Analysis of Disintegration of Agar Gel Particles with Different Textures using Gastric Digestion Simulator

Abstract

This study investigates the effect of the texture of agar gel as a model solid food on gastric digestion using a human Gastric Digestion Simulator (GDS). The GDS, which simulates gastric peristalsis, can investigate physical digestion phenomena such as disintegration of solid foods. Agar gels with different fracture stresses (56 to 219 kPa) and constant fracture stain (29%) were prepared by varying the agar concentration (1.5 to 4.5 wt%). Direct observation demonstrated that agar gel particles initially cut to a 5.0 mm cube gradually reduced in size and broke down into random shapes during simulated gastric peristalsis. The size distribution of the agar gel particles after the digestion experiment was analyzed using the sieving method. The fraction larger than 2.36 mm, which corresponds to the pylorus size, decreased with time: the wet weight ratio of that fraction to the total amount of agar gel particles was 18.0% at 180 min in the case of 1.5 wt% agar gel. The agar gel concentration did not affect the size distribution after 180 min, which shows that fracture strain plays a more important role in agar gel digestion. Our results provide useful information about the relationship between solid food texture and gastric digestion.