Starch structure-property relations as a function of barley germination times

Area of Science:

• Agricultural Science
• Food Chemistry
• Biochemistry

Background:

• Starch composition and thermal properties are crucial for barley processing.
• Germination, malting, and roasting significantly alter barley's chemical and physical characteristics.

Purpose of the Study:

• To investigate barley starch structural and thermal property changes during germination, malting, and roasting.
• To understand the impact of these processes on enzyme activity and fermentable sugar potential.

Main Methods:

• Differential scanning calorimetry (DSC) for starch thermal transitions.
• Size-exclusion chromatography (SEC) and fluorophore-assisted carbohydrate electrophoresis (FACE) for molecular fine structure analysis.
• Enzyme activity assays and starch content determination.

Main Results:

• Germination led to preferential amylopectin hydrolysis, increasing relative amylose content, gelatinization temperatures, and decreasing enthalpy change.
• Malting caused significant amylose degradation and reduced gelatinization temperatures.
• Roasting degraded starch and protein, halted enzyme activity, and drastically reduced starch enthalpy change due to loss of amylopectin crystallinity.

Conclusions:

• Barley starch undergoes significant structural modifications during malting and roasting.
• These modifications are key determinants for fermentable sugar yield during mashing.
• Understanding these changes offers insights into optimizing barley for fermentation processes.