Mixed biopolymer gels, comprised of spherical 'maltodextrin-rich' inclusions within a 'gelatin-rich' continuous matrix phase, have been shown to exhibit a form of 'pseudo-ductility' during tensile deformation, due to debonding of the inclusion/matrix interface during straining. A plane stress work of fracture technique, using thin sheet double edge notched tension (DENT) specimens, has been applied to these composites to assess the elastic and plastic contributions to crack growth during fracture. A transition from plane stress to mixed mode failure was observed to occur when the intact ligament length decreased below similar to 8B to 9B (where B is the sheet thickness). With the DENT technique, a specific essential work of fracture (elastic contribution) of similar to 110 J m(-2) was calculated for the current gelatin/maltodextrin composition, under plane stress conditions.