Study on multiscale structures and digestibility of cassava starch and medium-chain fatty acids complexes using...

Area of Science:

• Food Science
• Material Science
• Biochemistry

Background:

• Cassava starch (CS) is a widely used polysaccharide.
• Medium-chain fatty acids (MCFAs) can interact with starch to modify its properties.
• Understanding these interactions is crucial for developing novel food ingredients and applications.

Purpose of the Study:

• To investigate the effect of complexation with octanoic, decylic, and lauric acids (OA, DA, LA) on cassava starch.
• To analyze the structural, physicochemical, and digestion characteristics of the resulting cassava starch-fatty acid complexes (CS-FAs).
• To determine the role of fatty acid chain length in modulating CS-FA complex properties.

Main Methods:

• Complexation of cassava starch with OA, DA, and LA.
• Morphological analysis using electron microscopy.
• Structural characterization via X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) spectroscopy.
• Rheological measurements (G', G'').
• In vitro digestion studies to assess hydrolysis degree and resistant starch (RS) content.

Main Results:

• Lauric acid (LA) showed the highest complexation index with CS (88.9%).
• All CS-FA complexes exhibited a flaked morphology and a V-type crystalline structure (V6 or V7 polymorphs).
• Increased fatty acid chain length led to a more ordered fractal structure and enhanced gel network formation.
• CS-LA complexes displayed the lowest hydrolysis degree and highest RS content, indicating reduced digestibility.

Conclusions:

• Fatty acid chain length significantly influences the structural characteristics and physicochemical properties of cassava starch complexes.
• Complexation with MCFAs, especially longer-chain ones like LA, can reduce starch digestibility and increase resistant starch formation.
• These findings highlight the potential for manipulating starch functionality through complexation with fatty acids for targeted applications.