Structure and functionality of micronized maize starch differing in amylose content

Area of Science:

• Food Science
• Materials Science
• Physical Chemistry

Background:

• Starch is a key carbohydrate in food, with its properties influenced by structure.
• Physical modification techniques can alter starch characteristics for specific applications.

Purpose of the Study:

• To investigate the impact of micronization via jet milling on the structure and properties of different starch types.
• To evaluate the potential of micronization for producing tailored starch ingredients.

Main Methods:

• Four types of starch (waxy maize, normal maize, high-amylose, Gelose 80) were micronized using jet milling.
• Particle size, amylose content, lipid and protein content, molecular weight, crystallinity, gelatinization temperature, viscosity, hydrolysis rate, and swelling power were analyzed.

Main Results:

• Micronization significantly reduced particle size, with waxy maize starch showing the greatest reduction.
• Amylose content increased post-micronization, while lipid, protein, molecular weight, and crystallinity decreased.
• Gelatinization temperature, viscosity, and hydrolysis rate decreased, but swelling power increased.
• Higher amylose content correlated with greater resistance to mechanical force and a stronger influence on hydrolysis rate.

Conclusions:

• Jet milling is an effective physical method for modifying starch structure and properties.
• Micronization can be used to produce customized starch raw materials for the food industry.
• Amylose content is a critical factor influencing starch behavior during and after micronization.