Nutritional, microstructural, rheological and quality characteristics of biscuits using processed wheat germ

Area of Science:

• Food Science
• Nutritional Biochemistry
• Cereal Chemistry

Background:

• Wheat germ is a nutrient-rich byproduct of wheat processing.
• Stabilization methods are crucial to inactivate enzymes like lipase and lipoxygenase, preventing rancidity.
• Increasing protein and dietary fiber in food products is a key nutritional goal.

Purpose of the Study:

• To evaluate the effects of defatting and steaming on wheat germ composition and enzyme activity.
• To assess the impact of incorporating stabilized wheat germ into biscuit formulations.
• To determine the influence of stabilized wheat germ on dough rheology and final product quality.

Main Methods:

• Wheat germ was stabilized using two methods: defatting and steaming.
• Proximate analysis was performed to determine protein and fiber content.
• Enzyme activities (lipase, lipoxygenase) were measured.
• Dough rheological properties were analyzed.
• Biscuits were prepared with varying levels of wheat germ substitution (up to 40%).

Main Results:

• Defatting increased protein to 38% and significantly boosted soluble and insoluble fiber content.
• Steaming effectively inactivated lipase and lipoxygenase activity.
• Defatted wheat germ exhibited a greater weakening effect on dough rheology compared to steamed wheat germ.
• Biscuits made with 40% steamed or defatted wheat germ showed enhanced protein and dietary fiber.

Conclusions:

• Both defatting and steaming are effective stabilization methods for wheat germ, with distinct impacts on composition and enzyme activity.
• Incorporating stabilized wheat germ, particularly at a 40% level, offers a viable strategy to produce high-protein, high-fiber biscuits.
• Understanding the rheological effects of different stabilization methods is crucial for optimizing wheat germ utilization in baking.