Soybean protein films: Characterization and potential as novel delivery devices of Duddingtonia flagrans chlamydospores

Abstract

This study was aimed at assessing the potential use of soybean protein concentrate (SPC) - based film as vehicle for the delivery of Duddingtonia flagrans chlamydospores for the biological control of gastric nematodes in ruminals. Glycerol and dialdehyde starch (DAS) were used as plasticizer and cross-linking agent, respectively. Films were obtained by casting and characterized in terms of their physico-mechanical properties. The impact of cross-linking extent on moisture absorption, swelling and tensile properties of the resultant films was evaluated. The adequate tensile properties and stability in wet environment of SPC films cross-linked with 10. wt.% DAS was counterbalanced with the two-phase morphologies developed, irrespective of glycerol content, limiting their potential application as delivery devices. SPC films cross-linked with 5. wt.% DAS and plasticized with 30. wt.% glycerol exhibited the best compromise between solubility (only 29%), homogeneous morphology, adequate tensile strength (2.50. ±. 0.43. MPa) and elongation at break (18.72. ±. 2.34%) and swelling profile. The preliminary results of the release of D. flagrans chlamydospores in ruminal fluid revealed a slow release profile attaining 4.9% in a period of 24. h. Overall, these results substantiated the potential use of DAS-cross-linked SPC films as viable carrier matrix for D. flagrans release applications.