Interrogating Raisin Associated Unsaturated Fatty Acid Derived Volatile Compounds Using HS-SPME with GC-MS

Area of Science:

• Food Chemistry
• Oxidation Chemistry
• Analytical Chemistry

Background:

• Raisin flavor is influenced by volatile compounds generated during drying.
• Unsaturated fatty acids oxidation (UFAO) is a key process in volatile compound formation.
• Understanding UFAO mechanisms is crucial for controlling raisin quality.

Purpose of the Study:

• To investigate the generation mechanism of raisin-derived volatile compounds from unsaturated fatty acids oxidation (UFAO).
• To identify specific fatty acids (FAs) contributing to volatile compound formation during raisin drying.
• To establish a model reaction simulating raisin drying-like UFAO.

Main Methods:

• A model reaction system was developed at pH 4.2 and 60 °C to mimic raisin drying conditions.
• Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify and quantify volatile compounds.
• A mixture of fatty acids and individual fatty acids were analyzed over 20 days.

Main Results:

• GC-MS analysis identified 45 UFAO-derived volatiles in the model system.
• A mixture of all fatty acids produced the highest number of volatiles (39).
• Linoleic acid, erucic acid, oleic acid, and linolenic acid contributed significantly to volatile generation.

Conclusions:

• All tested fatty acids contribute to the generation of a greater number and higher concentrations of UFAO-derived volatiles.
• Specific fatty acids like linoleic and erucic acid yield unique volatile compounds.
• This study provides insights into the chemical pathways governing raisin flavor development.