigate how well the creamer remains stable in coffee and other beverages, including beer, while conducting additional flavor and consumer-acceptance evaluations. They also want to develop liquid concentrates and powdered versions that would be easier to store and transport.
The underlying study, titled Dual-Phosphorylated Pumpkin Seed Protein Pickering Emulsions: Structural Evolution, Interfacial Regulation, and Coffee Creamer Application Quality, was published in the Journal of Agricultural and Food Chemistry with DOI 10.1021/acs.jafc.6c12935.
For pumpkin growers and processors, the concept is still a long way from establishing a new market for seeds. But the research illustrates how food science may create new opportunities to extract more value from crops after the primary product has been harvested or processed.
Photo Credit: Pexels - Engin Akyurt