Modified Okara improves Noodle Properties: Effects on digestibility, structure, and functionality

Area of Science:

• Food Science
• Biotechnology
• Nutritional Science

Background:

• Okara, an agro-industrial byproduct, is often underutilized.
• Developing functional food ingredients from byproducts can improve sustainability.
• Noodle production can benefit from ingredients that enhance nutritional profiles and quality.

Purpose of the Study:

• To develop a modified okara using co-fermentation and enzymatic treatment.
• To evaluate the impact of modified okara on noodle quality, focusing on starch digestibility and rheological properties.
• To assess the nutritional and functional benefits, including dietary fiber content and antioxidant activity.

Main Methods:

• Okara was modified through co-fermentation with *Pleurotus ostreatus* and *Saccharomyces cerevisiae*, followed by cellulase treatment.
• Starch digestibility was analyzed by measuring rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS).
• Structural changes were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).
• Dough rheological properties were assessed using dynamic rheology.
• Soluble dietary fiber (SDF) content and antioxidant capacity (ABTS radical scavenging) were measured.

Main Results:

• Incorporation of 40% modified okara significantly reduced RDS (64% to 50%) and increased SDS (21% to 25%) and RS (6% to 14%), indicating slower glucose release.
• Structural analysis revealed promoted starch-protein-lipid complex formation and porous networks that encapsulated starch granules.
• Dynamic rheology showed improved dough elasticity (increased G') at low okara concentrations.
• Soluble dietary fiber content increased to 9%, and ABTS radical scavenging activity rose to 55% due to liberated phenolics.

Conclusions:

• Modified okara effectively alters noodle starch digestibility, promoting a shift towards slower glucose release beneficial for glycemic control.
• Microstructural modifications induced by okara enhance dough elasticity and encapsulate starch, improving noodle texture.
• The increased soluble dietary fiber and antioxidant activity highlight the functional benefits of modified okara.
• Modified okara serves as a sustainable and functional ingredient for producing low-glycemic-index noodles, repurposing agro-industrial byproducts.