Wheat Germ and Lipid Oxidation: An Open Issue

Area of Science:

• Food Science
• Agricultural Chemistry
• Nutritional Biochemistry

Background:

• Wheat germ (WG) has a short shelf life due to enzymatic oxidation after milling.
• Stabilization of WG is crucial for accessing its nutrients and bioactive compounds.
• Mechanical degermination exposes WG lipids to air, initiating oxidation.

Purpose of the Study:

• To investigate the link between durum wheat quality, storage, and wheat germ oil (WGO) quality.
• To evaluate lipid oxidation in WGO extracted using different methods.
• To characterize WGO composition, including fatty acids, tocols, sterols, and policosanols.

Main Methods:

• Analysis of acidity and peroxide values to assess lipid oxidation.
• Characterization of WGO using techniques to determine fatty acid, tocol, sterol, and policosanol content.
• Evaluation of different WGO extraction methods: cold press, solvent, and supercritical CO2.

Main Results:

• Raw material management is the primary factor in controlling lipid oxidation.
• The tempering phase before degermination is critical for oxidation development due to increased moisture and enzyme activation.
• Degermination, while necessary for stabilization, paradoxically initiates destabilization and oxidation.

Conclusions:

• Effective raw material management and optimized tempering are essential for preserving WGO quality.
• Understanding the oxidation process during tempering allows for strategies to mitigate lipid degradation.
• Improved WG stabilization enhances whole grain utilization and reduces waste.