[Biologic availability and metabolic transit of amino acids modified by technological processing]

Area of Science:

• Nutritional biochemistry
• Food science
• Toxicology

Context:

• Industrial food processing can create modified amino acids.
• Assessing the nutritional value and metabolic fate of these compounds is crucial.
• Rat models are used to study amino acid bioavailability and metabolism.

Purpose:

• To evaluate the biological availability of industrially modified amino acids in rats.
• To investigate the metabolic transit of these modified amino acids, including excretion and organ retention.
• To understand the impact of specific modifications like Maillard reaction products and isopeptides on nutrient utilization.

Summary:

• Epsilon-fructose-lysine is not utilized as a lysine source; much is degraded by gut flora or excreted.
• Premelanoidins are partially absorbed and metabolized, while high molecular weight melanoidins are excreted unchanged.
• Epsilon-(gamma-glutamyl)-lysine is well-utilized, likely hydrolyzed to release lysine, whereas epsilon-(beta-aspartyl)-lysine is not.
• Methionine sulfoxide is utilized, unlike methionine sulfone.
• Lysino-alanine formation reduces lysine and cystine availability and is partially excreted.

Impact:

• Provides critical data on the nutritional implications of processed foods.
• Highlights the varying metabolic fates of different modified amino acids.
• Informs food industry practices regarding amino acid modification and safety.
• Contributes to understanding nutrient bioavailability in the context of food processing.