Identification of Volatile Compounds in Pennycress Protein Isolates Produced by Both Alkaline and Salt-Based...

Area of Science:

• Agricultural Science
• Food Chemistry
• Analytical Chemistry

Background:

• Pennycress seeds are a potential protein source, but off-notes can limit their use.
• Understanding volatile compounds is crucial for improving pennycress protein quality.

Purpose of the Study:

• Identify and quantify volatile compounds responsible for off-notes in pennycress seeds and protein isolates.
• Determine the impact of different extraction methods (alkaline vs. salt) on the volatile profile and aroma of protein isolates.

Main Methods:

• Gas chromatography-mass spectrometry (GC-MS) for volatile compound identification.
• Gas chromatography-olfactometry (GC-O) to pinpoint aroma impact compounds.
• Quantification of volatiles relative to an internal standard.

Main Results:

• Ground pennycress seeds and defatted meals contain potent sulfur compounds (e.g., allyl isothiocyanate) and aldehydes from lipid degradation.
• Alkaline-extracted protein isolates exhibit strong off-notes due to aldehydes and sulfur compounds.
• Salt-extracted protein isolates have a milder aroma with fewer volatiles, primarily dominated by lipid degradation aldehydes.

Conclusions:

• The extraction method significantly influences the volatile profile and aroma of pennycress protein isolates.
• Salt extraction yields a less aromatic protein isolate compared to alkaline extraction, suggesting potential for improved flavor applications.