Extraction for profiling free and bound phenolic compounds in tea seed oil by deep eutectic solvents

Area of Science:

• Agricultural Chemistry
• Food Chemistry
• Analytical Chemistry

Background:

• Bound phenolic compounds in vegetable oils are under-researched due to extraction challenges.
• Deep eutectic solvents (DESs) offer a promising alternative to traditional organic solvents for phenolic compound extraction.

Purpose of the Study:

• To investigate the extraction of free and bound phenolic compounds from tea seed oil using DESs.
• To optimize DES extraction conditions (hydrogen bond donor and temperature) for phenolic compounds.
• To compare the efficiency of DES extraction with conventional methanol/water extraction.

Main Methods:

• Phenolic compounds in tea seed oil were characterized and quantified using ultra-high-performance liquid chromatography with mass spectrometry (UHPLC-Q-TOF-MS/MS and UHPLC-QqQ-MS/MS).
• Various DESs were screened for their efficacy in extracting free and bound phenolic compounds.
• Extraction efficiency was evaluated based on the type of hydrogen bond donor (HBD) and temperature.

Main Results:

• Twenty-five phenolic compounds were identified in both free and bound forms in tea seed oil.
• DES extraction using glycerol as the HBD at 50°C significantly enhanced the yield of free phenolic compounds (by 51.0%) and bound phenolic compounds (by 93.2%) compared to methanol/water.
• Extraction efficiency was found to be significantly influenced by the choice of HBD and temperature.

Conclusions:

• Deep eutectic solvents provide a highly efficient method for extracting both free and bound phenolic compounds from tea seed oil.
• The optimized DES method significantly outperforms conventional methanol/water extraction, advancing analytical capabilities for tea seed oil.
• This study contributes valuable data on the phenolic profiles of tea seed oil and establishes an improved extraction technique.