Novel Edible Microcarriers For The Scalable Production Of Cultivated Meat

Abstract

Cultivated meat, grown from stem cells in vitro, has the potential to supply ever-growing demand for meat products while alleviating negative impacts of intensive animal farming on the environment, food security and animal welfare. Despite recent advances, several challenges concerning scalability of production and affordability have impeded access to cultivated meat, even in countries where it has received official approval. This study uses silk fibroin, degummed from Bombyx mori cocoons, to design edible irregular microcarriers that mimic the extracellular matrix of skeletal muscle. Using both laboratory needle and industrial-scale needleless electrospinners, a 12% (w/w) silk fibroin in formic acid polymer solution was formed into non-woven nanofibrous mats (diameter: 98-166 nm) that were subsequently stabilised by immersion in monohydric alcohols to induce β-sheet crystallinity and prevent dissolution in aqueous solutions. Upon contact with bovine mesenchymal stem cells (bMSCs), the supports demonstrated excellent cytocompatibility, and good attachment and proliferation. Blending silk fibroin with 6.25% (w/w) zein enhanced the performance of the supports in static cell cultures without compromising their physical characteristics. To improve the surface-to-volume ratio and enable use in stirred tank reactors, non-spheroid fibrous microcarriers were formed by hand-slicing or cryomilling the electrospun mats. These promoted bMSC expansion, with cell yields comparable to those of commercial microcarriers. The blended silk fibroin/zein microcarriers outperformed all others in static conditions. In parallel, supermarket beef and plant-based burgers were tested to quantify their mechanical and textural properties. Seven burgers, with varying compositions of beef, fat and secondary ingredient contents, and social markers (e.g. price, brand), were tested. The results provided a range of sensory properties of traditional meat, which can inform the upstream production of cultivated meat products.