Change in morphological structure, tribological properties, and in vitro starch digestibility of texture-modified rice porridge by addition of okra mucilage

Texture-modified foods, combined with suitable nutrient digestibility, are important for people with chewing and swallowing dysfunction. Okra mucilage is an alternative thickener that might improve food texture and starch digestibility in rice porridge. This study investigated the effects of okra mucilage addition to rice porridge (10 % w/v concentration) on the tribological properties, lubrication properties, and in vitro starch digestibility. Mucilage, extracted from 0.4 % or 0.8 % dried okra powder, was added during porridge preparation. Based on the results, adding mucilage in the rice porridge enhanced the lubrication properties by decreasing the friction coefficient ( p < 0.05) and delaying in vitro starch digestibility by a reduction in the released glucose of the porridge during the gastric phase ( p < 0.05). Alteration of gelatinized rice particle characteristics in the rice porridge via okra mucilage addition could promote the lubrication properties and delay starch digestibility, including agglomeration of the particles (observed under a microscope) and a reduction in the viscosity and consistency index, while retaining the yield stress of the porridge. Therefore, okra mucilage addition, particularly in combination with large-sized ground rice in porridge, could modulate the lubrication properties and starch digestibility of the porridge for application in therapeutic diets.