Optimization of enzyme extractions for total folate in cereals using response surface methodology

Area of Science:

• Food Science
• Analytical Chemistry
• Nutritional Biochemistry

Background:

• Accurate total folate determination in cereal products is crucial for nutritional assessment.
• The AOAC Official Method 2004.05 uses a trienzyme digestion, but optimization could improve efficiency.
• Understanding the impact of individual enzyme digestion times is key to method refinement.

Purpose of the Study:

• To optimize the trienzyme digestion process for total folate extraction from cereal grains.
• To determine the significant factors affecting total folate recovery during enzymatic digestion.
• To develop a shortened, efficient method for approximating total folate in cereals and cereal products.

Main Methods:

• Response surface methodology was employed to optimize digestion times for protease, α-amylase, and conjugase (γ-glutamyl hydrolase).
• Statistical analysis (p-values, ridge analysis) was used to identify significant digestion parameters.
• Optimized conditions were validated against the AOAC Official Method 2004.05 using certified reference materials and various cereals.

Main Results:

• α-amylase and conjugase digestion times significantly impacted total folate recovery (p < 0.05 and p < 0.01, respectively).
• Pronase digestion time was not a significant factor (p > 0.1).
• Optimized digestion times ranged from 6.1 to 8.7 hours, yielding results comparable to the official method, with a predicted value close to the certified value for CRM 121.

Conclusions:

• A generalized trienzyme digestion protocol of 1 hour for Pronase, 2.5 hours for α-amylase, and 6 hours for conjugase can effectively approximate total folate in cereals.
• The optimized method offers significant time and cost savings compared to the official AOAC method.
• This shortened digestion approach minimizes potential folate degradation during prolonged incubation periods.