2, 5-diketopiperazines (cyclic dipeptides) in beef: identification, synthesis, and sensory evaluation

Area of Science:

• Food Chemistry
• Analytical Chemistry
• Organic Chemistry

Background:

• Beef flavor is complex, derived from numerous volatile and semivolatile compounds.
• Understanding these compounds is crucial for developing new food flavors.
• Previous analyses have not fully characterized the semivolatile components of cooked beef.

Purpose of the Study:

• To identify novel flavor compounds in stewed and grilled dry-aged beef.
• To discover new synthesis targets for creating authentic beef flavors.
• To investigate the organoleptic properties of newly identified compounds.

Main Methods:

• Gas Chromatography-Mass Spectrometry (GC-MS) analysis of cooked beef samples.
• Identification and characterization of over 1000 volatile and semivolatile components.
• Synthesis and organoleptic evaluation of ten identified 2,5-diketopiperazines (cyclic dipeptides).

Main Results:

• Over 1000 volatile and semivolatile compounds were identified in cooked beef, many for the first time.
• Ten 2,5-diketopiperazines (cyclic dipeptides) were detected in beef for the first time.
• Three cyclic dipeptides – cis-cyclo(L-Leu-L-Pro), cis-cyclo(L-Met-L-Pro), and cis-cyclo(L-Phe-L-Pro) – exhibited notable organoleptic properties.

Conclusions:

• The study successfully identified novel cyclic dipeptides in beef, expanding the known flavor profile.
• The identified cyclic dipeptides, particularly cis-cyclo(L-Leu-L-Pro), cis-cyclo(L-Met-L-Pro), and cis-cyclo(L-Phe-L-Pro), represent promising targets for artificial flavor development.
• This research provides a foundation for creating new meat flavors using identified compounds.