Rabbit and cow muscle cells have been grown on edible gelatine scaffolds that mimic the texture and consistency of meat in a move that scientists say provides “real texture” for lab-grown meat.
Although lab-grown or cultured meat could potentially revolutionise food production, there are several hurdles to overcome – namely how to scale up production and how to make it feel and taste more like real meat.
But now, writing in npj Science of Food, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have taken a major leap forward.
Kit Parker, the Tarr Family Professor of Bioengineering and Applied Physics at SEAS and senior author of the study, began his foray into food after judging a competition show on the Food Network.
“The materials-science expertise of the chefs was impressive. After discussions with them, I began to wonder if we could apply all that we knew about regenerative medicine to the design of synthetic foods,” he says.
“After all, everything we have learned about building organs and tissues for regenerative medicine applies to food: healthy cells and healthy scaffolds are the building substrates, the design rules are the same, and the goals are the same: human health.
“This is our first effort to bring hardcore engineering design and scalable manufacturing to the creation of food.”
Animal meat consists mostly of skeletal muscle (and fat tissue) which grows in long, thin fibres — as can be seen in the grain of a steak or when shredding pork or chicken. Reproducing these fibres is one of the biggest challenges in bioengineering meat.
“Muscle cells are adherent cell types, meaning they need something to hold onto as they grow,” said Luke MacQueen, first author of the study and a postdoctoral fellow at SEAS and the Wyss Institute for Bioinspired Engineering.
“To grow muscle tissues that resembled meat, we needed to find a ‘scaffold’ material that was edible and allowed muscle cells to attach and grow in 3D. It was important to find an efficient way to produce large amounts of these scaffolds to justify their potential use in food production.”
To overcome these challenges, the researchers used a technique developed by Parker and his Disease Biophysics Group known as immersion Rotary Jet-Spinning (iRJS), which uses centrifugal force to spin long nanofibers of specific shapes and sizes.
The team spun food-safe gelatine fibres to form the base for growing cells. The fibres mimic natural muscle tissue’s extracellular matrix — the glue that holds the tissue together and contributes to its texture.
The team seeded the fibres with rabbit and cow muscle cells, which anchored to the gelatine and grew in long, thin structures, similar to real meat. The researchers used mechanical testing to compare the texture of their lab-grown meat to real rabbit, bacon, beef tenderloin, prosciutto, and other meat products.
“When we analysed the microstructure and texture, we found that, although the cultured and natural products had comparable texture, natural meat contained more muscle fibres, meaning they were more mature,” said MacQueen.
“Muscle and fat cell maturation in vitro are still a really big challenge that will take a combination of advanced stem cell sources, serum-free culture media formulations, edible scaffolds such as ours, as well as advances in bioreactor culture methods to overcome.”
Still, this research shows that fully lab-grown meat is possible.
Gelatine fibres produced by “immersion rotary jet spinning,” a fibre-production system inspired by cotton candy. These fibres form the “base” to grow cells in — they mimic natural muscle tissue’s extracellular “glue,” which holds the tissue together and contributes to its texture.
“Our methods are always improving and we have clear objectives because our design rules are informed by natural meats. Eventually, we think it may be possible to design meats with defined textures, tastes, and nutritional profiles — a bit like brewing,” said MacQueen.
“Moving forward, the goals are nutritional content, taste, texture, and affordable pricing. The long-range goal is reducing the environmental footprint of food,” said Parker.