Probing gallic acid-starch interactions through Rapid ViscoAnalyzer in vitro digestion

Area of Science:

• Food Science
• Biochemistry
• Nutritional Science

Background:

• Phenolic compounds are recognized for inhibiting starch digestion by interacting with α-amylase.
• The molecular-level interactions between phenolics and starch can modulate this inhibitory effect.

Purpose of the Study:

• To investigate the influence of Gallic Acid (GA) addition timing on starch digestion kinetics.
• To explore the relationship between starch properties, GA concentration, and α-amylase inhibition.

Main Methods:

• In vitro starch digestion assays were performed using a Rapid ViscoAnalyzer (RVA).
• Gallic Acid (GA) was added either before or after starch cooking to assess its impact.
• Starch digestion rates and α-amylase inhibition were measured under varying conditions.

Main Results:

• When GA was added before starch cooking, starch digestion rates were similar to starch alone and faster than when GA was added post-cooking.
• Post-cooking GA addition led to strong α-amylase inhibition, which increased with starch paste viscosity for potato and wheat starches.
• No direct correlation was observed between intrinsic starch molecular characteristics and GA's inhibitory capacity.

Conclusions:

• The timing of Gallic Acid (GA) addition significantly affects starch digestion kinetics and α-amylase inhibition.
• Physical interactions, such as GA adsorption onto the starch paste surface, may influence inhibitory effects.
• Understanding these interactions is crucial for predicting the physiological impact of dietary phenolics on starch metabolism.