Physical and mechanical properties of plant-derived soft-shell capsules formulated with hydroxypropyl starches from different botanical sources

Abstract

Soft-shell capsules are prepared herein using hydroxypropyl starches from different botanical sources (maize, waxy maize, potato, and cassava) as a replacement for animal-based materials such as gelatin. The physical, mechanical, and morphological properties of the starch films are characterized to investigate the possibility of manufacturing soft-shell capsules. Starch films originating from tubers, including potato and cassava, exhibit higher tensile strength, resulting in higher hardness of the soft-shell capsules compared to those originating from maize and waxy maize starches. None of the starch-based soft-shell capsules broke in a brittleness test, and there are no distortion defects in the seams that seal the capsules. Disintegration and stability tests over six months show that although the soft-shell capsules manufactured from maize and potato starch disintegrate faster than those from waxy maize and cassava starch, all of the capsules disintegrate within 1200 s, which is acceptable for commercial application.