Rice starch modification by thermal treatments with avocado oil: Autoclave versus microwave methods

Area of Science:

• Food Science
• Material Science

Background:

• Rice starch modification is crucial for developing functional food ingredients.
• Heat-moisture treatment (HMT) and lipid addition can alter starch properties.

Purpose of the Study:

• To evaluate physical and chemical changes in rice starch modified by HMT using autoclave and microwave with avocado oil (AO).
• To assess the impact on thermal, structural, digestibility, and estimated glycemic index (eGI) properties.

Main Methods:

• Rice starch was modified using HMT with varying AO concentrations (2-8%) via autoclave (110°C, 1h) and microwave (50°C, 3min).
• Analysis included crystallinity, pasting viscosity, gelatinization enthalpy, in vitro digestibility, and eGI.

Main Results:

• Both HMT methods did not alter the type-A crystallinity pattern.
• Increased AO content reduced pasting viscosity, setback, relative crystallinity, and gelatinization enthalpy.
• Microwave treatment (M8%) significantly reduced digestibility and eGI, while increasing resistant starch content.

Conclusions:

• HMT with AO effectively increases resistant starch content in rice starch.
• Microwave-assisted HMT is an energy-efficient method for producing modified starches with improved characteristics.
• Modified rice starch shows potential for developing low-glycemic index food products.