Tuning Fusarium venenatum mycelium structure through genetic modification for customized texture and digestibility of...

Mycoprotein (MP) has attracted considerable amount of attention driven by its potential for high nutritional value, meat-like texture, and ideal production efficiency. This study investigated that the absence of genes encoding specific endogenous proteins (chitin synthetase and pyruvate decarboxylase) could lead to alterations in mycelium structure and considerable adjustments in mycelium polysaccharide (chitin) and total lipid content, which affected digestive characteristics such as gastric emptying kinetics and gastrointestinal protein digestibility through in vitro dynamic digestion. The Fusarium venenatum mycoprotein were named WT (wild type), FC02 (with reduced chitin content and low lipid content) and FCPD (with high lipid content that was more comparable to chicken breast). During the oral processing stage, chewed mycoprotein bolus of FC02 and FCPD was comparable with chicken breast bolus than the WT bolus in several textural parameters such as hardness, springiness and chewiness. During gastric digestion phase, the reduction of cell wall chitin content accelerated gastric emptying rate (t_1/2 = 96.9 min), whereas high lipid content delayed gastric emptying (t_1/2 = 109.3 min), showing a clear bidirectional change. Both mycelial fiber disintegration and protein release occurred mainly in the small intestinal, and the reduction of chitin was able to increase the protein digestibility (from 40.10 to 52.53 %), but the elevated lipid content decreased it again (38.77 %). With respect to bioactive peptides, FC02 and FCPD mycoprotein produced the highest number and percentage, respectively, suggesting multiple potential health benefits. This work demonstrates a promising strategy to create more meat-like mycoprotein products with controlled digestive behavior by modulating mycelium structure.