Hydrocolloids Decrease the Digestibility of Corn Starch, Soy Protein, and Skim Milk and the Antioxidant Capacity of Grape Juice.

Hydrocolloids have many applications in foods including their use in dysphagia diets. We aimed to evaluate whether hydrocolloids in foods affect the digestibility of starch and protein, and their effects on antioxidant capacity. The thickening hydrocolloids: locust bean gum and carboxymethyl cellulose, and the gel-forming agents: agar agar, konjac-glucomannan, and Hot & Soft Plus were blended with corn starch and soy protein, skim milk, or grape juice and were examined for their in vitro-digestability by comparing the reducing sugar and trichloroacetic acid (TCA)-soluble peptide, for antioxidant capacity by total polyphenol contents and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. The hydrocolloids resulted in a decrease in starch digestibility with the gel-forming agents. Hydrocolloids diminished TCA-soluble peptides in skim milk compared to soy protein with the exception of locust bean gum and decreased free radical scavenging capacities and total phenolic contents in grape juice. Our findings may provide evidence for the use of hydro-colloids for people at risk of nutritional deficiencies such as dysphagia patients.